What would cause rear brake shoes to overtighten?

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I have this ongoing extremely annoying problem with my rear shoes. After numerous trips to one of my mechs, he is stumped and said he cant help me out anymore but he says my shoes are overtightening over time for some reason. And when it overtightens, it causes extra drag and this super annoying sqeaking sound when braking and eventually (if i let it go and get worse), will do it when NOT braking.

Ok I will have new set of high quality shoes, new drums, new wheel cylinders, new spring kit, the high points of the backing plate where it rubs against the shoes, lubed with polymer grease. And over time, the shoes over tighten automatically. This can be anywhere from 3 weeks to 2 or 3 months.

Last time i had this all replaced was last fall and i mean everything on the back end was replaced, even the left auto adjuster cause they thought it was the auto adjustor.

Now all my mechs have tried diagnosing this but none can figure it out after numerous trips. But theres some obvious key points that weve noticed and almost certain are huge factors in whats causing this.

1) This problem is on and off. Dragging noise can be gone for 2 months but all of a sudden come back the next day and last the next 3 months and progressively get worse in noise.

2) Theyve all spun the back wheels with the rear jacked up. Even before or after the brake jobs, both wheels have a small high point that can be felt when spinning. Its just a small high point but during this high point, you can feel the wheel dragging noticably more than during the rest of the wheel spin. Exactly when the wheel is spun and goes through this high point is where the drag and noise occurs. Everytime.

3) Whenever you replace the shoes or readjust them, the noise is gone but will eventually come back.

When i had the shoes and everything replaced last fall, they would basically set the adjuster to the point where it has very very litte drag when spinning. Weve even tried backing the shoes all the way to its loosest setting and just have it auto adjust on its own over time. Still it overtightens over time causing the drag. And I prefer not to have the shoes backed all the way off cause then the stopping power on the rear is very minimul and not very effective.

Everytime i had them adjusted i would back up going about 20km/h and hit the brakes firmly about 4 or 5 times.

We cannot, for the love of god, figure out why there is a high point in both wheels cause obviously there shouldnt be. Replaced literally everything on the back end even including ebrake cables and nothing can get rid of the high point.

Cause im almost certain, get rid of the high points and extra drag and noise is gone.
 
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Probably not the brakes causing the high point since you've replaced everything. Axles or bearings maybe?

These are drum brakes, right? The auto adjusters in these systems tighten the brakes when they are applied in reverse. So if this vehicle has been backed up and stopped suddenly, then the adjusters are adjusting and an over adjustment might be possible in extreme cases.
 
Originally Posted By: Kuato
Probably not the brakes causing the high point since you've replaced everything. Axles or bearings maybe?

These are drum brakes, right? The auto adjusters in these systems tighten the brakes when they are applied in reverse. So if this vehicle has been backed up and stopped suddenly, then the adjusters are adjusting and an over adjustment might be possible in extreme cases.


Axles? Like you mean bushings? Checked all the bushings and they looked good. Mech even took the rear knuckle bushing out cause he was almost certain thats what it was but found out the bushing was still good and threw some anti seize grease around the bolt that goes inside the bushing cause he said it was dry. Noise was instantly gone for 2 weeks then came back.

Yes theyre drum brakes. Never again am i ever buying a car with drum brakes, ever. Worst nightmare ever.

From what i was told, auto adjustors shouldnt over tighten. They stop when it gets to the point where its at its maxed allowed setting where theres no extra drag. This was the first thing the mechs thought it was, but replaced them and didnt do jack squat.

As for the backing up techique to have the shoes fully adjusted. ive tried doing it going fast in R and hit the brakes firmly a few times. And ive also tried going slow and just hitting the brakes softly. But generally i was told it shouldnt matter if you do it soft or hard, shoes auto adjust everytime you go in R and hit the brakes.

And it has to be the brakes, cause otherwise why would the noise go away whenever i have the shoes adjusted or shoes changed out again but eventually comes back?
 
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Originally Posted By: FusilliJerry82
You could remove the adjuster bar and just have them adjusted periodically yourself.


I dont think my car has adjuster bar, the adjustments are done with a starwheel tool and it has this small knob on the auto adjuster that you just turn to adjust the shoes.

