Bye-bye Gov-Lock, Hello Tru Trac, plus gear swap and brakes

[n8in8or]

As the title shows, I have a few upgrades for the Tahoe coming up in the next couple weeks.

As mentioned in another thread, I have had some 3.42 gears for my 14 bolt waiting for installation. I have hated the Motive Gear ring & pinion ever since I installed them because they howl from 45-65 and make noise at other speeds, too. I set the gears up 3 times, having a good pattern each time and they always made noise. It wasn’t until AFTER I installed them that I found the bad reviews of the gears..... Once I installed the Moose and got the combo dialed in, this is when I decided I wanted to try a 3.42 gear - because 1st gear ends so quickly and it isn’t until 2nd gear that the truck really starts pulling. Some of that I believe is my torque converter, because it’s when it locks up that it really pulls and I don’t lock up the converter in 1st gear, but I also think a taller gear will help. So I went to Ebay and bought a used set of GM 3.42 gears. These will be getting installed and I can’t wait for them!



To go with the 3.42s, I just picked up a 96 front diff assembly. It already had the new actuator on it, so that’s nice. I took it to the pressure washer today to clean it up some. I will be installing a new pinion seal in it because it’s a little moist around the yoke.



I didn’t want to install the rear gears on the old Gov-Lock because it feels like a ticking time bomb waiting to blow up. It inconsistently locks and unlocks.....sometimes I even get a left wheel one tire fire, so not sure what that’s about. And for a few months now, if I’m at highway speeds for 20 minutes or more, when I get off at the exit the locker will be locked the first time I go around a corner. Not impressed. I have been researching lockers for a while and the Detroit Tru Trac sounds like a tough, reliable unit that doesn’t take anything away from daily driving enjoyment. So I finally pulled the trigger on one. I will be so much happier knowing I don’t have a grenade in the rear axle waiting to go off when I start spinning thr tires.



Since the bearings in the rear end are relatively fresh I wanted to try to reuse them. To do this I got a clamshell bearing puller. I’m sure hoping it works so I can save the bearings and also give me a couple shots at setting up pinion shim thickness without needing to destroy a bearing every time.



At the same time I decided I should do some brake upgrades. I replaced the front brakes a while ago and they’ve been fine, but I have always wanted them to be better. They pull to one side sometimes and they could just be stronger. My current setup is reman Autozone calipers, the best rotors Autozone sells and EBC pads (green stuff I think). I have been reading what some of you guys have been happy with so I took that info and made some purchases from Rock Auto and Amazon. Here’s what I picked up:

I went with the Raybestos R-300 performance rotors. They have a lot of nice features like rust prevention and grooved disc surface plus they’re supposed to be a heavy duty piece.



Then I went with the Powerstop Performance calipers. They seem a litte gimicky with the red powder coat, but it sounded like some of you like Power Stop, so I figured I’d give them a shot. Is this a mistake? It’s not too late for me to return them and get something else. I also went with the calipers and pads in the 3/4 ton size to gain some more stopping power.



The other thing I’m unsure of is the Power Stop Z36 pads. They too are supposed to be heavy duty, but I don’t know for sure how they will perform. Any thoughts?



And then to finish up the brake upgrade I got some braided brake hoses. This should really firm things up I hope.




I’ll probably be installing all of these goodies in about 2 weeks and I can’t wait to see how it drives with these upgrades! Please let me know your thoughts on the brake upgrades!

 

[MrMarty51]

Cant comment much about the brake up~grades but I like that Detroit locker. LOL

 

[JayTheCPA]

Have Yukon 3.42's and they are holding up well. Truck is slower off the line but I do not care about that. Pulls just fine.

For the brakes . . . I am using the 1 ton setup (all AC Delco) including the rear cylinders (for a dually) and proportioning valve. The Burb definitely stops much better than with the 3/4 ton OE parts. About every 5K miles I force the rear pads to self adjust which makes a difference on pedal feel and nose-diving while braking. Only thing I cannot solve is rotor warp as even with the beefy 1 ton rotors, they warped after ~10K miles.

Wile working on the rear, might want to check and see if adding 2" spacers will make the front / rear stance equal. If so, it should help with the truck's tracking stability on roads with ruts. Definitely did on the Burb.

 

[WarWagon]

Have Yukon 3.42's and they are holding up well. Truck is slower off the line but I do not care about that. Pulls just fine.

