535xi Shaking over bumps and unstable
 

As title says. Happens over bumps and its smooth on the highway (albeit some vibration at 80mph). It's really noticeable especially over bigger bumps it crashes/shakes and has bump steer. The only time it remotely feels planted like a BMW should is on the highway. The real problem is I've had multiple mechanics/shops look at it and everything is solid and tight. I'm expecting to be told to check ball joints/bushings/wheel play but there is no problem there had it check numerous times. I have new shocks and mounts and changed a few suspension parts because no one sees a problem. Had a hunter alignment done twice and had road force balance. I'm at a loss. It really does feel like worn shocks but they're brand new Sachs. Any advice?

This problem is getting depressing and I don't even care how much it's going to cost to fix it anymore I just want to know what it is.

What is the history with the car? It used to feel correct to you and now it does not? You recently bought it and it has never driven correctly?

I recently bought it. The Engine/transmission, body and interior were in really good shape, Less than 90k miles and it looked it. Had it checked out good and unless someone did a 100% perfect repair it has not been in a major accident with any frame damage at the least. Was aware of 2 control arms with some play and a worn ball joint. Figured that and the shocks would bring it back to good shape.

My xi drives a bit like that and I'm on the cusp of fitting new Billy B6 plus all the bits. I know my shox are original and with 230,000km on the clock they are defo worn out. I particularly feel 'patter' on small sharp bumps, but it doesn't bounce and keep bounding as if the shox are totally gone. Most likely the inch or so travel spots are worn out. That said, it does heave after bad dips.

If you've had a proper 4-wheel alignement, I can't imagine they wouldn't have found issues from prior body damage. Might be time for a frame measurement? Is the ride height normal? 535xi is supposed to be 619mm front/599mm rear with 17" rims, 632mm front/611mm rear with 18", both at 'normal load'. Normal load is 150lb in each front seat, 150lb in the center of the rear seat, and 46lb in the trunk and a full tank of gas. Measurement is from the center of the wheel arch to the lower lip of the wheel rim.

Ride height looks normal (I have 18in M sport wheels) I have considered the springs as a problem but I have no way of identifying them (apart from removing and measuring free coil length) and new ones are hard to find which is why I didn't bother replacing them. I have been trying to find information on E60 springs but there's not much out there, it was the last thing I was doing before making this thread.The only marking on the springs were a sticker that had a bar code and "F4" on it. There was one thing. When I replaced the shocks the springs were VERY hard to transfer over. It couldn't have been done without a proper wall mount and locking style spring compressor. The springs were pretty much touching coil to coil while changing them. Is that normal for XI struts? I've read that Bilsteins use longer rods for this reason or something so I didn't worry about it. I will find ride height specs for 18 in rims and measure it, although I'm not sure a few tens of mm difference would make the car act this way.

The hunter machine it was done on was a brand new state of the art machine at a dedicated alignment shop and I watched them do it. The alignment was out after replacing all the shocks and control arms but they had no problem aligning it.

Thanks for contributing.

Oops - I gave the measurements for 18" rims but didn't note it. 632 front, 611 rear. These are the xi specs in the Bentley manual. It doesn't specify anything for M-Sport suspension, so I would expect yours to sit lower.
I've not changed the shox yet, but have a floor mounted compressor that should do a good job. $120 at Princess Auto.

https://cimg9.ibsrv.net/gimg/5series...e1fc79671d.jpg
https://cimg8.ibsrv.net/gimg/5series...3fdfcd2bad.jpg

Update. When the car is sitting on the ground there is about a half inch of room at best for the bump stop. The spring is really compressed a lot but the ride height is normal. I will post pictures. Any thoughts?

If the ride height is normal on all 4 corners (as in within spec given earlier), there's nothing wrong. The bump stop is actually known as an auxiliary spring and is designed to be part of the suspension. The auxiliary spring is a combination of stiff foam and a pseudo air spring that seals to the top of the strut gland during compression. Back in my E34 days, I noted a difference between the M5 aux spring and one from a 540 where the M5 one was about a half inch shorter, allowing the suspension to "work" at a lower spot in the damper travel in an otherwise dimensionally similar strut.

The front forward arm bushing would be my first part to replace. I have 108k miles and all 4 front arms' bushings need to be replaced. Going over reflectors on the road makes the 5 move unpredictably.

I already changed those arms. There was some minor tearing but they felt tight. Changed them anyway. Didn't improve.