Car shakes at 90-100kmph (long)

[Mas (UK)]

Hi guys,

Although this is not a BMW car question, I know you guys are without equal when it comes to knowledge and helping friends out on car problems, so I am seeking your thoughts on a problem on my bro's car, a Peugeot 306 LHD european model, front wheel drive. The background is that his car was involved in a minor bang by another motorist to the ft-left wheel arch area. This was repaired under insurance, but he has told me that his car now shakes pretty badly when he's going around 90-100kmph. The wheels have been balanced, but I'm not sure if any alignment was carried out. Anyway, I drove with him the other day and the symptoms are heavy side-to-side shakes from the front of the car, enough to make the whole car shake pretty violantly like maybe you think a wheel is about to come off. It only seems to shake when it is in gear. If you take it out into neutral, the shakes just disappear. Some gears pronounce the shakes a bit more than others. I suspect there may be some damage to the driveshaft, which is why it only seems to shake when in gear. After only a half hour drive, I got out to check the wheel area and noticed a second problem. The steel wheel was hot like hell, you couldn't touch it! Here I suspect the shakes must make the brake disk and pads rub and the heat generated was enough to cook a good english breakfast on! I didn't notice anything major wrong with the disk, pads or drive shaft from a home DIY mechanics point of view (but I guess I'm not sure I would really know a good driveshaft from a bad one unless it was sitting in two pieces in front of me), although the rubber boot to the gearbox did have a tiny cut and some grease was leaking out.

I would be grateful for your assistance guys, especially if you have had any similar experiences, to try and find what parts may still be damaged so that we can get them repaired properly.

Cheers,

Mas

[632 Regal]

first guess would be a sticky brake caliper, that would super heat the disk and cause what you are discribing, secong guess is that there is an additional problem such as driveshaft or transmission from the accident. Last guess is a bent wheel or out of round tire, someone has to start complaining if you cant isolate the problem and have the shop fix the problem.
Good luck!

[bimmerd00d]

engine and/or transmission mounts possibly? suspension bushings?

[Mas (UK)]

first guess would be a sticky brake caliper, that would super heat the disk and cause what you are discribing, secong guess is that there is an additional problem such as driveshaft or transmission from the accident. Last guess is a bent wheel or out of round tire, someone has to start complaining if you cant isolate the problem and have the shop fix the problem.
Good luck!

when you take the car out of gear. I would guess if it's a sticky brake caliper, bent wheel or dodgey tire the shakes should continue until the speed is out of the natural vibration range. Would you think it's easy or common for a driveshaft or transmission to get damaged by minor bumps like this? I know it's an awkward question to ask not knowing the car yourself, but just wondering how tough these parts are. As for the driveshafts, should there be any play with them anyway? I can feel a bit (maybe 1-2mm) of play in both when I turn or pull them along their length in and out towards the gearbox.

I will get it booked in for another check-up though. Thanks again!

Cheers,

Mas

[Mas (UK)]

engine and/or transmission mounts possibly? suspension bushings?

mounts and bushings is still pretty basic so will get a pro mechanic to check these things out properly.

Cheers,

Mas

[Robin-535im]

mounts and bushings is still pretty basic so will get a pro mechanic to check these things out properly.

Cheers,

Mas

And it would only shake in gear. This was rear wheel drive though, and a 5-speed... But perhaps you have a bearing or such that is no longer rotating on-axis so that when a load is applied (i.e., car is in gear) the runout is so great that you feel it.

[632 Regal]

another quick thought is if they disassembled the driveshaft(s) and remounted them with the CV joints on the wrong axis it will also cause a vibration, also which may only rear its ugly face under a load.