For the brakes . . . I am using the 1 ton setup (all AC Delco) including the rear cylinders (for a dually) and proportioning valve. The Burb definitely stops much better than with the 3/4 ton OE parts. About every 5K miles I force the rear pads to self adjust which makes a difference on pedal feel and nose-diving while braking. Only thing I cannot solve is rotor warp as even with the beefy 1 ton rotors, they warped after ~10K miles.

Wile working on the rear, might want to check and see if adding 2" spacers will make the front / rear stance equal. If so, it should help with the truck's tracking stability on roads with ruts. Definitely did on the Burb.

Brake rotors are wear items. It's debatable if they are throw away items or can be surfaced. One of the pass/fail tests that IMO most overlook is the "hot-spots" that are visible before trash rotors are machined. Sometimes you can even feel it with a fingernail. The hot spots are from the temperature getting over 1200-1300 degrees F and the cast iron turning into cementite, iron carbide. The cementite can expand leaving you a fingernail hanger on the surface. The same material carbide cutting tool isn't going to knock this layer off and it can go deep. The cutting tool bounces off the stuff. You see hot spots = throw the rotors away!

On brakes cementite trashed rotors usually come back in 3000 miles for pedal pulse while stopping. The cementite expansion 'growing back' continues to cause a problem. In order to prevent brakes from overheating you have to 'roll' on the brakes after a hard stop: Don't keep the red hot pads over a red hot rotor while the rest of the rotor cools down. Roll it a bit to cool the entire rotor so you don't have a hot spot turning to cementite under the hot pads. Shift to reverse and back it up a few feet if you have too after a panic stop! Regardless this is why you see some people drift forward and stop again a few times at a stop light.

@n8in8or Will be interesting to see how the EBC pads work out. I have noted stopping distances from Duracrap pads to the faster stopping Wagners. (Also helps if the pad stays on the backing plate.)

Keep in mind: Slotted or drilled rotors cool faster than normal solid rotors. It can catch you on short freeway runs in town where hot brakes go cold and you have the longer cold friction stopping distance on the off ramp. (And say, like me, you were used to warm/hot brakes on that off ramp before...) Our 1995 350 4door Yukon did this. I wish I remembered what pad we were using, but, we went from 12K pad life to 17K pad life with slotted and/or drilled rotors. We used both and will only use slotted due to drilled rotor cracking. FWIW no real difference with cryo treated slotted rotors, but, the car we tried them was totaled before we could gauge life.

 

[n8in8or]

Cant comment much about the brake up~grades but I like that Detroit locker. LOL

I'm excited about it too!

For the brakes . . . I am using the 1 ton setup (all AC Delco) including the rear cylinders (for a dually) and proportioning valve. The Burb definitely stops much better than with the 3/4 ton OE parts. About every 5K miles I force the rear pads to self adjust which makes a difference on pedal feel and nose-diving while braking. Only thing I cannot solve is rotor warp as even with the beefy 1 ton rotors, they warped after ~10K miles.

Wile working on the rear, might want to check and see if adding 2" spacers will make the front / rear stance equal. If so, it should help with the truck's tracking stability on roads with ruts. Definitely did on the Burb.

I wish I could do the 1 ton stuff. Since I'm a half ton, the best I can do is add the 3/4 ton calipers and pads. I already have spacers on the rear of the Tahoe, though it isn't really as much of a problem with the 1/2 tons like it is with the 3/4 tons. I am going to inspect and adjust my rear brakes while I'm doing everything just to make sure they're all in order.

@n8in8or Will be interesting to see how the EBC pads work out. I have noted stopping distances from Duracrap pads to the faster stopping Wagners. (Also helps if the pad stays on the backing plate.)

Keep in mind: Slotted or drilled rotors cool faster than normal solid rotors. It can catch you on short freeway runs in town where hot brakes go cold and you have the longer cold friction stopping distance on the off ramp. (And say, like me, you were used to warm/hot brakes on that off ramp before...) Our 1995 350 4door Yukon did this. I wish I remembered what pad we were using, but, we went from 12K pad life to 17K pad life with slotted and/or drilled rotors. We used both and will only use slotted due to drilled rotor cracking. FWIW no real difference with cryo treated slotted rotors, but, the car we tried them was totaled before we could gauge life.

