Stubborn Body Mount Bolt

[Michael A.]

Preparing to remove the body from my 66 SB Roadster. All has been going well, thanks to my car's California lineage! That is until now. 7 of the 8 body mount bolts have come loose with minimal effort but the 8th is NOT cooperating. It is the rear most bolt on the driver's side. I was able to break it free with WD40 and a breaker bar. Unfortunately the bolt just turns and does not loosen, apparently stripped threads where it threads into the frame on top. I have atttempted to drive a wedge in the area where the middle cushion is between the frame and body, hoping to catch a thread but no luck.

Any suggestions on other methods before we try the die cutter to the bolt?

Thanks in advance for the advice & counsel.

Cheers

[James N.]

Re: Stubborn Body Mount Bolt

Isn't that where the bolt goes into a captured nut? I think so. Same thing happened to me on my '67 where the captured nut broke away from it's "cage". Had to grind off the bolt head.

[Michael A.]

Re: Stubborn Body Mount Bolt

That's the one Jim! I'm searching for options before going "nuclear".. Thanks.

[Bill M.]

Re: Stubborn Body Mount Bolt

the cage bolt is spinning i had the same problem. I used a dremmel and cut the head of the bolt into about 6 sections to get it apart. Took a while.

[Graeme B.]

Re: Stubborn Body Mount Bolt

I took the cage off the captured nut and found a socket that held the square nut to undo the bolt.
Good luck.

[Hector G.]

Re: Stubborn Body Mount Bolt

Don't go nuclear. Pull the carpet back, and as suggested by Graeme, pull off the cage, get a socket or sneak an opened ended wrench in under the cage without pulling off the cage to hold the nut to undo the bolt. The cage is held in place by two rivets if memory serves me right. In my case, one of the rivets came loose and would not hold the nut in place. I was able to use an open ended wrench to hold the nut and remove the bolt. I replaced the cage and rivet after reinstalling the bolt/nut. Not an easy task to reinstall the rivet.

[Michael A.]

Re: Stubborn Body Mount Bolt

Update to the saga. Thanks all for the comments and suggestions. The nut and bolt were rusted solidly together and I could not remove the bolt with wrenches. I ended up drilling off the head of the bolt from below and succeeded in raising the body up off of the frame. It now rests comfortably on the body dolly and the frame is out for sandblasting and paint.

My next challenge is to remove the body mount cage from inside the convertible top well, replace the captured nut and reassemble. It looks like a nasty job. Some questions for those of you who have been down this path before:

1) Do I need to remove the spring and hinge assembly to get at the body mount cage? If so, any tips on how to do this as that is a pretty serious spring?
2) It appears I need to drill out some rivets to remove the cage and replace the captured nut. Is that correct? Any suggestions on best procedure for reinstalling the rivets? Is it a two man job?

Cheers,

[Keith B.]

Re: Stubborn Body Mount Bolt

Pry the cage up. Take a 1"open end wrench and put on nut. Remove bolt. You don't need to remove anything but the carpet.

[Richard M.]

Re: Stubborn Body Mount Bolt

Mike,

If it's really bad, you have to grind the bolt head in slices as mentioned. If it's not too badly rusted it may come off with some liquid/strongarm help. FYI, the nut cage is riveted to the body before the #4 body mount is riveted.

This post (and subsequent follow ups) will show you how to repair it, in "typical" form...

This post will show you how to repair it, atypically. It's the shortcut, but effective method. This method allows repair without pulling the body or the #4 mount. It also makes the repair invisible from under the car.

Rich

[Michael A.]

Re: Stubborn Body Mount Bolt

Pry the cage up. Take a 1"open end wrench and put on nut. Remove bolt. You don't need to remove anything but the carpet.

Keith - unfortunately what is left off the bolt is still rusted to the nut. I don't think prying the nut cage open will work as there still is a fair amount of the bolt shaft that is rusted to the nut. I had to cut drill the head of the bolt off so that I could remove the body from the frame.

Richard - Thanks for the links to the two posts with all of the pictures. From the looks of things, I will need to remove the decklid tower and spring to get at the nut cage and then drill out the rivets to replace the cage and nut. Am I understanding that correctly?

[Richard M.]

