Rear brake is driving me nuts...

[luigi164]

Any noise from the axle bearings? When they test drove it were the brakes smoking? If the bearings were causing the heat they should be making all kind of noise.

No, no weird sounds from the bearings...and if they were bad I would expect also some backlash in the axle ?
Everything heats up, axleflange, drums, the rim...but the hottest point was at the centre.
I'm also NOT convinced that the bearings are so bad and cause that much heat. Specially because the axle right behind the backingplate is not hot at all. I would think that would also be hot ?
I'm totally confused what's going on here. Talked with several people about this but with no solution yet. Next saturday I'm gonna take a look again with a friend of mine...

To be continued

 

[traintech55]

Two questions, 1st. are your brakes working correctly now even though the drums are getting hot? 2nd. have you checked the fluid level in the rear end yet? You just might be low enough to lube the bearing but not carry the heat away.

 

[BigblueC]

Everything heats up, axleflange, drums, the rim...but the hottest point was at the centre.

I would expect the center to be the hottest even if there wasn't a problem. The center is soaking up heat from all directions vs just one direction at the edge of the rim, and there is less air movement at the center vs the edge. This may have been addressed already and I just didn't see it, where did you get your shoes and hardware from? Since I'm having a similar issue I think that could be a factor for us. I got my stuff from Oreilly's.

 

[celticwarlock]

You have such an oddball issue on your hands that I can't be sure that it will help, but have you tried chamfering the lining of the shoes? I have found that larger drum systems respond well to this sort of technique. On numerous occasions, when dealing with drum systems on my vans over the years, this measure has proven essential for keeping the brakes at a manageable temperature. I have seen the side edges chamfered also, but I have never found that to be necessary.

 

[70bigblockdodge]

Bearings are greased, and if it were that bad you would surely hear it. Has to be air in wheel cylinders or bad hose as mentioned earlier.

 

[luigi164]

Two questions, 1st. are your brakes working correctly now even though the drums are getting hot? 2nd. have you checked the fluid level in the rear end yet? You just might be low enough to lube the bearing but not carry the heat away.

Brakes are working perfect, no issues at all, also when they are hot and as said before: no drag at all.
Fluid level is o.k. but has nothing to do with the bearings as said by 70bigblockdodge, they are greased.

I would expect the center to be the hottest even if there wasn't a problem. The center is soaking up heat from all directions vs just one direction at the edge of the rim, and there is less air movement at the center vs the edge. This may have been addressed already and I just didn't see it, where did you get your shoes and hardware from? Since I'm having a similar issue I think that could be a factor for us. I got my stuff from Oreilly's.

Got mine from Rockauto:
More Information for RAYBESTOS 335SG

 

[John A]

Can you post a picture of your master cylinder?

 

[luigi164]

Can you post a picture of your master cylinder?

Here you go:

 

[John A]

If this were my car here is something I would check. Remove the master cylinder from the car and see if the piston at the rear of the master is against the snap ring ,in the fully returned position. Is there any fluid seeping out the back? I see some fluid on you your booster. Just some things to check, John.

 

[luigi164]

Next episode:
Have taken the drums and shoes to a machineshop. Drums are turned and there were new linings placed on the shoes. The old (actually new !) linings were removed and new ones were installed. The new ones are a bit thicker and softer. Now the primary and the secundary shoes have the same thickness.
Installed the brakes and adjusted them. The adjuster is now almost fully turned in. With the old linings the adjuster was about 3/4 inch out. With the wheels of the ground they turn free. When braking, they stop. Brake release: wheels free agian so IMHO no hydraulic problem ??

Also checked the pushrod at the master: clearance is good. Piston also completely against snapring.

Testdrive: good pedal, car stops good but: both sides HOT !!
Got the car jacked up (again pff...) and with both wheels of the ground wheels turned a little heavier but not thát much.
So, started the engine, put it in D and let it run for about 5 minutes. Hit the brakes a few times and left wheel stops right away. Brake release: wheel turns again. In Reverse ( for the right wheel) the same thing. And on both sides, drums got HOT !!

Loosened the wheellugs a bit and noticed that wheel turned easier now. Tightend the lugs again and wheel turned heavier...Got the wheel of and the drum turn free but: when I push the drum harder on the axleflange it turns heavier.....Whats going on here??
I was fed up with it and left it that way. Next weekend I'm gonna take another look at it..

 

[70bigblockdodge]

Your axel adjustment is not right. Tighten or loosen the adjuster (behind flange at backing plate to housing area) to set to FSM specs.