The EBC pads have been ok, but I'm not sure they're worth the price tag in my opinion. They're a bit noisy at light braking, too, which is kind of annoying. I have noticed some pulling, but I'm guessing that is more due to the Autozone calipers than the pads. I read that you were using the Wagner pads, Thermo Quiets I think? I was ready to buy those, but it seemed too good to be true that a $20 set of pads (at Rock Auto) were that good. Are you really THAT happy with them? I might return the Durastop pads, but then again, maybe I should be the guinea pig? I read the article you shared about that police department that tested different brake pad formulations....that article was AWESOME! I made sure to get semi-metallic pads this time around. Thanks for the comment on the slotted rotors....I'll have to keep that in mind.

 

[THEFERMANATOR]

You can also install the 1 3/16" drw wheel cylinders into your rear brakes since you have a 9.5" 14 bolt. That's good for a substantial bump over your current 1" wheel cylinders.

 

[n8in8or]

You can also install the 1 3/16" drw wheel cylinders into your rear brakes since you have a 9.5" 14 bolt. That's good for a substantial bump over your current 1" wheel cylinders.

Good to know. Wow, that would be a huge bump! I'm not sure I need that because I sometimes have problems with the rears locking up as is.

 

[JayTheCPA]

The Burb used to lock the rears as well whenever there was moisture of any sort (including high humidity).

With the the larger wheel cylinders and 1 ton proportioning valve, it is extremely rare to skid a rear tire.

Although, tough to tell whether the Tahoe will duplicate the experience of getting rid of the rear grabbing if it is using smaller shoes than the Burb.

 

[n8in8or]

The Burb used to lock the rears as well whenever there was moisture of any sort (including high humidity).

With the the larger wheel cylinders and 1 ton proportioning valve, it is extremely rare to skid a rear tire.

Although, tough to tell whether the Tahoe will duplicate the experience of getting rid of the rear grabbing if it is using smaller shoes than the Burb.

YES! That is exactly the problem I have, too! Did you change rear shoes, too, or was it just the wheel cylinders and proportioning valve that you changed to address the problem?

 

[n8in8or]

The Burb used to lock the rears as well whenever there was moisture of any sort (including high humidity).

With the the larger wheel cylinders and 1 ton proportioning valve, it is extremely rare to skid a rear tire.

Although, tough to tell whether the Tahoe will duplicate the experience of getting rid of the rear grabbing if it is using smaller shoes than the Burb.

Actually, thinking about this some more....... I bet the larger wheel cylinders WOULD help my problem. The larger volume of the cylinder should reduce the sensitivity of the rear brakes because it would take longer to fill the inside of the cylinder. But then, once fully engaged, the larger diameter of the piston would apply greater force to the brakes. This might be just what I need to make this work properly! Hmmmmm. I'm thinking now that I may be wise to change my shoes too since I'm running the Autozone Duralast shoes in the rear as well....

 

[Will L.]

Anytime you install pads,rotors, shoes, or drums: burnish them right away. Makes huge difference in stopping and lifespan.

 

[WarWagon]

I read that you were using the Wagner pads, Thermo Quiets I think? I was ready to buy those, but it seemed too good to be true that a $20 set of pads (at Rock Auto) were that good. Are you really THAT happy with them? I might return the Durastop pads, but then again, maybe I should be the guinea pig?

Duracrap pads ruined one of the last USA cast rotors I was able to obtain. Post 12 in the Carnage thread where, yes, I am known to screw up an Anvil. Wagner pads, Thermo Quiets went on after that and stopped better with less pedal pressure. (We use Wagner on the side job stuff and they work well.) Rear shoes being high quality also made a difference. I don't understand Rock Auto's ability to sell some decent stuff at a low price when parts stores charge so much for bottom of the barrel no-quality garbage. I put my foot in mouth already when they are 50% the $100 expected cost for quality rear shoes. Oh wait higher prices because Autozone fires vets for stopping robberies due to their pu$$y no hero policies. I grow tired of doing jobs over because of the race for the cheapest part served by places like Autozone. Clearly I don't like Autozone for a couple good reasons.

If this was wear-out the holes that hold what's left of the pad would be worn not broken rough. The Duracrap pad came off the backing with a thump like a nail coming out of a tire hitting the underside. Then a few quick pumps of the brakes before they came back had me considering plan "B" putting the parking brake to the floor before unavoidable plan "C" was stopping in someone's back seat...

