warped drums... or not?

[stouchton]

Hi folks - got a simple question pertaining to "grabbing" drums, as in feel warped.

Was wondering if something else in the braking system can cause this feel?

My drums felt fine prior to pulling them to check bearings/seals. After putting her back together - paying good attention to rear hub torque and proper seating of front wheel bearings without being tight - I now feel like I have warped drums! I did make sure each drum made it back to where it came from.

The feel is bad enough for me to be considering purchasing new drums - just seemed funny that all seemed fine before?

Any thoughts appreciated.....

Scott

[Patrick L.]

Warped drums will pulsate more than cause a grab. I'm wondering if the leading edges on your shoes are not tapered and possibly causing the grab.
How do the wheels turn when they are off the ground ? Are they free, or just the normal touching just a bit ?

[Rowdy]

I had a grab on the chassis I bought for the delivery. Turned out the wheel studs had been welded in instead of being swedged. They were hitting the e-brake carriers and had bent the carriers. The brakes were supposedly rebuilt by a shop local to where I bought the chassis. Most of the NOS parts used for the rebuild were ruined during the work done or because of the way it was done or things overlooked like leaking seals. A real mess at any rate. Rod

[stouchton]

Wheels rub slightly when off the ground - rub for about 1/4 to 1/3 of a rotation and then spin freely. Seemed to recall it feeling the same way prior, and then I could not feel anything when braking.

It does feel like a pulsation when braking - seems like there is a momentary increase in braking force as the wheel rotates. Really feels just like a warped drum.

With other cars I would have simply changed / turned the drums. Just seemed kind of odd that it appeared after removing / remounting drums - has me wondering if I did something wrong......

[Patrick L.]

Originally Posted by stouchton

Wheels rub slightly when off the ground - rub for about 1/4 to 1/3 of a rotation and then spin freely. Seemed to recall it feeling the same way prior, and then I could not feel anything when braking.

It does feel like a pulsation when braking - seems like there is a momentary increase in braking force as the wheel rotates. Really feels just like a warped drum.

With other cars I would have simply changed / turned the drums. Just seemed kind of odd that it appeared after removing / remounting drums - has me wondering if I did something wrong......

Can you tell if the problem seems to be front or rear ?
Its pretty hard to do something wrong with the fronts, but, not so the rears. I'm wondering if a rear drum has a problem, such as, key not quite correctly installed, etc.
I know Ford says not to cut the drums [steel], but, I don't have a problem with cutting them just a bit.

[Mitch//pa]

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did you readjust them after packing the bearings?? maybe that set it off......
disconnect a brake rod one at a time to see how that changes it

[Jacksonlll]

If your wheels don't sit flat on the drum touch down point, you can pull the drum out of shape when you tighten the lug nuts. This happened to me when I had a little bit of "proud" weld that got between the wheel and drum.. Make sure they fit flat against the drum.

[bunnyc]

Are the lug nuts tightened with a torque wrench to the proper torque? Drums can be distorted by over tightening.

[stouchton]

Thanks for the input guys.

I think it is the rear - I have them adjusted to come in first.

Wheels are properly torqued, and seemed to mount just fine but it is worth looking at. The thoughts on the rear axle key are interesting because one key fought me......

I did repack the bearings and re-adjusted the brakes.

Looks like I will be pulling them off to take a look at! I did adjust them a little tighter - wonder if the leading edge could now be coming into play?

[stouchton]

OK.... fixed it, but not exactly sure what it was.

Decided to simply back off each adjuster one click and take her for a test drive.

Warped drum feeling was gone, and she braked well. With moderate pressure could lock up all four.

[stouchton]

Right now thinking the leading edge of the shoes are not tapered (trying to remember....).

Next time I have to pull the wheels off will check.