Polyurethane Body Mount Problems

[madmatt1]

I just changed out all of the body mounts on my 95 Bronco with a set from Prothane....
I reused the factory washer / sleeves, after grinding off the flared portion, and used new grade 8 bolts.
After torquing the bolts to factory specs, which I believe is 65 lbs on the cab mounts, and 45 or so on the core support,
I went for a test drive and all seemed well. After a couple of weeks, and a couple of trips of light off road use, i started
noticing some really bad creaking and popping noises from pretty much all of the mounts. Turning at a stop or low speeds
makes the worst of it, with some really nasty noise from the front mounts...

Anyways, I'm wondering if anyone has experience to share in terms of making these things quiet. I went over all of the bolts
again,and they weren't loose, however the factory torque spec doesn't seem to be nearly enough to keep them from moving around.
I also did not grease them with anything, but I'm wondering if I should have? Any tips would be appreciated!

[Wrightracing.net]

When it comes to the poly mounts using grease is a must, it will stop them from making noise. The mounts are supposed to move a bit that's the point of a poly mount, instead of a solid mount.

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[ChaseTruck754]

I found out early on the hard way that poly does need to be greased or it's a noisy SOB!

So yeah, time to take um back apart & lube um up!

[madmatt1]

I appreciate the insight, fellers!
Now, to find the motivation to do that all over again....

[Wrightracing.net]

I found out early on the hard way that poly does need to be greased or it's a noisy SOB!

So yeah, time to take um back apart & lube um up!

Hey Steve, I have not used them for body mounts before, but do you think delrin bushings would need to be greased.

I know they a impregnated with a type of lubrication, so probably not.

On my Old School rebuild of my Bronco, I want to mount the body semi solid, but with a little isolation from vibration and sound from the frame. The Rollcage is going to be mounted on delrin bushings also.

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[ChaseTruck754]

I haven't use delrin much but I've never greased it. Like you said it's self lubricating. Kind of like oil impregnated bronze.

I saw you mention that body mount idea in your thread (which I'm totally looking forward to that build by the way!) and I almost commented but held back. Since you're asking here I'll give my $0.02. In my opinion delrin pretty much is solid mounting. While i haven't done what you are suggesting I don't think delrin with give you much of the isolation you are looking for. If it were me I'd skip the body mounts all together and just "mount" the body by tying it to the cage solidly. Meaning attachment plates, etc. and welding the cage to the body. Then just run your cage tubes through the bottom of the body and then mount the cage to the frame with poly bushings for the isolation. The poly will give the little flex needed to give the isolation you are after. I think delrin is a bit to hard/rigid to do what you are looking for here. I'd make sure to put zerk fittings in the bushings to control the squeak down the road in time, but this design should keep things rigid where you want rigid, but won't amplify the vibrations near as badly as a truly solid mounted setup.

[Wrightracing.net]

I haven't use delrin much but I've never greased it. Like you said it's self lubricating. Kind of like oil impregnated bronze.

I saw you mention that body mount idea in your thread (which I'm totally looking forward to that build by the way!) and I almost commented but held back. Since you're asking here I'll give my $0.02. In my opinion delrin pretty much is solid mounting. While i haven't done what you are suggesting I don't think delrin with give you much of the isolation you are looking for. If it were me I'd skip the body mounts all together and just "mount" the body by tying it to the cage solidly. Meaning attachment plates, etc. and welding the cage to the body. Then just run your cage tubes through the bottom of the body and then mount the cage to the frame with poly bushings for the isolation. The poly will give the little flex needed to give the isolation you are after. I think delrin is a bit to hard/rigid to do what you are looking for here. I'd make sure to put zerk fittings in the bushings to control the squeak down the road in time, but this design should keep things rigid where you want rigid, but won't amplify the vibrations near as badly as a truly solid mounted setup.

Thanks Steve, The plan from the start has been to completely weld the cage to the body, but I want a bushing material that is more rigid then poly without the issues of poly. So we will see.

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[ChaseTruck754]

I get the desire for sure. Try the delrin out & let us know. It could be the new, hot ticket! I like the stuff for sure, I just think it's a bit too hard to really do what you want. It is not metal though, so maybe it will isolate bit??? Only way to know is to try it.

[Mrz181]

have you checked out autofabs's cab mounts they have fabricated body mounts that incorporate a place to tie in the cage using their poly bushings

[Wrightracing.net]

have you checked out autofabs's cab mounts they have fabricated body mounts that incorporate a place to tie in the cage using their poly bushings

Yes, I know John and he does great work and that design is a great design for a stock body. But, I am putting a Early Bronco Body on a Late 1986 chassis where the body and cage mounts are going a different route.

Ok that is all on here, I am sorry, we got off track from the original post.

When I get more work done, I will post in my thread.

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