Brake upgrades using factory parts for GMT-400(88-00 OBS), and 94-99 DODGE 2500/3500

[staatsof]

So I've finished my braking system refurbishment. It was a pretty big repair. I haven't added up all the parts but a good guesstimate is $500 in parts for:

New rotor, pads and SS hoses up front.

All new SS brakelines.

A SS drop hose in the rear.

New backing plates, drums, hardware kit, upgraded cylinders, bearings and seals and the tech bulletin specified brake shoes.

The tech bulletin prop vale was also installed.

Labor, additional supplies, the inner bearings in the rear and a new PS pump to hydroboost because it was leaking came to almost $2K.

The change was immediate but I'm going to make sure the rears are adjusted as they can be so I'm in for one more NC trip as well as their repairing an aluminum step the snapped with the lift. Argh

To me it's a whole lot better. I'm not done checking it out and I want the step on the driver's door fixed fixed first.

What surprised me were the rotors taken off. They're 3 years old, premium Raybestos with the wiggly slots and two sets of pads have been replaced in way too quickly a time frame or mileage IMHO. I don't know the caliber of that last set of pads because they were an emergency replacement but that's when the system really went down hill. The rotors look burnished a shinny black so I can imagine that the coefficient of friction was just awful. This explains the very poor performance. I'm not sure why they got this way.

I went with smooth Raybestos rotors of the same caliber (coated) this time because I needed them in a hurry. The wavy slots didn't seem to do much for my situation anyway. I wasn't expecting to have to replace the rotors which is more time consuming than standard slip over rotors and one of the ABS sensors had to be replaced as it was stuck in, so they said ... ? So this added a fair amount to the job.

Doing all of the brake lines was also a while you're command decision and that took time. The rear, cross axle, spring wrapped ones were the only horrible ones. But I had to order the entire set to get those. The reports are they went in just fine. A+ for Inline on that.

I'll post some before and after photos including the specs for the hoses I could find any other way. I went with rectangular banjos up front from Earl's but they sent me extended nipple round ones in the part number correct boxes. So I had to wait another week to fix that, very weird.

More later.

 

[staatsof]

Here are some photos of the front hoses in place.




I used a 2.5" long piece of .25" ID fuel hose sliced down one side and slipped over the brake hose as an insulator with this as center clamp bolted with a single SS bolt.

https://www.mcmaster.com/8863T35



https://www.mcmaster.com/97646A253


I wanted a very sturdy clamp that was wide enough. I wish it were stainless but I have enough clamps to do another 24 replacements or trucks ...

At each end I secured the split hose with a small wire tie.

These are the bolts I used which also work for securing the wheel cylinders to the backing plates.
Photos of that a bit later it's like 11 F here this morning. Brhhhhhh.

Parts from Inline:



I used two of these Earls 9977031ERL Banjo Adapter

More later.

 

[staatsof]

Here's what some of what got replaced looked like. The cooling fins on those drums were like layers of baked filo pastry.
It's so brutal with the salt here and then the roads beat the crap out of suspension parts.

Those rotors are really polished. The grooves in the one happend on the previous set of pads.
I think the imbalance was just so bad that no pads or rotors could have done well. The last pads were of an unknown type or quality but the previous ones were very good stuff.

I went with Performance Friction 045920 this time. For $25 including shipping this deal was hard to beat and these pads get very good reviews.

https://www.ebay.com/itm/Performanc...236141&hash=item2abc96a903:g:jAgAAOSw0~pb-aV1

So far I'm quite impressed with the bite and stopping power.
The Suburban feels like a proper functioning vehicle again and not an exercise machine for my right leg.

 

[jln2688]

Now on to the front brakes. 6 lug trucks used a 2.94" diameter piston in the front calipers, 8 lug single rear wheeled trucks used a 3.15" diamter piston, and dual rear wheeled trucks used a 3.285" diamter piston. For those with 6 lug wheels, you DO have an easy to swap in factory brake upgrade in the 8 lug single rear wheeled pads and calipers. GM offerred these from the factory on TAHOES sold for police and fire department use, and will work with your stock rotors. Also of note is that the 8600 GVWR 8 lug calipers actually provide more clamping force than the SSBC dual piston calipers at a fraction of the cost. And since it was a factory option, it all just bolts on, and is available at most any auto parts store for cheap.

I am not that up to speed on what years this is good for, and I'm not a mechanic. What year Tahoe am I looking at getting these calipers and pads for my 6 lug? I have an 89 K1500 6 lug. Is this the right 6 lug to do this conversion you are talking about? I do not know the measurements of these calipers that are on there now. Thanks for your help in advance.

