Hi. Don't know if anyone can help me, as the braking system on my Blazer is driving me crazy. Basically when i bought the car it needed serious work on the rear brakes and I replaced rotors, calipers, pads, parking brake shoes and both parking brake cables. Big bucks (parts for this car are expensive in the UK). Ever since I had the work done I've never been happy with the operation of the parking brake. Basically, unless I really loosen the parking brake adjuster until the cables are flopping around at the side of the car, the parking brake will not release properly and the brakes will bind.

Even with the parking brake adjuster backed right off if I release the brake and reverse off the drive the car will move okay, but as soon as I roll the car forward it will travel about three yards then there will be a thump from the back brakes as the parking brakes catch and the car will slow. When I accelerate away it will take about 100 yards before the parking brake shoes have 'centered' themselves and will stop rubbing on the drum. This is usually accompanied by much brake squeal. Also, if i gradually apply the handbrake while the car is moving, the parking brake will apply with a "thud", as if they suddenly grab the drum, rather than with a smooth, gradual motion.

I've never come across a parking brake system like this. I find it difficult to believe those weird, horseshoe-shaped shoes will flex enough without a hinge in the centre, but obviously they must. However, they seem to move about on the backplate and catch, as they are only held down by a small flexible retainer at the top and I can move them around on the backplate quite easily.

Does this sound familiar to anyone, or does the Blazer just have a rubbish parking brake system? Am i missing a part, maybe? Any advice would be much appreciated.

Many thanks. Lee

 

Lee, im not sure what year you have but ive actually seen rear brake shoes put on backwards and cause that issue, long shoe at the front short in the rear vice versa, not positive this is your problem but worth a look.

 

Hi. Thanks for your reply. It's a 2000 Blazer 4WD LT (UK spec with right-hand drive). I didn't realise that the brake shoes were different lengths, although I can remember that the old shoes were stamped on one side with "this side out" or something similar. I didn't fit the new shoes, so I'll have a look tonight to see if they are on the right way round. If that isn't the problem do you think shaving some of the friction material off the leading and training edges of each shoe would help..? Cheers. Lee.

I've done a bit of research online and it sounds like part of the problem may be that the new shoes haven't been adjusted properly when they were put on (mechanics in the UK don't generally understand Blazers). I suppose that if there is quite a gap between the shoes and the drum then when the cable is pulled the shoe will move on its mountings and only part of it will touch the drum, causing it to ******. Well it sounds plausible to me, but I'm no mechanic, so I'm going to check it out tonight...

Lee

 

For what it is worth some vehicles have different length shoes (primary & secondary) and some do not. I do not know if reversing them will cause your problem but it will cause one of the shoes to wear out very early.

Here is how to tell which shoe goes where if they are different lengths. Assuming the wheel cylinder is at the top as most are if you put your finget at the top and rotate your finger in the direction the brake drum would turn if the vehicle is moving foreward the first shoe your finger would come to it the primary shoe. The primary shoe is always the shortest shoe. The reason it the wheel cyl. pushes this shoe in the direction of rotation while the rotation of the drum at the bottom of this shoe tries to push the shoe away from the drum. But the other shoe is pushed to the drum at the top and the bottom of the secondary shoe is pulled toward the drum creating more friction (braking force) This causes the secondary shoe to do more braking than the primary shoe so this is why the secondary shoe has more lining. The secondary shoe is called self energising.

Old Chrysler products had 2 single piston wheel cylinders. This allowe3d both shoes to be self energising and gave better braking performance.

To adjust your shoes just rotate the adjuster until you can barely get the drum to go on. Then apply the brake to center the shoes. Remove the drum and if rotate the adjuster to move the shoes out as far as you can and still get the drum on. If you did not do so take the adjuster apart & clean the threads with a tooth brush. Put a thin coat of brake grease on the threads & screw it together. Put a dab of the grease under the cap on the end of the adjuster.

 

This might help......

With Rear Disc Brakes

1. Raise and support the rear of the vehicle safely using jackstands.
2. Remove the rear tire and wheel assembly.
3. Remove the caliper and rotor.
4. Disconnect the parking brake cable from the parking brake lever.
5. Adjust the shoe diameter using the adjuster nut. Turn the nut clockwise to increase the diameter until the rear wheel will not rotate forward without using excessive force. For location of the nut as refer to the accompanying illustration.
   
6. Location of the rear parking brake assembly adjustment nut
   
   
7. Attach the parking brake cable to the lever.
8. Install the caliper and the rotor.
9. Install the wheel and tire assembly.
10. Adjust the rear parking brake cables as outlined earlier in this section.
11. Lower the vehicle and check for proper operation.

 

Many thanks for your help, people. I've not had chance to look at the brakes yet, but hopefully should find time this evening. Cheers. Lee