Silverado 1500 new brake issue

[fishpick]

I cross posed this on the GM-Tech forum - sorry - after posting there I noticed that GM-Tech is taking a leave and wish him the best - sorry for the cross post.

 

Here's the story - this forum was very helpful in describing the issues with the rear Silverado brakes and their tendency to wear out fast! Also other good technical stuff here... So - I got new rotors and pads from a local auto store - fought like hell to get the rear rotors off (large mallet - d**n emergency brake design) and have the whole thing done up new and happy - so I thought.

 

Now with the new rotors and pads - when rolling along there is a scraping / grinding sound (lower frequency than a squeal) that is made as a function of the rotation of the wheel... When the brake petal is depressed the sound is neither better or worse - just gets slower as the rotation slows...

 

Here is my hunch - the stupid pads for the emergency brake are now somehow rubbing on the inside of the rotors after pounding the piss out of the old ones to get them off... so, my hunch is I need to take off the calipers and rotors - again - and fiddle around with the shoes that make up the e-brake... Also - since putting new rotors on - the emergency brake pedal in the cab goes all the way to the floor - where as before it only went about half way.

 

Questions : Does this sound like it makes sense? Do the e-brake shoes adjust like any other drum/shoe system (I recall seeing the star adjuster when the rotor was off)? Is there anything else I should be looking at? How do you adjust the emergency brake cable to make the pedal travel less?

 

Thanks in advance.

[Rolandd]

Several things:

 

I would drive the truck to a speed where you can hear the noise and then apply the e-brake slowly and see if the noise changes. If it does, you know where your issues are. If it does not, I would carefully inspect the brakes for the backing plates rubbing or foreign matter in the caliper or between the pads and rotors. It is possible that you knocked something in the e-brake loose and it is rubbing on the inside of the rotor, check for this possibility as well.

 

I would only adjust the e-brake with the adjusters as you indicated that the e-brake pedal was engaging at a reasonable height before you did the brake work. I would only adjust the cable if there is no other adjuster or the e-brake system is properly adjusted and the pedal is not behaving well. You don't want to use the cable to adjust the brakes because then the internal adjuster will hang loose and the brakes will not apply with even force (only one shoe may apply adequate pressure) which can stress the system to break other parts.

[ChevyTech007]

This bulletin should apply: Subject: Scraping Noise From Rear of Vehicle (Replace Parking Brake Shoe Kit and Clean Drum in Hat Rotor) #02-05-26-002A - (01/28/2003)

 

 

 

Models: 2002-2003 Cadillac Escalade, Escalade EXT

 

1999-2003 Chevrolet Silverado 1500 Series Pickups

 

2000-2003 Chevrolet Suburban, Tahoe 1500 Series Models

 

2002-2003 Chevrolet Avalanche 1500 Series Models

 

1999-2003 GMC Sierra 1500 Series Pickups

 

2000-2003 GMC Yukon, Yukon XL 1500 Series Models

 

 

 

 

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This bulletin is being revised to add Suburban and Yukon XL models. Please discard Corporate Bulletin Number 02-05-26-002 (Section 05 - Brakes).

 

 

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Condition

Some customers may comment on a scraping noise from the rear of the vehicle while driving. The noise may be intermittent.

 

Cause

Condition may due to the parking brake shoe contacting the drum in hat rotor without the parking brake being applied, causing premature wear on the shoe lining.

 

Correction

Replace the parking brake shoe and install a new designed spring clip retainer. Follow the service procedure below to correct this condition.

 

Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in the General Information sub-section of the Service Information (SI Document ID #639546).

Remove the tire and the wheel. Refer to Tire and Wheel Removal and Installation in the Tires and Wheels sub-section of the Service Information (SI Document ID #656965).

Relieve the tension on the park brake cables by loosening the nut at the equalizer.

Mark the relationship of the rotor to the hub.

Remove the brake caliper bracket mounting bolts.

Notice: Support the brake caliper with heavy mechanic's wire, or equivalent, whenever it is separated from it's mount and the hydraulic flexible brake hose is still connected. Failure to support the caliper in this manner will cause the flexible brake hose to bear the weight of the caliper, which may cause damage to the brake hose and in turn may cause a brake fluid leak.

 

Remove the brake caliper and brake caliper bracket as an assembly and support with heavy mechanic's wire or equivalent. DO NOT disconnect the hydraulic brake flexible hose from the caliper.

Remove the rotor retaining push nuts from the wheel studs (if applicable).

Notice: DO NOT use a hammer to remove the rotor from the hub; it may cause damage to the rotor.

