Replace rear brake shoes on a GM full-size truck.
New Back Brakes:

Replacing Rear Brake Shoes On A
1996 GMC Yukon Or Chevy Tahoe/Suburban

May Also Apply To GMC Sierra And Chevy Silverado Full-Size Pickup Trucks

 

In This Article:

Return springs are removed and the brake shoes are removed. The parking brake lever is disconnected from the rear shoe. The old adjuster lever is installed on the new shoe. The new brake shoes are secured with hold-down springs and the return springs are installed.

Related Articles:

Skill Level: 3 (Intermediate) Time Taken: About 4 Hours

By Bruce W. Maki, Editor

Start:

Replacing drum brake shoes is a lot more complicated than replacing disc brake pads. There are a bunch of springs and levers and they all need to move in just the right way. I've seen experienced mechanics get tripped-up by drum brakes they weren't familiar with... so it's understandable if a do-it-yourself mechanic gets a bit confused or frustrated by the complexities of drum brakes.

I recently replaced the rear brakes on my 1996 GMC Yukon. It's been at least 15 years since I've done rear brakes on a GM product, although I got plenty of practice on GM cars and trucks when I received my mechanic's training back in the mid-90's.

After I raised the truck and placed it on jack stands, I removed the wheels. GM truck placed on jack stands, wheels removed.

 

Removing the brake drum.

I pulled the brake drum off.

On some vehicles, (like my Dodge Dakota) the brake drums rarely just pull straight off. Sometimes it may be necessary to back off the brake adjusters to retract the brake shoes, then the drum will come off easily.

On many older vehicles a lip of rusted metal develops on the inner-most edge of the brake drum because the drum is slightly wider than the brake shoes and that little strip of metal never wears down.

 

Stuck Brake Drums?

I've seen two types of stuck brake drum problems: The face of the drum has become rusted onto the axle hub, or the brake shoes won't retract.

Drum Rusted To The Hub: I start by applying a liberal amount of rust penetrant around the wheel studs and center of the hub. Then I try prying between the brake drum and the backing plate. If the drum doesn't move, I hammer on the drum... between the studs and on the back of the drum (pushing it away from the backing plate). If that doesn't work, I would use a torch to heat up the drum between the studs, then pry and hammer again.

Brake Shoes Won't Retract, Typically this is caused by the parking brake being stuck in the applied position. Older vehicles often develop a serious rust problem in the rear cables that activate the parking brake. Even if there is an access hole to reach the adjuster star-wheel, the adjuster won't let the brake shoes retract because the parking brake is keeping them applied. See below for solution...

Brake Shoes Interfere With Drum: This problem here is usually caused by a small ridge of rust or metal at the inboard edge of the drum's wear surface. If the vehicle doesn't have access holes to reach the adjuster "star-wheel", or if the star-wheel won't move, then the drum may need to be forced outward while that ridge scrapes across the brake shoes. This requires a lot of prying with big pry bars (two is better than one) and rotating the drum.

As a last resort, the heads on the brake shoe hold-down pins can be ground off from behind the backing plate. Then the drum-and-shoe unit can be pulled away from the backing plate, and maybe the adjuster can be reached and turned to let the shoes retract. If the parking brake is stuck, it may be possible to disconnect the cable where it attaches to the parking brake lever.

 

Some Tools Of The Trade:

This is a pair of brake pliers.

This tool has 3 separate functions.

Brake spring pliers.

 

End of brake pliers used to remove springs from post.

This end is used to remove springs from where they hook around a post.

You place this end on the post and turn the tool, and that metal tab catches the hook on the spring and lifts it away from the post.

 

This end is used to install a hooked spring on a post.

You place the spring's hook over the rod, then set the end of the tool against the post and lift the tool until the spring slides down the rod onto the post.

End of brake pliers used to install return springs.

 

Brake pliers used for installing and removing springs. The short end of the brake pliers is used to hook and unhook springs, but I hardly ever use this feature.

