PT cruiser "knocking" problem

avalon68

I recently bought a PT cruiser (auto-in case that makes a diff) and there is a knocking sound coming from the front driverside wheel when the brakes are applied. The noise only occurs when the car is warm - so maybe after 10 min of driving, and is louder at lower speeds. The knocking is faster at higher speeds, and slower at slower speeds so I thought maybe it was a problem with the break pads rubbing or sticking or something (obviously I know very little about cars!). I took it back to the garage and they assured me it wasnt the breaks - and the car stops fine so maybe theyre right. So far they have - replaced front-rear control arm bushings, front sway bar bushings and balljoints and a gasket for a hub bearing.......but the noise is still there!:mad: In the last couple of days I think I can hear a slight noise as I drive along from that wheel too....but Im so paranoid about it now Im not sure - has anyone had similar problems? Or any suggestions from anyone in the trade as to what it could be?

avalon68

anyone?

Owen

Does the pitch of the noise get higher as the wheel speed increases? If it's a hum/drone which gets a higher pitch as you drive your wheel bearing is gone.

As they've done most of the bushings already, next culprit for noises at the front end would either be a wheel bearing, or a CV joint. Other people who've more knowledge than me on suspension/drive systems will be along shortly to answer your questions. We've also got a motors technical forum, you should request access to it, and ask the experts in there.

avalon68

PaintDoctor wrote: »

Does the pitch of the noise get higher as the wheel speed increases? If it's a hum/drone which gets a higher pitch as you drive your wheel bearing is gone.

As they've done most of the bushings already, next culprit for noises at the front end would either be a wheel bearing, or a CV joint. Other people who've more knowledge than me on suspension/drive systems will be along shortly to answer your questions. We've also got a motors technical forum, you should request access to it, and ask the experts in there.

Thanks paintdoctor; The noise is almost undetectable when driving along at speed, and when I apply the brakes it becomes louder the slower the car gets - as the car nears a stop it sounds like somone banging something with a sledge hammer:( Only occurs when the car is warm though, and gets progressively louder the warmer the car gets.

Odelay

Did they just replace the gasket for a hub bearing or bearing itself? I'd have started with replacing the actual bearing.
Does it happen only when breaking or when breaking and turning? If so then a roll link maybe the issue. Or else part of the plastic wheel arch could be loose and rubbing off the wheel when turning.

Owen

When you're braking on a smooth road (Not a rough one, as the ABS will kick in and disrupt the feel of the pedal), do you feel pulses coming up through the pedal? It could be a warped disc.

Either which way, if your current mechanic has exhausted his skill set, try someone else who'll diagnose it properly.

avalon68

@ Odelay - its not any worse or better while turning - normally just occurs during braking. @ paintdoctor, no vibrations through the pedal that Ive noticed anyway. I bought the car in this dealership which is why I have been returning there (as its free). Having just emmigrated here recently I dont have a lot of cash to spare right now which is why I have been unsble to go to another garage. Its due a state inspection soon though so I may have to just go elsewhere...

CV joints would knock when turning. Perhaps the anti rattle clips are missing off the pads. Some mechanics may not notice this.