Mystery of the smoking nuts

[Korys_thing]

Got a car that had strip of deep wear in rear driver drum. Recently replaced both rear drums, shoes, and spring sets only to have it start smoking on me.

3 days back, took it to a brake shop and they said nothing looked wrong, they went over all 4 brakes, adjusted, and bled. For the green light to drive and they felt good.

Got hot yesterday. Took apart hub and checked the bearings and they seem good. Backed off the brakes a good amount. Still getting a weird rub

Drove it today, the more I drove the more I felt them start drag. Pulled over and measured the temp of the lugnuts and bearing hubs. 291 degrees on BOTH rear sides. Front brakes a cool 110.

Driver side rear wheel free spins for half a rotation and then drags (almost needs two hands to turn) for half a rotation. I think the new shoes/drum are also trying to wear a line in the same spot as the old ones. I can’t for the life of me see anything warped and can’t see any obvious rub spots on the shoes. Been through at least 2 brake shops and countless car folks and nobody had any ideas.

Help! What do I possibly look at next?

-wheel bearings seem pretty good. Even if one was bad would it heat up both sides?

-any common reasons for a gouge like the one in the photo? Hard to tell but it’s pretty deep.

-included a photo of my brake shoe set up. Does that little gap on the left of the pin tell me anything? I can’t get it to sit any more flush than that. The only spring I can’t find a replacement for is the one attached to the bar going to the ebrake, couldn’t that be messing things up this bad?

-is it possible that the back plate or hub is warped and causing this? Why are both my back hub assemblies so hot?

I feel like this this has its back wheels up in the air more than on the ground these days.

 

[RustyRatRod]

Double check that the self adjusters are on the correct sides.

 

[Korys_thing]

Double check that the self adjusters are on the correct sides.

Hmmm, don’t think I realized/remembered the screws have specific lefts and rights. I’ve been adjusting them so I like to think I’d have noticed but you could be on to it something. I’ll have to check it tomorrow.

I’d love if that were the solution

 

[Bewy]

If the adjusters were reversed, they would be releasing the brakes, not tightening them. So I doubt that is the problem.
You may have rust/sludge in the lines that are preventing the fluid from releasing the wheel cyl. If new wheel cyls, maybe piston/seals are tight? Swap side to side & see if problem moves.

 

[halifaxhops]

Did you cut the drums to make sure they are round then arch the shoes to fit them?

 

[Newbomb Turk]

Did you cut the drums to make sure they are round then arch the shoes to fit them?

The last time I asked about getting the shoes arched to the drums the guy had no clue what I was talking about.

All the good friction houses in my area are long gone. It’s a shame.

 

[halifaxhops]

You can always joe dirt them take some PSA paper put it on the CUT drum and turn and rotate the assembly. Works great. Yeah it hard to even find a place that will cut drums and rotors. I am lucky around here have two friends with Amamco lathes. New definately does not mean round or true.

 

[RAT ROD AL]

Inquiring minds want to know ! What is a "Friction House"

 

[SIX225]

Sounds like the brakes work for a while and then start to drag. How's the linkage at the master cylinder? Mine was installed wrong (bent retainer plate, pivot bolt too tight) and binding not allowing the compensation ports to work properly. Also, are the parking brake cables free and adjusted?

 

[Plymouth 65]

Where are the shoe hold downs to the backing plate? 65

 

[townsend]

Looks like the standard hold down spring and anchor clip for early A body 9 inch brakes.

Pardon Our Interruption...

Pardon Our Interruption...

 

[RAT ROD AL]

Where are the shoe hold downs to the backing plate? 65

Walt,the earlier A body has different shoe retainers than later.

 

[Dana67Dart]

Where are the shoe hold downs to the backing plate? 65

9" brakes its the round springs at 4 and 7

As for adjuster... when the lever comes down the adjuster should expand.

Everything in your photo looks good for the left hand side (LH lug studs and brake like coming from the left!)

Only thing I see based on the photo and the FSM is the auto adjuster cable loop end in the FSM shows it between the front spring and the rear spring. UNLESS it is causing a catch point I don't see that being the issues

red is shown behind the loop
green is in front of the loop

NOW some things that can mess with brakes

1. The backing plates worn excessively where the shoe rides on its standoffs. This can cause all kinds of issues.
2. Parking brake not adjusted properly
3. out of round drum (Get a new drum and have that checked for runout before you install. Your now heated up and used ones my have warped from too much heat, take them to the store you purchased them from and have them turn them or at least check)
4. Bent axle (check the axle flange face for runout)
5. drum not seating flat when wheel is torqued (55 ft lb)
6. fluid not returning to the MC (internally damaged flex hoses)
7. Are the shoes the correct OD and width (I can not see the backing plate in your photo, do you have 10" shoes and drums on 9 " backing plates? do you have 9" hardware (springs etc) on 10" drums?)

