cut out a section of the frame rail..nicely btw..

get in there with a torch and heat up the sleeve that the bolt goes through along with the nut that it screws through ( if there is one, not sure) weld on a nut to the bolt and try to remove..if you cant get a nut welded on. drill a hole, use an easy out to slowly remove the bolt..

you can either weld the frame rail piece back into place or use body seam sealer..

ive had a few mdx's where the right rear subframe bolt seizes inside the frame because of the ac evap drain water finds a way to get inside and eat it away..this is what i have done..cheaper than a body shop and entire frame rail replacement from the customers pov.

 

I'll say it again, but:

- the bolt broke with around 160ftlbs of torque applied to it, I'd rather not shear off an EZ-out in the bolt.

- there isn't any material to weld to.

I've gotten the subframe down and have now borescoped all the holes as well as the inspection holes, and have documented everything. A few notes-

- bolt is broken off about 5mm below the surface. There is at least 3" of bolt still inside the hole.

- there is just one nut/threaded portion for each of the 3 bolt holes on each frame/unit body raile (each side). I thought maybe there was one on the bottom surface and then one higher up, but that's not the case.

- the internal nuts in the unit body for the forward bolt are 20mm long. They are recessed 10mm from the bottom/outside surface that the subframe bolts up against.

- the internal nuts on the middle and rear holes are only 10mm long and are recessed 20mm from the surface.

- based on the one forward bolt I got out OK, the threaded material in the frame/unit body is harder than the bolt. The bolt lost some thread height mid-way, but the threads in the chassis seem fine.

I've started drilling out the bolt and really wish I had a rotisserie for the car! It's a PITA drilling up like that. I'm centered (almost perfectly) and making progress, but it's slow. Having old drill bits doesn't help. I'm going to attempt some new bits now that I've started but am optimistic I will be successful.

 

Keep the drill speed low and use plenty of cutting oil.

 

[QUOTE=hecash,Jan 23 2010, 08:41 PM] As I recall, these bolts are designed to stretch when installed and only installed to the proper torque specification.

 

You're not supposed to lower it with the bolts.
Support the engine with a jack while removing the bolts until you see the marked section - where the thread is missing.
Then lower the engine onto the bolts.

One bolt is strong enough to lift the car so 4 can take the weight of the engine.

Maybe this is how the threads got damaged in the first place?
Using the bolts to lower the engine.
Might cause lots of wear as those bolts do not have a any lube on them.

 

I disagree that it's a typo. I can't tell you how many times that I've done this. The bolts are plenty strong enough to hold up the engine/trans.

What I can tell you is that the manual says to replace them once they have been loosened. I am not sure I agree that they would be torque-to-yield but I can't see why else Honda would say to replace them.

I haven't worked on this more today but will resume tonight and post back on the progress.

 

I can tell you that not many people replace the bolts after lowering the subframe.

 

I know I didn't...

 

I know of 1 car that had them reused at least 6 times

 

Last I checked they were only a couple of bucks per bolt at Majestic. They are on nat'l backorder though. I had to grab a used set today to make sure I had some to replace the broken/stripped ones.

On the typo comment, sorry I didn't catch that. I have seen actual typos in Honda manuals so I am always on the lookout so I took the comment seriously.

I never lower the subframe by the bolts, always by a jack w/large wood block to span the F/R braces. I can understand people doing it and agree it's bad.

So tonight I got a lot further drilling, but then ran out of bits. I have the right sizes but they are too dull to make progress. I will pick up some more and finish it tomorrow. I'll tell you, this sucks so bad I think in the future I will remove and clean the bolts/holes and anti-sieze them when I do touch them.

I also can barely move my arms/hands from managing the drill up under the car!