69 Charger Front Brake Drum Catching on Backing Plate

[robl72]

Hi All,

Cant figure this one out. I have 11 x 3 front OE drums on my 69 Charger R/T 440. I took it to get aligned and was told my drivers side lower ball joint was bad. I took it home changed both lower ball joints, and figured I would change the brakes, bearings, raceway and seals as well.

The passengers side hub tightened down to spec and I adjusted the brakes no problem. On the drivers side when I tighten up the hub to spec the backside of the drum catches on the rim edge of the backing plate. Like I said new bearings, races and seals all installed correctly. Does anyone have any idea why this would happen. I found what I thought was a high spot on the backing plate rim and attempted to grind some off. Each time I take some off it still catches in the same spot.

Only thing I will say is that when I originally took both drums off I noticed that the drivers side was looser and had some end play. Now I am thinking it was not tightened down previously for this same reason.

Any thoughts on this?

If I did not make something clear in my question please ask for clarification. This is not an easy one to articulate.

Thank you!

 

[pnora]

You could try the drum and bearings from the other side and see what happens.

 

[robl72]

Sorry forgot to mention that I did do that and the same thing happened. I though maybe it was the spindle but it looks fine and the bearings seem to sit properly. I can see that whoever rebuilt this they did use the foam axle to backing plate gasket as required and it appears that it squashed down OK....Do you think I need to keep grinding on this high spot?

 

[pnora]

Sorry forgot to mention that I did do that and the same thing happened. I though maybe it was the spindle but it looks fine and the bearings seem to sit properly. I can see that whoever rebuilt this they did use the foam axle to backing plate gasket as required and it appears that it squashed down OK....Do you think I need to keep grinding on this high spot?

Something does not sound right. Without seeing it its hard to say whats wrong. With trying the drum swap it almost seems like the backing plate is bent. Can you post some pictures?

 

[493 Mike]

Sounds like it could be a bent spindle. Dukes of Hazzard car?
Mike

 

[robl72]

Sounds like it could be a bent spindle. Dukes of Hazzard car?
Mike

This maybe a stupid question but how do I confirm this? obviously by eyesight it looks OK.

And no not a Dukes of hazard car... just the opposite this thing is babied...LOL...

 

[pnora]

This maybe a stupid question but how do I confirm this? obviously by eyesight it looks OK.

And no not a Dukes of hazard car... just the opposite this thing is babied...LOL...

If it did not do this before I would be measuring races and bearings. Its possible that one is made wrong and locating the drum closer to the backing plate. As said possible bent spindle. You could swap the backing plates from side to side.

 

[Car #4]

Could be a bent backing plate, I've had it happen. Like pnora said, switch the backing plates and see if the problem moves. You'll either find the problem or eliminate one possibility.

 

[robl72]

See the below pics. If you look close at the first pic you can see the wear mark on the backing plate edge. if you look at the third pic you can see the slight mark its making in the drum rim. Not sure if the pics of the spindle help at all.

I will take a look at the raceways and the bearings. They are NOS Timkens, USA made and they seemed to be fine when I installed them.

The backing plate and the spindle do not look bent by just looking at it, so not sure which way to go with this.

If I didn’t make it clear in my previous post . I have already removed the brake shoes and began grinding material off of the edge that shows the wear spot… I believe I took off quite a bit but it is still catching in the same spot.
I may keep grinding on that spot on the backing plate.

Thanks for everyone's input.

 

[1STMP]

If the drum hits in the same
spot after it's been installed
on the spindle (different
drum orientations), the
spindle is bent.
If the drum were to make
contact at various locations
on the backing plate (at
different drum orientations),
the problem would be in the
drum.
I agree with others here.
Bent spindle.

 

[Car #4]

A bent backing plate would produce the same results.

 

[1STMP]

A bent backing plate would produce the same results.

If it were the backing plate,
only one corresponding
mark would be on the drum,
unless the drum was
reinstalled on different
orientations according to the
lugs. An indicator as to
what is actually going on.
If it is the backing plate,
a good wack with a big
hammer should clearance
the plate and drum. Use a
punch on that spot.

 

[robl72]

All done. I kept grinding on the backing plate and eventually took off enough material to get it to work. Bottom line was that the spot that was catching was larger than the remaining circumference. I put a micrometer on it and found three inches of the backing plate rim were cast larger than the rest. Not surprised for Mopar but I don't understand how it was not a problem previously. Anyway I was able to torque it down according the service manual and back it off a space and set in the cotter pin. Spin the drum and moves perfect with no catch.

Thank you for everyone's replies.