Rear Brake Problem

[J45p3r]

Heard the scrapers on my rear brakes a couple weeks ago and finally got around to changing them yesterday. Rear passenger side was worn to the scraper on the inside, but the drivers side still looked to have at least 50% pad left on the inside and 75% on the outside.

 

SO, I got everything changed out and lubed nicely (the sliders are and were free). So, suspicious of that drivers side brake, I parked the rear axle over some ice in the drive way and did a power brake. No matter how hard I pushed the brakes (to the floor even), the left rear wheel would start to spin with very little throttle application. Seems that brake isn't and hasn't been working? The pedal has a nice firm feel, doesn't act like air to me. Do I have a bad caliper?

[c4cruiser]

Sounds like a rusted/stuck piston in that caliper. Also possible that something is blocking the brake line and not allowing enough pressure into the caliper.

 

You didn't say how many miles are on the truck, but it might be worth replacing the calipers on that axle and doing a complete brake fluid flush.

[J45p3r]

Thanks for the reply, the truck has just under 70,000 miles.

 

I was able to push the piston back pretty easy with the clamp when I changed the pads. So it didn't seem stuck, but maybe it is only coming out so far and then gets stuck.

[asepgrad98]

i bet its a fluid pressure problem and not a caliper if you could push the piston back in easily.

[J45p3r]

Is there a correct way to measure the fluid pressure at the caliper? A gauge of some kind?

 

I think before I replace the caliper I will do a fluid flush.

[rjirvine]

That would be a good idea. I got a pressure bleeder kit off of ebay (looks like a garden sprayer) and wouldn't have it any other way. Remember it's right rear, left rear, right front and then left front. I use valvoline synpower brake fluid and like it. Depending on road salt in your area, it wouln't be a bad idea to replace the bleeder screws or at least have some on hand before you start (mine were toast). And as luck would have it, i think the fronts and rears are different sizes, but cant remember exactly.

[98 Z71 SLT]

J45

 

DON"T do ANYTHING to your brakes. There's nothing wrong with them!!!

 

Years ago, GM issued a TSB about the right rear INBOARD brake pad wearing out more rapidly then the rest of the rear pads. Their "excuse" for this was that salt/dirt/road grime would collect on the inboard pad, and sort-of eat-away at the lining.

 

Don't screw around with something that isn't broke. You said your pistons went back into the calipers ok, and you said the sliders were free.

 

There is nothing wrong with your rear brakes, man. Just let them alone.

 

Jack up the rear of the truck, getting the wheels off the ground.

Put the trans in neutral, with front wheels blocked.

Have a pal step on the brake pedal, WITHOUT STARTING THE ENGINE.

Now, you go and try to rotate the left rear wheel. Not gonna happen.

This concludes your brakes are working.

 

NEVER assume brakes are / are not working by doing burn-outs.

[J45p3r]

J45

 

DON"T do ANYTHING to your brakes. There's nothing wrong with them!!!

 

Years ago, GM issued a TSB about the right rear INBOARD brake pad wearing out more rapidly then the rest of the rear pads. Their "excuse" for this was that salt/dirt/road grime would collect on the inboard pad, and sort-of eat-away at the lining.

 

Don't screw around with something that isn't broke. You said your pistons went back into the calipers ok, and you said the sliders were free.

 

There is nothing wrong with your rear brakes, man. Just let them alone.

 

Jack up the rear of the truck, getting the wheels off the ground.

Put the trans in neutral, with front wheels blocked.

Have a pal step on the brake pedal, WITHOUT STARTING THE ENGINE.

Now, you go and try to rotate the left rear wheel. Not gonna happen.

This concludes your brakes are working.

 

NEVER assume brakes are / are not working by doing burn-outs.

I definitely wouldn't call it a burn out. I was parked on glare ice, and applied very little throttle with the brake pedal to the floor and the wheel broke free and spun with ease.

 

My issue isn't that the inside wore down more than the outside, it is that the inside pad on the right side was spent completely and the inside pad on the left still had 50% life.

[98 Z71 SLT]

[

[98 Z71 SLT]

[

 

 

 

My issue isn't that the inside wore down more than the outside, it is that the inside pad on the right side was spent completely and the inside pad on the left still had 50% life.

