brake shake

[aaadave]

well, got the 10'' brakes on the dart and all seems to work good. they only problem i have is brake vibration. when you get down on the brakes, it shakes just like disk brakes will when the rotors are warped. can these drums warp and cause this? they look to be in good shape. thanks, dave.

 

[Purple Haze]

Might be a bent backing plate.

 

[slant6/4speed]

Drums do not warp so much as they get out of round. Did you have the drums checked or turned before you put them on?

 

[aaadave]

could be maybe, it does it on both sides. if you go slow and hit the brakes lightly. you can hear the shoes scrubbing off and on just like the drum is out of round. i changed out my 9'' brakes for these and everything came from the donor car including the shoes. the drums were changed at one time because the lug knurls were cut down. dave. edit. sorry slant/6, i was typing while you were posting. no i did'nt check the drums for anything, i just installed everything at one time cause it all looked good. might just get some new drums and try that.

 

[slant6/4speed]

Measure first, you maybe able to just have them turned.

 

[1968FormulaS340]

Contamination on the shoes and/or drum during assembly.

 

[aaadave]

ya, could be the shoes, they were pretty grungy from what looked like an old seal leak. cleaned them up with brake cleaner then hit them with sand paper, but might be to far gone. i'll try some new shoes before i go any farther. thanks, dave.

 

[67Dart273]

From the SOUND of your post, you are trying to "get by" and that's not gonna work.

Shoes that are worn "in" to one drum cannot be expected to seat decent in another drum with a different wear pattern, so if you happened to swap sides, that right there is enough

Grungy, oily/ greasy/ used shoes are NOT down the road to good brakes.

Drums that are out of round, worn uneven, or worn "big" are not on the "good brakes" list, either.

MINIMUM I'd buy new quality shoes, and have the drums turned AND CHECKED for diameter. Most passenger car drums cannot be legally turned more than .060. The PROBLEM with "worn big" or "turned big" (oversize) drums is that ONLY THE CENTER area of the shoe contacts the drum--because now you are putting a "small circle" (the shoes) into a "large circle" (the worn drum. It will NOT stop well. You will glaze the center area of the shoe surface, and it will cease to stop much, meanwhile, the OUTER areas (tops and bottoms) of the shoes won't be doing ANY work.

It's a mess. Do it right.

 

[cosgig]

Yep, one thing about brakes is that you need to have everything perfectly clean and above all "new" when you do the brakes. That means no used shoes, which have been glazed by use and will not clean up no matter what you do. Also, when you turn the drums, they are mounted on the lathe by the bearing races, so they should turn true to the bearings, and thus the spindle. Of course, they could be off when mounted and probably are a little, as nothing done off the car will ever be perfect ewhen reinstalled, but they should be close. I vote for new shoes, and a fresh turn on the drums again to match the new shoes. Make sure you adjust them too, that'll go a long way to correct operation. And, with drums, they need to be re-adjusted often to keep them working at their peak!!! Good luck, Geof

 

[chryslerfat]

Also if you can pull the drums because they are free from the hubs the face of the drum could be bent causing the pulse. I would start with drums and new shoes.

 

[packerman16]

i agree with all that has been said on the brakes,
i have found on ocassions the wheel breaings will cause shaking .
just my 2 cents ,i worked on brakes around 40years.