Rear subframe mounting bolt stuck

[jlevie]

To use the bigger hammer the rear of the car needs to be 3' or more in the air. A lift works (obviously), but 6-ton jack stands on a couple of 4x8x8 concrete pavers also works.

[rickyb916]

So you've got the nut off and you're now trying to pop the bolt up through the body? If you're only jacking one side you may be putting it in a bind. Just guessing at that though. Try a metal sledge vs the dead blow. If you can't see the tip of the bolt still it's probably because the subframe is still pulled down a little (after you put the c-clamp on it). You may need to jack on the subframe to raise it back up and expose the bolt.

I think you're right, I was literally brainstorming and should have caught it last night but Yeah I think the bolt is binding in the sleeve of the bushing with only one side raised. Going to get good wheel chocks, pb blaster, BFH and some red bull.

Use a bigger hammer, something in the 14-16lb range.

Not sure if one that heavy and big would fit or would I be able to get sufficient leverage.

are you using a breaker bar? You can try to tighten it a tiny bit before you loosen it to help free up the threads.

Also you can hit the head of the bolt to free up corrosion in the threads

Breaker bar? I have the nut off and the top doesn't have anything. I gave it some light taps, maybe i'll try harder ones.

bolt looks like this:




Thanks e30_202 and everyone else who has responded with tips.
Going to give it a go in about a hour when I'm back from my bike ride to the hardware store!

[e30_302]

So you've got the nut off and you're now trying to pop the bolt up through the body? If you're only jacking one side you may be putting it in a bind. Just guessing at that though. Try a metal sledge vs the dead blow. If you can't see the tip of the bolt still it's probably because the subframe is still pulled down a little (after you put the c-clamp on it). You may need to jack on the subframe to raise it back up and expose the bolt.

[catalyst.]

are you using a breaker bar? You can try to tighten it a tiny bit before you loosen it to help free up the threads.

Also you can hit the head of the bolt to free up corrosion in the threads

[jlevie]

Use a bigger hammer, something in the 14-16lb range.

[rickyb916]

No I'm using the bushing kit that doesn't need the subframe to be completely off/down.

Sent from my HTC EVO LTE

[matthugie]

Are you trying to get the entire subframe out? If you only have one side of your subframe loose it isn't going to go anywhere. The bolts on the sides are very long, and they both need to be off (as well as the diff mount and driveshaft) before dropping it.

[rickyb916]

1991 318. The mounting holes for the rear subrframe still had the 'foam' in it, so I'm assuming these are the stock bushings and never taken out mounting bolt.

I got the SIR tools bmw bushing kit (rented from bmwm42, highly recommended)

Jacked up the rear driver side and I took off the mounting plate nut off, I've heated up the bolt (the top, the top bottom (under the car where you see the bolt go up into the body) and tried hitting it with a dead blow hammer (2 and 4lb, hard to really get good leverage with the car on a stock jack and stands) with no luck. (I didn't heat it until glowing red, but for at least a good 1-1:30(min) and tried.
I used some teflon chain lube and even some mx shock oil(all I had, going to get pb blaster tomorrow) and put it on the top bolt and it dripped down right away (So the foam isn't holding it back), didn't work.

I used a bigger c clamp and got it to hook onto the subframe and the bolt didn't move up, but the subframe lowered more.

Also with the car jacked up, used another jack with a big bolt (grade 8) and put it on the base of the second jack and lowered the first jack to try and ghetto press it out, didn't work either.

My next step I guess is to drill it? I tried using a drill set (not even sure what material it was) and couldn't get it to go past more then 1~mm, battery was dying on the cordless, going to try the corded one tomorrow.

Also note, when I lowered the car back down after all of my attempts and the mounting bolt isn't going all the way through the bushing? bent?
I have a good amount of tools, lacking air and power tools though, neighbor has most common air and power tools though.


1. How else can I go about this?
Getting pb blaster tommorrow along with a heavier metal sledge (was using a 2/4 composite).
Neighbor has an air hammer, but his compressor is a huge one that would be a PITA to go across the street with it.
Can possibly move my car close to their house but don't want to block their driveway while I work on my car.

2. What kind of drill bit (material) would work good on this alum. bolt?
And how far do I go down?

3.Is only jacking up one side a good/bad idea? any other tips are greatly appreciated.

Thanks! Only have 6 more days with this tool and only have the next two days off.