rear brake squeak

[mohammad]

I had drums and shoes replaced last month, ive put about 500km on the new rear brakes. when creeping/driving at very low speeds like under 10kmph the rear brakes now make a squeaking sound. they also sometimes do it at moderate city speeds but less consistently.

The mechanic "dissassembled" and "inspected" the brakes and said their was no issue. The mechanic says its a 50/50 chance that buying OEM shoes could fix the squeaking. Its gotten alot better after the first few hundred km but it still sounds very annoying when doing low speed things like mcdonald's drive throughs or parking.

My questions are as follows:
1. did trying to save a few dollars on shoes screw me?
2. do other people have similar issues with their rear brakes?

[foama]

It could be, the drums are a bit worn and therefore a bit larger in diameter. The new linings would then press on the drums tighter in their mid section and initially cause squeaking. That should go away by itself (wearing in) soon.

It could be, the outer edges of the linings were not lightly sanded off during installation. The 90° angle at the edges should be lightly "broken" aka rounded. That sort of squeak should also go away by itself soon.

It could also be, the little raised portions of the backing plate, where they touch the metal of the linings did not receive a light coating of grease or copper paste. That alone does not cause brakes to squeak, but can worsen the above "problems".

I assume braking is perfectly in order. If it were mine, I would probably have a good look at the insides and check for obvious problems. I do think you have a good chance of the squeaking to go away by itself.

[Mark]

I had drums and shoes replaced last month, ive put about 500km on the new rear brakes. when creeping/driving at very low speeds like under 10kmph the rear brakes now make a squeaking sound. they also sometimes do it at moderate city speeds but less consistently.

The mechanic "dissassembled" and "inspected" the brakes and said their was no issue. The mechanic says its a 50/50 chance that buying OEM shoes could fix the squeaking. Its gotten alot better after the first few hundred km but it still sounds very annoying when doing low speed things like mcdonald's drive throughs or parking.

My questions are as follows:
1. did trying to save a few dollars on shoes screw me?
2. do other people have similar issues with their rear brakes?

Have you tried adjusting the parking brake lever to see if that makes a difference?

[foama]

Assume you have checked the rear brakes are not dragging?

[mohammad]

Foama:
I forgot to mention, I also had both drums and all hardware replaced, all parts aftermarket.

How long do you think I should wait before loosing hope?. It was originally horrible at any speed 40kmph or less it would squeak all the time. But now after 400+km it only squeaks mostly around 10kmph or less sometimes at higher city speeds. Ive never seen advice about sanding down the lining before.

I have not checked if the rear brakes are dragging or not, the mechanic told me they are designed to drag as it reduces the pedal travel when applying the brakes. The squeak occurs even when not braking so i imagine the shoes must be dragging.

Mark:
The mechanic told me that he already backed off the parking brake, i beleive him because the cover for the parking brake adjustment was open when I picked up the car and because the first set of shoes he tried to install didnt fit so he probably must have tried playing with the parking brake adjustment at some point.

New question: I understand there is that little spring at the bottom that holds the shoes together and maybe stops them from sliding upward. What stops the shoes from sliding downward and rubbing against the drum?

[foama]

You said the brakes squeak when not braking. The mechanic backed off the handbrake cable some undefined time after squeaking started. That tells us they were and are still dragging to some extent. If they have been dragging for a few 100 km the linings may probably be glazed by now. Glazed linings and still squeaking? Something is definitely wrong.

I would have taken the drums off and had a good look at everything. There must be something visibly wrong, and it is most likely noticeable by looking properly. In principle there is nothing wrong about using aftermarket parts. If the handbrake cable was too tight after the repair, the brakes will drag. Also the automatic adjustment can not work, because the linings need to receed a bit after braking for the adjuster to work. If it was so tight that the brakes were initially dragging, they would be glazed by now.
If your mechanic is stumped and hasn't understood what is wrong by now, consider taking it to some other place for a good checking.

[Fummins]

At this point are you positive it's even the rear brakes making noise? I often have people tell me they hear a noise from the rear then I find the opposite corner of the car actually making the noise. Did you install drums with the wheel bearings already installed?

I have had to back off the parking brake adjuster nut(rear of the center console) in order to get the drum on after installing new rear brakes. That was a lot easier than trying to sand down the shoes. I've had a few with sticky cables too, the platic coating wore off the cable where it bends before entering the backing plate.