 

This tool is for removing and installing brake shoe hold-down springs. Brake shoe hold-down spring tool.

 

Removing The Old Brake Shoes:

GM truck rear drum brakes.

The rear brakes before disassembly.

Before removing any parts, I used compressed air to blow the dust off the rear brake area.

USE ADEQUATE VENTILATION! Brake dust may contain asbestos, which is a really dangerous material. Even though asbestos hasn't been used in new brake linings for over a decade, there still may be asbestos linings on some cars.

When I blew the dust off the brakes, I opened the garage door and placed a large fan downwind of the work area, and another fan upwind. This ensured that the dust was expelled from the garage.

 

IMPORTANT!

When replacing rear brake shoes, it's always best to complete one side before starting the other side. This way you can alway look at the other side to see how parts are supposed to be installed.

 

I used the brake pliers to unhook the outermost spring from the top mounting post. Removing brake return springs with brake pliers.

 

Removing brake spring with Vise-Grips. To remove this spring, I clamped it in a pair of bent needle-nose Vise-Grips and pulled it off.

 

I used the brake pliers to unhook this metal rod that connects to the brake adjuster mechanism. Removing adjuster rod with brake pliers.

 

Removing hold-down springs with special tool.

I removed the shoe hold-down springs.

This can be kinda tricky. I had to reach around behind the backing plate and hold the pin with one hand while using the tool to push inwards and turn 90 degrees to release the round metal cup-clip.

 

The hold-down spring and pin. Drum brake shoe hold-down spring, GM truck.

 

Pin for hold-down spring, GM.

Closer view of hold-down pin.

While it's hard to see in this photo, the end has a "T" shape (red arrow) that engages the round clip.

 

Before going any further, I removed the E-clip (red arrow) that holds the parking brake lever to the rear shoe. Retainer clip that connects parking brake lever to brake shoe, GM truck.

 

Once the parking brake lever had been separated from the rear shoe, I was ready to remove the pair of brake shoes.

Removing pair of brake shoes on GMC Yukon. I grabbed each shoe and spread them apart, then I pulled them away from the axle.

 

After removal, the shoes were still connected by the adjuster screw and the lower spring. Old brake shoes after removal, held together by adjuster and spring.

 

Removing adjuster mechanism on GM rear brake shoes.

I twisted the shoes around and slipped the adjuster screw off the "web" of the shoes.

Then the spring just fell off.

 

Be Careful!

Don't lose this little wave spring that goes between the parking brake lever and the rear shoe. The hardware kit I bought did not supply any of these.

Wave spring used between parking brake lever and brake shoe, GM truck with rear drum brakes.

 

Metal bar or strut used for parking brake mechanism, GM truck rear drum brakes. This metal bar (or strut) connects the shoes at the top. Its purpose is to push on the front shoe when the parking brake is applied.

 

The drum brake backing plate after all the parts have been removed. Drum brake backing plate after shoes have been removed.

 

Cleaning contact points on drum brake backing plate, with file.

I used the tip of a file to scrape off the rusty metal at the 6 contact points on the backing plate.

These contact points are just small raised areas in the metal plate.

 

I applied a thin dab of Syl-Glyde brake lubricant to the contact points. I wiped off the excess with a paper towel.

DON'T use too much lube here, or it might drip onto the brake drum and linings, which will seriously reduce the braking ability.

Silicone brake grease applied to contact points on backing plate, GM truck rear drum brakes.

 

Something's Fishy...

These are the brake shoes that were on the truck... Old brake shoes from 1996 GMC Yukon, showing incorrect length of brake lining on primary shoe.

And these are the replacement shoes.

The arrows point to the upper end of the brake lining. Notice that the lining on the original shoe ended at a higher point than the new part.

 

New brake shoes showing how primary shoe has shorter lining.

