What would cause rear brake shoes to overtighten?

[Carnoobie]

Originally Posted By: mechtech2
The high point is the drums, not the shoes.
It is a minor problem that most drum brakes have, to various degrees.
Are your emergency brake cables/system OK?
Adjusters are often inter related with them.


Yes seems the ebrake system is working fine.

 

[Carnoobie]

Originally Posted By: Tegger
Originally Posted By: Carnoobie
im double checking right now on whether this cars shoes auto adjust by going fwd or backwards. Im pretty sure its R though cause this car is different from most.

It is a bit different, but not in the way you're thinking of.

The adjustment mechanism is at the top of the assembly, right under the hydraulic cylinder.

The adjuster lever (on the leading shoe) has two arms: "A" and "B". The lever is pulled downwards by a spring. That force makes arm "A" sit against the adjuster (clevises and star wheel) while arm "B" is poised above the star wheel. When you step on the brakes, the shoes move apart, causing the adjuster to be pushed away from the lever by the action of arm "A" and its spring, allowing arm "B" to dip down towards the star wheel.

Once the shoes wear enough, the dipping action of arm "B" becomes sufficient to turn the star wheel a little bit. All that's required is to step on the brake pedal to push the shoes apart. The spring and lever do the rest.


ill double check to make sure my tensioner turning knob is facing the right. Gonna take it to one of my mechs in a bit.

Originally Posted By: eljefino
+1 on the e-brake cable, it helps the adjusters on a lot of cars, especially chrysler k cars.

Go for a drive, try to gain speed but don't use the brakes, just coast up the hill to a stop. Quickly pull the drum and check the brake shoes for heat. If they're hot on the wheel cylinder side you have a line pressure problem, hot on the adjuster, there's your issue.

Why don't you just take detailed pictures of your brakes with the drums off? A honda expert might say, oh, your spring hardware kit is in backwards and rubbing, or something like that.


ill take some pics

Originally Posted By: Tegger
Originally Posted By: Carnoobie
When you say no play, do you mean when wiggling the drum (when its on the hub) side to side or forward and back? and are we talking with the drum bolted in or just by hand?

The hub and the hole in the drum should be exactly the same size (with a few thou tolerance).

With the drum fully-seated ON the hub, and the wheel and the parking brake OFF, you should not be able to shift the drum front-to-back or up-and-down. The only available movement should be a bit of rotation, on account of the fact that the holes for the wheel-studs are slightly larger than the studs themselves.


From what i last remember theres no give at all when the drum is on and bolted on.

 

[Carnoobie]

the one thing that [censored] me off about this problem is that its on and off. Ive made trips to the mechs before only to not have the sound be happening. Really [censored] me off.

 

[440Magnum]

Originally Posted By: Carnoobie

When you say rear wheel bleed valves do you mean the rear brake line going to the drums? Cause ive never even heard of it. Always thought its just a brake line going to each rear drum.


I mean the same valve you use to bleed air out of the brake system. One per wheel, mounted on the caliper front) or back side of the brake backing plate (drum).

 

[Carnoobie]

im not taking car to mech today. Hes busy and im too fed up with this to wanna waste anymore money on this POS. I honestly would rather drive it off a cliff if i could.

 

[KrisZ]

Sell it then, It's got a Honda badge on it, so no matter what POS it is, you will fetch a premium for it.

 

[Carnoobie]

Originally Posted By: KrisZ
Sell it then, It's got a Honda badge on it, so no matter what POS it is, you will fetch a premium for it.


Rebuilt status. Would take way too much of a loss.

It has rebuilt status not cause it was in an accident but cause 3yrs ago the car was broken into and the interior was all ripped out and stolen.

 

[George7941]

Originally Posted By: Carnoobie
im not taking car to mech today. Hes busy and im too fed up with this to wanna waste anymore money on this POS. I honestly would rather drive it off a cliff if i could.


You do not have a big problem. You can certainly disable the adjuster mechanism and just tighten up the shoes every six months or so manually. No big deal.

If you cannot deal with this problem how are you going to handle far bigger problems life is going to cast your way?

 

[Carnoobie]

Originally Posted By: George7941
Originally Posted By: Carnoobie
im not taking car to mech today. Hes busy and im too fed up with this to wanna waste anymore money on this POS. I honestly would rather drive it off a cliff if i could.


You do not have a big problem. You can certainly disable the adjuster mechanism and just tighten up the shoes every six months or so manually. No big deal.

If you cannot deal with this problem how are you going to handle far bigger problems life is going to cast your way?


How do you disable the adjuster mechanism? I dont even know forsure if this is the cause of the problem.

I could be wrong but i read online that you can tighten the shoes by just applying the ebrake all the way up and release 10times. Not sure if true.

 

[Tegger]

Originally Posted By: Carnoobie
From what i last remember theres no give at all when the drum is on and bolted on.

You don't bolt the drum down, you just seat it on the hub. If you bolt the drum down, you can't check for movement.

You seat the drum, then try and move it radially in any direction. No play should be evident. Only rotation should be present, and that limited by the studs.

This just occurred to me: Is the hub totally clean of rust? If there's rust on the hub, the drum may fail to seat completely, and sit off-kilter on the hub. This will present an out-of-round and out-of-true surface to the shoes.

It only takes two- or three-thousandths of an inch to cause problems with brakes, so you basically need to approach the issue with a machinist's touch.

 

[George7941]

Originally Posted By: Carnoobie


How do you disable the adjuster mechanism? I dont even know forsure if this is the cause of the problem.

I could be wrong but i read online that you can tighten the shoes by just applying the ebrake all the way up and release 10times. Not sure if true.


