Brakes Getting HOT

[jackf]

Have standard 9 inch rear end, small bearings. Put new shoes, hardware, and drums on.  Wheels spin freely.  Drums come off easily.  No binding.  After 20 mile drive, backing plates are so hot you will blister your hand if you touch them.  Aluminum wheels are actually getting hot.  No evidence of binding or shoes rubbing when car is sitting still. Rolls easily.  Will coast down slightly inclined driveway if in neutral.  Please help.  Unsafe to drive at present.

 

[1sostatic]

Another friction point is bearings - normally associated with some noise though.

 

[Stanglover]

This is NOT a dumb question because I've done it myself, as have many others I'm sure. (we just don't freely admit it!)

Did you forget to release the parking brake or make sure it was completely released? If you've had the brakes apart, is that mechanism connected correctly. Again I say this because I've just done my rear brake drums, first time in many years, and I needed to redo the parking brake levers.

I would double check everything, redoing it all if necessary. Also are the shoes on the correct sides of the drum. If all is good, then definitely bearings need to be checked.

 

[jackf]

Should have mentioned that I thought bearings first, so I replaced them with new Timkins. Also replaced seals while I was in there. Parking brake is not on, but when I was messing with it yesterday with rear end off the ground I discovered that if I put the parking brake on the drivers side wheel locks but the passenger side spins freely. Not good, but probably unrelated to problem as both sides heat up. Again, drums slide off very easily, no binding possible when sitting still. Can't imagine what, but almost like something changes once car gets rolling. Very confused. Thanks for the help !

PS Wheel Cylinders are new as well.

 

[B229218]

Should have mentioned that I thought bearings first, so I replaced them with new Timkins.  Also replaced seals while I was in there.  Parking brake is not on, but when I was messing with it yesterday with rear end off the ground I discovered that if I put the parking brake on the drivers side wheel locks but the passenger side spins freely.  Not good, but probably unrelated to problem as both sides heat up.  Again, drums slide off very easily, no binding possible when sitting still.  Can't imagine what, but almost like something changes once car gets rolling.  Very confused.  Thanks for the help !

Sounds like adjusters installed wrong side(s) I did this once. also, make sure return springs are new and play with them to see if they return spring.  Are cylinders new? You could get a brake pressure gauge and see differences of L to R pressure .

 

[Stanglover]

Those adjuster can be very confusing especially you don't keep them separated. I made that mistake! I needed to physically check the thread rotation to make sure I had left and right correct. Very important. Good point.

 

[Carolina_Mountain_Mustangs]

Just tossing something out there. Is there any wear showing up on the rest pads for the shoes on the backing plates?  I think the shoes have I believe 3 formed areas on each of the metal shoes that hold the lining. This was formed to give the shoe a better contact area. Check your backing plates and see if there is a step worn in the embossed areas. Would it be possible that the shoes go out to the drum and get hung on a step on the baking plate? If there is a step take a small grinder with sanding disc and smooth out the area. Also put a small amount of dics brake lube on the surface. 

Also are the springs that hold the shoes back on the baking plates in good shape do you have the cups for the springs turned the right way? Depressed center going into the spring so it sits flat on the shoe and seats properly.

 

[1sostatic]

Hmmm  :chin:

have the right diameter shoes been installed ?

 

[mjlan]

Primary and Secondary shoes in the right spots?

 

[jackf]

Took car to brake shop. They said all was well. Turned out of round drums (brand new) and bled air from front brakes. Drove it home. Driver side fine. Passenger side hot as heck. Drum untouchable. Wheel very hot. Could wheel cylinder (brand new) be sticking or something ?

 

[Don C]

Jack up front of car, remove wheel, push brake pedal down firmly and release. Turn drum, see if you feel any dragging.

Another possibility is a bent spindle, which pushes the drum against the brake shoes. Inspect the shoes and drum for any unusual wear marks.

Are bearings adjusted properly? Are the races seated properly?

 

[Carolina_Mountain_Mustangs]

In the past I have seen the rubber brake fluid lines deteriorate inside and work like a check valve. Once pressure in in the cylinder and you release pedal the fluid takes time to bleed back keeping brake on.  I would take the hose off of the one that heated up and check inside. Or simply replace them.

 

[jackf]

Took car to brake shop.  They said all was well.  Turned out of round drums (brand new) and bled air from front brakes.  Drove it home.  Driver side fine.  Passenger side hot as heck. Drum untouchable. Wheel very hot.  Could wheel cylinder (brand new) be sticking or something ?

Changed wheel cylinder, no joy.  Took drum off and watched brakes as wife pushed brake pedal - shoes were hanging up, not returning.  Bought new shoes.  Found deep gouge in one of the three contact points on backing plate.  Polished all of them, greased em up, put on new shoes and problem is gone.  Not sure what exactly fixed it, but it's fixed.  Thanks to all who helped me on this.  My car would not run without you !

 

[Bill73Ragtop]

If you found deep grooves (gouge) in the contact pads, you may need to to monitor them. If you ground the material away enough to eliminate the grove, material will be pretty thin.

One solution used to be fill the grooves with welded bead and grind smooth & level, otherwise replacement of the backing plates.

 

[boilermaster]

Jackf,

Glad you got your problem sorted, a couple of things to consider when dealing with drum brakes and backing plates and wheel bearings.

Don't just take it for granted that the backing plates are true to the axle flange/ wheel hub.

Backing plates can and will bend and the same holds with the brake shoes themselves.

When doing a drum brake job, take the time to lay the shoes on a known flat surface and make sure all 3 contact pads line up on where they are going to rest on the backing plate. do NOT ask why I know this! .

also I like to use a simple sliding square from the axle to the contact pads of the backing plate to assure that all 6 are of equal distance to the flat on the axle flange.

Also bear in mind when adjusting drum brakes on a lift that there is no load on the wheel bearings, and any wheel bearing play WILL make your brake shoe to drum clearance tighter with the car weight on it. this is much more of a problem where the axle is actually the inner race I.E. chev dodge where the rear whwwl bearing presses into the housing and not on the axle.

Boilermaster