 

The front (or primary) shoe is supposed to be different than the rear (secondary) shoe.

The primary shoe has a shorter lining, and the lining is thinner than the secondary shoe.

It turns out that the last person who replace the back brakes didn't notice the difference between the shoes.

Comparison of brake linings between primary (front) and secondary (rear) brake shoes, GM.

 

Adjuster Screw:

Brake adjuster mechanism after disassembly.

I took apart the adjuster screw.

Note the thin washer that goes between the star wheel and the short piece.

 

I cleaned up the star wheel and threads on a wire wheel. Cleaning adjuster screw threads on a wire wheel buffer.

 

Cleaning parts on a wire wheel. I also cleaned up the other parts.

 

I applied a thin dab of brake lubricant to the threads and the smooth end of the star wheel. Applying silicone brake grease to rear drum adjuster mechanism.

 

Installing New Brake Parts:

Portion of drum brake hardware kit, GM truck. This is HALF of the brake hardware kit that I bought from my local NAPA store.

 

Swapping The Brake Adjuster Lever:

Rear drum brake adjuster lever before removal from old brake shoe. The brake adjuster lever needs to be removed from the old rear (secondary) brake shoe and installed on the new shoe.

 

The adjuster lever is fastened with this round cup device (red arrow).

This cup is just pressed into a hole in the brake shoe.

Cup-shaped press-fit fastener used to secure adjuster lever to secondary brake shoe, GM truck.

 

Separating adjuster lever from brake shoe, GMC or Chevy truck.

I used a pry bar to separate the adjuster lever from the old shoe.

 

A Problem With The Adjuster Lever:

The "T"-shaped cup (red arrow) thing didn't fit tightly in the holes in the remanufactured brake shoes.

But I solved the problem...

New cup fastener did not fit tightly.

 

Sockets used to modify cup fastener for adjuster lever, NAPA aftermarket parts. I used a 1/2" drive, 1/2" socket and a 1/4" drive 5mm socket to flare the small end of the T-fitting .

 

This is how I arranged the sockets. Then I clamped the ends of the socket in a bench vise and tightend the vise until there was no more slop. Socket arrangement used to flare the metal cup and make it tighter.

 

Small socket used to widen T-shaped fastener for adjuster lever.

Closer view of the small socket:

I picked a socket that had a tapered end that just fit inside the small end of the T-fitting.

 

Closer view of the large socket:

I picked a socket that fit snugly inside the cup part of the T-fitting.

Larger socket used as backer for special fix, General Motors rear drum brakes.

 

 

Installing The New Brake Shoes:

Lower spring attached to bottom of new brake shoes, GM. I installed the lower spring between the primary and secondary brake shoes.

 

Note the position of the lower spring...

The spring goes behind the rear (secondary) shoe, and in front of the front (primary) shoe.

Close-up of lower spring.

 

Brake adjuster installed between lower ends of brake shoes, GMC and Chevy full-sized truck. Then I installed the adjuster screw.

 

Before any further assembly, I applied a thin layer of brake lube to the pivot point on the parking brake lever, and I set the wave spring in place. Brake grease applied to parking brake lever pivot point.

 

Checking for brake fluid leak at rear wheel cylinder by pulling rubber boot back.

I also pulled the rods out of the wheel cylinder and looked inside the rubber boot to check for brake fluid leaks.

The area inside the boots should be damp with fluid, but there should not be any pooling of liquid. If I had discovered any liquid, the wheel cylinder would need to be replaced, because that would indicate a worn out seal on the piston inside the wheel cylinder.

Checking for leaks here is important! Even a small leak now would mean that brake fluid will eventually leak onto the brake linings or drum, which will severly reduce the braking ability.

 

I set the brake shoes in place. I just spread the tops apart and wrapped them around the axle hub. Installing new brake shoes, GMC Yukon, Tahoe, Suburban, Silverado, Sierra trucks.

 

Rear drum brake shoe installation tips.

