90 GMC Sierra rear brake change

[90gmcsierraL59]

I bought this truck in 04 with 99K on it and changed the rear brake shoes shortly thereafter. Last Sunday on my way home from work I heard a light grinding noise from the rear brakes when I pulled up in the driveway. I quit driving it and I got it up on the lift today.

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I got my money's worth for sure, 157K on those shoes. I have replaced the front brake pads and rotors several times since 04 and I was surprised to note that other than the cracked front RH shoe with the chunk missing depicted the shoes and drums looked usable. The wheel cylinders were both seeping from the front cup. I ordered all new components from NAPA and was shocked they had everything in stock except the riveted shoes and the drums. I ordered the shoes and drums and will pick them up with the wheel cylinders, a hardware kit and two adjuster kits tomorrow.

 

[Caman96]

How often did you adjust the brakes?

 

[90gmcsierraL59]

Not very.

 

[Caman96]

So, if not properly adjusted, they aren’t doing much. Not wearing much, that is. But hey, here you are 157k later.

 

[Schurkey]

Yup. Getting excessive service-life out of the rear shoes probably means you're not using the rear brakes much, leading to excess wear on the fronts, poor braking performance, and a low pedal.

Common as dirt with the crappy 1500-series 254mm (10") leading-trailing rear brakes. Let me guess: You don't use the park brake much, and the park brake cables are seized.

Buying new wheel cylinders, shoes, drums, etc. for the 254mm brakes is a waste of money. Ideally, you'd swap to the infinitely-better, more powerful 11.x Duo-Servo rear brakes, and there's no better way to do that than to find a light-duty 2500 axle with the 9.5" ring gear in the correct gear ratio, and the better brakes bolted to it. You need a C2500 axle for a 2WD truck, and a K2500 axle for a 4WD truck. The 2WD is a tougher swap, because the C2500 axles have 6-lug wheels.

If you do keep the crappy 254mm rear brakes, you MUST use the park brake frequently.

Whatever you do with the brakes, be sure to bleed the ABS properly. If you have the iron-body RWAL, there's a bleeder screw right on it. If it's the newer aluminum unit, you'll need a scan tool to chatter the valves. I don't remember when GM switch RWAL units--it'd be around 1990.

 

[90gmcsierraL59]

Thanks for the advice.

 

[movietvet]

Yup. Getting excessive service-life out of the rear shoes probably means you're not using the rear brakes much, leading to excess wear on the fronts, poor braking performance, and a low pedal.

Common as dirt with the crappy 1500-series 254mm (10") leading-trailing rear brakes. Let me guess: You don't use the park brake much, and the park brake cables are seized.

Buying new wheel cylinders, shoes, drums, etc. for the 254mm brakes is a waste of money. Ideally, you'd swap to the infinitely-better, more powerful 11.x Duo-Servo rear brakes, and there's no better way to do that than to find a light-duty 2500 axle with the 9.5" ring gear in the correct gear ratio, and the better brakes bolted to it. You need a C2500 axle for a 2WD truck, and a K2500 axle for a 4WD truck. The 2WD is a tougher swap, because the C2500 axles have 6-lug wheels.

If you do keep the crappy 254mm rear brakes, you MUST use the park brake frequently.

Whatever you do with the brakes, be sure to bleed the ABS properly. If you have the iron-body RWAL, there's a bleeder screw right on it. If it's the newer aluminum unit, you'll need a scan tool to chatter the valves. I don't remember when GM switch RWAL units--it'd be around 1990.

It's like you dare someone to not do as you suggest. It is not a waste of HIS money to fix what he has. He is satisfied with what he has and will get many more miles out of what he has and be happy. Or, he can take your suggestion and go better but PUSHY can block the learning curve. Your theory is spot on and me and you both know that with proper adjusted rear shoes, the front brakes can still wear out twice as fast because they do most of the braking.

Recommendations are what it is all about and explaining the differences and what the benefits and drawbacks are. Your insistence is like it's gotta be your way and that is the only way. Your info as a trained tech/mechanic is spot on and I do have very thick skin but man, you are................

I ran in to guys like you in the service and in the shops. I stayed away, just like I will here.

 

[90gmcsierraL59]

Thank you all for the advice. I will be putting the stock parts back on the truck and am considering deleting the RWAL delete per a another thread on the forum. https://www.gmt400.com/threads/1990-c1500-abs-rwal-removal.11427/

It looks simple enough and makes sense to me. The truck has always stopped well. I disconnected the RWAL box years ago after getting the brake warning light and replacing the control box followed by the brake light coming back on 100 miles later.

 

[90gmcsierraL59]

Thank you all for the advice. I will be putting the stock parts back on the truck and am considerdeleting the RWAL delete per a another thread on the forum. https://www.gmt400.com/threads/1990-c1500-abs-rwal-removal.11427/

It looks simple enough and makes sense to me. The truck has always stopped well. I disconnected the RWAL box years ago after getting the brake warning light and replacing the control box followed by the brake light coming back on 100 miles later.

 

[90gmcsierraL59]

As noted I do rarely use the parking brake. The cables are not frozen. I assume that after initial adjustment that applying brakes when backing up is what moves the adjusters if it's like everything else I have ever owned with mechanical drum brakes. Please enlighten me if I am ignorant of how the system actually works in my truck.