 

Important: The rotor may not be easily removed from the hub due to a rust build up on the outside edge of the drum and hat portion of the rotor.

 

Remove the rotor from the hub. If the rotor cannot be removed from the hub by pulling on the rotor, use J 46277 rotor removal tool.

Notice: Place J 46277 between the rotor surfaces in the vent section of the rotor. DO NOT place J 46277 on the back side of the rotor surface, it may damage the rotor surface.

 

Using removal tool J 46277 on slide hammer J 6125B, remove the rotor by placing removal tool J 46277 in the vent section of the rotor at the twelve, three, six and nine o'clock positions, not necessarily in that order.

Clean the rust ridge from the drum portion of the rotor using a grinding stone and rotor resurfacing kit J 41013.

Remove the spring clip bolt (3) and retainer (2) and discard.

 

 

 

Important: Minimum thickness of the parking brake shoe lining in any given spot is 1.5 mm (0.06 in).

 

Measure the parking brake shoe thickness in multiple spots. Replace the parking brake shoe if the thickness is less than 1.5 mm (0.06 in). Continue with step 14.

If the parking brake shoe lining is greater than 1.5 mm (0.06 in), continue with step 19.

 

 

 

Rotate the parking brake shoe (1) out from the bottom and pull it out of the adjuster. Discard the shoe.

Remove the park brake shoe assembly from the vehicle by placing one of the open ends of the shoe over the axle flange and rotate the shoe until it has cleared the flange.

 

 

 

Turn the adjustment screw (1) to the fully home position in the notched adjustment nut.

Install the new park brake shoe assembly (1) from the parking brake shoe kit, P/N 88982875, to the vehicle by placing one of the open ends of the shoe over the axle flange and rotating the shoe until it is behind the flange.

Slide the shoe into the adjuster and position the shoe to the backing plate. Install the retaining spring clip (2) and bolt (3 ) from the parking brake shoe kit, P/N 88982875. If using parking brake service kit 88982875, SKIP STEP 19.

Replace the retaining spring clip (2) and bolt (3) from the parking brake retaining spring clip kit, P/N 88982879.

Tighten

Tighten the bolt (3) to 5 N·m (44 lb in).

 

 

 

 

 

Set the J 21177-A so that it contacts the inside diameter of the rotor.

 

 

 

Position the J 21177-A over the shoe and the lining at the widest point.

 

 

 

Important:

 

• The parking brake adjustment screw threads should not exceed 5 mm (0.2 in) of exposed thread.

 

• The clearance between the park brake shoe and the rotor is 0.6604 mm (0.026 in).

 

 

The parking brake adjustment screw threads should not exceed 5 mm (0.2 inch) of exposed thread.

Notice: Whenever the brake rotor has been separated from the wheel bearing flange, clean any rust or foreign material from the mating surface of the rotor and flange with the J 42450 hub cleaning kit. Failure to do this may result in increased lateral runout of the rotor and brake pulsation.

 

Use the J 42450-A to clean all rust and contaminants from the mating surface of the hub flange.

Use the J 41013 to clean all rust and contaminants from the inside diameter of the hat section of the brake rotor to prevent any foreign material from getting between the brake rotor and the hub flange.

Align the mark on the rotor with the mark on the hub and install the rotor by slowly turning the rotor while pushing the rotor towards the axle.

Install the caliper and the bracket as an assembly to the vehicle.

Perform the following procedure before installing the caliper bracket mounting bolts.

• Remove all traces of the original adhesive.

 

• Clean the threads of the bolt with brake parts cleaner, P/N 12346139 (Canadian P/N 10953463), and allow to dry.

 

• Apply threadlocker, GM P/N 12345493 (Canadian P/N 10953488), or Red LOCTITE™ #272, to the threads of the bolt.

 

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

 

Install the caliper bracket mounting bolts.

Tighten

Tighten the brake caliper bracket mounting bolts to 175 N·m (129 lb ft).

 

Repeat this procedure on the other side of the vehicle.

Tighten the nut to the intermediate cable at the equalizer.

Tighten

Tighten the nut to 3.5 N·m (31 lb in).

 

Install the tire and wheel assembly. Refer to Tire and Wheel Removal and Installation in the Tires and Wheels sub-section of the Service Information (SI Document ID #656965).

Lower the vehicle.

Verify that the self adjuster lock-out pin has been removed.

Fully apply and release the park brake pedal three times.

Parts Information

Part Number

Description

 

88982875

Parking Brake Shoe Kit

 

88982879

Parking Brake Retainer Spring Clip Kit