Cross-threaded Engine Cradle Bolt

[razorboy]

Hey Lads,

So I have been having some creaking, groaning issues coming from the front end. Happens backing up, then moving forward and in slow turns.

Decided after doing some research here to go ahead and check the 6 engine cradle bolts in the front. I discovered one that was a little loose on one side and then one that is obviously cross threaded and broken on the other side. It is the rear one of the 3.

It appears as though someone banged it in there cross threaded and then whatever it threads into has broken. I would suspect that it is some sort of insert welded to the other side? Anyway, the bolt just spins by hand but won't tighten up and more importantly, won't come out either.

Has anyone had this to deal with before and what did you end up doing to get the bolt out and then repair the mount to be able to put a new one in?

Cheers
Bernie

[X53Jay4.8is]

Originally Posted by razorboy

Hey Lads,

So I have been having some creaking, groaning issues coming from the front end. Happens backing up, then moving forward and in slow turns.

Decided after doing some research here to go ahead and check the 6 engine cradle bolts in the front. I discovered one that was a little loose on one side and then one that is obviously cross threaded and broken on the other side. It is the rear one of the 3.

It appears as though someone banged it in there cross threaded and then whatever it threads into has broken. I would suspect that it is some sort of insert welded to the other side? Anyway, the bolt just spins by hand but won't tighten up and more importantly, won't come out either.

Has anyone had this to deal with before and what did you end up doing to get the bolt out and then repair the mount to be able to put a new one in?

Cheers
Bernie

Need more clarification but if its the engine cradle mount then just change out the mount.

[razorboy]

Originally Posted by X53Jay4.8is

Need more clarification but if its the engine cradle mount then just change out the mount.

Its the tubular subframe at the front.
Has 6 mounting points using a 6 point bolt I believe?

The one on the very rear on the drivers side is the one that is cross threaded.

[razorboy]

I wanted to follow up on how I managed with this for anyone in the future.

So as it turns out, the hole wasn't stripped out or anything, it was the bolt itself that was stripped in the center of its threads. That's why it kept spinning and wouldn't come up.

What I have to do was get a pry-bar between the head of the bolt and the frame and while holding a 10lb electric impact in the other, had to nail at it slowly while keeping constant pressure on the head of the bolt. Man, my arms were numb by the time I was finished. I was doing this on my back in the driveway too.

So anyway, I bought the appropriate tap size to redo the threads but that was almost impossible. The threads were so beat to hell that there was no way to get the tap to start cleanly. I ended up getting about half way through the threaded portion before the tap started getting really tight and I was worried I might snap it off inside the hole. I'd be done then.

Found a bolt that was shorter than the original with the same diameter and thread pitch and got it in there tight.

Didn't do a damn thing to stop the creaking and groaning in the front end.....lol. Well at least it's the way it's supposed to be - more-or-less.

B

[Fifty150hs]

Originally Posted by razorboy

I wanted to follow up on how I managed with this for anyone in the future.

So as it turns out, the hole wasn't stripped out or anything, it was the bolt itself that was stripped in the center of its threads. That's why it kept spinning and wouldn't come up.

What I have to do was get a pry-bar between the head of the bolt and the frame and while holding a 10lb electric impact in the other, had to nail at it slowly while keeping constant pressure on the head of the bolt. Man, my arms were numb by the time I was finished. I was doing this on my back in the driveway too.

So anyway, I bought the appropriate tap size to redo the threads but that was almost impossible. The threads were so beat to hell that there was no way to get the tap to start cleanly. I ended up getting about half way through the threaded portion before the tap started getting really tight and I was worried I might snap it off inside the hole. I'd be done then.

Found a bolt that was shorter than the original with the same diameter and thread pitch and got it in there tight.

Didn't do a damn thing to stop the creaking and groaning in the front end.....lol. Well at least it's the way it's supposed to be - more-or-less.

B

check all of the suspension fasteners. Had this problem. Cranked every thing down after putting thread locker on. No more clunking.

[wpoll]

The creaking may be the six bolts holding the large reinforcing plate under the engine - those suckers need to be really tight otherwise the whole plate creaks etc.

These bolts have been endlessly debated here, as BMW state they should never be re-used but replaced - single use hardware. I'm not going to comment on that aspect one way or the other (step away from the fuse...!) but I have heard that if they aren't tight enough, the reinforcing plate (or the bolts) creaks like mad.

[razorboy]

Originally Posted by wpoll

The creaking may be the six bolts holding the large reinforcing plate under the engine - those suckers need to be really tight otherwise the whole plate creaks etc.

These bolts have been endlessly debated here, as BMW state they should never be re-used but replaced - single use hardware. I'm not going to comment on that aspect one way or the other (step away from the fuse...!) but I have heard that if they aren't tight enough, the reinforcing plate (or the bolts) creaks like mad.

Interesting

Thanks, I have learned a new one this evening

B

[wpoll]

Originally Posted by razorboy

Interesting

Thanks, I have learned a new one this evening

B

And a heads-up - the bolts have nuts on the top side, so you need to remove a whole lot of tupperware to get the nuts when tightening them up.