[mohammad]

You said the brakes squeak when not braking. The mechanic backed off the handbrake cable some undefined time after squeaking started. That tells us they were and are still dragging to some extent. If they have been dragging for a few 100 km the linings may probably be glazed by now. Glazed linings and still squeaking? Something is definitely wrong.

I would have taken the drums off and had a good look at everything. There must be something visibly wrong, and it is most likely noticeable by looking properly. In principle there is nothing wrong about using aftermarket parts. If the handbrake cable was too tight after the repair, the brakes will drag. Also the automatic adjustment can not work, because the linings need to receed a bit after braking for the adjuster to work. If it was so tight that the brakes were initially dragging, they would be glazed by now.
If your mechanic is stumped and hasn't understood what is wrong by now, consider taking it to some other place for a good checking.

Im probably just not explaining the thing well, New drum including bearing and shoes and hardware all went in on the same day, on that day the mechanic also backed off the parking brake, failed to install a set of shoes, then successfully installed a different set of shoes. squeaking started the second i drove off the mechanics lot. Ive accepted that this is not a problem that will be fixed over the internet.

Foama, can you please answer my other question: I understand there is that little spring at the bottom that holds the shoes together and maybe stops them from sliding upward. What stops the shoes from sliding downward and rubbing against the drum?

[foama]

Quote: What stops the shoes from sliding downward and rubbing against the drum?


The correctly installed shoes have the said spring on the bottom, pushing them together to hold them firmly in place. On the upper area there is a horizonal bar that is lengthened by the adjuster. The length of that bar including the adjuster with its adjustable length create the resting position of the shoes. Also numerous springs that all have a certain purpose and must be correctly installed. No room for any error! All that firmly pushes the shoes together in resting. The correct distance of the shoes from the drum while in resting is important, and that is where the adjuster comes in.
When the handbrake is applied, the lever pivots on the horizontal bar effectively lengthening the bar and thus pushing both shoes outward onto the inside of the drum. The handbrake is applied.
When the brakes are applied by pedal, both pistons of the cylinder push the shoes outward onto the inside of the drum.
In both cases, if the shoes were a bit off center, that is if they were a bit too high or too low, the braking pressure pushing them onto the drum would center them. Once centered, they stay centered practically for ever. The springs in total are rather strong, and keeps shoes from sliding up or down as the car moves or parks.

If you look at some of the threads in this forum, you can see photos of the rear brakes. There are two different drum diameters, 180mm and 203mm. The 203mm are for later models and far superior because they last almost twice as long. There are also two different sort adjusters possible, you have either the one or the other. One sort is a conventional star wheel adjuster, the other is with two small roundish levers with a bit inbetween, reminiscent of Lockheed type adjusters. Both sorts of adjusters serve the same purpose of effectively lenghthening the horizontal bar to ensure the linings have the correct play, being the distance from the drums. If they were too far away, the pedal and lever would have to travel too much. If they were too close, the brakes would drag, creating high fuel consumption and swiftly ruining the linings by glazing them. Linings grossly overheated will become glazed, that means they will become smooth like glass and be permanently ruined. If the linings (shoes) were too far away from the drums in their resting position, the adjuster would take up the resting position a little each time the brakes were applied, and they would from then on rest a bit closer to the drum.
If you take a good look at and examine your brakes, you will eventually exclaim "AHA!" and understand the function of all those parts. Its not rocket science, but has to be assembled absolutely correctly to work properly. Maybe the adjuster or one of the numerous springs is not in the correct place? That would lead to glazed linings, dragging and the resulting problems,

[Wallythacker]

brakes need to be broken in. try this before losing all hope

Start driving, and speed up to 60 mph
Brake quickly to slow down to 20 mph
Immediately speed back up to 60 mph
Repeat step one 8-10 times
Cruise at a high speed without braking for 5-10 minutes

if no better try this approach

Perform 30 stops from 30 miles per hour with a 30-second cooling interval between stops. These stops will be performed at a decelerating rate of 12 feet per second or less. This means that it should be a gentle easy stop.

• The 30/30/30 Burnish Procedure beds the pads and shoes into the rotor and drums. It also deposits the necessary friction transfer to the rotors and drums for optimum brake performance.