Rear brake is driving me nuts...

[luigi164]

Been strugling a long time to get my rear (drum) brakes work properly.
In fact they do but ...the right rear keeps heating up.

Started with:
- new brakeshoes (left and right)
- new mastercylinder
- new wheelcylinders
- new springs and other hardware
- new brake hose
- new brake fluid

Adjusted the brakes a zillion times according the FSM, checked and double checked, and yes big shoe is at the rear...
Checked the parkingbrake cable.
Wheels turn free with no drag.
Brakes release immidiatly after braking or using the parkingbrake. Checked this with both wheels of the ground and a helper to handle the brakes. So I think there's no pressure being held somewere.

Now the testdrive:
Car brakes and stops very well. After a few firm stops, left is warm, right too.
A few miles later with normal traffic and no panicstops: left still warm, right is heating up..
Slowly driving home, a few miles, right rear is hot !!
At home I jack up the rear and right wheel turns free but is very hot ( cannot hold my hands on the rim) Drum, backingplate and the flange hot !!

Been dealing with this issue for weeks now and I can't figure it out. Am I missing something?
Been thinking about the rear bearing but the car passed the yearly inspection last month so that would have been a problem back then..

Btw, been searching on different Mopar-forums about this problem and I seem not to be the only one with this but didn't find the answer yet..

So any help or suggestions would be great..

Edit: forgot to mention but I even left the selfadjusters out just to eliminate them to be the cause of this..

Thanks, Luigi

Ow, FYI : Chrysler Newport 1971 with power disc/drum

 

[70bigblockdodge]

Taking a shot here but it my be the end play adjustment letting the brake rub the side of the drum. Axel moving in and out of housing causing the edge of the friction material to rub the drum. Any evidence of rubbing the drum in non swept part of the drum.

 

[saforwardlook]

Given what you have done, it seems you have covered the bases. Only thing I can think of is whether there is any evidence of differential fluid on the pads when you remove the drum. The axle seal might be slowing leaking and depositing on the pads and swelling them as you drive, causing them to drag, but if the wheel is too hot to touch, and it still turns freely after a longer drive, then I am not so sure this is a useful thought.

 

[BigblueC]

I'm going through the same basic problem, so I'm interested in how this gets solved. Like you I have replaced, assembled, and adjusted multiple times but always end up with the right rear wanting to drag and become noticeably hotter than the other wheels after ~10 miles.

 

[Darter6]

This is just a thought...Check to see if the shoe that has the park brake lever attached is completely retracted to the center pin where the springs attach.Just had this on a 68 Valiant with 10'' rear brakes. The brake lever was hitting the wheel cylinder stop tab that is welded to the backing plate.It was not letting the shoe retract completely.And it was only on the right side.....Ground down the tab a bit and all was good.Never in all my years working on Mopars did I have this happen.But there is always a first.Again just a thought.

 

[Pete Kaczmarski]

After the test drive and the shoes cool down...what does the drums look like? are they clean or after test drive looks alittle greasy? Just went thru somewhat similar on the front of the '62 Chrysler 300. We burned the shoes cleam with a torch and used brake clean. When used they heated up and the non visible brake fluid came up of the brake shoes. We replaced the shoes and perfect since late last season.

 

[Fury440]

Maybe put a straight edge on the backing plate, if it's warped it might be your problem.

 

[luigi164]

Taking a shot here but it my be the end play adjustment letting the brake rub the side of the drum. Axel moving in and out of housing causing the edge of the friction material to rub the drum. Any evidence of rubbing the drum in non swept part of the drum.

No, axel is not moving in/out to much...

Given what you have done, it seems you have covered the bases. Only thing I can think of is whether there is any evidence of differential fluid on the pads when you remove the drum. The axle seal might be slowing leaking and depositing on the pads and swelling them as you drive, causing them to drag, but if the wheel is too hot to touch, and it still turns freely after a longer drive, then I am not so sure this is a useful thought.

No, everything is bonedry inside...