Yes this works but honestly its such a pain in the [censored] like you wouldnt believe. Having to readjust them every month or whatever is total [censored]. Cause itll just start dragging again and again!

I still think its the high point when the wheel is spun thats causing it. I just cant figure out how to get rid of it.

Ok get this, when ive had my shoes readjusted, the high point is still there when spinning the wheel! This is literally 2mins after adjusting the shoes!

I need to get this of this high point in the back wheels cause my front ones when i spin the wheels, slow or fast, it spins freely and no drag.

Back wheels, itll spin freely for 90% for 90% of each wheel spin then it hits the high point where it drags.
 
Originally Posted By: Trav
Many times there are two different shoes, the short shoe is the front or forward shoe. Did they check this?


Yes i did but with my car, apparently both shoes on each wheel are the exact same size (a civic thing i guess). Even the OEM ones. I have Napas top end shoes on right now and theyre literally the same size. Checked them before having them put on last fall. Even tried a couple other brands to see and again all same size.
 
Originally Posted By: Carnoobie
Yes theyre drum brakes. Never again am i ever buying a car with drum brakes, ever. Worst nightmare ever.

Drums are really, really reliable. They're much better suited to a North-eastern climate than discs.

Originally Posted By: Carnoobie
From what i was told, auto adjustors shouldnt over tighten. They stop when it gets to the point where its at its maxed allowed setting where theres no extra drag. This was the first thing the mechs thought it was, but replaced them and didnt do jack squat.

There's something really wrong here. Maybe your aftermarket parts?

The adjuster generally consists of a lever and a star wheel. The lever rides against the side of the star wheel and rises and falls as you step on the brake pedal or when you pull up on the parking brake lever. As the shoes wear, the lever climbs higher and higher on the star wheel until it finally grabs one of the star-wheel teeth and rotates the wheel as the lever falls again. After that, it cannot turn the wheel any more until it rises enough to catch the next tooth.

Unless something's really messed up, it's impossible for the adjuster to over-adjust the brakes.

Originally Posted By: Carnoobie
As for the backing up techique to have the shoes fully adjusted. ive tried doing it going fast in R and hit the brakes firmly a few times. And ive also tried going slow and just hitting the brakes softly. But generally i was told it shouldnt matter if you do it soft or hard, shoes auto adjust everytime you go in R and hit the brakes.


What kind of car is this? The last car I encountered with brakes that adjusted in reverse was a 1970 Ford. All newer cars I've encountered (with automatically-adjusted brakes) have drums which adjust as you drive normally, or when you use the parking brake.

How are the front brakes? Are they sticking-on too? Has the brake master cylinder been replaced recently?
 
I think the brake adjusters have a left and right side. Maybe they are on the wrong side and are adjusting out on forward braking. Also as someone else mentioned, you can put in manual adjusters and tweak them occasionally.
 
If anything the auto adjusters get too loose over time and don't work right
smile.gif
Almost all wheels/drums seem to have some slight high and low spots, its typically not an issue.

Sorry if I missed what car this was?

Thinking out loud, wondering:
1 - Some master cylinders have a residual check valve to keep a slight amount of pressure on the system after the brake pedal has been released. These check valves keep about 5-10 psi pressure on the wheel cylinders cup seals. They also resist a large volume of brake fluid returning to the master cylinder. Could be an issue with the check valve at the MC - if the valve is not working right, it is not releasing enough pressure, causing the rear wheel cylinder (not the adjuster) to apply more and more pressure to the shoes.

2 - There is a 3-way distribution block probably on the rear axle. Brake line comes from MC and then each line heads out to each rear wheel. I had a very difficult wheel bleed issue years ago that I could not figure out. Turns out that the block itself had partial internal blockage, replaced it and all was good. Thats an easy one to check but of course you would need to re-bleed the rears to do so since you would have to look inside of it.
 
Originally Posted By: Tegger

There's something really wrong here. Maybe your aftermarket parts?


Ive tried two different high end aftermarket parts and both same thing. Before putting on the current shoes i have on now, i was about to try OEM and pay the extra but didnt. Decided to try a better quality napa brand.