 

[THEFERMANATOR]

Now on to the front brakes. 6 lug trucks used a 2.94" diameter piston in the front calipers, 8 lug single rear wheeled trucks used a 3.15" diamter piston, and dual rear wheeled trucks used a 3.285" diamter piston. For those with 6 lug wheels, you DO have an easy to swap in factory brake upgrade in the 8 lug single rear wheeled pads and calipers. GM offerred these from the factory on TAHOES sold for police and fire department use, and will work with your stock rotors. Also of note is that the 8600 GVWR 8 lug calipers actually provide more clamping force than the SSBC dual piston calipers at a fraction of the cost. And since it was a factory option, it all just bolts on, and is available at most any auto parts store for cheap.

I am not that up to speed on what years this is good for, and I'm not a mechanic. What year Tahoe am I looking at getting these calipers and pads for my 6 lug? I have an 89 K1500 6 lug. Is this the right 6 lug to do this conversion you are talking about? I do not know the measurements of these calipers that are on there now. Thanks for your help in advance.

You can use the calipers from any of the 2500 8 lug trucks. As to pads, you can use the 8 lug truck pads, but you have to do some grinding on the outboard pad to clear the rotor. Otherwise you can use the stock pads to fit your truck, and bend the retainers on them some to go onto the larger calipers.

 

[Guss327]

OK good info thanks to all. If I understand for may 1993 k1500 suburban 6 lug
For improved braking I need to source the 6 lug same year 2500 calipers rotors n pads. the caliper has a piston of 3.15 diameter n have improved clamping with a Quality rotor and pad. This will work with the sst flex lines and my all new sst hard lines. did I miss anything for my veh.? Or am I not understanding all the info clear for my 1993 6lug 4x4 1500 suburban.

 

[THEFERMANATOR]

OK good info thanks to all. If I understand for may 1993 k1500 suburban 6 lug
For improved braking I need to source the 6 lug same year 2500 calipers rotors n pads. the caliper has a piston of 3.15 diameter n have improved clamping with a Quality rotor and pad. This will work with the sst flex lines and my all new sst hard lines. did I miss anything for my veh.? Or am I not understanding all the info clear for my 1993 6lug 4x4 1500 suburban.


View attachment 55845

No, 6 lug is all the same size calipers. The bigger calipers came on 8 lug single rear wheel trucks.

 

[Goldhawg]

I know many out there are less than thrilled with the performance of there stock brakes, so I figured I would do this thread to post up what stock parts can be easily swapped in to improve the braking performance of our trucks.


Now on to the front brakes. 6 lug trucks used a 2.94" diameter piston in the front calipers, 8 lug single rear wheeled trucks used a 3.15" diamter piston, and dual rear wheeled trucks used a 3.285" diamter piston. For those with 6 lug wheels, you DO have an easy to swap in factory brake upgrade in the 8 lug single rear wheeled pads and calipers. GM offerred these from the factory on TAHOES sold for police and fire department use, and will work with your stock rotors. Also of note is that the 8600 GVWR 8 lug calipers actually provide more clamping force than the SSBC dual piston calipers at a fraction of the cost. And since it was a factory option, it all just bolts on, and is available at most any auto parts store for cheap......And to those doing the GMT-800 front brake upgrade, the 3.285" single piston caliper actually provides MORE clamping force than the dual 2.25" diamter pistons of the newer calipers, BUT they win out because of the greatly increased friction area of the MUCH larger pads.....Leaving this one open for now, but please lets keep it to technical info and responses since it is a sticky. And if anybody sees a mistake, please point it out so we can keep this info as correct as possible.

I have a 99 2dr 4WD Tahoe that had the mushy brake pedal so I decided to do the NBS MC upgrade and the police Tahoe caliper swap per this post. I have 6 lug wheels. The police caliper does fit the bracket (almost) but I had two problems which I'll try to describe since I didn't take pics. First and most importantly, the calipers outer parts that are closest to the hub need to be ground down slightly. And worse, the pads stick out further, and I ended up having to grind quite a bit (about 1/8-3/16") of pad off the outer most pad (didn't have to touch the inner pad) because it was touching the center hub portion. The only thing I can think is that since these were with 8-lug wheels that those rotors had a slightly smaller diameter hub portion. The calipers/pads will not go on far enough to bolt up w/o doing this. And 2nd, on the drivers side only, I had a rough casting spot on the bracket itself that contacted the most inner part of the piston part of the caliper casting, so I had to take a grinder and take a bit off the bracket. I now only have maybe a 1/16" clearance between the metal of the hub and the brake pad, but it doesn't rub.

I can report the pedal feel is excellent and the brakes seem to work fine; I haven't had chance to really get on them to see if they bite better with the police calipers. But I'm not particularly happy about grinding the pads. I'm sure they're fine, but I don't want to have to do this every time. I will probably drive a year and next summer swap to the NBS disc and NNBS rotors (I just got some 18" 2019 takeoffs that once I sold my stockers were cheaper than getting new tires!).