 

[n8in8or]

I’m looking at brake shoes on Rock Auto and I’m noticing that the AC Delco ones say:

• New revolutionary brake friction material, consisting of ceramic and soft metal fibers

Is this what was developed for the TSB I keep hearing about? If so, these are pretty tempting. A set of riveted shoes is $35, so not terrible.

 

[JayTheCPA]

Did you change rear shoes, too, or was it just the wheel cylinders and proportioning valve that you changed to address the problem?

I did change shoes (IIRC Raybestos expensive ones) but not sure whether that was the cure.

While I do not have any scientific data, my personal suspicion is that the OE parts for the rear brakes allowed corrosion / crud to build-up. Now that the brakes are working properly with the upgraded system, the drums and shoes are probably more polished which is a more likely reason of why they rarely grab. So, I suspect the cure was a system level correction as opposed to just one part.

I’m looking at brake shoes on Rock Auto and I’m noticing that the AC Delco ones say:

• New revolutionary brake friction material, consisting of ceramic and soft metal fibers

Is this what was developed for the TSB I keep hearing about?

IIRC, the 'Durastop' designation was the result of that TSB effort. As always, will defer to better experts.

 

[MrMarty51]

I’m looking at brake shoes on Rock Auto and I’m noticing that the AC Delco ones say:

• New revolutionary brake friction material, consisting of ceramic and soft metal fibers

Is this what was developed for the TSB I keep hearing about? If so, these are pretty tempting. A set of riveted shoes is $35, so not terrible.

I usually try to get the softer shoes and pads, less wear on the rotors. It has worked well for Me so far. Had over 100,000 miles on the last set I installed on the 93 K1500 and was still stopping nice when I sold it.
I am not a jab the throttle and jam the brakes kind of a driver though.

 

[Twisted Steel Performance]

Just a fyi , a thermal dispersant will help cool the rotors. And a heat barrier on the back of the pads slowes heat transfer a lot.

 

[WarWagon]

I usually try to get the softer shoes and pads, less wear on the rotors. It has worked well for Me so far. Had over 100,000 miles on the last set I installed on the 93 K1500 and was still stopping nice when I sold it.
I am not a jab the throttle and jam the brakes kind of a driver though.

My Trailblazer SS would take the rotors under spec before the pads we're completely worn down. This was in under 20k miles. Same with some spots cars. IMO this isn't bad for most as rotors are trashed anyway for most.

 

[n8in8or]

Just a fyi , a thermal dispersant will help cool the rotors. And a heat barrier on the back of the pads slowes heat transfer a lot.

That’s a really interesting idea. I hadn’t thought of that.

 

[THEFERMANATOR]

The ac delco professional(not the advantage line) is the same as GM's revolutionary durastop shoes that are the go to ones. I believe they are the same as rayvestos blue professional's, but I'm not certain so I spend the couple of extra bucks for the ac delco's to be certain I get the good ones.

It looks like I may have to take back what I said on the wheel cylinders. 2 door 4x4 tahoes with heavy duty rear brakes and 10" drums came with the 1 3/16" wheel cylinders stock. If you have 11" drums they got 1" wheel cylinders. 4 doir tahoes with 11" drums got only got 13/16" wheel cylinders, so as you see there can be quite the spread. And when you throw different proportioning valves into the mix, your head can spin. So you may already have the big wheel cylinders.

 

[n8in8or]

The ac delco professional(not the advantage line) is the same as GM's revolutionary durastop shoes that are the go to ones. I believe they are the same as rayvestos blue professional's, but I'm not certain so I spend the couple of extra bucks for the ac delco's to be certain I get the good ones.

It looks like I may have to take back what I said on the wheel cylinders. 2 door 4x4 tahoes with heavy duty rear brakes and 10" drums came with the 1 3/16" wheel cylinders stock. If you have 11" drums they got 1" wheel cylinders. 4 doir tahoes with 11" drums got only got 13/16" wheel cylinders, so as you see there can be quite the spread. And when you throw different proportioning valves into the mix, your head can spin. So you may already have the big wheel cylinders.

Interesting. I just looked up the ones that I bought when I did the 14 bolt conversion and they are the 1" bore cylinders. So it looks like I can upgrade if I choose to.