Quote:
The adjuster generally consists of a lever and a star wheel. The lever rides against the side of the star wheel and rises and falls as you step on the brake pedal or when you pull up on the parking brake lever. As the shoes wear, the lever climbs higher and higher on the star wheel until it finally grabs one of the star-wheel teeth and rotates the wheel as the lever falls again. After that, it cannot turn the wheel any more until it rises enough to catch the next tooth.

Unless something's really messed up, it's impossible for the adjuster to over-adjust the brakes.


So its not possible for any auto adjuster to overtighten the shoes? I just dont understand how i could back the auto adjuster all the way to its loosest setting, spin the wheel by hand, and still feel high point in the spin. This high point has to be whats causing the drag and noise cause ive felt it and heard it first hand before.

Quote:

What kind of car is this? The last car I encountered with brakes that adjusted in reverse was a 1970 Ford. All newer cars I've encountered (with automatically-adjusted brakes) have drums which adjust as you drive normally, or when you use the parking brake.


Honda civic, total POS. From my research these shoes adjust when going in R and whenever using the handbrake.

Quote:
How are the front brakes? Are they sticking-on too? Has the brake master cylinder been replaced recently?


Front brakes and fine. I spin them by hand and theres no drag or high points whatsoever. Master Cylinder hasnt been replaced but i was told it wouldnt be that. I dont know how one would go about testing if it was.

[/quote]
 
Originally Posted By: pcoxe
I think the brake adjusters have a left and right side. Maybe they are on the wrong side and are adjusting out on forward braking. Also as someone else mentioned, you can put in manual adjusters and tweak them occasionally.


Tried that, adjusters are in the right way. Manual adjusters? You sure? I dont think you can for civics.

Originally Posted By: Trav
WOW what a problem. Have you tried disconnecting the hand brake? I'm wondering about the cable returning to position.


Well last summer actually found out that one of the ebrake cables was sticking and when releasing the ebrake all the way, it wouldnt bring the shoes back to its original fully backed off position so it was causing some drag. So thats when we replaced both ebrake cables and it doesnt seem to have this problem anymore.
Cause what was happening was, when i pull the ebrake handle from inside the car, i look at the 2 cables connected to the main ebrake lever going to the drums and one would slide in and out more so than the other. We even tried adjusting the cables too from the lever.
 
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Don't overlook the forehead-smacking possibilities: is the self adjuster assembled correctly, or is it reversed? On lots of vehicles, you CAN reverse the whole assembly by accident. The adjuster should actuate only when the brakes are applied and the car is moving BACKWARD.

Look at the second animation here:
http://auto.howstuffworks.com/auto-parts/brakes/brake-types/drum-brake2.htm

The rear of the car is to the LEFT, so when looking at a brake assembly, the adjuster cable and guide should be on the REARWARD brake shoe.
 
Originally Posted By: Mud
If anything the auto adjusters get too loose over time and don't work right
smile.gif
Almost all wheels/drums seem to have some slight high and low spots, its typically not an issue.


So the high point i have and can feel when spinning the rear wheels is normal? Cause it drags when going through this high point. When the wheel goes through this high point, its when i get the noise.

Quote:
Sorry if I missed what car this was?


POS civic


Quote:
Thinking out loud, wondering:
1 - Some master cylinders have a residual check valve to keep a slight amount of pressure on the system after the brake pedal has been released. These check valves keep about 5-10 psi pressure on the wheel cylinders cup seals. They also resist a large volume of brake fluid returning to the master cylinder. Could be an issue with the check valve at the MC - if the valve is not working right, it is not releasing enough pressure, causing the rear wheel cylinder (not the adjuster) to apply more and more pressure to the shoes.


Interesting. Any way to test this valve?

Quote:
2 - There is a 3-way distribution block probably on the rear axle. Brake line comes from MC and then each line heads out to each rear wheel. I had a very difficult wheel bleed issue years ago that I could not figure out. Turns out that the block itself had partial internal blockage, replaced it and all was good. Thats an easy one to check but of course you would need to re-bleed the rears to do so since you would have to look inside of it.


Ill have to look into this but i dont think theres a distribution block on the back of my car.
 
