Subframe moves a bit on the bushings when jacked - replace?

[butters]

I've searched and seen this before but wanted to start a new thread. These bushings only have about 3-4k miles on them. They are OE rubber, I was going for the ride quality.

I noticed when jacking the rear of the car from the subframe, as I felt to make sure I wasn't crushing anything, I felt the subframe move up relative to the bushing. That can't be right.

Here's a photo from underneath, while the car is sitting on jack stands on the subframe:



Do I need to replace these, or is something else wrong? Both sides look about the same.

[Northern]

The subframe should not be sliding around on the bushings like that. No idea why it would be doing that with an oem bushing unless the subframe or metal sleeve on the bushing failed.

On the upside, it may be really easy to remove them.

[butters]

Hopefully.

What should prevent the subframe from sliding up?

[Mr. Tasty]

the bushing

[butters]

Right, but looking at a stock bushing there doesn't seem to be an upper lip or anything so I'm not understanding the mechanism.

In my picture, should the upper washer keep the subframe squeezed against the bottom lip of the bushing?

[AndrewBird]

The bushing is pressed into the subframe, so it won't/shouldn't move even when jacked up. The fact yours does means there is something wrong.

[butters]

I snapped a photo of the subframe bushing with the car sitting at rest on the rear wheels. This is the other side from what's shown above but both look the same.



Looks like I have to tackle this job. I didn't do it myself the first time but I suppose the 2nd time around shouldn't be as bad. I'll have to research doing it as non-invasively as possible - tips appreciated.

I wonder, this might actually be the cause of a driveline vibration I'm poking around for. Buzzy feeling while accelerating & slowing around 3k rpm, and generally buzzy on the highway above 75mph (above 3k rpm). That would be a relief, I'll report back.

[ravenlord89]

Drop the entire subframe and have someone with a press remove and install the bushings. It isn't worth the hassel of doing it any other way. Also now would be a good time to do the trailing arm bushings. You live in a rust free area and your car looks pretty rust free. I would say as long as you are mechanically inclined you should be able to do it in under 4 hours.

[butters]

I did the rtab's at the same time as the subframe so they're already new. I might fiddle with a DIY solution with the subframe dropped a few inches.

[petrolhead]

Don't lift your car from the rear subframe. I can't remember what BMW instructions say about that but it's a bad idea anyway. Especially with stock subframe and diff bushes.

I removed bushes partially by jacking the subframe ends :), quite effective.

In normal driving conditions the wheel load pushes the subframe downwards.

[ayemattyyy]

Also, make sure your bushings are installed correctly. There are little nubs/dimples on the subframe that you can see correlate to spots on the bushings. Make sure they line up. Good luck.

Matt

[muppetman342]

I replaced the subframe bushings myself about two years ago, and have had this ever since...finally going to address it this winter, but I'm honestly not sure what to do. They were new Corteco bushings, the only thing I could think of is if maybe the bushings are bad and were made too small. I can't fathom that the subframe would have expanded in some way. Contemplating going poly since they have an upper lip to prevent this movement. Also suppose I could put a couple set screws through the subframe bushing barrel and into the bushing sleeve.

[twright]

Did you remember to put the big washers on before you replaced the subframe on the frame?

[muppetman342]

Did you remember to put the big washers on before you replaced the subframe on the frame?

Yep, but as you can see in the OP's photos, those don't do much to prevent movement for the first ~1/2"