This is a Bendix Ford backing plate but it illustrates the potential issues

 

[junkyardhero]

Inquiring minds want to know ! What is a "Friction House"

a ***** house with no lube


(all kidding aside a business that does brake and clutch re-lining or sells those components)

 

[Dana67Dart]

Does that little gap on the left of the pin tell me anything?

that shoe is not returning completely?

 

[Dana67Dart]

The only spring I can’t find a replacement for is the one attached to the bar going to the ebrake, couldn’t that be messing things up this bad?

My understanding is that spring on the e brake bar is more of an anti rattle

 

[Texas Red]

I grew up with a guy I ended up racing round d round cars with whose parents owned a auto repair shop. His policy was to never rip both sides apart leaving
one side as it came in for reference. This is a great policy that worked for him and has always worked for me as well. I once owned a Mercedes Benz
where the factory repair manual stated never cut the rotors or drums which went on to state that the mechanic was to let the brake shoes wear into the rotor if a replacement was not available.... but cutting rotors or drums was not acceptable. As we have all experienced they warp very easily after being cut ...... Especially if they are cut beyond what is stamped into the rotor stating as a minimum measurement as I had done in the past.

 

[Texas Red]

I use a ceramic lube on rear drum brakes parts during reassemble. Just like never seize dont go crazy
but a little to keep those parts returning to their correct position on the backing plate as brought up already.

 

[Oldmanmopar]

The rear brakes are the first to apply and the last to release. Sounds like your pedal is not releasing all the way. could be and after market master and the nole in the piston is not deep enough for that length push rod. Loosen the master cylinder up and slide a 1/8 shim behind each side and tighten it and take it for a ride, Just a test, Seen this in the past where it was the push rod was to long for the master cylinder. The hotter the brakes get the tighter they get.

 

[TT5.9mag]

Both rears are fed by a single hose. When both do the same thing you gotta start looking at commonalities. My guess is a possible bad soft hose feeding them. Internal collapse type of thing that’s preventing both brakes from releasing

 

[dano]

Contaminated brake fluid.

Water entered the systems, gets hot and boils (lower boiling point), out gasses and expands. Once cool, back to normal until hot and does it again.

 

[junkyardhero]

Both rears are fed by a single hose. When both do the same thing you gotta start looking at commonalities. My guess is a possible bad soft hose feeding them. Internal collapse type of thing that’s preventing both brakes from releasing

^^ this

i just had a 72 van that had a bad drop line to the rear. same symptoms till it just locked 'em up tight.

i'd be giving the hairy eyeball to the whole system from the master, to the lines and all the way back. especially so if anything has been "upgraded"...

 

[Korys_thing]

Did you cut the drums to make sure they are round then arch the shoes to fit

Nope. I know it’s a good practice but doesn’t appear to be an option brake shops here are familiar with. It feels like this could solve some issues if I find a place.

Sounds like the brakes work for a while and then start to drag. How's the linkage at the master cylinder? Mine was installed wrong (bent retainer plate, pivot bolt too tight) and binding not allowing the compensation ports to work properly. Also, are the parking brake cables free and adjusted?

I installed a new one about 4 months back. Not sure about the pivot bolt, I’ll take a look and see if it’s all releasing properly. Parking brake cable is free but “adjusted” who knows. I didn’t mess with it when I reinstalled. Asked the bRake shop to double check it. Seems to release when I need to take the drum off.

You may have rust/sludge in the lines that are preventing the fluid from releasing the wheel cyl. If new wheel cyls, maybe piston/seals are tight? Swap side to side & see if problem moves.

Might be in to something. Doesn’t explain why the old drum pre-new wheel cylinder had a crazy gouge in it. But there are old
Lines and some brand new cylinders.

The more responses I’m reading I’m starting to think it’s a combination of things. I’ll have to check the master cylinder being too tight, rear brake line segment being damaged, and maybe some contaminated brake fluid.

Additionally I’ll have to figure out what the hell is dragging so bad.

The rear brakes are the first to apply and the last to release. Sounds like your pedal is not releasing all the way. could be and after market master and the nole in the piston is not deep enough for that length push rod. Loosen the master cylinder up and slide a 1/8 shim behind each side and tighten it and take it for a ride, Just a test, Seen this in the past where it was the push rod was to long for the master cylinder. The hotter the brakes get the tighter they get.

I replaced the master cylinder with the same that was in there prior but this feels like what’s happening.

I’m gonna need a good friction house if i don’t figure this out soon…keep yall posted

 

[413]

What axle, 8 3/4? How is the rear wheel bearing adjustment? If too loose then they will be dragging all the time. But no as bad with the wheels off the ground.

 

[Dana67Dart]

I’ll have to check the master cylinder being too tight

Do you have Manual or power brakes?

Easy way to tell if there is a brake pedal /pushrod issue on manual brakes. With your hand move the bottom of the brake pedal toward the rear of the car. there should be a lot of play. maybe even an inch. WATCH that the rod does not fall out. IF IT DOES it was not fully inserted into the keeper in the MS piston hole