Originally Posted By: 440Magnum
Don't overlook the forehead-smacking possibilities: is the self adjuster assembled correctly, or is it reversed? On lots of vehicles, you CAN reverse the whole assembly by accident. The adjuster should actuate only when the brakes are applied and the car is moving BACKWARD.

Look at the second animation here:
http://auto.howstuffworks.com/auto-parts/brakes/brake-types/drum-brake2.htm

The rear of the car is to the LEFT, so when looking at a brake assembly, the adjuster cable and guide should be on the REARWARD brake shoe.



Thats exactly how i have mine in now.
 
Originally Posted By: pcoxe
I think the brake adjusters have a left and right side. Maybe they are on the wrong side and are adjusting out on forward braking.

Adjusters expand as they operate normally. If you put them on the wrong sides (assuming they'd fit that way), they would contract instead, and the rear brakes would stop working.

What kind of car does the OP have?
 
Originally Posted By: Tegger
Originally Posted By: pcoxe
I think the brake adjusters have a left and right side. Maybe they are on the wrong side and are adjusting out on forward braking.

Adjusters expand as they operate normally. If you put them on the wrong sides (assuming they'd fit that way), they would contract instead, and the rear brakes would stop working.

What kind of car does the OP have?



04 Civic

im still trying to figure out why theres a high point when i spin the back wheels. Is this normal and not a way to get rid of it? id say the wheels spin 90% free and 10% high point on 1 single point of a spin.
 
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Originally Posted By: Carnoobie
Originally Posted By: 440Magnum
Don't overlook the forehead-smacking possibilities: is the self adjuster assembled correctly, or is it reversed? On lots of vehicles, you CAN reverse the whole assembly by accident. The adjuster should actuate only when the brakes are applied and the car is moving BACKWARD.

Look at the second animation here:
http://auto.howstuffworks.com/auto-parts/brakes/brake-types/drum-brake2.htm
The rear of the car is to the LEFT, so when looking at a brake assembly, the adjuster cable and guide should be on the REARWARD brake shoe.



Thats exactly how i have mine in now.

OK, just thought I'd check ;-)

I also have to wonder if its a residual pressure valve problem. Front disk/rear drum vehicles are actually so much more complicated to build than disk/disk vehicles that it really hacks me off that car companies charge a premium for rear disks. Rear disks have GOT to be cheaper to put on a car. Anyway, I digress: One of the complications for rear drums is that there always has to be a small (key on SMALL!) positive pressure inside the wheel cylinders of a drum brake, otherwise the seals can roll over and leak. If you do that with the front disks, they'll drag like MAD because unlike drums they don't have a return spring. So there has to be a special valve to keep a small pressure on the rear (but NOT the front disk) brakes. Usually the residual pressure valve (RPV) is built in to the godawfully complicated "combination valve" that is between the master cylinder and the brakes and also handles pressure proportioning and safety splitting the system, but some vehicles put the RPV in the outlet of the master cylinder. Sometimes its as simple as a goofy little "duckbill" valve that will hold about 1 or 2 psi of pressure in the line to the rear wheels, but folds in on itself above that pressure to let the fluid return. Note that weak springs in the rear brakes can be overcome by a too-strong RPV, too.

Here's how I'd test to see if its a brake fluid pressure problem:
Drive the car until the problem appears (the brakes are dragging/squeaking). Then instead of pulling the wheel off, just crack open one or both of the rear wheel bleed valves. If the problem goes away, its pressure and you can look into the brake hydraulic system for the problem. If it stays, then its mechanical and the adjusters need some kind of work.
 
I figure this should help and give you guys a better idea of the noise im getting.

Listen to this clip that i recorded last fall, I was just in a dead lot doing some light braking. sorry had to play it off the computer to get it on youtube.

Start at 19secs in and listen very closely to the end of the clip with your SOUND all the way up! Might have to listen a few times to get an idea. As you can tell from the sound, the sound is relative to brake pressure. Hold the brakes longer and the sound extends and gets drawn out.

CLIP TO LISTEN TO WITH SPEAKERS UP!

http://www.youtube.com/watch?v=Vw806YVyE74[color:#FF0000][/color]
 
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