Brake Drum Mounting and Binding on Brake Backing Plate

[Jeeps4Brains]

I have been rebuilding the front axle from the differential bearings outward. I have followed the Manual all the way. I have bolted the hub flange on, then the brake backing plate, mounted the slave cylinder and shoes, seated the bearing races and greased the bearings, seated the inner hub seal and tightened the axle retaining nut all to specs. The brake shoes are backed all the way off.

Here is the problem: when I mount the break drum and start to tighten the flat head retaining screws it is hitting the brake backing plate and dragging. It is not constantly touching and dragging but as you really tighten the flat head screws like I feel they should be and rotate the hub it drags bad and is hard to turn. When I take the drum off I can see where it is dragging on the brake backing plate and the drum has paint residue on the back edge of it.

The previous owner had purchased bearings number 18590 and races 18520. Are these the correct bearings and races? Maybe they are too short in stack height and let the hub mount deeper on the Axle hub?

If the bearings are right does the backing plate need to be bent backwards? How much clearance is normally between the drum back edge and the backing plate?

Any ideas would help.

[wesk]

You've got it all in the right order and the correct bearings. That leaves a bent back plate, incorrect drum, or incorrect back plate. There is generally about 1/32" to 3/32" clearance.
_________________
Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100

Mjeeps photo album: http://www.willysmjeeps.com/v2/modules.php?set_albumName=Wes-Knettle&op=modload&name=gallery&file=index&include=view_album.php

[Jeeps4Brains]

I thought about the drums but they are the ones that came off the Jeep to start with. I even took one of the rear drums off and compared it to the front ones and it looks the same.

I had another thought. What if when it was painted the paint pooled in the valley that the drum runs in. It could add about 1/32 to the surface. I might try removing the paint before I try bending the brake backing plate. Bending the plate mounted on the axle might be tricky as it holds all the break components.

This reminds me of when I restored a Mustang speedometer and painted the needle with florescent paint. Well the paint was too thick and heavy. The needle would struggle to get to the vertical and then flop down to about 120mph. LOL And it only had a 6 cyl.

Thanks, Wes. I will post what happens.

[Jeff_H]

Also make sure the drum is sitting flat on the plate behind it. When I reassembled my drum after changing the wheel cylinder it rubbed against the backing plate after I did the screws up tight. Turned out it had not seated squarely. I now do not use the three screws to pull the drum in place but use a rubber mallet to make sure it is seated squarely. Perhaps you could try omitting the screws and tightening the drum on with the wheel in place using the wheel nuts. I f all OK go back and put the screws in.

Jeff H

[Jeeps4Brains]

Well everything worked out. There was not too much paint on the backing plate but too much paint on the base of the hub. Like Jeff said using the screws to seat the drum does not ensure that it gets seated evenly.

I had to take a small chisel and carve off some layers of paint primer and rust encapsulator just around the base of the hub to allow the drum to seat. Then it was much better but the drum was still warped. So I had to buy new drums. Now there is no problem.

Just goes to show that too many layers of paint sometimes can cause problems.

Since this is the first milestone for the Jeep I plan on taking pictures of the finished front axle and posting it for show. Now it is time for Knuckle Pudding

[DJ]