Author Topic: Rear subframe problem... (Read 6388 times)

anisotropy · « **on:** August 09, 2007, 07:03:26 PM »

When I removed my subframe the other day and rather than the subframe mounts sliding out of their holes in the body they simply broke -so I now have two little circles of aluminum (or whatever it is) stuck inside the holes. They are absolutely welded in there so I guess I'm going to have to grind them out, my question is - has anyone had this problem /done this before and have any tips? I'm thinking a dremel might be the easiest? :confused:

ak96ss · « **Reply #1 on:** August 09, 2007, 07:24:05 PM »

Boy does this bring back bad memories... I know EXACTLY what you are talking about.

A Dremel will work - you have to watch it, though, and make sure you don't grind the mount. I soaked them in copious quantities of PB Blaster, then used a cutoff disk to slice a wedge out of the part that was stuck up there. Then, a chisel to collapse the circle in and out of the mount.

Huge PITA.

Look here: http://www.m42club.com/forums/showthread.php?t=491

D. Clay · « **Reply #2 on:** August 09, 2007, 08:31:21 PM »

The hole in the bushing is smaller than the hole in the body. I used a tap and cut threads in the bushing and then put a bolt in it and beat it out from the top. The other one stripped the threads and I had to drill and chisel it out. An extensive vocabulary of derogatory terms for cars, parts, tools, and things mechanical in general will be a big help.

anisotropy · « **Reply #3 on:** August 10, 2007, 04:08:37 AM »

Thanks, glad others have been there. I think it'll have to be the dremel and chisel method, I've already stripped threads I made on both sides with a tap and bolt. I think I used up most of my swearwords on the handbrake cables but I'll see what I can do...

e9nine · « **Reply #4 on:** August 10, 2007, 08:06:32 AM »

Quote from: ak96ss;31322

Boy does this bring back bad memories... I know EXACTLY what you are talking about.

A Dremel will work - you have to watch it, though, and make sure you don't grind the mount. I soaked them in copious quantities of PB Blaster, then used a cutoff disk to slice a wedge out of the part that was stuck up there. Then, a chisel to collapse the circle in and out of the mount.

Huge PITA.

I went through the same deal as most did as well. A lot of enhancements to the swear dictionary as you can only say F*k and Shiet but so many times :rolleyes:

Be strategic about it. Use PB blaster, cut wisely and chisel wisely.

Good luck (you're gonna need it)

ak96ss · « **Reply #5 on:** August 10, 2007, 08:24:45 AM »

And don't forget to LIBERALLY coat the new mount with antiseize when you put it in!!

You may not ever change those bushings again, but if you do, you'll thank yourself for your foresight!

bmwpower · « **Reply #6 on:** August 10, 2007, 09:00:24 AM »

Quote from: ak96ss;31353

And don't forget to LIBERALLY coat the new mount with antiseize when you put it in!!

You may not ever change those bushings again, but if you do, you'll thank yourself for your foresight!

Wouldn't that cause the bushing to move inside the mount..potentially?

He needs proper tool to remove the mounts. With the right tool you can remove the mount even if it is ripped from the metal surround.

e9nine · « **Reply #7 on:** August 10, 2007, 09:58:30 AM »

Quote from: bmwpower;31354

Wouldn't that cause the bushing to move inside the mount..potentially?

He needs proper tool to remove the mounts. With the right tool you can remove the mount even if it is ripped from the metal surround.

He's not talking about the actual bushing. Just the point that slots into the frame of the car, the part that usually breaks off.

anisotropy · « **Reply #8 on:** August 10, 2007, 11:45:08 AM »

PB Blaster? Is that like better WD40, don't think we have it here?

gearheadE30 · « **Reply #9 on:** August 10, 2007, 12:02:32 PM »

I'm getting a little bit of rear steer out of my car over bumps and in transitions so I was going to drop the subframe and put new pounts on it. After hearing this, I may wait a bit longer

ak96ss · « **Reply #10 on:** August 10, 2007, 12:27:03 PM »

PB Blaster is like WD40, just a little better. Really, any penetrating oil should help, if it can work its way in there.

The antiseize goes especially on the metal nub that is in direct contact with the mount on the body. They are dissimilar metals and prolonged contact, especially where any moisture is involved, essentially welds the darned things together.

Here is a comparison between what came out on my car, and what should have been there - new mount on the bottom:

And this is what was left in the mount on the car body:

Mind you, this was also on both sides of my car. Hopefully, the antiseize will prevent this.

bmwpower · « **Reply #11 on:** August 10, 2007, 12:28:39 PM »

Quote from: e9nine;31361

He's not talking about the actual bushing. Just the point that slots into the frame of the car, the part that usually breaks off.

We're talking about this subframe mount, right?

nevermind...just saw above post

e9nine · « **Reply #12 on:** August 10, 2007, 12:43:17 PM »

Quote from: gearheadE30;31374

I'm getting a little bit of rear steer out of my car over bumps and in transitions so I was going to drop the subframe and put new pounts on it. After hearing this, I may wait a bit longer

Man up and do it. It's almost like doing a transmission or clutch job without a lift. It's a PITA but def. well worth it once done. Waiting longer doesn't make it any easier. It's a good thing to get the t.arm bushings, S.S lines and other work done at the same time. This isn't a task that you repeat ever so often either.

I don't look forward to doing it again on my 325i again but I will next year. Considering the fact that I auto-x and go to the track, a rear end that wags in the turns or the slalom is a bad thing. Mine was so bad that the tires would rub :mad: and going into some high speed turns, it's simply not safe.

PB Blaster is better than WD 40. I have never gone back to WD after using PB Blaster personally.

ak96ss · « **Reply #13 on:** August 10, 2007, 12:53:29 PM »

Quote from: e9nine;31380

Man up and do it. It's almost like doing a transmission or clutch job without a lift. It's a PITA but def. well worth it once done. Waiting longer doesn't make it any easier. It's a good thing to get the t.arm bushings, S.S lines and other work done at the same time. This isn't a task that you repeat ever so often either.

Yeah, I did my clutch in the driveway on jackstands, too!

anisotropy · « **Reply #14 on:** August 10, 2007, 04:30:33 PM »

In the suspension rebuild 'how to' (or somewhere) the idea is mentioned of using an m16 tap down the middle (putting it up the alloy bit from the bottom) and then sticking a bit of studding or something down from above and hitting it with a hammer. -I only noticed this afterwards but it sounds like it could've been a better method for getting it out in one piece.
Mine are like the pics above but have broken flush with the body so I don;'t even have that lip to work with. corked them up for the moment at the bottom and FILLED the hole with WD40 from above.