 

[FellowTraveler]

I have a 99 2dr 4WD Tahoe that had the mushy brake pedal so I decided to do the NBS MC upgrade and the police Tahoe caliper swap per this post. I have 6 lug wheels. The police caliper does fit the bracket (almost) but I had two problems which I'll try to describe since I didn't take pics. First and most importantly, the calipers outer parts that are closest to the hub need to be ground down slightly. And worse, the pads stick out further, and I ended up having to grind quite a bit (about 1/8-3/16") of pad off the outer most pad (didn't have to touch the inner pad) because it was touching the center hub portion. The only thing I can think is that since these were with 8-lug wheels that those rotors had a slightly smaller diameter hub portion. The calipers/pads will not go on far enough to bolt up w/o doing this. And 2nd, on the drivers side only, I had a rough casting spot on the bracket itself that contacted the most inner part of the piston part of the caliper casting, so I had to take a grinder and take a bit off the bracket. I now only have maybe a 1/16" clearance between the metal of the hub and the brake pad, but it doesn't rub.

I can report the pedal feel is excellent and the brakes seem to work fine; I haven't had chance to really get on them to see if they bite better with the police calipers. But I'm not particularly happy about grinding the pads. I'm sure they're fine, but I don't want to have to do this every time. I will probably drive a year and next summer swap to the NBS disc and NNBS rotors (I just got some 18" 2019 takeoffs that once I sold my stockers were cheaper than getting new tires!).

Nice Tahoe!

 

[jrsavoie]

I have a 99 2dr 4WD Tahoe that had the mushy brake pedal so I decided to do the NBS MC upgrade and the police Tahoe caliper swap per this post. I have 6 lug wheels. The police caliper does fit the bracket (almost) but I had two problems which I'll try to describe since I didn't take pics. First and most importantly, the calipers outer parts that are closest to the hub need to be ground down slightly. And worse, the pads stick out further, and I ended up having to grind quite a bit (about 1/8-3/16") of pad off the outer most pad (didn't have to touch the inner pad) because it was touching the center hub portion. The only thing I can think is that since these were with 8-lug wheels that those rotors had a slightly smaller diameter hub portion. The calipers/pads will not go on far enough to bolt up w/o doing this. And 2nd, on the drivers side only, I had a rough casting spot on the bracket itself that contacted the most inner part of the piston part of the caliper casting, so I had to take a grinder and take a bit off the bracket. I now only have maybe a 1/16" clearance between the metal of the hub and the brake pad, but it doesn't rub.

I can report the pedal feel is excellent and the brakes seem to work fine; I haven't had chance to really get on them to see if they bite better with the police calipers. But I'm not particularly happy about grinding the pads. I'm sure they're fine, but I don't want to have to do this every time. I will probably drive a year and next summer swap to the NBS disc and NNBS rotors (I just got some 18" 2019 takeoffs that once I sold my stockers were cheaper than getting new tires!).

If you ever decide to sell it, feel free to message me.

Looks like a nice ride

 

[THEFERMANATOR]

A member here also ran into the grinding the pads. If you use 1500 pads with the 2500 calipers, they're supposed to work without grinding.

 

[Goldhawg]

A member here also ran into the grinding the pads. If you use 1500 pads with the 2500 calipers, they're supposed to work without grinding.

I didn't try the outer 1500 pad, but the inner 1500 pad doesn't fit with the metal prongs that keep it in place in the piston, due to the larger piston diameter. I suppose one could bend those prongs but I just went out and bought the police pads. The inner (that goes in the piston) then was fine, but the outer needed grinding. I suppose one could also mix and match. I may try as I had virtually new pads on before this swap. Nevertheless I think I'll go with the larger NNBS rotors and calipers next year.

 

[Pistachiobob]

I know many out there are less than thrilled with the performance of there stock brakes, so I figured I would do this thread to post up what stock parts can be easily swapped in to improve the braking performance of our trucks.

First things first, make sure your brake system is up to par, meaning you have done all of the TSB's and such(rear brake linings if you have the big drum brakes, and roportioning valve if you have a SUBURBAN). Making sure you have the core braking system up to par is crucial for ANY of it to work. Next I like stainless braided brake lines as they take away all that sponginess to the pedal. And at teh age of our trucks, the rubber lines are for the most part getting past time to replace just due to age.

I'm going to start with the rear brakes. I know many want disc brakes, but if you're on a budget you do still have options for many of us if you have a 14 bolt axle. The 9.5" semi float and 10.5" full float both share wheel cylinders. The 9.5" semi float rear axle for the most part got 1" wheel cylinders(RAYBESTOS #WC37781). The 10.5" full float axle if it was single rear wheel got 1 1/16" wheel cylinders(RAYBESTOS #WC37290), and dual rear wheeled trucks got 1 3/16" wheel cylinders(RAYBESTOS #WC37337). So if you have a single rear wheeled truck, you can for very little money swap in a set of 1 3/16" wheel cylinders from out of a dual rear wheeled truck and get a noticeable increase in rear braking. As to linings, the TSB from GM calls for the switch to the DURASTOP rear shoes if you have the 13X3.5" shoes(AC #17452R, but should be the same as RAYBESTOS #452PG). Also for many with 2.5" wide shoes, check your drums as many have found they had the 3.5" wide drums with 2.5" wide shoes. Sorry guys with 6 lug trucks and the 10 bolt axle, I'm unaware of any brake upgrades for them.