 

[1970cat]

Your axel adjustment is not right. Tighten or loosen the adjuster (behind flange at backing plate to housing area) to set to FSM specs.

yes, your axles are not out far enough. when you tighten the wheels it sucks the center of the drums in against the hub, distorting the drums in the process.

 

[luigi164]

yes, your axles are not out far enough. when you tighten the wheels it sucks the center of the drums in against the hub, distorting the drums in the process.

Could this adjustment just suddenly change because I've never touched that. Before I had the shoes replaced I've never had any issues with hot drums. But I will check that anyway..

 

[70bigblockdodge]

Could this adjustment just suddenly change because I've never touched that. Before I had the shoes replaced I've never had any issues with hot drums. But I will check that anyway..

It's free to check.

 

[luigi164]

yes, your axles are not out far enough. when you tighten the wheels it sucks the center of the drums in against the hub, distorting the drums in the process.

Please explain to me. The only thing I can immagine is that when tightening the wheels, and at the same time the drums, is that the outside edge of the shoes touch the inside of the drums ?
I've been measuring everything up today but IMHO the edge of the shoes don't go that far into the drums...

 

[70bigblockdodge]

Too much end play in the axels and because of the taper in the bearings they are miss aligning radially when on the ground/weight on wheels to create the drag. That is my best guess and it is free to check/adjust/fix.

 

[luigi164]

Update:
No axle end play at all. But, found an issue what cóuld be the cause of all this...
I think and found out that the shoes are not staying centered. Because the linings are thicker now I need the adjuster to be almost fully turned in, this making the holddownpin from the primary shoe points down and is not coming almost straight out of the backingplate.
The bottom of the shoes, connected with the adjuster, can be moved a little left and right. I think that's normal. I put on the drum, snug the parkingbrake cable a few times and hit the brakes a few times to center the shoes. The I adjust the shoes till I hear the shoes slightly rubbing the drum. Wheels on, tighting the lugs: huge drag.
Remove the drum, push the bottom of the shoes to the rear, drum and wheel back on: no drag at all !
Then, turn the wheel forward couple of rounds: no drag
Turn the wheel backwards a couple of rounds: wheel starts turning heavier.
Forward again: wheel turns heavier and even got a spot I almost can't turn the wheel anymore.
Did this also with wheels powered by the engine and hit the brakes a few times, forwar and backwards: same result.
So, I think shoes go out of centre when in use. Also think that this is caused by the little drag of the thicker lining on the primary shoe and activates the secundairy shoe and so making it more drag..
This was already mentioned by mr Cantflip....so maybe he IS a genius
Question is now: what to do? Any suggestions?

 

[Dobalovr]

mr Cantflip....so maybe he IS a genius

He resembles that remark....

 

[traintech55]

Ok, if I read this correctly, the pins that hold the shoes to the backing plate are on an angle, (they do not go straight into the shoe) at rest. Also did you lube the shoe contact points (6) on the backing plate? If the retaining pins are not straight into the shoe that will cause big time binding problems.

 

[celticwarlock]

Update:
No axle end play at all. But, found an issue what cóuld be the cause of all this...
I think and found out that the shoes are not staying centered. Because the linings are thicker now I need the adjuster to be almost fully turned in, this making the holddownpin from the primary shoe points down and is not coming almost straight out of the backingplate.
The bottom of the shoes, connected with the adjuster, can be moved a little left and right. I think that's normal. I put on the drum, snug the parkingbrake cable a few times and hit the brakes a few times to center the shoes. The I adjust the shoes till I hear the shoes slightly rubbing the drum. Wheels on, tighting the lugs: huge drag.
Remove the drum, push the bottom of the shoes to the rear, drum and wheel back on: no drag at all !
Then, turn the wheel forward couple of rounds: no drag
Turn the wheel backwards a couple of rounds: wheel starts turning heavier.
Forward again: wheel turns heavier and even got a spot I almost can't turn the wheel anymore.
Did this also with wheels powered by the engine and hit the brakes a few times, forwar and backwards: same result.
So, I think shoes go out of centre when in use. Also think that this is caused by the little drag of the thicker lining on the primary shoe and activates the secundairy shoe and so making it more drag..
This was already mentioned by mr Cantflip....so maybe he IS a genius
Question is now: what to do? Any suggestions?

Deepen the channels in the shoes (where they get seated against the adjuster and/or the top pin boss) so when they are installed, there's a bit more room between the shoe and the drum surface? I have had to do this before on a car or two over the years.

I can't be sure how that might affect your retaining pin issue, though.

Ultimately, what you describe suggests that when the shoes are centered in the drum, they are being shifted in a way that causes drag. One way to fix this would be to change the shoes' relationship to their mounting points (as I have described) so that when they are snugged into the drum, they don't cause interference. I think this could work.