I recently purchased a really nice 2014 535i, 99k miles, from a BMWCCA member in the Atlanta area. It's the M-Sport version. A few months later I noticed the front bumping when the brakes are applied. The front wheel moves forward and backward when the brakes are applied at parking lot speeds. Having owned BMW's for 30 years, and remember E46 control arm problems, I knew it was probably the control arms so I ordered a pair of Lemforder, #31126775971 & 2, and had the local BMW dealer install them. It didn't change anything and the front still bumped when applying the brakes. BMW tech did install them correctly w/the weight of the vehicle on the suspension before tightening the arms. He suggested installing the other suspension arm, 31126794203 & 4, and I bought Lemforder again and had them install them. Nothing changed and there is still bumping. I've never had an issue with Lemforder before but now worried. So thought I'd better get the OEM BMW part. BMW won't sell just the bushing for the control arm any longer (for this application) so you have to buy the complete arm. When I went to order them from BMW I noticed in the parts description it says "Without awd, without m model. 3.0L turbo, without awd. 5 series. Right. Hybrid 5. 3.0L turbo, rwd. 4.4L turbo, rwd, without M6. Without gt. 535d. 640i. 650i." What does BMW consider M Model? I'm thinking the M5 but I do have the M-Sport option. I did supply my VIN and ordered the 31126775971 & 2 arms again but this time the BMW OEM parts. When the new control arms arrived I took the car to my old friend, a retired BMW Master Tech, for him to install the arms. Just wanted another set of eyes to look at the problem. He replaced the arms and the problem is still there w/the wheel moving backwards and forwards on light braking. My friend still has the car because he wanted to see what else it could be but it's got him pretty much stumped too. I figure at 99k miles the control arms were probably at the point where they should be replaced anyway but it's not fixing the problem. The car otherwise drives fine. If my Master tech friend hasn't found the answer I might have to see if the dealer still gets visits from a BMWNA rep for problems that can't get figured out locally. My gut tells me it's control arms but replacing them hasn't changed anything. Oh, the sway bar links were replaced too. BMW tech thought that might be the problem but it wasn't. Running out of options. Paul Lee Montgomery, AL
Hmm well on the surface that seems like it should be a diagnosable mechanical issue - yes, something obviously moving & not holding in place what it should, so, what are the options. Maybe look at realoem.com front suspension diagrams, see if you can google up any more detailed diagrams, and also checkout the other big BMW online message forums particularly anything for your specific model, & post question there as well. Bimmerfest, Bimmerpost, Bimmerforums.... With as much movement as you describe seems like finding what's loose would be fairly obviated pushing and prying on things with it up on a lift... you'd think, anyway!
Yep, been hitting most of the online forums and nothing constructive as to resolution. Just the "something is loose" comments. The only thing my tech can make move with his huge screwdriver (pry bar) is the thrust control arm bushing (it's new) but I think some movement is normal. Wanted to add that the bumping is evident at any speed when you jab the brakes quickly. Some have said to look at the brakes but it doesn't sound like a brake problem to me as they're in good condition and the steering wheel doesn't jerk one way or the other. I have the car back now and it drives really nice but the bumping is still there if I get on the brakes quickly. I did send the problem to Mike Miller in Tech Talk (Roundel) to see if he has anything interesting to say besides "somethings loose." Will probably have to drop it off at the dealer again to see if they can arrange someone qualified to have a look at it.
