The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 05-11-2009, 12:17 PM   #1
ZombieWeinerDog
Registered User
 
ZombieWeinerDog's Avatar
 
Join Date: Oct 2008
Location: Sparta, MI
Posts: 446
Another Brake problem

My rear drum brakes are new and sometimes when i press the brake hard enough, the rear end of the truck starts to shake very badly. wuts wrong?
__________________
1972 longbed- 454
1967 shortbed- 355
ZombieWeinerDog is offline   Reply With Quote
Old 05-11-2009, 01:15 PM   #2
68gmsee
Active Member
 
68gmsee's Avatar
 
Join Date: Jul 2007
Location: Centrally located between Houston, Austin and Waco. BCS area.
Posts: 7,947
Re: Another Brake problem

Quote:
Originally Posted by ZombieWeinerDog View Post
My rear drum brakes are new and sometimes when i press the brake hard enough, the rear end of the truck starts to shake very badly. wuts wrong?
Does this mean it does only when you really press hard like for a quick stop?
Also, did it start right after you replaced the rear brakes?

Rear brakes are mainly assisting the front brakes under normal braking conditions. When you really stomp on them then they will come into play and are desingned to wedge themselves under a quick stop.

Several things may cause rear brake shaking.

1. defective brake shoes- grabby, contaminated with oil, cheap material.
2. shoes not mating evenly with the drums.
3. out of round or warped drums.
4. rear drums not smooth
5. bad rear shocks
6. worn axle rubber bushings
7. worn trailing arms bushings

Lots of things, but the thing is to eliminate them one at a time.
68gmsee is offline   Reply With Quote
Old 05-11-2009, 02:15 PM   #3
ZombieWeinerDog
Registered User
 
ZombieWeinerDog's Avatar
 
Join Date: Oct 2008
Location: Sparta, MI
Posts: 446
Re: Another Brake problem

Quote:
Originally Posted by 68gmsee View Post
Does this mean it does only when you really press hard like for a quick stop?
Also, did it start right after you replaced the rear brakes?

Rear brakes are mainly assisting the front brakes under normal braking conditions. When you really stomp on them then they will come into play and are desingned to wedge themselves under a quick stop.

Several things may cause rear brake shaking.

1. defective brake shoes- grabby, contaminated with oil, cheap material.
2. shoes not mating evenly with the drums.
3. out of round or warped drums.
4. rear drums not smooth
5. bad rear shocks
6. worn axle rubber bushings
7. worn trailing arms bushings

Lots of things, but the thing is to eliminate them one at a time.

well its not shocks, there brand new. it doesnt happen alot, but it happens when i push the brakes hard enough to stop pretty fast
__________________
1972 longbed- 454
1967 shortbed- 355
ZombieWeinerDog is offline   Reply With Quote
Old 05-11-2009, 02:51 PM   #4
68gmsee
Active Member
 
68gmsee's Avatar
 
Join Date: Jul 2007
Location: Centrally located between Houston, Austin and Waco. BCS area.
Posts: 7,947
Re: Another Brake problem

Well, that's one of the list.

If I were to venture a guess, I'd say something to do with the shoes. I've gotten some real crappy shoes in the past. Parts just ain't what they used to be.

One thing that can happen with new brakes is the mating surface hasn't conformed to the drum so it may take some time for them to break in. In the past, I've had them turned at the same time I did the drums but I'm not sure they do that these days.
68gmsee is offline   Reply With Quote
Old 05-11-2009, 02:55 PM   #5
Bus Ted Knuckle
Son of a gun
 
Bus Ted Knuckle's Avatar
 
Join Date: Jan 2007
Location: Hot Springs, Arkansas
Posts: 1,636
Re: Another Brake problem

So you drums are new? If not, I'd say they are warped. If they are new...take em back and try another set.
__________________
Bill

BEATERS ARE NEATER
Bus Ted Knuckle is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 10:57 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com