Then I made sure the parking brake lever post was inserted in the hole in the rear shoe. I re-installed the original E-clip (1) because the clips supplied with the hardware kit broke when I tried to install them.

Note that the wheel cylinder push-rods (2) have been placed properly in their slots in the brake shoe web. I also set the parking brake cross-member in place (3). The spring goes toward the front, and the fork in the rear end of the bar needs to go over both the parking brake lever and the rear shoe.

At this stage, these various parts want to fall out of place, so it's important to make sure they remain installed correctly before fastening the shoes down.

 

I installed the rear hold-down spring over a new pin (which gets pushed through the rear of the backing plate.

I did the rear shoe first, because it includes the extra hassle of the parking brake lever. Then I installed the hold-down pin and spring on the front shoe.

Installing brake shoe hold-down springs and cups.

 

Brake shoe hold-down spring/cup/pin device, General Motors truck.

This procedure can be a real b-i-t-c-h.

I inserted the pin with the flat end oriented vertically, then I tried to orient the slot in the cap vertically and watch through the hole in the tool until I managed to get the pin through the slot.

Then I just turned the tool a quarter-turn and let go.

If this procedure takes you 10 or 15 minutes for each spring, don't get frustrated... this really is a tricky job for anybody who isn't highly experienced. Remember that the shoes can be slid around a fraction of an inch in any direction to align the hole in the shoe with the corresponding hole in the backing plate. When the pin is straight it's a lot easier to install the spring and cap.

 

Using the brake pliers, I installed the metal rod that connects the adjuster lever to the post at the top. Using brake pliers to install metal rod over post.

 

Installing new brake shoe return spring, GM.

Then I installed this spring that connects the adjuster lever to the post.

I used a pair of bent needle-nose Vise-Grips to just pull the spring hook over the hook in the end of that rod mentioned above. This took a bit of strength.

 

The last part I installed was the front return spring. I used the brake pliers to slip the spring over the post. Using brake pliers to install return spring.

 

Drum brake return springs, GM truck. Return spring after being installed.

 

Photos Of Completed Drum Brake Job:

I made these photos extra large to make it easier to see the details.

Overall view of rear drum brakes on 1996 GMC Yukon.

Rear drum brake assembly, 1996 GMC Yukon, Tahoe, Suburban, Silverado, Sierra trucks.

 

GM truck rear drum brake assembly after replacement.

The secondary shoe and the rear area of the drum brakes.

 

The front area, with the primary shoe, which is shorter than the rear shoe.

Primary brake shoe on GM truck rear drum brakes.

 

GM truck rear brake assembly showing adjuster star-wheel.

Bottom area showing star-wheel adjuster screw and adjuster lever.

When assembled, the bottom of the lever needs to be very close to the star wheel, or just above it. If the lever is too far outward it won't function and the brakes won't self-adjust, which means that eventually the rear brakes won't be doing anything.

 

Final Adjustments:

Before the truck is ready to drive, the brake adjuster needs to be turned so there is the proper amount of clearance between the brake linings and the drum.

If the clearance is too much, the brakes will never be able to self-adjust when stopping while backing up.

If the clearance is too little, the back brakes will grab too hard and the drum will overheat and warp, which you will feel as a pulsating brake pedal when the brakes are applied. I made this mistake once with another truck, and I had to buy new brake drums.

Drum Problems:

The drum on the other side of the truck (done earlier) had a lip of rusted metal around the inboard edge. There was no way I could check the brake tightness with this lip, because the inside diameter was smaller than the main part of the drum surface.

I used an angle grinder to carefully grind away the lip, checking the surface with a steel ruler to make sure the raised ridge was gone. I was extra careful not to grind away too much metal.

To get the proper initial setting of the adjuster screw, I expanded the screw a couple of turns and tried slipping the drum over the brake shoes. I repeated this process until the drum would just barely turn by hand.

