Technical Single brake drum overheats

I am posting this for a friend and hope the mods will let it ride since the body style is pre-'65. This is for a friend (really) and has us all stumped. Any help will be appreciated. Here's the situation as he writes it:

1969 Dodge A108…

The problem: I replaced all the brake shoes, including in the right rear brake shoes. The new shoes have a lot thicker lining than the one I removed. Now the right rear drum gets very hot after driving even five miles.
400F on the right rear 110F on the left rear
The axle, however, is not hot. Not even near the bearings.

What I’ve already done (not in this order):
replaced the new brake shoes, no effect
replaced the rear brake wheel cylinders, rear brake hose, both rear brake lines, no effect
adjusted the end play in the rear axle, no effect
replaced the right rear wheel bearing and bearing seal, no effect
swapped left and right rear brake drums, no effect
checked that the parking brake releases completely, it does.
checked tire pressures, all OK
[I]loosened the brake shoes so they didn’t touch the drums (backed off the self adjusters), no effect THEN [I]pinched off the rear brake hose, checked that the brake shoes were not touching the drums (while both rear wheels were off the ground), checked that the rear brakes were disabled, drove three miles, right rear brake drum still gets very hot.
[/I][/I]


Note: at this stage, I noted that the right rear axle had VERTICAL play, maybe 3/16 inch. The left rear axle had non-measurable vertical play. It think this vertical play would cause the right rear brake shoes to touch the drum when the car was put back on the ground, making the shoes drag all the time, with resulting heat.


Lastly, I took the van to a shop. They claimed the axle end-play adjuster was so loose that it allowed vertical movement. They tell me they adjusted (tightened) it and removed the vertical play. The right rear was very hot after a short test drive . We're not sure where the heat is-axle, brake drum or ?

Thoughts or suggestions most welcome.

 

You have pretty well eliminated everything that can be eliminated.

I'm going to say that the wheel bearing on that side is bad. Is the center of the axle flange 400 degrees also? Or is it cooler than the outer part of the drum?

 

3/16” axle play is way to much. When on the ground all the weigh would be on the lower arc of the shoes against the drum. I’m surprised the van would move. I’d remove that drum, backing plate, axle and look at the housing. As a point I have no experience with that year MOPAR rear brake and axle system.,

 

My vote too. If that bearing was run that loose long enough to get it that hot, it's now bad if it wasn't already. The fact that its still running hot after being adjusted is confirmation IMO....

 

grooves worn in backing plates will hold shoes out or delay their return.

 

Thanks, I don't know if the axle flange is hot or cooler than the drum, Mr48chev, but I'll ask.

 

Btw..... 1969 is POST 65, not pre 65.

Have someone step on the brakes while turning that wheel. Keep trying when they release the brake and see if it takes a while for it to release. If it does, find out why. Did you replace the return springs?

 

Yes, thanks. What I meant was that the body style of the vehicle dates from 1964, so, in some respects and hopefully, fits the HAMB definition of pre-1965.

 

Next time you have the drum off on that side, shoot some pics from a couple different angles and post them here. Maybe even take a shot or two of the drum as well. Someone here may spot something that's out of place.

 

I would replace the wheel bearing, you know it needs it. If that does not help you will have to keep looking, but you have pretty well eliminated everything else.

 

Where's the heat being generated? Brake or bearing. You basically said it's not the bearing, so it must be the brake. You'd think you'd be able to tell if it's seriously dragging. The sloppy axle is the key suspect. You can't check it (shoe-to-drum contact, brakes not applied) while it's assembled and on the ground. Try putting a load on the wheel (by hand, with it jacked up) and see if you still have axle slop and can get brake contact (noise). Fix the sloppy axle problem.

 

Thanks. I'll pass these thoughts on. I am pretty sure no one thinks the bearing is the issue. I, personally, haven't seen the axle.

 

If the axle moves up & down 3/16'', you have a wheel bearing problem or a housing problem, or both. It's that simple.

 

What's an axle end-play adjuster?

 

sgtlethargic:
I have know idea on a dodge A100 but on a Speedway Engineering Full Floating rear end there are timkin bearings on the outside that you set pre-load on and grease separately. We have seals on the inside of the tubes to keep the rear gear oil in the center. (A lot of left turns in a 20 lap race)
If this van has a 3/4 ton truck floater we've been wasting a lot of time here trying to fix a non floater.

 

Some Mopars have an adjuster on one side to allow for bearing adjustment. They use a tapered roller bearing.

 

In the OP’s first post, among the things done to that date....includes having “replaced the right rear wheel bearing and seal”........

Ray

 

Jimmy six made a good point, those tapered bearings need to be packed with grease. I would pull the axle to inspect the bearing and service it if need be...

 

Is the exhaust exiting directly onto the right rear drum?

 

Black Sheep pretty well answered SGTlethargic's Post but yes, for several years Some Mopar axles had an end play adjustment on one side that you adjusted endplay with after you had had the axles out.
His post on packing the tapered bearings is spot on too. The bearings have to be packed when/before they are installed. There is a seal that goes in the housing that doesn't let gear oil get to the wheel bearing.

 

So the bolt end rides directly on the adjuster shaft with metal-to-metal contact? And that takes up vertical slack, versus end play (axial slack?)?

 

The adjuster face turns in against the race/cup. The bearing cone is held on the axle by a collar. It's been 30 something years since I had on of those apart and if memory serves right You adjust it so you have .010/.012 end play measured with a dial indicator.

 

If there is still vertical movement after the adjustment, you have a problem. If the wheel bearing has been changed, and adjusted, and there is still vertical movement, you may have problem with the axle, or the housing.

If there is no longer up and down movement of the axle, that problem has been fixed.
If there is still a brake problem, I believe that after you remove the brake shoes, you will see some groves worn into the backing plate flat sections where the shoes ride. You need to weld the grooves in the backing plate up and grind each flat surface back flat again. The worn groves worked OK with the old brake shoes because material was worn off the shoe linings and the shoes wouldn't drag against the drum. Now the new linings are thicker, and the new lining drags across the drum. If there are groves where the brake shoe contacts the backing plate that you can catch a finger nail on, it may be enough to cause a brake drag. I've seen groves over 1/4" deep and 1/4" wide. it was a wonder those shoes could even make contact with the drum., and new shoes caused the drum to be tight enough you couldn't turn it by hand. welded the groves up, ground them flat, added a touch of white grease to the flats to help not to cause another grove from forming. Gene

 

If he didn't pack the new wheel bearing with grease and pack it correctly that would be the issue. Unlike some others they don't get any gear oil from the housing to lube them.

 

I believe it does!...I believe the mods do as well...

 

Short brake shoe lining toward the front and long lining to the rear?

 

ooh,good thught

 

I have to point out that the owner and second mechanic are REALLY good and serious car guys. Think Gus Wilson. This one is a real stumper.

 

Both my truck and OT Hot Rod have Mopar 8.75” diffs, so I’ve been through this drill several times. There is a thrust button between the axles, end play is adjusted on one side. I try to set at .008 -.010

 

From my friend, Dave: "Is it possible for the thrust button in anti-slip differentials to come
out when the axle is removed? Seems There were two thrust buttons, back to
back, in the center of the differential. They were held together by a
small rod through the center of both. Sometimes the rod breaks, and the
thrust button comes off and lays in the differential case.

Do you have an exploded view of my 8 3/4 Mopar differential?"