Nasty vibration coming from the rear brakes

[johnny625]

Ok now, after doing the rear brake shoes on my Cit xsara, I have a nasty vibration coming from the rear brakes. It seems to happen when I brake from higher speed only, no vibration when going straight or when cornering. 

I can also make the vibration happen by lifting the handbrake slightly when going at speed. 

What I have checked so far:

The rear brakes are adjusted properly and the handbrake has a good hold. 

No significant brake shoes dragging when turning the wheels by hand, there is some though (I do believe that there needs to be some slight drag anyway) 

I don't think its the rear beam itself, doesn't look knackered at all, tbh

I don't think its a wheel bearing issue as there is no noise or no play when the wheels are jacked up. 

The brakes are good, simply the whole rear of the car vibrates when braking from higher speed. 

Could simply brake drums be warped like brake disks? 

[DeeTurbo]

Yeah could be.

Have you had the tires balanced recently?

[welshpug]

get it on a brake testing roller, should be able to tell quite quickly if the drum/s are ovalled or have uneven corrosion.

[johnny625]

The tires are balanced.

It must be the drums.

[Martin306]

The tires are balanced.

It must be the drums.

I'd still swap back to front just in case any weights have come off that you've not noticed.

How did they suddenly become warped? Think about it, you've only changed the shoes, no?

Another point to note, sometimes cheap shoes can give you this problem until they bed in, I had a vibration issue on my 106 drums and I filed a chamfer on the leading edge of the shoes which fixed the vibration.

[johnny625]

Yeah, only have changed shoes.

But to be honest the old shoes were quite gone, with the adjusting things not working properly, I don't think they were doing much braking wise, so any warpage of the drums might have gone unnoticed.

I will try to chamfer the leading edge of the shoes, and hopefully go for a rear disk set up this spring.


Thank you for your suggestions.

[johnny625]

Just to clear up, if anyone else has a similar problem. The rear drums were warped (not being concentric to the stub axle). I took them to a machining shop, they turned them on a lathe and now everything is fine. No vibration at all when braking.

[Eeyore]

Just to clear up, if anyone else has a similar problem. The rear drums were warped (not being concentric to the stub axle). I took them to a machining shop, they turned them on a lathe and now everything is fine. No vibration at all when braking.

Nice fix. I firs thought it was warped discs but havent heard of this on drums before. Bizzare that that happened! How much was the machining vs buying new drums?

[welshpug]

its more common on drums than discs, disc warping is particularly rare actually and is usually pad deposits or corrosion.

[johnny625]

Lol, very sorry for the late reply, but machining here is peanuts cheap. A lot of people do have small machining shops and are happy to take on any job they can.

The whole machining of the both drums cost me a whooping 8 euros, much cheaper than buying new drums. Was done in 20 minutes too...