Access and removal of rusted rear body mounts

[Laredo Matt]

I'm at the final stages of getting ready to remove the body and put it on a dolly. The front four body mounts are out. The remaining six are rusted and corroded and the bolts are just spinning in the cages or won't even budge.

Removed
2- Core support mounts - cut to remove
2- Driver / passenger side mounts - removed. Had to replace passenger front pan so had access to cage, cut driver pan to get access. Both were spinning freely so wouldn't have been able to remove without access.

Remaining
2 in front of rear seat - no access holes and spinning in cage
2 - rear axle - spinning in cage
2 - tailgate - won't budge

I have a couple of options for removing the remaining 6 but wanted to hear from folks who have done it to make sure I take the smartest path.

Option 1 (my first thought but am hesitant)
- cut access panels in the floor over each to gain access to the cage. I'm hesitant as welding back in is something I'm just learning and would prefer not to have to do that if I can avoid. I'm still learning.

Option 2
- use a sheet metal hole cutting blade and then replace with rubber body plugs. This seems easier than trying to weld back in and allows for future serviceability if needed. There are also already some so it will look factory if you could actually see them.

I'm definitely leaning to option 2. I can find rubber plugs up to 1 3/4" which I think should be enough. Of course I'd clean, prime and paint edges of cut to prevent future rust.

Anyone have other suggestions that have worked well that didn't require cutting? I've spent days already and done with busting knuckles on this.

A couple of pictures of current state

https://photos.app.goo.gl/r2y3Em1zhRB9MXor8

thanks in advance...matt

[Hspencer]

I used a reciprocating saw to cut off my two rear one. The cage nuts were were spinning. I plan to cut out from underneath to repair then weld back.


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[Hspencer]

I used a reciprocating saw to cut off my two rear bolts. The cage nuts were were spinning. I plan to cut out from underneath to repair then weld back.


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[SJTD]

I used a hole saw as you propose and drilled the bolts. They had nice indentations in the end pretty much on center from when they were formed that guided the drill down the middle. Used a drill a bit under the tap drill size and the remains unscrewed.

Drilled the threads in the square plates out anyway to use them as washers with nuts and lock washers and plastic plugs in the floor. I saw no point in making new cages to replace the originals.

I figger those cages were never intended to hold the nut plates for removal. They were for holding them on the assembly line.

[tgreese]

... I figger those cages were never intended to hold the nut plates for removal. They were for holding them on the assembly line.

Indeed. The design certainly did not consider any need to remove the body other than perhaps collision repair in the expected life of the vehicle, say a decade or so. No revenue potential otherwise.

[Laredo Matt]

I used a hole saw as you propose and drilled the bolts. They had nice indentations in the end pretty much on center from when they were formed that guided the drill down the middle. Used a drill a bit under the tap drill size and the remains unscrewed.

Drilled the threads in the square plates out anyway to use them as washers with nuts and lock washers and plastic plugs in the floor. I saw no point in making new cages to replace the originals.

I figger those cages were never intended to hold the nut plates for removal. They were for holding them on the assembly line.

Thanks for the responses.

I'm going to try and cut the rear mounting bolts with the sawzall and then deal with it when I have the body off and on a dolly.

My plan is to pursue option 2 - cutting holes and then using rubber body plugs for easy future access vs. welding sheet metal back back in place.

I like the idea of using the square plates as washers. No plan to replace cages as I don't see value either.

[Laredo Matt]

I used a hole saw as you propose and drilled the bolts. They had nice indentations in the end pretty much on center from when they were formed that guided the drill down the middle. Used a drill a bit under the tap drill size and the remains unscrewed.

SJTD

for the four rear mounts, were you able to cut the holes entirely in either the depressed or raised floor channels and get direct access or did you have to cut across the low and raised portions?

I don't think body plugs will work if cutting across so likely the former. When cut, Wwere you able to get directly over the mounting point or did you have to cut to the side and angle in to get access?

Hope that is clear.

Eyeballing it, it looks like the mounting cages might be centered so you'd have to cut across both depressed and raised channels to get directly over it.

I'm gonna measure later when I finish work but thought you might recall of the top of your head.

cheers

[SJTD]

The rearmost two, at the tailgate, I used a 1-1/2" hole saw. It went over the rear edge a little and was still off-center of the bolts. I think if you used a 1-1/4" and stayed on the flat area you'd be able to drill the bolts but you'd be well forward of their C/L's. You sure don't want to drill down the side of the crossmember.

The next two at the front of the rear wheel well I was able to get a wrench on the nut plates or maybe wedged them after removing the cages. All from underneath.

The next two that are even with the B pillar I had to go through the floor but I don't think the floor was drilled. My hole is in the approximate center of the existing depression.

The front two I got out without trouble since the cages are in place and the holes in the floor aren't over the bolts. I can feel them about 3" forward of the existing holes. If yours are stuck I guess you'll need to measure carefully and make another.

I don't think you'll have to deal with the corrugations at all if I'm understanding your question and only the rearmost might end up in a nonflat area.

[Hspencer]

This may help with the rear ones

http://ifsja.org/forums/vb/showthread.php?t=188009


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[Laredo Matt]

I don't think you'll have to deal with the corrugations at all if I'm understanding your question and only the rearmost might end up in a nonflat area.

Yep, you got it and are correct. Corrugations not an issue when I got back and was able to look at it. thnx.

[Laredo Matt]

This may help with the rear ones

http://ifsja.org/forums/vb/showthread.php?t=188009


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great pictures...thnx. Plan is clear, now it's just execution!

Hopefully I'll be done early enough today with other commitments to get started on it. My plan is to repair the front (driver/passenger floor pan) mount square nuts. I've already got the bolts out and cages removed. They' nuts are in good shape so I think I want to weld them in solid while the body is still on so alignment is spot in when I finally get to put the body back on. That should prevent them spinning should I need to remove in the future for any reason. I may also repair one of the rear corners the same way after cutting in an access hole. That way I have 3 known good aligned points before I take it off.