Now on to the front brakes. 6 lug trucks used a 2.94" diameter piston in the front calipers, 8 lug single rear wheeled trucks used a 3.15" diamter piston, and dual rear wheeled trucks used a 3.285" diamter piston. For those with 6 lug wheels, you DO have an easy to swap in factory brake upgrade in the 8 lug single rear wheeled pads and calipers. GM offerred these from the factory on TAHOES sold for police and fire department use, and will work with your stock rotors. Also of note is that the 8600 GVWR 8 lug calipers actually provide more clamping force than the SSBC dual piston calipers at a fraction of the cost. And since it was a factory option, it all just bolts on, and is available at most any auto parts store for cheap. Next up is those of us with 8 lug trucks and single rear wheels. As many of us know the rotors go behind the hub bearing, so they are not fun to change, and the factory rotors tend to warp easily if you actually use your truck and get the brakes hot. But were in luck, the 3500 dual rear wheeled trucks use very similiar brakes, but the rotors are roughly a 1/4" thicker, the pads are nearly identical except for thicker backing plates, and again, it all just bolts on. So you can easily and cheaply upgrade the brakes as well on 8 lug single rear wheeled trucks(but you MUST use ALL the DRW brake parts to do so. The calipers are roughly a 1/4" wider where they sit down over the rotor to accomodate the thicker rotor). If you have a dually though, you already have the biggest brakes available from the factory.

And to those doing the GMT-800 front brake upgrade, the 3.285" single piston caliper actually provides MORE clamping force than the dual 2.25" diamter pistons of the newer calipers, BUT they win out because of the greatly increased friction area of the MUCH larger pads. Now on to some pics I took.


DRW on the left, and SRW on the right, you can clearly see theres ALOT more meat i nthe DRW rotors but they are the same exact height.View attachment 46807 DRW on the left, and SRW on the right
View attachment 46808Heres a side by side pic of the 3 different pads. On the left is the 6 lug pads, middle is 8 lug SRW, and on the right is DRW pads.
View attachment 46809

Also, if you happen to have an older 94-99 DODGE 2500/3500, alot of this info applies to you as well. DODGE bought there brakes from GM back in the early days, so alot of our stuff directly bolts onto theres. They used a 7500 GVWR though for the 3.15" calipers, and went to the 3.285" calipers for anything over that. BUT DODGE never used bigger than a 1 1/16" rear wheel cylinder, so the GM 1 3/16" is a popular bolt in upgrade for them.

Leaving this one open for now, but please lets keep it to technical info and responses since it is a sticky. And if anybody sees a mistake, please point it out so we can keep this info as correct as possible.

In

 

[Pistachiobob]

Dear Fermanator: I read with great interest your stock part swap to improve the braking of the 1999 K2500 GM vehicles (Silverado PU or 3/4 Ton Suburban). I’ve now thrown almost $1200 at this problem, and would like to strangle the GM engineers for not addressing this issue back in ‘99. That said, I’m seriously considering your suggestion. I spent $750 on purchase of slotted EBC ROTORS and their yellow stuff pads. They were a marked improvement, but the pads were almost down to bear metal after only 17K miles, and they wanted to soak me for $175 plus shipping for another set of pads!
My question for you references the proportioning valve. I installed the newer version with the softer spring, but my rear shoes were still only about 110 F after a test stop. My friend and I studied the old valve, and decided to try removing the plunger and spring regulating flow to the rear wheels inside the proportioning valve. Hard stop tests showed the ABS operating normally, and the rear drums now at 155F, indicating more breaking activity. Do you see any negatives to our having done this? The braking has improved, even with Wagner QS pads as $68 replacements for the EBC yellow pads. Thank you for your help!!
Bob

I know many out there are less than thrilled with the performance of there stock brakes, so I figured I would do this thread to post up what stock parts can be easily swapped in to improve the braking performance of our trucks.

First things first, make sure your brake system is up to par, meaning you have done all of the TSB's and such(rear brake linings if you have the big drum brakes, and roportioning valve if you have a SUBURBAN). Making sure you have the core braking system up to par is crucial for ANY of it to work. Next I like stainless braided brake lines as they take away all that sponginess to the pedal. And at teh age of our trucks, the rubber lines are for the most part getting past time to replace just due to age.