Re: Stubborn Body Mount Bolt

Richard - Thanks for the links to the two posts with all of the pictures. From the looks of things, I will need to remove the decklid tower and spring to get at the nut cage and then drill out the rivets to replace the cage and nut. Am I understanding that correctly?

Mike,

I see now that you already cut the #4 mounts bolt heads and have the body free. Sorry I missed that part.

As you now have likely seen, in order to properly replace the nut cage as originally configured, you must also remove the #4 underbody mount. This is because the nut cage is riveted to the body BEFORE the #4 mount is riveted.

In order to do this work, access to remove and replace all rivets can only be accomplished with the decklid towers removed. And while they're out, restore and replace springs. Access to the upper tower horizontally installed bolts is cumbersome. The bolts are 5/16-18, 1/2" hex heads. The outer bolt is the most difficult to access, and as mentioned in my posts, you do not have much room to get at it and it is prone to rust. Plan to be a contortionist to get in there. Make certain that the body is supported under the rear edge of the luggage floor to your body dolly. Because you're working on the #4 body mounts, you cannot use those as supports.

You cannot use a penetrant on the 5/16" upper mount bolts inner/blind threads before removal. You could drill holes in the reinforcement as peek holes to get a nozzle straw in there, but I've never opted to do that. I test "jerk" the bolts with a socket wrench to see if they move at all before anything. To date I've done many tower removals, and I've been lucky. Never broke a bolt off..........yet.

I use a combination of 3/8" drive ratchet sockets and extensions to get the bolt to move. Once it's twisted free a bit, you then have rust on the remaining threads to deal with. I've tried to squirt some juice up in there but it's tough and usually just makes a unhelpful mess and gets the bolt head slippery.

Here is what your view will appear. The bolt you see is the inner.


The outer bolt, hidden deep in the confines on the far side of the tower, is the toughest to get at. It's doable of course, but tricky. Much patience required. You can see the "gutter" reinforcement. The threaded steel nutplate for the 5/16" bolts is riveted to the rearward side of the reinforcement.


Here is the opposite side.


Whatever you do, do twice. In other words, do both towers and both mounts, as you will be needing to restore the towers and always use new springs while everything is apart. You only want to do this task once so I suggest you get it all now while the body is off.

Good Luck, and use a backbrace, pillows, have all tools at hands reach, and most of all a pre-Advil dosage is absolutely necessary.

Rich

[Harry S.]

Re: Stubborn Body Mount Bolt

Does this help?

[Michael A.]

Re: Stubborn Body Mount Bolt

Well darn. I guess I will be taking my Advil before heading out to the garage this morning! Thanks for the great pics and advice. And I may have a real benefit to the "bubba-hole" in my rear bulkhead!


It's a souvenir from someone who no doubt used it to simplify the task of replacing the power antenna! I will try to put it to use this morning to spray those upper tower bolts and will even try to see if it gives my access to the pesky outer bolt you mentioned! It's not exactly lemonade from lemons but it's something!

My plan is to take the rear deck and towers out while the body is resting on the #4 post of the body dolly. Then I'll support it before removing #4 body mount. Should be an interesting morning.

[Michael A.]

Re: Stubborn Body Mount Bolt

Does this help?

Excellent Harry. Great document. All of this documentation from you and Richard both scares me and helps me! I'm hoping my drains are not plugged and I don't have to go into the fabrication work you did.... but if I do, I am well armed! I will post what I find. Now, where's the Advil?

[Michael A.]

Re: Stubborn Body Mount Bolt

Thank you Richard and Harry for your documentation and suggestions. Here's the end result of this morning's efforts:



The deck lid towers came out with a minimum of resistance and nary a curse was spoken! I did not attempt using the bubba hole for the driver side and was able to get that nasty hidden bolt out with 1/4' drive socket (see picture) with an extension and 1/2" deep well socket. The 3/8" drive with extension and 5/8" socket was used for the bolt at the base of the tower. It took a bit of patience but it no bolt required more than "normal" amount of force to break free. It must have been my Donald Trump sized hands that helped get into those tight quarters!

My brother (chief mechanical advisor) and I are now debating as to whether we should attempt to free up the broken body mount bolt and avoid the rivet removal task. I'm leaning toward the full remove and replace as long as we are this far.

Thanks again for the support.