AMC Eagle Den Forum

The Shop => Axle / Differential => Topic started by: Jurjen on May 15, 2011, 05:58:45 AM

Title: Driveline vibration: rear brake drums and shoes
Post by: Jurjen on May 15, 2011, 05:58:45 AM
Some of us have drive line vibration and the most common causes are:

- unbalanced tires.
- brake drum lost its balancing weight.
- dented unbalanced drive shaft
- sloppy transmission mounting
- universal joint problems
- rear wheel bearings
- wear in the rear differential.

I have checked all these items, everything was OK, but I still had a little vibration above 60mph.
This year before the yearly inspection I wanted to give the emergency brake cables a good grease job.
I dismantled the rear brakes and noticed that, after removing the three little retainer screws, the drums were hard to remove. 
This is caused by the brake shoes: there is wear inside the drums, but a small rusty "ridge" of material is left and
the drum is "clamping" over the brake shoes. To make removing the drums easier next time, I removed the ridge with a course round file.
After assembly I took it for a test ride and the driveline vibration is gone!
My theory is that the brake shoes are normally scraping this "ridge" , turning it into a vibration above 60mph.
I just wanted to share this information.






Title: Re: Driveline vibration: rear brake drums and shoes
Post by: eaglesx4 on May 15, 2011, 07:22:24 AM
I had the same thing happen in 2007.  I had forgotten about that one.  One of the techs where I worked kept telling me it was the brakes and I disagreed.  After a few weeks of this, I gave him the car and told him to fix it.  Vibration was gone and it was in the rear.
Title: Re: Driveline vibration: rear brake drums and shoes
Post by: IowaEagle on May 15, 2011, 10:13:49 AM
Same thing happened to me a few years back.  Brake job cured it too.
Title: Re: Driveline vibration: rear brake drums and shoes
Post by: A-A EAGLE on May 15, 2011, 01:28:56 PM
Hey Jurjen,

The Dutch are doing well with all thoose good tips andt tricks!

Anjo
Holland
Title: Re: Driveline vibration: rear brake drums and shoes
Post by: tougeagle on May 26, 2011, 08:13:02 PM
Quote from: Jurjen on May 15, 2011, 05:58:45 AM
Some of us have drive line vibration and the most common causes are:

- unbalanced tires.
- brake drum lost its balancing weight.
- dented unbalanced drive shaft
- sloppy transmission mounting
- universal joint problems
- rear wheel bearings
- wear in the rear differential.

I have checked all these items, everything was OK, but I still had a little vibration above 60mph.
This year before the yearly inspection I wanted to give the emergency brake cables a good grease job.
I dismantled the rear brakes and noticed that, after removing the three little retainer screws, the drums were hard to remove. 
This is caused by the brake shoes: there is wear inside the drums, but a small rusty "ridge" of material is left and
the drum is "clamping" over the brake shoes. To make removing the drums easier next time, I removed the ridge with a course round file.
After assembly I took it for a test ride and the driveline vibration is gone!
My theory is that the brake shoes are normally scraping this "ridge" , turning it into a vibration above 60mph.
I just wanted to share this information.








Keep in mind that drums also have a minimum thickness and if you are developing a ridge it means they may not be machinable.... thanks for the tip also :)