I'm going to start with the rear brakes. I know many want disc brakes, but if you're on a budget you do still have options for many of us if you have a 14 bolt axle. The 9.5" semi float and 10.5" full float both share wheel cylinders. The 9.5" semi float rear axle for the most part got 1" wheel cylinders(RAYBESTOS #WC37781). The 10.5" full float axle if it was single rear wheel got 1 1/16" wheel cylinders(RAYBESTOS #WC37290), and dual rear wheeled trucks got 1 3/16" wheel cylinders(RAYBESTOS #WC37337). So if you have a single rear wheeled truck, you can for very little money swap in a set of 1 3/16" wheel cylinders from out of a dual rear wheeled truck and get a noticeable increase in rear braking. As to linings, the TSB from GM calls for the switch to the DURASTOP rear shoes if you have the 13X3.5" shoes(AC #17452R, but should be the same as RAYBESTOS #452PG). Also for many with 2.5" wide shoes, check your drums as many have found they had the 3.5" wide drums with 2.5" wide shoes. Sorry guys with 6 lug trucks and the 10 bolt axle, I'm unaware of any brake upgrades for them.

Now on to the front brakes. 6 lug trucks used a 2.94" diameter piston in the front calipers, 8 lug single rear wheeled trucks used a 3.15" diamter piston, and dual rear wheeled trucks used a 3.285" diamter piston. For those with 6 lug wheels, you DO have an easy to swap in factory brake upgrade in the 8 lug single rear wheeled pads and calipers. GM offerred these from the factory on TAHOES sold for police and fire department use, and will work with your stock rotors. Also of note is that the 8600 GVWR 8 lug calipers actually provide more clamping force than the SSBC dual piston calipers at a fraction of the cost. And since it was a factory option, it all just bolts on, and is available at most any auto parts store for cheap. Next up is those of us with 8 lug trucks and single rear wheels. As many of us know the rotors go behind the hub bearing, so they are not fun to change, and the factory rotors tend to warp easily if you actually use your truck and get the brakes hot. But were in luck, the 3500 dual rear wheeled trucks use very similiar brakes, but the rotors are roughly a 1/4" thicker, the pads are nearly identical except for thicker backing plates, and again, it all just bolts on. So you can easily and cheaply upgrade the brakes as well on 8 lug single rear wheeled trucks(but you MUST use ALL the DRW brake parts to do so. The calipers are roughly a 1/4" wider where they sit down over the rotor to accomodate the thicker rotor). If you have a dually though, you already have the biggest brakes available from the factory.

And to those doing the GMT-800 front brake upgrade, the 3.285" single piston caliper actually provides MORE clamping force than the dual 2.25" diamter pistons of the newer calipers, BUT they win out because of the greatly increased friction area of the MUCH larger pads. Now on to some pics I took.


DRW on the left, and SRW on the right, you can clearly see theres ALOT more meat i nthe DRW rotors but they are the same exact height.View attachment 46807 DRW on the left, and SRW on the right
View attachment 46808Heres a side by side pic of the 3 different pads. On the left is the 6 lug pads, middle is 8 lug SRW, and on the right is DRW pads.
View attachment 46809

Also, if you happen to have an older 94-99 DODGE 2500/3500, alot of this info applies to you as well. DODGE bought there brakes from GM back in the early days, so alot of our stuff directly bolts onto theres. They used a 7500 GVWR though for the 3.15" calipers, and went to the 3.285" calipers for anything over that. BUT DODGE never used bigger than a 1 1/16" rear wheel cylinder, so the GM 1 3/16" is a popular bolt in upgrade for them.

Leaving this one open for now, but please lets keep it to technical info and responses since it is a sticky. And if anybody sees a mistake, please point it out so we can keep this info as correct as possible.

 

[Pistachiobob]

Dear Fermanator: My 3/4T 1999 Suburban is a C2500, NOT the 4WD K2500. My mistake in my first post!!
Bob
QUOTE="THEFERMANATOR, post: 513094, member: 343"]
I know many out there are less than thrilled with the performance of there stock brakes, so I figured I would do this thread to post up what stock parts can be easily swapped in to improve the braking performance of our trucks.

First things first, make sure your brake system is up to par, meaning you have done all of the TSB's and such(rear brake linings if you have the big drum brakes, and roportioning valve if you have a SUBURBAN). Making sure you have the core braking system up to par is crucial for ANY of it to work. Next I like stainless braided brake lines as they take away all that sponginess to the pedal. And at teh age of our trucks, the rubber lines are for the most part getting past time to replace just due to age.

