Cab Mount bolt removal problem

[dmw319]

So I was trying to change my cab mounts and from what I have read/seen, the front bolts go in from the top down and the back mounts go in from the bottom up. My front mounts look doable... but when I look at the back mounts, they literally look like pointed spears. Anyone seen this before or have any idea how I could remove them to replace the mounts? I have the kit from GMC Pauls.

Here are pics:

https://savedalone.files.wordpress.c.../08/mount1.jpg

https://savedalone.files.wordpress.c.../08/mount2.jpg


Thanks!

[Grumpy old man]

Looks like they have rotted away , Jack it up and see if you can get a set of vise grips on whats left .

[dmw319]

Originally Posted by Grumpy old man

Looks like they have rotted away , Jack it up and see if you can get a set of vise grips on whats left .

tried that. one side didnt budge at all and the other seemed loose (i could move it back and forth) but wouldnt turn. maybe it needs more pb blaster

[Grumpy old man]

the upper nut on the rear cab mounts are a caged nut under the gas tank . The replacement cab mounts come with that upper nut just in case the original is seized and needs to be replaced like yours . Time to pull the gas tank .

And while your at it replace the fuel tank sender / pick up and the fuel tank /cab gasket while its apart .

[67C10Step]

^^^^^ I'd say Grumpy is spot on here. The time you take to pull the seat and gas tank will be less and more rewarding than the frustration under the truck trying to get those bolts out.

I am having to re-learn the ins and outs of dealing with rust, stuck bolts, etc. as I get started on my project. Right now the side grinder and air hammer are my best friends.

[dmw319]

Originally Posted by Grumpy old man

the upper nut on the rear cab mounts are a caged nut under the gas tank . The replacement cab mounts come with that upper nut just in case the original is seized and needs to be replaced like yours . Time to pull the gas tank .

And while your at it replace the fuel tank sender / pick up and the fuel tank /cab gasket while its apart .

i did know they are caged nuts.. but i dont think my kit came with that upper nut.

how hard is it to remove the seat/tank?

[Grumpy old man]

Easy , !/2" socket and rachet and a couple line wrenches to loosen fuel lines , 8 bolts holding down the seat and 6 across the top of the tank use 2 people to lift them out of the truck . And be careful with your hands under the seat the spring that helps move it forward is strong and sharp so keep your hands out of the way of the seat tracks .

[dmw319]

thanks! Probably best to do it when the tank is mostly empty too. haha

[dmw319]

also, my set from GMC Pauls... one of the bushings from each set has a flat side. anyone know why this is?

[landarts]

On the last project I removed the gas tank and soaked the caged nut with Kroll oil and then put a large breaker bar on it to get it to spin. On the front ones I just used a Sawzall.

[dmw319]

Originally Posted by landarts

On the last project I removed the gas tank and soaked the caged nut with Kroll oil and then put a large breaker bar on it to get it to spin. On the front ones I just used a Sawzall.

only problem with this plan is that I have nothing to put the breaker bar on (see pics)

[57taskforce]

Originally Posted by dmw319

only problem with this plan is that I have nothing to put the breaker bar on (see pics)

If you can get something on the bolts a little heat from a propane torch on the nuts will do wonders. (Obviously remove the tank first)

[Mts67C10K20]

If you have access to a welder put a nut over the point of the stud and weld the center
That will give you something to get a socket on in combination with the penetrating oil
Good luck

[bigmac73]

Since there is nothing worth saving from those bushing kits, I would just cut of the head of the bolt on the lower side, or cut through the middle of one of the bushing gaps and be done with it. And whack it out with a punch

[mr48chev]

I'm thinking that on the one minus the head rust is holding the shank of what is left of the bolt to the steel inner collar of the bushing

Looking at the photos of both again you have nothing but rust holding the back down. It should lift up if you put a jack under the back of the cab and raise it up. It looks like it has been that way for a long time. The one side shows that the cab moved around so much that it wallowed out the hole that should be round. That bracket will have to be repaired or replaced.

[Grumpy old man]

Look at the pictures !!! , There's nothing left of the bottom of the bolt to use any type tool to remove it . The top nut is held in place by a capture nut under the fuel tank . The fuel tank has to come out to release the capture nut and then use the new body mount bolt/bushings/nut to re attach it . I would change out the frame mount if you can find one or at least repair what's left of the original one .

[dmw319]

Originally Posted by mr48chev

I'm thinking that on the one minus the head rust is holding the shank of what is left of the bolt to the steel inner collar of the bushing

Looking at the photos of both again you have nothing but rust holding the back down. It should lift up if you put a jack under the back of the cab and raise it up. It looks like it has been that way for a long time. The one side shows that the cab moved around so much that it wallowed out the hole that should be round. That bracket will have to be repaired or replaced.

Originally Posted by Grumpy old man

Look at the pictures !!! , There's nothing left of the bottom of the bolt to use any type tool to remove it . The top nut is held in place by a capture nut under the fuel tank . The fuel tank has to come out to release the capture nut and then use the new body mount bolt/bushings/nut to re attach it . I would change out the frame mount if you can find one or at least repair what's left of the original one .

the bracket itself is fine. I know it looks like its been wallowed out, but its not. that is just the remainder of the bushing that is left.

but yes, the bolt is very useless. ive lifted the body up with a jack and it stays completely attached. probably because the front mounts are fine and can be replaced normally.

do I HAVE to take the tank out to release the capture nut? I was thinking I could try and weld something onto that remaining "spear" and try and get it to turn out.

[dmw319]

anyone else know why the bushing from GMC pauls has the straight side? it may be obvious once I try to put them in, but it'd be nice to know ahead of time

[GMCPaul]

Originally Posted by dmw319

anyone else know why the bushing from GMC pauls has the straight side? it may be obvious once I try to put them in, but it'd be nice to know ahead of time

They have a flat edge on 1 side of the front bottom tapered cone bushings because GM originally made them this way, why GM did this we've never been able to determine in our research. So it's flat because it's a exact reproduction of the originals.
Paul Jr @ GMCPauls

[dmw319]

Originally Posted by GMCPaul

They have a flat edge on 1 side of the front bottom tapered cone bushings because GM originally made them this way, why GM did this we've never been able to determine in our research. So it's flat because it's a exact reproduction of the originals.
Paul Jr @ GMCPauls

Thank you very much!

Since my cab mounts are so shot.. I can't really tell the way they are supposed to look. Do you have a diagram of the mounts I bought from yall that say which piece goes where/in what configuration? I am generally aware/capable of probably figuring it out, but it would be nice to have it from the source!

Thank you very much for your response.

[GMCPaul]

The barely thicker hockey puck style mount goes in rear with thinner in hockey style puck in front ( the front and back upper bushing both have metal isolation collars that protrude from them and these should be pointed down through frame bracket), the tapered cone with flat edge is front mount bottom, tapered cone dished in through middle goes in bottom rear.
Shim as required to perfect gaps and alignment. Torque Front Bolts = 70-90ft lbs Rear bolts= 35-55 ft lbs
Use torque range to further adjust gaps and body panel alignment.
Paul Jr @ GMCPauls

[dmw319]

Thanks!