GMT 800 Brake Conversion > Silverado HD 2500

[Ardenq]

Changing out the lower control arms from stamped/welded steel to forged is on my to do list. I anticipate have to cut off the stamped steel LCAs from the torsion because nothing would remove them the last time I was in there doing ball joints. The forged LCA go on and off easily.

any update on the forged swap? I have stamped arms and I ran into a similar problem as you with the lower ball joint. It didn’t seem to sit all the way in. If I keep reaming I’ll need a 1/2 spacer to keep the nut from borrowing out on the threads. Have you had any problems with the lower ball joint not being completely seated? It’s similar to what you have in your pictures.

 

[Big T]

any update on the forged swap? I have stamped arms and I ran into a similar problem as you with the lower ball joint. It didn’t seem to sit all the way in. If I keep reaming I’ll need a 1/2 spacer to keep the nut from borrowing out on the threads. Have you had any problems with the lower ball joint not being completely seated? It’s similar to what you have in your pictures.

I been doing the Covid work from home since 3/7, but at our Ranch in Montana. The ‘94 Suburban with the stamped LCAs is at our Fullerton home. Looks like that project to install the forged LCAs is getting deferred again. I was in the middle of replacing the IP on this truck when an emergency forced me up to the Montana home and then the WFH order hit.

I did need to use washers as spacers under the nut to the ball joint. I just over did it some with the ream, though I was using the ball joint to measure the depth. We have had no issues with it.

 

[DieselAmateur]

@Big T, this video was shared today which covers the GMT800 brake upgrade. Apparently you can swap in GMT800 LCAs and not have to ream out the lower knuckle.

My question for you is were you able to re-use the stock (GMT400) brake hoses on your conversion? According to the video the stock hoses were too short, and the 800s were too long, but he was able to find one in between, albeit with a 3/8" to 1/4" adapter too

 

[Big T]

@Big T, this video was shared today which covers the GMT800 brake upgrade. Apparently you can swap in GMT800 LCAs and not have to ream out the lower knuckle.

My question for you is were you able to re-use the stock (GMT400) brake hoses on your conversion? According to the video the stock hoses were too short, and the 800s were too long, but he was able to find one in between, albeit with a 3/8" to 1/4" adapter too

I was able to use my hoses, but they were braided stainless, not the originals.

The peeling clear coat on that hood is exactly like mine.

 

[Grisley1958]

That's one thing I haven't figured yet is the hoses. Big T do remember where you got your braided stainless lines and what the part number is?

 

[DieselAmateur]

I have not used any of these, but a little googling found this:

Russell part #672370. Cheapest at around $90. Not sure why they don't list this for all 88-00 trucks on their website but here's the link for cross reference. Seems there's slight difference for 2WD and 4WD trucks too

Russell Performance Brake & Clutch - Russell Performance

Brake & Clutch Hoses and Fittings by Russell Performance cover a wide range of Street Legal, DOT, Universal and competition applications for your performance brake and clutch needs.

www.russellperformance.com

Skyjacker brand, part # FBL97

Skyjacker Stainless Steel Front Brake Line - FBL97

Whether you're looking to maintain, optimize, or upgrade, we offer competitive pricing on Skyjacker Stainless Steel Front Brake Line - FBL97 for your Truck or Jeep at 4 Wheel Parts. With our selection of quality brands and expert advice, we help boost your vehicle's performance and make a...

www.4wheelparts.com

and I had this bookmarked from who knows when but it lists the length of the front hoses at 25" which according to the aforementioned video is perfect

'88-00 GMT400 Stainless Braided Vehicle Brakeline Kits

We've built layer upon layer of strength and protection into our all new, exclusive top-quality, DOT-approved extended braided stainless steel brake line kits! They have a tough teflon tube at the core, but the next layer is a Kevlar braid, then an extra protection layer, the stainless braid...

www.offroaddesign.com

 

[Grisley1958]

Thank You!

 

[Big T]

That's one thing I haven't figured yet is the hoses. Big T do remember where you got your braided stainless lines and what the part number is?

I would have to do some searching here, as it’s been a few years.

 

[Big T]

I have not used any of these, but a little googling found this:

Russell part #672370. Cheapest at around $90. Not sure why they don't list this for all 88-00 trucks on their website but here's the link for cross reference. Seems there's slight difference for 2WD and 4WD trucks too

Russell Performance Brake & Clutch - Russell Performance

Brake & Clutch Hoses and Fittings by Russell Performance cover a wide range of Street Legal, DOT, Universal and competition applications for your performance brake and clutch needs.

www.russellperformance.com

Skyjacker brand, part # FBL97

Skyjacker Stainless Steel Front Brake Line - FBL97

Whether you're looking to maintain, optimize, or upgrade, we offer competitive pricing on Skyjacker Stainless Steel Front Brake Line - FBL97 for your Truck or Jeep at 4 Wheel Parts. With our selection of quality brands and expert advice, we help boost your vehicle's performance and make a...

www.4wheelparts.com

and I had this bookmarked from who knows when but it lists the length of the front hoses at 25" which according to the aforementioned video is perfect

'88-00 GMT400 Stainless Braided Vehicle Brakeline Kits

We've built layer upon layer of strength and protection into our all new, exclusive top-quality, DOT-approved extended braided stainless steel brake line kits! They have a tough teflon tube at the core, but the next layer is a Kevlar braid, then an extra protection layer, the stainless braid...

www.offroaddesign.com

I know that I got the stainless brake lines from inlinetube.com:

1999-06 Chevrolet GMC 2/4WD 2500HD 3500 All Cab & Bed Lengths Complete Brake Line Kit, Stainless

1999-06 Chevrolet GMC 2/4WD 2500HD 3500 All Cab & Bed Lengths Complete Brake Line Kit, Stainless

www.inlinetube.com

They also have the braided stainless hoses. I can measure the length of mine tomorrow.