I'm going to start with the rear brakes. I know many want disc brakes, but if you're on a budget you do still have options for many of us if you have a 14 bolt axle. The 9.5" semi float and 10.5" full float both share wheel cylinders. The 9.5" semi float rear axle for the most part got 1" wheel cylinders(RAYBESTOS #WC37781). The 10.5" full float axle if it was single rear wheel got 1 1/16" wheel cylinders(RAYBESTOS #WC37290), and dual rear wheeled trucks got 1 3/16" wheel cylinders(RAYBESTOS #WC37337). So if you have a single rear wheeled truck, you can for very little money swap in a set of 1 3/16" wheel cylinders from out of a dual rear wheeled truck and get a noticeable increase in rear braking. As to linings, the TSB from GM calls for the switch to the DURASTOP rear shoes if you have the 13X3.5" shoes(AC #17452R, but should be the same as RAYBESTOS #452PG). Also for many with 2.5" wide shoes, check your drums as many have found they had the 3.5" wide drums with 2.5" wide shoes. Sorry guys with 6 lug trucks and the 10 bolt axle, I'm unaware of any brake upgrades for them.

Now on to the front brakes. 6 lug trucks used a 2.94" diameter piston in the front calipers, 8 lug single rear wheeled trucks used a 3.15" diamter piston, and dual rear wheeled trucks used a 3.285" diamter piston. For those with 6 lug wheels, you DO have an easy to swap in factory brake upgrade in the 8 lug single rear wheeled pads and calipers. GM offerred these from the factory on TAHOES sold for police and fire department use, and will work with your stock rotors. Also of note is that the 8600 GVWR 8 lug calipers actually provide more clamping force than the SSBC dual piston calipers at a fraction of the cost. And since it was a factory option, it all just bolts on, and is available at most any auto parts store for cheap. Next up is those of us with 8 lug trucks and single rear wheels. As many of us know the rotors go behind the hub bearing, so they are not fun to change, and the factory rotors tend to warp easily if you actually use your truck and get the brakes hot. But were in luck, the 3500 dual rear wheeled trucks use very similiar brakes, but the rotors are roughly a 1/4" thicker, the pads are nearly identical except for thicker backing plates, and again, it all just bolts on. So you can easily and cheaply upgrade the brakes as well on 8 lug single rear wheeled trucks(but you MUST use ALL the DRW brake parts to do so. The calipers are roughly a 1/4" wider where they sit down over the rotor to accomodate the thicker rotor). If you have a dually though, you already have the biggest brakes available from the factory.

And to those doing the GMT-800 front brake upgrade, the 3.285" single piston caliper actually provides MORE clamping force than the dual 2.25" diamter pistons of the newer calipers, BUT they win out because of the greatly increased friction area of the MUCH larger pads. Now on to some pics I took.


DRW on the left, and SRW on the right, you can clearly see theres ALOT more meat i nthe DRW rotors but they are the same exact height.View attachment 46807 DRW on the left, and SRW on the right
View attachment 46808Heres a side by side pic of the 3 different pads. On the left is the 6 lug pads, middle is 8 lug SRW, and on the right is DRW pads.
View attachment 46809

Also, if you happen to have an older 94-99 DODGE 2500/3500, alot of this info applies to you as well. DODGE bought there brakes from GM back in the early days, so alot of our stuff directly bolts onto theres. They used a 7500 GVWR though for the 3.15" calipers, and went to the 3.285" calipers for anything over that. BUT DODGE never used bigger than a 1 1/16" rear wheel cylinder, so the GM 1 3/16" is a popular bolt in upgrade for them.

Leaving this one open for now, but please lets keep it to technical info and responses since it is a sticky. And if anybody sees a mistake, please point it out so we can keep this info as correct as possible.
[/QUOTE]

 

[Pistachiobob]

Fermanator: I’m sorry to have made yet ANOTHER mistake. My friend corrected me in what we removed from the proportioning valve on the back of the ABS UNIT. We did NOT remove the plunger! We only removed the spring and the shouldered “O Ring” from inside the proportioning valve. We then fully seated the plunger stem into the end cap. The brakes now seem well balanced.

Next Question: Will the 3.5” C3500 SRW drums and shoes fit my 14 bolt semi-floating axel without modification? Does the backing plate require changing? Thank you so much for your help!! Bob

Dear Fermanator: My 3/4T 1999 Suburban is a C2500, NOT the 4WD K2500. My mistake in my first post!!
Bob
QUOTE="THEFERMANATOR, post: 513094, member: 343"]
I know many out there are less than thrilled with the performance of there stock brakes, so I figured I would do this thread to post up what stock parts can be easily swapped in to improve the braking performance of our trucks.

First things first, make sure your brake system is up to par, meaning you have done all of the TSB's and such(rear brake linings if you have the big drum brakes, and roportioning valve if you have a SUBURBAN). Making sure you have the core braking system up to par is crucial for ANY of it to work. Next I like stainless braided brake lines as they take away all that sponginess to the pedal. And at teh age of our trucks, the rubber lines are for the most part getting past time to replace just due to age.