Grinding the teeth off the adjuster wheel will certainly disable it and there are, most likely, even easier ways to disable the adjusting mechanism, depending on your setup. You could probably just omit the adjuster cable.

 

[Carnoobie]

Originally Posted By: Tegger
Originally Posted By: Carnoobie
From what i last remember theres no give at all when the drum is on and bolted on.

You don't bolt the drum down, you just seat it on the hub. If you bolt the drum down, you can't check for movement.

You seat the drum, then try and move it radially in any direction. No play should be evident. Only rotation should be present, and that limited by the studs.

This just occurred to me: Is the hub totally clean of rust? If there's rust on the hub, the drum may fail to seat completely, and sit off-kilter on the hub. This will present an out-of-round and out-of-true surface to the shoes.

It only takes two- or three-thousandths of an inch to cause problems with brakes, so you basically need to approach the issue with a machinist's touch.




Theres no rust on the hub or backing plate.

Well if you mean just slide the drum on and check for side to side and fwd and back wiggle without holding the drum with one hand up against the backing plate....then im almost certain it wiggles forward and back cause i know when ive had the drum spun in the past, the person would always have to hold one of the studs with the other hand.

 

[Carnoobie]

Originally Posted By: George7941
Originally Posted By: Carnoobie


How do you disable the adjuster mechanism? I dont even know forsure if this is the cause of the problem.

I could be wrong but i read online that you can tighten the shoes by just applying the ebrake all the way up and release 10times. Not sure if true.


Grinding the teeth off the adjuster wheel will certainly disable it and there are, most likely, even easier ways to disable the adjusting mechanism, depending on your setup. You could probably just omit the adjuster cable.


i first need to find out if the auto adjustor is the problem and if my shoes are being automatically overtightened. But been told that its impossible for auto adjustors to overtighten shoes.

 

[Carnoobie]

Another thing i wanted to mention is that this noise originally first started last year when i had the OEM honda drums on. Just all of a sudden one day out of the blue it started.

 

[mechtech2]

Originally Posted By: George7941
I doubt there is any car where the auto-adjusters are activated while braking going forward since the star-wheel teeth will wear out in no time at all this way. The teeth and the lever do not get lubricated well enough to stand up to this regimen.


Of course they adjust when going forward. Both star and wedge types.
They simply compensate when too much brake shoe movement is perceived. When the shoes actuate, they move, and the adjuster will actuate if needed.
I have heard about reverse braking for decades, but can't see why. Maybe the hard sudden stops when doing it this way moves them a bit more - a left handed reason for any success.

 

[eljefino]

^ I think it has to do with the golden age of Madison Avenue. I recall a chrysler ad from the 1950s where they introduce self adjusting brakes. For all I know it could be marketing decided to hype it as happening when you back up so it wouldn't freak you out "taking control" driving forwards.

I keep hearing about the "diagonal split" hydraulics for brakes. All of my cars have a front/rear split, I presume to go with different needs of disc/drums.

 

[Tones]

Are you sure this isn't just a sticking wheel cylinder? Have you ever changed the brake fluid? Old fluid can gum things up and cause the cylinders to hang. Are you getting it on both sides, or just one?

 

[George7941]

Originally Posted By: mechtech2


Of course they adjust when going forward. Both star and wedge types.
They simply compensate when too much brake shoe movement is perceived. When the shoes actuate, they move, and the adjuster will actuate if needed.
I have heard about reverse braking for decades, but can't see why. Maybe the hard sudden stops when doing it this way moves them a bit more - a left handed reason for any success.


I am familiar with star type adjusters, so I will use it for illustration. The self-adjuster mechanism is designed to activate when braking in reverse. There is a reason why the adjuster mechanism is ALWAYS on the secondary shoe. When braking in reverse, the top of the sec shoe gets pulled off the top anchor much more than the top of the primary shoe because of the "wrap-around" effect.. This is especially true when the brakes are of the servo-action type (no fixed anchor at the bottom). This extra movement of the top of the secondary shoe is what activates the adjuster. When going forward the top of the sec shoe does not get pulled out as much since the wrap-around forces are acting the opposite way, and hence the adjuster is not activated.

If the adjusting lever rubbed against the star wheel teeth every time you braked (going forward), the adjuster mechanism would wear out pretty quickly.

 

[eljefino]

^ So the u-shaped "hook" on the shoe that rides on the pivot point also acts like a cam, if the shoe moves too far back out it goes further down, enough so the cable pulls the adjuster one magical click's worth of adjustment. The spring up top holding the shoes against each other with the cylinder in the middle will equalize wear and not let this adjustment happen prematurely. Genius. (Right?)

 

[Tegger]

Originally Posted By: George7941
The self-adjuster mechanism is designed to activate when braking in reverse. There is a reason why the adjuster mechanism is ALWAYS on the secondary shoe.

You guys have absolutely NO clue. Pull a drum off any Honda drum brake and look for yourself: The adjuster is on the LEADING shoe (not the trailing shoe, which you erroneously refer to as the "secondary" shoe).

Honda drums self-adjust when you step on the brake at ANY time, even when the vehicle is not moving. Adjusting effect is enhanced if the vehicle is in forward motion during pedal-press on account of servo-action of the leading shoe, but adjustment is effected regardless.

Regarding brakes that adjust when the vehicle is moving in reverse: In the cases of which I am familiar, there is a cable attached to a fixed pin at the top of the brake assembly. This cable's other end is attached to an adjuster and star-wheel that is at the BOTTOM of the TRAILING shoe. When you brake in reverse, servo-action on the TRAILING shoe causes the cable to pull the adjuster UP. When you eventually let off the brakes, the trailing shoe is forced home by its springs, and the adjuster turns the star wheel as it returns to its rest-position.