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Brake grind...I think.

Printed From:
Category: The Garage
Forum Name: Suspension, Steering, Brakes & Wheels
Forum Description: What makes it stop, turn, and smooths the ride
Printed Date: Jan/21/2020 at 3:45pm

Topic: Brake grind...I think.
Posted By: DocLong
Subject: Brake grind...I think.
Date Posted: Apr/17/2019 at 5:27am
65 Classic, Wagner brakes. Everything is new except the drum. I didn't install, I just removed the drums and was in shock.

When driving I get an RPM dependant grind. If I engage the parking brake a couple clicks it goes away. I've had the rear drums off several times and can't determine what's rubbing. 

Any thoughts?

Posted By: Trader
Date Posted: Apr/17/2019 at 6:20am
If it's a rubbing sound as you describe, then it's likely one of the pistons is sticking in the (wheel) brake cylinder. Applying the parking brake is resetting everything.
If applying the parking brake resets everything then likely everything is assembled correctly.
Try lubricating the usual places and bleeding that brake cylinder first.

Posted By: akimmet
Date Posted: Apr/17/2019 at 9:32am
Bad wheel bearings can also make noises like that.
This is because the brakes are also applying pressure to the wheel bearing which may make the noise louder, or go away.

Posted By: 6PakBee
Date Posted: Apr/17/2019 at 1:27pm
If it's truly a "grinding" sound, typically that is metal-to-metal.  You should see evidence of that either in a wear track or filings.  If it is a brake dragging, that is a different sound that usually leads to an overheated drum.  If you have an infra-red thermometer, take the car out for a drive and let it coast to a stop.  Then measure the temperature of the drums from the rear and see which one is the culprit.  Yes, you can use your hand but be careful, I got a nasty burn from a rear drum by just laying my hand on it.


Roger Gazur
1969 'B' Scheme SC/Rambler
1970 RWB 4-spd Machine
1970 Sonic Silver auto AMX

All project cars.

Posted By: tomj
Date Posted: Apr/17/2019 at 11:54pm
look inside the drum too for shiny spots. backing plates wear, shoes dont' stay parallel to the drum surface (cocked at an angle).

sound is in the rear only?

lift the rear on jackstands, in neutral. "jack" the wheel+tire up with a 2 x 4 or something. and/or shake the crap out of wheel and tire. it shouldn't move! see if you can wiggle the tire up and down. you should, or may, be able to feel axle end play, not a lot, purely in and out. there should be ZERO up/down fore/aft motion. put your ear near the axle tube end, rotate the wheel "fast". if you can hear the bearing rumble, it's (both) are bad. check both sides.

climb under and shake the crap out of the driveshaft. it ought not move or rattle at all.

with one rear wheel at a time jacked, and fronts blocked, start and put it in gear. that might make bad bearings rumble and roar.

if one side is bad, the other is too.

1961 roadster american, 195.6 OHV, T5
1968 american, 199ci, T96

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