 

You don't have any issues. You have normal rear disc GM truck brakes, believe it or not.

 

Now you have new rear brakes. But, if you insist you have something wrong, well, believe what you wish.

 

Do a search for that GM tsb

 

[jrrod2004]

Copy of TSB........

 

 

 

 

 

 

Document ID# 1336875

2003 GMC Truck GMC C Sierra - 2WD

Subject:Right Rear Inner Brake Pad Wear (Install Rear Wheel Mud Flaps) #00-05-23-005B - (05/27/2003)

 

 

Models:1999-2004 Chevrolet Silverado 1500 Series Pickup Models

 

 

1999-2004 GMC Sierra 1500 Series Pickup Models

 

 

This bulletin is being revised to change the content from Informational to Technical. Please discard Corporate Bulletin Number 00-05-23-005A (Section 05 - Brakes).

 

Condition

Some customers and dealers may comment on accelerated rear brake wear on some of the above listed vehicles. This condition occurs mainly on the right rear inboard brake pads and on vehicles that are exposed to extensive off-paved roads.

 

Correction

Install a mud flap forward of each rear wheel using the following procedure. Installation of these mud flaps and following the recommended off-road driving information provided in the vehicle's Owner's Manual should greatly reduce the possibility of accelerated rear brake component wear.

 

Important: Always work from outboard to inboard, drilling one hole at a time and securing with a fastener. Follow the sequence of the procedure. This will prevent distortion of the mud flap.

 

 

1. Raise the vehicle. Support the vehicle.
   
2. Locate the pickup box side panel rear brace.
   
3. Remove the existing outboard upper fastener on the brace.
   
4. Install the mud flap through the "V" of the brace. Install the previously removed fastener in the hole (2) of the mud flap to the brace. Do not tighten the fastener at this time.
   
    
   
5. Using the mud flap as a template, locate and mark the location of the hole (1) in the pickup box wheelhouse.Important: After drilling the holes, apply the appropriate anti-corrosion primer. Refer to the GM Refinish Material Booklet #4901M-D (English) or #4901-D-F (French) for additional information.
    
   
6. Center punch the marked location and drill a 6.35 mm (1/4 in) hole. Install the plastic retainer in the hole (1) of the mud flap.
   
7. Tighten fastener at the hole (2) location of the mud flap.Tighten
   Tighten the fastener to 25 N·m (18 lb ft).
    
    
   
    
   
8. For vehicles with short box, use the following procedure:

   8.1. Push the mud flap to make contact with the rear side of the underbody cross sill and mark the location of the hole (3) of the mud flap.

    

    

   8.2. Center punch the marked location and drill a 5.159 mm (13/64 in) hole.

    

    

   8.3. Install the screw.

    

   Tighten
   Tighten the screw to 4 N·m (35 lb in).
    
   

   8.4. Repeat the above steps for hole locations 4 and 6.

    

   
   
    
   

9. For vehicles with long box, use the following procedure:

   9.1. Push the mud flap to make contact with the front side of the underbody cross sill and mark location of the hole (5) of the mud flap.

    

    

   9.2. Center punch the marked location and drill a 5.159 mm (13/64 in) hole.

    

    

   9.3. Install the screw.

    

   Tighten
   Tighten the screw to 4 N·m (35 lb in).
    
   

   9.4. Repeat the above steps for hole location 6.

    

   
   

10. Repeat the above steps for the opposite side.
    

Parts Information

Part Number

 

Description

 

Qty

 

15765007

 

Flap Package - Rear Mud

 

1

 

Parts are currently available from GMSPO.

 

Warranty Information

For vehicles repaired under warranty, use:

 

Labor Operation

 

Description

 

Labor Time

 

B7787*

 

Flap Package, Rear Mud -- Install (Both)

 

0.6 hr

 

*This is a unique labor operation number for use only with this bulletin. This number will not be published in the Labor Time Guide.

 

 

 

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

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© Copyright General Motors Corporation. All Rights Reserved.

 

 

Document ID# 1336875

2003 GMC Truck GMC C Sierra - 2WD

[J45p3r]

Ah, describes my situation to a tee. Thanks for that, I'll check in to that fix.

[jrrod2004]

no prob. merry xmas.