Body mounts......

[Doppleganger]

So my truck is a really clean left coast ride. Zero rust - everything **** and span. I go to see if the body mounts will break loose. Left front does but is stiff. I use a judicious amount of PB on it....it loosens about 3/16" and then stops. Will click loud....hoping its still loosening but seems more like that stupid idea of a tack welded nut has come loose and is spinning - dunno. The right front feels like it wants to be an asshat too.

I have it loose - is there a strategy here, such as cutting the bolt to free the cab from the frame? Seems it would be easier to deal with the cab off the truck and on its back. I hate the thought of cutting a perfect floor, then tack welding it back down - was thinking more of finding dead center of the bolt and drilling a hole (1" diameter?) to access the nut and also then to use a flat rubber grommet to close it.....like I have seen in other vehicles use for years. Something GM should have done for access to the nut.

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[shiftpro]

So my truck is a really clean left coast ride. Zero rust - everything **** and span. I go to see if the body mounts will break loose. Left front does but is stiff. I use a judicious amount of PB on it....it loosens about 3/16" and then stops. Will click loud....hoping its still loosening but seems more like that stupid idea of a tack welded nut has come loose and is spinning - dunno. The right front feels like it wants to be an asshat too.

I have it loose - is there a strategy here, such as cutting the bolt to free the cab from the frame? Seems it would be easier to deal with the cab off the truck and on its back. I hate the thought of cutting a perfect floor, then tack welding it back down - was thinking more of finding dead center of the bolt and drilling a hole (1" diameter?) to access the nut and also then to use a flat rubber grommet to close it.....like I have seen in other vehicles use for years. Something GM should have done for access to the nut.

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Flame wrench bro... carefully blow the head of the bolt off. You might nick the big curvy washer but that's not a problem. Just be prepared to lift the cab higher than normal.

 

[Frankenchevy]

A couple of mine made that noise when loosening them, I swore I was going to snap something. Turns out they were just chattering from sticking-releasing-sticking-releasing. I just kept shooting penetrating oil up there and praying. I used new bolts and copious amounts of anti-seize when I reinstalled knowing they’d likely be back out in the near future.

 

[Ken B]

PB Blaster can after can..spray it work the bolt as far as it will got . spray more walk away. I finally got them all out. after 39 years they all came out. Just waiting on new mounts that are backordered from LMC

 

[legopnuematic]

On the 85 cab I sold, (St Louis built, and lived in Saint Louis, Missouri winters) I didn't spray anything on them, or anything special. Put the socket on the 1/2 impact and let it rip, all 4 came out without issue. 1 Bolt was about rusted in 2 aswell.

most of the time the click sound is the bolt going from being stuck to not stuck. You'll know when the caged nut breaks.

 

[Scott91370]

Mine was exactly like this - no rust, under side of the truck still looks new and bolts were a pita to get out. There was A LOT of blue lock tight holding them in place. I used a 36" breaker bar to get them out. Even if you cut them you'll still have to get the stud out and you won't have a bolt head to do it with. KEEP TWISTING.

 

[Matt69olds]

Drill a tiny hole in the floor right above the body mount. Spray lots of PB blaster or your rust penetrate of choice into the hole. Wait a few days, spray again. When you think you have sprayed enough, spray some more and let it soak.

Yes, I know it sucks drilling a hole in pristine floors, but if the cage nut breaks loose, your going to need a much bigger hole to fix it.

 

[AuroraGirl]

A couple of mine made that noise when loosening them, I swore I was going to snap something. Turns out they were just chattering from sticking-releasing-sticking-releasing. I just kept shooting penetrating oil up there and praying. I used new bolts and copious amounts of anti-seize when I reinstalled knowing they’d likely be back out in the near future.

i also had a engine cradle mount of similar design not look rusty that the only thing that rusted was the bolt most of the way up. it snapped off in the captive nut with a cm sticking out in a little nub. same sounds.

But if its that bad twisting it off wasnt gonna do him more worse than not twisting. and his truck isnt from rust belt

 

[PrairieDrifter]

When I did mine on my suburban I had a couple that did the exact same thing, it's just the tension and rust breaking free, I soaked mine through access holes in the floor support. I did end up having to make a hole in the floor for one of em, it was most likely as stuck if not more than yours is.

Don't cut it until you've got no bolt head left to work with, otherwise you'll have to weld some nuts on what's left and keep at it. I used I think a 48 inch 1/2 inch drive breaker bar and I think I even needed a cheater pipe lol

 

[Frankenchevy]

When I did mine on my suburban I had a couple that did the exact same thing, it's just the tension and rust breaking free, I soaked mine through access holes in the floor support. I did end up having to make a hole in the floor for one of em, it was most likely as stuck if not more than yours is.

Don't cut it until you've got no bolt head left to work with, otherwise you'll have to weld some nuts on what's left and keep at it. I used I think a 48 inch 1/2 inch drive breaker bar and I think I even needed a cheater pipe lol

Dang, that’s stuck...

@Doppleganger , if yours are that stuck, take anything that I said with the context that mine came out with a standard length 1/2” drive craftsman ratchet.

 

[Bextreme04]

When I did mine on my suburban I had a couple that did the exact same thing, it's just the tension and rust breaking free, I soaked mine through access holes in the floor support. I did end up having to make a hole in the floor for one of em, it was most likely as stuck if not more than yours is.

Don't cut it until you've got no bolt head left to work with, otherwise you'll have to weld some nuts on what's left and keep at it. I used I think a 48 inch 1/2 inch drive breaker bar and I think I even needed a cheater pipe lol

I agree with this.. mine were rusty, muddy, and really stuck. Lots of PB blaster and a 1/2" breaker bar with a cheater pipe. They are huge bolts... you most likely can't get enough torque on them to shear the bolt.

 

[Doppleganger]

I do think its still turning (caged nut is holding), but is so tight its all I can do to turn it with a breaker + cheater bar. I have a 1300 ft lb (1400 blows per minute) Aircat 1150 air impact that has been ripping 3/4 bolts off at will that wont budge this one. UFB. I've been soaking the bolts around the bushings from underneath - the small hole above the nut sounds like a great idea too - could still plug it with a grommet after I'm done.

Once they're out, I'll run a tap through it then a new bolt bathed in anti-seize.

 

[PrairieDrifter]

I do think its still turning (caged nut is holding), but is so tight its all I can do to turn it with a breaker + cheater bar. I have a 1300 ft lb (1400 blows per minute) Aircat 1150 air impact that has been ripping 3/4 bolts off at will that wont budge this one. UFB. I've been soaking the bolts around the bushings from underneath - the small hole above the nut sounds like a great idea too - could still plug it with a grommet after I'm done.

Once they're out, I'll run a tap through it then a new bolt bathed in anti-seize.

Try and jack the cab up slightly so you can see the bolt through the bushing turning or not. The one bad one I had would only move a 1/16 of a turn and would pop really loud like that with pretty much all of my force, I got the shakes on a couple of pulls lol, you know when you torque on something so hard you start "shaking". My built in torque wrench says it was all of 200-250 ft lbs of torque.

But I did end up getting it out, and the new one went in with no issues. Keep at her!

 

[Scott91370]

So...where ya at one this? Just curious of the bolts survived...

 

[Doppleganger]

Been working on the DD......steering rack leaked, so I bought a NEW (not reman) from Rock only to have it leak worse. Got a good used one that works just fine. Car is being aligned and the rack is on its way back....so back to the saga 'how the bolt turns' later today.