 

[DieselAmateur]

When @Big T said he was able to re use his hoses, I interperted that to mean original GMT400

Makes sense though that you'd need the GMT800 hoses if the banjo bolt fitting on the GMT800 caliper is different

From the video it would appear you need a GMT800 hose with a reducer fitting to tie into the GMT400 hard brake line on the frame

 

[Big T]

When @Big T said he was able to re use his hoses, I interperted that to mean original GMT400

Makes sense though that you'd need the GMT800 hoses if the banjo bolt fitting on the GMT800 caliper is different

From the video it would appear you need a GMT800 hose with a reducer fitting to tie into the GMT400 hard brake line on the frame

Yeah my aftermarket braided stainless lines with banjo fittings worked on the GMT 800 brake conversion.

Have not finished the video, but he alludes to some using threaded adapters to the GMT 800 tie rods. I used the adapters on my '99 and reamed the spindles on the '94. If I had to do it all over again, I would not use the adapters. The adapter on the passenger side had some minor play in the threads after it was spun into the GMT 800 tie rod. Over time, I believe that play caushed wear in the upper control arm bushings which you can see in the following videos:

October 31, 2021

youtube.com

Upper Control Arm Passenger Side

youtube.com

In order to correct this, I will need to thread the larger side of the adapter all the way down to where it’s machined smaller to go into the tie rod, then install a jam nut. Of course I need to redo the upper control arm bushings and replace the bolts. I have a set of black urethane bushings at the Fullerton home and I just got a set a bolts. So more knuckle busting work ahead.

 

[Big T]

@Big T, this video was shared today which covers the GMT800 brake upgrade. Apparently you can swap in GMT800 LCAs and not have to ream out the lower knuckle.

My question for you is were you able to re-use the stock (GMT400) brake hoses on your conversion? According to the video the stock hoses were too short, and the 800s were too long, but he was able to find one in between, albeit with a 3/8" to 1/4" adapter too

I measured mine and they are roughly 26" end-to-end.

 

[Big T]

I measured mine and they are roughly 26" end-to-end.

In the video he said 27" = sweet spot. So mine are right there. I anchored them to the Upper Control Arm (UCA) using stainless rubber lined clamps.

I noted he errantly reamed at an angle and had to used spacers. I reamed too deep using the ball joints as a guide. Thought it would give clearance to the CV hub. I had to use spacer washers (2), but there are no issues.

Not so sure about his deletion of the dust ring on the CV axle as I thought that rode inside a seal, preventing water intrusion.

He said GMT 800 light duty, heavy duty spindles from 1999-2001. Not so sure that it's limited to those years.

Otherwise, nice video made off stealing the ideas and work of others off the internet. The stopping power of these brakes is worth it.

 

[Grisley1958]

I ordered my parts from rockauto last night. Moog upper control arms, bushings and moog ball joints for the lowers, new Timken bearings, ES409 tie rod ends, calipers, pads and stabilizer links. I think I can clean up the rotors, they have some rust from sitting but no wear. $1049.00 with tax and shipping but pretty much everything will be new and I have the caliper cores to send back.

 

[Big T]

I ordered my parts from rockauto last night. Moog upper control arms, bushings and moog ball joints for the lowers, new Timken bearings, ES409 tie rod ends, calipers, pads and stabilizer links. I think I can clean up the rotors, they have some rust from sitting but no wear. $1049.00 with tax and shipping but pretty much everything will be new and I have the caliper cores to send back.

With rotors, I ended up about $1,200

 

[Grisley1958]

I still have to get the hoses too.

 

[ak diesel driver]

I thought he said it was the light duty arm that was 99-01

 

[DieselAmateur]

He says the knuckles from a Light Duty 99-2000 are used so that you can re-use original tie rod ends. Something of a unicorn part in my opinion, seems it's easier to get a 99-07 2500 knuckle and use ES409 tie rod ends instead

here's the 88-98 stainless hoses from inline tube, assuming these are the ones @Big T already had on his rig they should bolt right up to the GMT800 caliper

1988-98 Chevrolet GMC Truck Blazer Suburban 4wd 1/2-3/4 ton, 4WD, 3pc Hose Kit, Stainless

1988-98 Chevrolet GMC Truck Blazer Suburban 4wd 1/2-3/4 ton, 4WD, 3pc Hose Kit, Stainless

www.inlinetube.com

 

[ak diesel driver]

I'm wondering how much of the gmt800 dually stuff would interchange with mine

 

[Big T]

He says the knuckles from a Light Duty 99-2000 are used so that you can re-use original tie rod ends. Something of a unicorn part in my opinion, seems it's easier to get a 99-07 2500 knuckle and use ES409 tie rod ends instead

here's the 88-98 stainless hoses from inline tube, assuming these are the ones @Big T already had on his rig they should bolt right up to the GMT800 caliper

1988-98 Chevrolet GMC Truck Blazer Suburban 4wd 1/2-3/4 ton, 4WD, 3pc Hose Kit, Stainless

1988-98 Chevrolet GMC Truck Blazer Suburban 4wd 1/2-3/4 ton, 4WD, 3pc Hose Kit, Stainless

www.inlinetube.com

Says 24” on the hose length. Wondering if that is the length between the fittings? I measured 26” end-to-end.