I'm going to start with the rear brakes. I know many want disc brakes, but if you're on a budget you do still have options for many of us if you have a 14 bolt axle. The 9.5" semi float and 10.5" full float both share wheel cylinders. The 9.5" semi float rear axle for the most part got 1" wheel cylinders(RAYBESTOS #WC37781). The 10.5" full float axle if it was single rear wheel got 1 1/16" wheel cylinders(RAYBESTOS #WC37290), and dual rear wheeled trucks got 1 3/16" wheel cylinders(RAYBESTOS #WC37337). So if you have a single rear wheeled truck, you can for very little money swap in a set of 1 3/16" wheel cylinders from out of a dual rear wheeled truck and get a noticeable increase in rear braking. As to linings, the TSB from GM calls for the switch to the DURASTOP rear shoes if you have the 13X3.5" shoes(AC #17452R, but should be the same as RAYBESTOS #452PG). Also for many with 2.5" wide shoes, check your drums as many have found they had the 3.5" wide drums with 2.5" wide shoes. Sorry guys with 6 lug trucks and the 10 bolt axle, I'm unaware of any brake upgrades for them.

Now on to the front brakes. 6 lug trucks used a 2.94" diameter piston in the front calipers, 8 lug single rear wheeled trucks used a 3.15" diamter piston, and dual rear wheeled trucks used a 3.285" diamter piston. For those with 6 lug wheels, you DO have an easy to swap in factory brake upgrade in the 8 lug single rear wheeled pads and calipers. GM offerred these from the factory on TAHOES sold for police and fire department use, and will work with your stock rotors. Also of note is that the 8600 GVWR 8 lug calipers actually provide more clamping force than the SSBC dual piston calipers at a fraction of the cost. And since it was a factory option, it all just bolts on, and is available at most any auto parts store for cheap. Next up is those of us with 8 lug trucks and single rear wheels. As many of us know the rotors go behind the hub bearing, so they are not fun to change, and the factory rotors tend to warp easily if you actually use your truck and get the brakes hot. But were in luck, the 3500 dual rear wheeled trucks use very similiar brakes, but the rotors are roughly a 1/4" thicker, the pads are nearly identical except for thicker backing plates, and again, it all just bolts on. So you can easily and cheaply upgrade the brakes as well on 8 lug single rear wheeled trucks(but you MUST use ALL the DRW brake parts to do so. The calipers are roughly a 1/4" wider where they sit down over the rotor to accomodate the thicker rotor). If you have a dually though, you already have the biggest brakes available from the factory.

And to those doing the GMT-800 front brake upgrade, the 3.285" single piston caliper actually provides MORE clamping force than the dual 2.25" diamter pistons of the newer calipers, BUT they win out because of the greatly increased friction area of the MUCH larger pads. Now on to some pics I took.


DRW on the left, and SRW on the right, you can clearly see theres ALOT more meat i nthe DRW rotors but they are the same exact height.View attachment 46807 DRW on the left, and SRW on the right
View attachment 46808Heres a side by side pic of the 3 different pads. On the left is the 6 lug pads, middle is 8 lug SRW, and on the right is DRW pads.
View attachment 46809

Also, if you happen to have an older 94-99 DODGE 2500/3500, alot of this info applies to you as well. DODGE bought there brakes from GM back in the early days, so alot of our stuff directly bolts onto theres. They used a 7500 GVWR though for the 3.15" calipers, and went to the 3.285" calipers for anything over that. BUT DODGE never used bigger than a 1 1/16" rear wheel cylinder, so the GM 1 3/16" is a popular bolt in upgrade for them.

Leaving this one open for now, but please lets keep it to technical info and responses since it is a sticky. And if anybody sees a mistake, please point it out so we can keep this info as correct as possible.

[/QUOTE]

 

[Big T]

Dear Fermanator: My 3/4T 1999 Suburban is a C2500, NOT the 4WD K2500. My mistake in my first post!!
Bob
QUOTE="THEFERMANATOR, post: 513094, member: 343"]
I know many out there are less than thrilled with the performance of there stock brakes, so I figured I would do this thread to post up what stock parts can be easily swapped in to improve the braking performance of our trucks.

First things first, make sure your brake system is up to par, meaning you have done all of the TSB's and such(rear brake linings if you have the big drum brakes, and roportioning valve if you have a SUBURBAN). Making sure you have the core braking system up to par is crucial for ANY of it to work. Next I like stainless braided brake lines as they take away all that sponginess to the pedal. And at teh age of our trucks, the rubber lines are for the most part getting past time to replace just due to age.

