86 Caprice Rear Brakes Vibrating/Pulsing

The rear Brakes of my car were pulsing (I have already done a complete front
brake job). I changed the drums, but not the shoes as they still look good.
I sanded them a bit. With the new drums the brakes went from pulsing to
vibrating. Today I jacked the car up and made the hubs spin with the engine.
There is little to no side to side movement but definitely a bit of up and
down movement on the outside edge of the hubs. There is little play in the
bearings. . The vibrating seems to get worse as the car is driven. Do I just
need new shoes or could axle runout be an issue? I have worked on these
models for 25 years and never encountered this problem...
Thanks

On Dec 9, 2:43 pm, "Big Al" > wrote:
> The rear Brakes of my car were pulsing (I have already done a complete front
> brake job). I changed the drums, but not the shoes as they still look good.
> I sanded them a bit. With the new drums the brakes went from pulsing to
> vibrating. Today I jacked the car up and made the hubs spin with the engine.
> There is little to no side to side movement but definitely a bit of up and
> down movement on the outside edge of the hubs. There is little play in the
> bearings. . The vibrating seems to get worse as the car is driven. Do I just
> need new shoes or could axle runout be an issue? I have worked on these
> models for 25 years and never encountered this problem...
> Thanks

How do you know it is the rears?! What do you mean by "pulsing"?!

Big Al wrote:
> The rear Brakes of my car were pulsing (I have already done a complete front
> brake job). I changed the drums, but not the shoes as they still look good.
> I sanded them a bit. With the new drums the brakes went from pulsing to
> vibrating. Today I jacked the car up and made the hubs spin with the engine.
> There is little to no side to side movement but definitely a bit of up and
> down movement on the outside edge of the hubs. There is little play in the
> bearings. . The vibrating seems to get worse as the car is driven. Do I just
> need new shoes or could axle runout be an issue? I have worked on these
> models for 25 years and never encountered this problem...

I'd first be sure the drums themselves weren't out of round. Chinese?

--
Dec. 6 (Bloomberg) -- Government officials and activists flying to Bali,
Indonesia, for the United Nations meeting on climate change will cause
as much pollution as 20,000 cars in a year.

I can tell it<s the rears cause the vibration is felt in my butt, not in the
steering at all (front brakes are completely new), the car stops straight
too. I cheeped out not changing the rear shoes when I changed the drums.
Might be a bad interaction with the old shoes and new drums?

They are Monroe, I believe made in the states or Mexico, I though of that
too, switched them around this afternoon, the vibration is less but still
coming from the driver"s side. I will try new shoes soon, should have done
it in the first place.


> I'd first be sure the drums themselves weren't out of round. Chinese?
>
> --
> Dec. 6 (Bloomberg) -- Government officials and activists flying to Bali,
> Indonesia, for the United Nations meeting on climate change will cause
> as much pollution as 20,000 cars in a year.

"Big Al" > wrote in message ...
>I can tell it<s the rears cause the vibration is felt in my butt, not in
>the steering at all (front brakes are completely new), the car stops
>straight too. I cheeped out not changing the rear shoes when I changed the
>drums. Might be a bad interaction with the old shoes and new drums?

Try using the parking brake to slow the car. Do you feel the vibration then?

Did you have the new drums turned? They could have been stored/shipped
improperly and be out of round.

Yes, to be sure I used the parking brake, the problem is in the back.
Never thought of having the new drums turned, but that might find/solve the
problem.
Thanks




"> > Try using the parking brake to slow the car. Do you feel the vibration
then?
>
> Did you have the new drums turned? They could have been stored/shipped
> improperly and be out of round.
>

The old drums were ancient, probably only the second set on the car, so who
knows...

"Steve Austin" > wrote in message
...
> Big Al wrote:
>> I can tell it<s the rears cause the vibration is felt in my butt, not in
>> the steering at all (front brakes are completely new), the car stops
>> straight too. I cheeped out not changing the rear shoes when I changed
>> the drums. Might be a bad interaction with the old shoes and new drums?
> If the old drums were turned oversize, the old shoes will be worn in to an
> oversize diameter. They will hit on the edges first. Most noticeable as
> a "grabbiness". Try new shoes.