Vibrating, rumbling when braking above 45 mph

[371RR]

I have a 71 Roadrunner 383 I purchased about a year ago. It has the large 11" drums all around. Anything above 45-50, when braking, even gently, It will vibrate or grumble, nothing below about that speed. I just replaced everything over the weekend; drums, shoes, springs, adjusters, wheel cylinders, etc., with premium good parts, nothing cheap and I still have the problem. From what I can tell everything is tight and it is smooth as silk even towards 100, until I touch the brakes. It has only clocked 78,000 miles, but It does not look like the upper a-arm bushings have been replaced and I doubt the LCA's have been rebuilt. I saw nothing unusual with the parts I took off and still had quite a bit of shoe material left. The shoes came off with the shorter length material on the front shoes, so that is the way I installed the new ones. Any thoughts?

Thanks........!!!

 

[Basket case]

check the idler arm. Mine did the same thing and there was slop in the idler.

 

[371RR]

check the idler arm. Mine did the same thing and there was slop in the idler.

Will do......Thanks!

 

[furyus]

I had a Dodge truck do that. Turns out it was the new drums I put on. Put the old ones back on, no issues.

 

[Dennis H]

www.musclecarbrakes.com

 

[badlite]

Master cylinder might be sticking, holding shoes against drums a little to tightly.

 

[Cranky]

Did you have the drums checked for true? Old ones and the new ones? I've seen new drums have run out too.....just because they are new doesn't mean they are right.

 

[Basket case]

yup...used to go thru alot of new parts at the parts store that weren't any good.