I'm going to start with the rear brakes. I know many want disc brakes, but if you're on a budget you do still have options for many of us if you have a 14 bolt axle. The 9.5" semi float and 10.5" full float both share wheel cylinders. The 9.5" semi float rear axle for the most part got 1" wheel cylinders(RAYBESTOS #WC37781). The 10.5" full float axle if it was single rear wheel got 1 1/16" wheel cylinders(RAYBESTOS #WC37290), and dual rear wheeled trucks got 1 3/16" wheel cylinders(RAYBESTOS #WC37337). So if you have a single rear wheeled truck, you can for very little money swap in a set of 1 3/16" wheel cylinders from out of a dual rear wheeled truck and get a noticeable increase in rear braking. As to linings, the TSB from GM calls for the switch to the DURASTOP rear shoes if you have the 13X3.5" shoes(AC #17452R, but should be the same as RAYBESTOS #452PG). Also for many with 2.5" wide shoes, check your drums as many have found they had the 3.5" wide drums with 2.5" wide shoes. Sorry guys with 6 lug trucks and the 10 bolt axle, I'm unaware of any brake upgrades for them.

Now on to the front brakes. 6 lug trucks used a 2.94" diameter piston in the front calipers, 8 lug single rear wheeled trucks used a 3.15" diamter piston, and dual rear wheeled trucks used a 3.285" diamter piston. For those with 6 lug wheels, you DO have an easy to swap in factory brake upgrade in the 8 lug single rear wheeled pads and calipers. GM offerred these from the factory on TAHOES sold for police and fire department use, and will work with your stock rotors. Also of note is that the 8600 GVWR 8 lug calipers actually provide more clamping force than the SSBC dual piston calipers at a fraction of the cost. And since it was a factory option, it all just bolts on, and is available at most any auto parts store for cheap. Next up is those of us with 8 lug trucks and single rear wheels. As many of us know the rotors go behind the hub bearing, so they are not fun to change, and the factory rotors tend to warp easily if you actually use your truck and get the brakes hot. But were in luck, the 3500 dual rear wheeled trucks use very similiar brakes, but the rotors are roughly a 1/4" thicker, the pads are nearly identical except for thicker backing plates, and again, it all just bolts on. So you can easily and cheaply upgrade the brakes as well on 8 lug single rear wheeled trucks(but you MUST use ALL the DRW brake parts to do so. The calipers are roughly a 1/4" wider where they sit down over the rotor to accomodate the thicker rotor). If you have a dually though, you already have the biggest brakes available from the factory.

And to those doing the GMT-800 front brake upgrade, the 3.285" single piston caliper actually provides MORE clamping force than the dual 2.25" diamter pistons of the newer calipers, BUT they win out because of the greatly increased friction area of the MUCH larger pads. Now on to some pics I took.


DRW on the left, and SRW on the right, you can clearly see theres ALOT more meat i nthe DRW rotors but they are the same exact height.View attachment 46807 DRW on the left, and SRW on the right
View attachment 46808Heres a side by side pic of the 3 different pads. On the left is the 6 lug pads, middle is 8 lug SRW, and on the right is DRW pads.
View attachment 46809

Also, if you happen to have an older 94-99 DODGE 2500/3500, alot of this info applies to you as well. DODGE bought there brakes from GM back in the early days, so alot of our stuff directly bolts onto theres. They used a 7500 GVWR though for the 3.15" calipers, and went to the 3.285" calipers for anything over that. BUT DODGE never used bigger than a 1 1/16" rear wheel cylinder, so the GM 1 3/16" is a popular bolt in upgrade for them.

Leaving this one open for now, but please lets keep it to technical info and responses since it is a sticky. And if anybody sees a mistake, please point it out so we can keep this info as correct as possible.

[/QUOTE]

You can make all the claims you want about the GMT 400 clamping power, but there is no comparison to the GMT 800 braking power. Not even close. Don’t fear the conversion!

 

[THEFERMANATOR]

As far as I know, the semi-float axle cannot accept the 3.5" wide shoes and matching drums. The mod you describe is what people are doing when doing a rear disc brake conversion to get more pressure to the rears, I haven't read of anybody having problems with it. Pad wear is going to be a problem in these trucks. The gmt800 calipers are dual piston, but when you do the math, they have roughly the same piston surface area as the drw calipers, the big difference is they spread it out over a larger pad, so there pads last alot longer. Short of going to all drw stuff, there isn't much more you can do. If you have a vacuum break booster you can do the nbs master cylinder swap, but this won't work if you have hydro-boost.

And it's funny because gmt800 owners complain there breaks are crap, and GM should have addressed them at the factory.

 

[Will L.]

Yup. Owned gmt400, gmt800, srw and drw trucks as well as suburbans.
Gm brakes suck as bad as their a/c.

 

[Pistachiobob]

Fermanator! Thank you for the kindness of a reply! To summarize:
1. My 8 lug C2500 2WD semi floating Axel WILL NOT ACCEPT the 3.5” drums and shoes.
2. I can upgrade the FRONT BRAKES using ALL the GMT800 parts without difficulty, and improve the braking for a reasonable cost.
Did I get it right??

Grateful to you!!
Bob