Hello All -

I was hearing a metal-on-metal sound from rear of car when braking over the past couple of weeks from my 1996 Accord which I bought from a used lot here in Houston, so I decided to tackle brake job on both axles, and this is what I found when I did the rear first, see pics. The 1st is the driver's side, rear-facing shoe, and the 2nd is the driver's side, front-facing shoe. (I haven't done the front yet, but have decent kit, and have no bad or strange sounds from the front axle, and will be doing it w/in a week).

I replaced the rear wheel cylinders, drums, and shoes, and with enough worrying about the previous "problem", I know that its better than it was, but I'm wondering what would cause such uneven wear on brake shoes which are supposed to be "self-adjusting", from the center-point, out.

Why would there be uneven wear like this? Can it be blamed on a previous ****-poor brake job? Or, is there possibly an inherent fault in the design of this particular brake system that I should be concerned about?

Has anyone seen this before? Is there any way to attempt to prevent it in the future? It certainly explains the grinding sound!

Thank you for any replies.

 

I am not very familiar with doing drum brakes, but you definitely have uneven wear.

Which side of the shoe is worn down? the side towards the top of the car, cylinder, or the side towards the bottom?

 

Seems like the brakes were dragging.
Check all the hardware that holds the shoes in place. They can get fouled up with caked-on brake dust. The brake shoes need to "float" so they can release from the drum. Check that they can slide around on the brake backing-plate without sticking.

Check that the handbrake cable moves freely. Corroded cable won't let the brake release all the way? Same with that lever for the handbrake cable.

You replaced both wheel cylinders? Was the old one free to move nicely? Maybe one of the 2 pistons was sticking in the cylinder?

 

Hard to call. Can't see in the second pic where the adjuster fits. That would tell of it was the "top" or bottom of the shoe (in the first pic I can tell that the "left side" is the top because of the cut out for the adjuster). I will assume the worn out part in the 2nd pic was/is the top and go with Jim's comment "Maybe one of the 2 pistons was sticking in the cylinder". In the future, get the spring hardware kit and replace them when replacing the shoes...if you're on a budget, you might be able to go "every other" shoe replacement with new hardware.

 

Thank you for all your replies. The front-facing shoe was worn on the bottom, and the rear-facing shoe was worn on the top. After reading comments, I did remember that the front facing cylinder piston did NOT move freely, and was REALLY gunked up.

Please correct me if I'm wrong, but I'm thinking that if the front piston was sticking and not responding evenly with the rear piston, then when brakes were applied, the top of rear shoe would move out against inner drum, and due to the floating fulcrum design, the front shoe would then be forced out against the inner drum because the top of it would be "stuck in"? Also, it looks like the front shoe had slid down, or "dropped", due to the ability of the retaining clips to allow assembly to move as needed. Why the clips allow that, instead of only a linear, evenly outward movement of the shoes, parallel to the inner drum, you know?, is beyond me. I'm sure that's possible in design.

And when I find the time, I'm gonna remove both rear wheels again, and have someone depress brake and emergency brake while I watch to see how they are aligned for even operation before I go on my merry way, which I should have done when job was complete. (Next time!).

Lastly, like all comments I've read regarding frustrating, or difficult brake jobs, I must agree: The 2nd wheel goes A LOT more smoothly than the 1st, which is something to look forward to....only 1 wheel is an actual pain.

 

Be careful trying to press the brake pedal without drums installed. The pedal will go all the way down to the floor & you might blow a piston completely out of the cylinder. That'll make a horrible mess.

Gunky cylinders are a bit like sticking caliper slide pins. When you apply the brakes there's plenty of force. It's whan you release the brakes that they stick & leave the brakes dragging.

When you release the brakes & the front piston sticks out, the drag of the spinning drum pushes that shoe downwards, rather than retracting inwards away from the drum.

 

Tip for the next time you change the shoes, if you don't already know this. They can come off almost "fully" assembled. If you compress the wheel cyl all the way, un-do the lower spring (holding the two shoes to each other), spread the bottom of the shoes to get them around the lower pivot, then the hold down pins, then pull the top of both shoes (getting them off the wheel cyl)...now you have the shoes pretty much off....remove the e-brake cable by kind of tiilting the shoes down (top down) and you've got them on the gorund. Much easier to play with that top spring, adjuster and e-brake lever when they are off and siting on the ground. Not sure if you follow me on this, I'll try to take pic's for the future next time I have to do this. Just my two cents.

EDIT: And next time you do, please replace the springs (as I already stated). It is just as important to replace the springs as it is the "hardware" on the front pads.

 

Thank you, JimBlake: I was only talking about depressing brake pedal or e-brake with full assembly intact, only wheel/tires removed. Your analysis of the "drag of the spinning drum" sounds spot-on, thank you for your insight.

poorman212: I did read about changing drum spring hardware, and did knowingly put it off, even with doubts about my decision while wrestling with the main spring. I definitely plan to replace the rear brake spring-n-clip hardware on the next shoe replacement, maybe even sooner in hindsight. And I really appreciate the advice about removing the entire shoe/spring assy from the bottom, instead of from the top. That's the kind of "work-around" which can save a lot of stress and headaches. As related, I was trying something similar with re-assembly, but had a real tough time with that lower spring, seeing as it's so tight, even by the upper spring's standards!, but I can see what you're describing, and it's an especially useful idea (because you're NOT talking about removing the lower spring as it sits, which would be almost impossible to do without seriously damaging it.)

After bleeding rear brakes, all seems well, doing fine, no noises or sounds, and its off to do the front pads next! Thanks again for all the timely, and experienced replies. Thank You, HAF.........It's good to know when you're "in the right place".