Rear Brake Drag - Normal or Not?

[Pilotdave]

Have just rehabbed and installed right rear brake setup and the drum is dragging on the linings. Here's the background: new cast iron drum, new brake linings, drum turned and shoes arced. Replaced many small parts in the brake unit. Converted to Flathead Ted's floating brake set-up. On the rear brakes the only significant changes from stock are (a) different brake adjuster wedge (actually a two-piece arrangement with a floating wedge that's separate from the adjusting screw) and (b) long spring is not used. I checked the shoes for centering - that seems fine.

With adjusting screw at loosest position, the drum drags. I can turn it with one hand fairly easy. Is this amount of drag okay? Or do I have an issue to fix?

Thanks for your help.

[Bubby Sharp in KY]

Pilotdave, You might try tapering the ends of the shoes as the ends of the shoes have a tendency to stick up a little . Good luck with the FH floaters. I couldn't keep mine from squeeling and grabbing especially on the first stop of the day . Took floaters off and got rid of squeel and grabbing. You might also check the parking brake for drag.The rivets on the end of the band that rides on the carrier must have the rivets countersunk slightly to keep from sticking up . Let us know if yours have any issueswith grabbing. Bubby Sharp in KY

[J Franklin]

How much has it been driven after the work was done? You might just have to work them in a bit. How much drag?

[Mike V. Florida]

There are several other posts refering to not being able to even get the drums on the car with new linings. Seems like the new linings are thicker then older versions.

If they are adjusted as you say I'm with J Franklin You might just have to work them in a bit.

[BRENT in 10-uh-C]

Have you put the ommitted spring back on the shoes to see if the dragging goes away?

Did you mic the outer diameter of the installed shoes to see if the new lining is indeed too thick? Many variables at this moment so anything said is purely a guess.

[1931 flamingo]

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It may be the e/brake lining dragging. Did you "center" the shoes, I see you had shoes arced. Otherwise I would continue assemblying the other side and put some miles on it to wear in. JMO
Paul in CT

[columbiA]

I have teds floaters & I love them.A slight drag will be OK.Drive around for awhile with out useing the brakes & see how hot the drums are. If barely warm I wouldnt worry about it.As for thepark brake lining,Ive always had to grind the repop lining a bit to get the drum to go on.It could be that lining that is dragging.

[Pilotdave]

Thanks, everyone. Not an inch driven yet - I have 3 more corners to do! The e-brake could be dragging but I didn't replace them. The main source is the service brake. The amount of drag is enough so the drum won't turn freely at all. I can't adjust it to lighten the drag. I have to put some energy into turning the drum. The drag is not enough to lock it up. Both ends of both shoe linings are tapered. I did not mic the shoes after installation as I am not equipped to do so. I did center the shoes - they were good as installed, perhaps because I had the tracks rebuilt and ground to 1" from the rivets.

The challenge for me is that the written advice is that there should be a "slight drag." I don't know how much "slight" is, nor have I found any good way to translate what I am finding into "slight." I posted about this because the amount of drag I have seems more than it should be, but I have no experience on which to base that. Open to any suggestions!

It could be, as some suggest, that I need to assemble everything, adjust it and drive it some. At this point, I haven't even cycled the brake on and off, let alone driven it.

Thanks again!

[pat in Santa Cruz]

Even if your E brake lining is the old one, new drums seem to be tight there. Try them without the service brake shoes to determine exactly where the drag is. If it is the service shoes, one thing I have found is that the old grease and dirt behind the adjuster wedge, ground into the back of the bore, can hold the adjuster out as much as 3 revolutions. With new shoes, one revolution will create drag. Remove the adjuster and see if you can clean any crud off the backing plate where it bottoms out so you can retract it just a bit further.

[Pilotdave]

Pat, thanks for the idea. I can see how such a build up would be a problem. In this case, I have fully disassembled everything and cleaned the backing plates. I'm pretty certain that I cleaned the adjusting screw bore, but it's worth checking.

I'm saying it's the service brake as the adjuster was turned in a couple of turns initially and the drum wouldn't go on. I turned the adjuster all the way out and the drum went on. Could be having trouble with the e-brake shoe, though, and I would have no way to know that at this point. I can remove those shoes and see if anything changes - easier to do than removing the service brake shoes.

Will report further!

[columbiA]

With new CI drum, the E brake bore may be a bit smaller ID than old worn drum.Also as has been said, make sure adjuster wiil screw all the way out. Remove a brake shoe & peer in & see if adjuster wedge is right back to the BP as far as it will go.I like to run a tap thru the adj hole to clean up the threads & use anti-seize on the threads when reasembling.Just 1 turn short of full release can make a difference.

[Pilotdave]

Good point about the cast iron drum e-brake diameter. Hope to check this Friday. I did run a thread cleaning tap through the adjusting screw hole.

[Patrick L.]

While you have the drum off, just for the heck of it, try and turn the axle to see how much,if any, drag the differential is causing..

[Purdy Swoft]

If the bearing race on the outer end of the axle housing is worn bad enough, it will cause the brakes to drag when the tire is on the ground.. The bottom of the axle housing where the bearing rolls is where the wear happens, because it carries the weight of the car. You can feel the bottom of the race with your hand and if it is badly worn it will be obvious. This condition will cause the brake lining to drag on the bottom of the drum when the tire is on the ground. If the housing is badly worn it can be turned down and sleeved back to original specs. Being as I have a large collection of disassembled backends, I usually just replace the housing.

[Pilotdave]

Okay - investigation done and - I believe - problem resolved. First, responses to new suggestions.

I can easily turn the axle with my hand - no real differential drag.

I did inspect the axle housing and the bearing for noticeable wear. My finger check said they were okay.

There was a very small amount of debris in the bottom of the adjuster core.

Now to the resolution.

Several of you pointed me in the direction of the e-brake linings. I removed the e-brake shoes, reinstalled the drum, and the drag dropped substantially to what seemed to be a very reasonable version of "slight." I sanded the e-brake lining so that there is no appreciable difference between the drag with and without the e-brake installed. Eureka!

Thanks to everyone who offered ideas. I have to confess that I nearly ignored the e-brake theory since I "knew" that it wasn't the cause of the problem. The moral of this story is that one needs to listen carefully to all the suggestions and questions - even those one is "sure" don't apply.

I think that I am now on the right track. Let's see if I can get through the left rear on my own!

[Jim Parker Toronto]

Dave, have your drums measured to make sure that they are 11.000' + .005 and that the E-brake is 9.625" + .005. While the E-brake is a "static brake", you really don't want it rubbing the new drum. You will not see any significant wear on these linings.

[Pilotdave]

Jim, I could see some wear on the e-brake lining, but that came from the old (now discarded) steel drum. E-brake isn't rubbing the new drum based on the "feel test" for drag. I will check with my machine shop buddy about measuring the drums.