What's the deal with this body mount?

[Mastiff]

I got half of them in place. Just set in place and the weight put back down. I noticed a few things. On the inner bed mounts, the poly kit comes with some big washers to go on top of the top bushing, between the bushing and the bed. Thing is, it's right against the bed, and the hole in the washer is round and too small for the square part of a carriage bolt to fit. I'll probably go with hex all around, but did anyone else run into this? If I wanted to keep the hex, I guess I'd have to open up the washer opening.

The other thing is what to do with that bracket thing near the rear most mount. I don't think the bottom bushing will fit in it the way the factory one did. I could just push it forward out of the way, but I don't really see any way to get it out of the frame without dropping the tank. How did everyone deal with this? rebelgregory, you say you cut it down, I assume you didn't do that with it still in the frame?

 

[K85 Octane]

hmmm
I went hex head all around and at the time of install, my tank was out, so I kinda remember something in the back but it wasn't a problem. Damn I've got a bad memory

 

[rebelgregory]

Tank was out when I did mine as well. Not much you can do with the tank in.

 

[Fordum]

I realize you are about half way through, plus you already bought the bolts. But, as an alternative to either hex or carriage, you might want to consider Allen type bolts in either dome or countersunk.

If you get the hardened ones, the head is very resistant to stripping out. The tool and die shop I consult for uses them for just about everything, and I have never seen a stripped out head.
And they have equipment that is 10 years or more old that they built come into the shop for refurbishing or sharpening, and the bolts come right out.

I used to curse Allen head screws because the hex socket stripped out when I tried to remove them.
I just did not realize the difference in quality between the cheap hardware store bolts and good steel ones.

Couple of examples:

NOTE: I do not necessarily recommend stainless steel, or even this company. I don't think I have ever done business with them.
I was just looking for pictures of the different bolt head styles, and they popped up with good pics.
Plus the stainless just looked so nice.

http://www.probolt-usa.com/stainless-steel/stainless-steel-bolts-dome-head.html

http://www.probolt-usa.com/stainless-steel/stainless-steel-bolts-and-washers-countersunk.html

 

[Mastiff]

Good idea. Actually, torx would be perfect here if I could find some in grade 5/8 that are the right size. I'm ready to get done though, so if they don't have what I need at Ace I'll just go hex. It wouldn't actually be a big deal to swap them later now that everything is broken loose.

 

[Mastiff]

Well, I don't know the right thing to do (besides lowering the tank) but I just pushed that bracket thing forward in the frame rail until I found a hole in the frame that lined up with one of the captive nuts. Bolted it in place so it won't rattle. Next time the tank is out, I'll remove them.

 

[Mastiff]

Done. The bushings in the middle were in great shape, but the stuff at the ends wasn't so great. The bolts were rusted half way away. All the rectangular shaped bushings were squashed down quite a bit. The 5" bolts for the very back were not long enough for the new poly bushings. I had to go back and buy 6" ones. I also figured out I could get those bracket things out of the frame from the back if I turned them on their side and pried hard enough. Not fun, but better than dropping the tank or having them along for the ride for 3 years.

I just snugged everything up, didn't toque the heck out of it. I'll drive it around the block a few times and snug them again.

Photo album:

 

[rebelgregory]

Job done!

 

[Mastiff]

I torqued the mount bolts down to 35-50 ft/lbs and now the truck seems pretty rattly. I can't quite tell where the noises are coming from. I wonder if this is sort of normal, going from old rubber to new poly? Transmitting more vibration to the body? I'd love to get rid of the rattling, but maybe it's not possible in a 30 year old truck...

 

[y5mgisi]

The polls vs rubber was a pretty harsh difference on my pickup. I'm pretty sure I'm going to go back to rubber on it some day.

 

[K85 Octane]

haha
start tightening any bolt you see
I didn't notice any difference when I swapped out the rubber for poly, then again I'm sure I have other noises drowning out any additional noises

 

[chulisohombre]

I didn't know there was a torque setting back when I put mine on. Just tightened them down until I started to see the bottom bushing start to squish. No rattles. If there is a loose bolt, you may be able to feel Around and see if a washer is loose and moving. Then figure out if something got run the way of it getting Fully tight. If it looks to be nothing stopping it from bottoming out just tighten it up some more. As the poly wears in it will probably need to be tightened a couple times to keep it locked in tight. I checked my after a week and then a month later I make sure the bolts stayed tight. They did need a little tightening at that Point. I put like a extra turn on each bolt the last time I did it and haven't had To touch them since.

 

[Mastiff]

If you search around on this forum you'll find the factory specs. I already forgot, but it boiled down to about about 50 on the big ones under the rocker and 35 on the others IIRC. When I was doing it, the 50 seemed like a lot. The bushings were squishing in quite a bit.

I don't think the rattling is from one of the mounts, they all look tight. I suspect it's just making something else more obvious. I could be wrong though. I'll put a wrench on them all just to make sure.

 

[chulisohombre]

Poly are harder mounts. More engine and road bumps are going to go through the chassis a bit more now may have to give the whole truck a once over to catch any residual rattles or loose bolts.