This is just a thought...Check to see if the shoe that has the park brake lever attached is completely retracted to the center pin where the springs attach.Just had this on a 68 Valiant with 10'' rear brakes. The brake lever was hitting the wheel cylinder stop tab that is welded to the backing plate.It was not letting the shoe retract completely.And it was only on the right side.....Ground down the tab a bit and all was good.Never in all my years working on Mopars did I have this happen.But there is always a first.Again just a thought.

Shoes are fully retracted to anchorpin when released..

After the test drive and the shoes cool down...what does the drums look like? are they clean or after test drive looks alittle greasy? Just went thru somewhat similar on the front of the '62 Chrysler 300. We burned the shoes cleam with a torch and used brake clean. When used they heated up and the non visible brake fluid came up of the brake shoes. We replaced the shoes and perfect since late last season.

As said, everything is dry, absolutly no brakefluid or other grease to see...

As an other try I changed the drums today from left to right and viceversa...
No difference, rightrear still heating up...

 

[cantflip]

Just a stab in the dark here... how about posting some pics of the assembly with the drum off and park brake released... maybe we can spot your problem.

 

[luigi164]

Just a stab in the dark here... how about posting some pics of the assembly with the drum off and park brake released... maybe we can spot your problem.

Will take some pictures and post them...

 

[70bigblockdodge]

Might just be bad irons/machined incorrectly (nowadays go figure) try swapping just the front shoes side to that way you do not have to switch the pin. Worth a try?

 

[luigi164]

Might just be bad irons/machined incorrectly (nowadays go figure) try swapping just the front shoes side to that way you do not have to switch the pin. Worth a try?

That's what I've been thinking to do also. This problem keeps me awake sometimes and last night I thought of doing the swap... As you say, primary shoes first, if that doesn't work I can also swap the secundary...Got something to do next weekend..

 

[luigi164]

As promissed a few pics of the brakes: RR in rest:

And RR servicebrakes in use:

BTW: I left the selfadjusters out.

Today a little test drive. At first I turned the adjuster of the parkingbrake fully out, so there was absolutely no tension on the cable...
No more then 5 miles with no hard braking: hot hot hot !!

Wheel turned not fully free when I jacked the rear up. After cooling down, wheel turn free agian ????. .

Maybe tomorrow I change the shoes from left to right and viceversa and see what that brings.

 

[65sporty]

I don't see anything wrong in the pic's.

 

[cantflip]

New return springs appear to be in order. They may make a bigger difference than you think.

BTW the little mangled horse shoe looking retainer should come with the spring kit.

Other than the missing hardware that had my brain screaming "what's missing here" until I scrolled down... I don't see anything else.

I try to always replace the springs with the shoes as they can weaken dramatically from heat and stopping cycles. Reassembled adjust the star wheels until the brakes drag a bit (even until they drag a lot, then back them off) the star wheel is the primary adjustment. Then adjust the slack from the cables until the park brake holds. Your FSM may have slightly different instructions but will be very similar.

I don't know your drum brake background, but they are often adjusted incorrectly.

It wouldn't surprise me if the shoes are incorrectly made somehow, but I sure couldn't tell from a picture.

 

[70bigblockdodge]

I try to always replace the springs with the shoes as they can weaken

They are new springs they are painted black.

 

[Big_John]

I saw something similar in another forum and it was a real head scratcher. Turned out to be a bad brake hose. The ID of the hose had deteriorated to where it acted like a one way valve. There was enough to let the pressure release when it sat, but in use, it would hold the brake on.

 

[Polara_500]

Yeah, but it's a rear brake and the flex hose feeds both sides so that doesn't really fit the symptoms.

 

[traintech55]

I had this problem on the front brakes of a 92 grand caravan. Turned out to be a plugged brake hose. You might have a clog or a slight kink in the line on that side. I would remove it completely and try to blow air thru it from both sides.

 

[Big_John]

I had this problem on the front brakes of a 92 grand caravan. Turned out to be a plugged brake hose. You might have a clog or a slight kink in the line on that side. I would remove it completely and try to blow air thru it from both sides.

Had something similar on my step-son's Taurus. His buddy had changed brakes pads for him and let the calipers hang.