Rear subframe bushing bolt problem

[Tim Irwin]

I've tried several different ways to fully seat the rear subframe bushing. Tonight I tried a longer bolt that matched the threading on the regular bold to pull a metal cup up against the bushing. I was still unable to seat the bushing, but that's another matter.

I'm pretty sure I didn't cross thread the bolt, as it felt reasonably normal going in, but it's now frozen about 1/4 of the way out. I can't get it to go either in or out with either a breaker bar or a reasonable impact wrench.

I figure I'm probably really messed up with this, but if anyone has any ideas other than a stronger impact wrench (which I'll probably try once I get my hands on one), I would really appreciate it.

[showme]

If there's any way you can heat the bushing (threads that the bolt are inside of), it would open up the pressure on the bolt. Sounds like it's either cross threaded or the threads aren't a match. (?) If there's rubber up there, heating wouldn't be an option, though. Spray it with PB blaster?? It'd be a bummer to break it off in there. If you get it out, I'd definitely tap it out and chase the bolt threads, if possible. Maybe there was some gunk up in the hole or on the threads(?) Sorry, I'm just guessing, there. But, as far as the tight fit goes, with steel, heating the surrounding area causes the hole to open a fraction, and sometimes does the trick. But how you would get a torch up there to do it without messing up any rubber bushing, I don't know. Any body else got any experience in this?

[MarkM]

Its hard to say what is actually siezed...is the bolt seized in the threads, or is the bolt shank seized inside the sleeve of the mount. It sounds like you have just installed a new mount, in such case the bolt would not be seized inside the mount, but rather in the threads. Without knowing, here are some pointers, some of which may apply to your situation:

1) Bottom line, I think you need to get the whole business out (bolt, mount, etc.), then inspect, clean, etc then re-install

2) If this is an old mount and unattended or a long time, then the bolt shank may be seized (rusted) inside the mount, in such case you will need to burn it out...apply heat (propane torch) to the bolt until the whole mount burns, then just pry out the pieces, and start over. The reason for this is that with the bolt rusted to the sleeve, when you try to unscrew the bolt, the whole rubber portion of the mount gives, and you cant get solid purchase on the bolt against the sleeve. You need to fry/burn the rubber with a torch, remove the bolt, then knock off the remaining sleeve with the bolt in a vise. To re-use the bolt, clean/sand/file off the corrosion, and slather on anti seize so it wont seize in the new mount.

3) When installing a new mount, you can't seat the mount using the center bolt..the rubber portion of the mount will "bottom out" before the mount is fully seated. Plus the bolt is not long enough to catch the threads with the mount protruding. You need a shop made tool (I made one out of oak and threaded rod) to pull the mount in by applying force to the rigid sides of the mount...you also need to apply silicone grease to allow the mount to slide in. When the mount is fully seated in this manner, THEN install the center bolt. I am worried that you used a different longer bolt...was it the same thread size? If not, this is obviously the problem. No matter what, you need to remove this bolt.

4) If the bolt is cross threaded, you simply need to take it out in any way you can (breaker bar), and remove the mount, then try to re-install only the bolt to try to properly install the bolt and "chase" the threads...I think it is unlikely that you cross threaded the original bolt, because that bolt is "self aligning and self threading", although with a different bolt cross threading is not out of the question, especially if thread size of the new bolt is incorrect.

I hope this helps...

Mark

[Tim Irwin]

I was trying to use a homemade press to get the bushing all the way in. I have a M14-1.5x120 bolt running through a stack of washers and a metal cup (oil filter wrench). Unfortunately the cup pushed on the "wings" of the bushing, not the sides near the bolt, so it didn't work. Since the M14 bolt has a shaft that is smaller than the factory bolt, it shouldn't be seized on the bushing.

The bolt came out enough that the cup and washers are loose with the subframe being supported by a jack, but that's all the farther it's come.

I think the threaded rod would have been the better way to go as you are putting less strain on the factory threads in the welded in mount. Where did you find a metric threaded rod?

[MarkM]

Originally Posted by Tim Irwin

I think the threaded rod would have been the better way to go as you are putting less strain on the factory threads in the welded in mount. Where did you find a metric threaded rod?

You don't need a metric threaded rod. The rod does not get threaded into the threaded bolt hole...you slip it into the sub frame hole then install a washer and nut in between upper surface of the sub frame and the body of the car. Another way to do it is to position a bottle jack onto the shopmade tool which will push against the rigid sides of the subframe mount, then you lower the car (which is held up by another jack) to use the weight of the car to push in the mount.

You do need to put silicone grease onthe mount...this also results in the mount squeezing out of its position after it is inserted and you remove pressure holding it in...just try it a few times, maybe removing a little too much silicone grease, until it is inserted andit stays.

Good luck

Mark