Then I removed the drum and turned back the adjuster one-half turn.

Note On Adjusting: When the adjuster is expanded (normal adjuster action) the outer part of the star wheel is pushed down. When retracted, the outer part is moved upward.

 

Just For Kicks:

After setting the adjuster screw, I marked it with a paint marker.

After I back up and stop a dozen times, I will check the brakes to make sure that the adjusters have moved, which will tell me that the self-adjuster mechanism is functioning properly.

Marking adjuster star-wheel to check for movement.

 

Applying brake grease to axle hub to prevent brake drums from rusting and seizing to hub.

Before installing the brake drums, I smeared a very thin layer of brake lube on the face of the axle hub. This will ensure that the drums are easy to remove next time.

Why do I do this? I have seen lots of older vehicles that had brake drums that were rusted onto the hub, and removing the drums was very difficult. Removed frozen brake drums often requires heating the center part with a torch and beating it with a hammer. It's a real pain in the @$$.

Next I installed the brake drums and replaced the wheels.

 

Brake Drums -
Replace, Turn, Or Just Re-Use?

My experience with my own vehicles is that rear brake drums don't seem to need resurfacing nearly as often as front brake rotors. It's commonly said that rear brakes only do 30% of the total braking effort on a rear-wheel drive vehicle, and 15% on a front-drive vehicle.

I've done at least a dozen rear brake jobs, and I can only recall one case where I needed to replace the brake drums, and that was because the drums were warped from overheating. (The overheating was caused by having the adjusters too tight after replacing brake shoes.)

There have been a few times when I've had the brake drums turned on a brake lathe to smooth out the surface. This service usually costs about $10 to $15 per drum.

But mostly I've been able to re-use the drums without turning them, but only after I have checked the surface with a steel ruler to make sure the inner surface is uniform and flat from front-to-back. The drawback of turning the brake drums is that it removes some metal, which makes the drum thinner and more prone to warping. The drums can only be turned a couple of times before the diameter is too big, and then they need to be replaced. I prefer to inspect the rear brakes occasionally, and replace the brake shoes before the linings have worn down to a point where the metal backing or the rivets are grinding into the drums.

For best results, get the brake drums turned, or replace them.

 

Warning:

After replacing brake shoes, the linings may not be close enough to the drum to actually grab. The result is a very low brake pedal the first time you hit the brakes... and possibly no ability to stop. I've heard of mechanics that backed a car out of the garage and promptly crashed into a parked car.

Before moving the vehicle, you MUST pump the brake pedal until it feels firm and normal. If the brake pedal won't become firm, then there could be other problems, such as parts intalled improperly or a brake fluid leak.

 

Another Warning:

In my mechanic's training the instructors stressed the importance of braking gently until the new linings have been "broken in". The instruction we got was to make about 30 stops from moderate speeds (30 to 35 miles per hour) with only light-to-moderate pressure applied to the brake pedal. After that, you can slam on the brakes to impress your friends with your mechanic's skill.

Apparently, hitting the brakes too hard before the linings have broken-in can cause overheating and damage to the linings.

Read our Disclaimer about brake repairs

More Info:

Tools Used:

  • Basic Mechanic's Tools
  • Brake Pliers
  • Brake Spring Tool
  • Vise Grip Pliers
  • Prybars
  • File
  • Wire Wheel On Bench Grinder
  • Jack Stands
  • Floor Jack

Materials Used:

  • Remanufactured Brake Shoes, NAPA Part TS-473
  • Rear Brake Hardware Kit,
  • Automotive Brake Parts Cleaner
  • Syl-Glyde® Brake Lubricant

Related Articles:

References:

  • Automotive Braking Systems, by Thomas W. Birch, published by Harcourt Brace Jovanovich, 1988

 

 
 
 
 
 
 
 
 
 
 
 
 
 

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© Copyright 2009 Maki Media Group LLC

Written May 5, 2009