Squeaking poly cab mounts

[bobs409]

I went with the poly type cab mounts and at first they were fine but now I'm getting alot of squeaking. I just tried snugging them up but it didn't help.

Any tricks to fixing the squeak?

Thanks,

Bob

[69GMCLonghorn]

There is a special grease that should always be used with poly bushings. You'll need to pick some up, pull the bushings apart and lube 'em up!!

I may be doing the same thing in the near future... I hope I don't end up with squeaks.

[STOCKISH]

I had the same issue on a truck I used to have. I had to lube them every couple months. I just switched them out for the factory rubber stuff.

[Hart_Rod]

Do you have the red or the black ones? Supposedly the black ones have graphite in them to help reduce the squeaking. You can do what I do for noises like that, just turn the radio up a little louder, .

R/

[special-K]

Replace with factory-type rubber.Poly mounts like to squeek.

[Classic Heartbeat]

Weld the body to the frame... Just kidding. The only real way to stop the sqeeking perminently is to go back to rubber. WES

[Greaser]

I have always heard powder graphite, so dust and dirt doesn't stick to it like penetrating oil, or petroleum jelly.

[bobs409]

These are black. Going back to rubber is not what I want to hear, I bought another set already to put in on my other truck.


Thanks,

Bob

[dfwright]

So is the conventional wisdom to use poly for everything but the cab mounts, and use rubber for those, or are there other places that rubber should be used?

[cadillacart]

I have heard that in general Polyurethane will squeak. Also from personal experience on my honda civic. I replaced all of he front end rubber with with poly and now it sounds like the car is a POS when driving over bumping surfaces. I think I will opt for rubber from now on.

[Classic Heartbeat]

Polyurethane is bad for body mounts, and engine mounts. They defeat the purpose that the manufacturer used the rubber for. Rubber mediates movement, and vibrations. Polyurethane does not do this, at least not effectively. The chassis on these trucks are "C" channel chassis, designed to flex and move with the conditions of the road. (This is why they are bolted and riveted together. Bolts and rivets allow for flexibility) Unlike the bodies and their parts witch are spot welded together and can not move like or with the chassis. This is why GM used rubber mounts and did not bolt the bodies directly to the frame. The flexibility of the rubber is needed to preserve the body by absorbing at least most of the movements that the chassis does under normal circumstances. Same goes for the engine, it torques, flexes and vibrates, so it is mounted on rubber mounts so the vibrations and movements are not translated throughout the vehicle. Causing problems in the chassis and body. The long and short of my point is poly is good for suspension, but that is all. It is good for suspension because it tightens it up so the vehicle handles better. WES

[tim21391]

thats why they are a little cheaper..

[bobs409]

Actually, they were the same price. Since I'm keeping my trucks for life and drive them all the time, I opted for the poly for durability.

After seeing how long my "repop" fuel filler neck grommet lasted, I just couldn't make myself try repop body cushions. I just invisioned all those cracks!

[special-K]

Rubber lasts a very very long time.There are plenty of trucks with original 40 year old oEM mounts.There are no 40 year old poly mounts.
The question I always asked is why would someone want to stiffen what needs to give?Urethane bushings were created to firm up suspension,then they expanded into all bushings when they caught on.Look at the stresses on suspension bushings compared to body.The suspension wants to stay put while the rest of the truck wants to go where the forces of physics is taking it...just about the whole truck.The body is bolted rigid to the frame and intended to stay that way...together.But,bushings are used to allow some give to absorb vibration as well as take stresses off of lighter sheet metal versus heavier steel chassis.I have a rigid-mount Harley and the bike is constantly trying to fall apart.Bolts always backing off and lighter metal is always splitting.My feet try to vibrate off the footboards,mirrors are useless,and hands get vibrated.the seat helps,but the butt can get numb,too.The newer rubber-mounts have none of these characteristics.
I guess there have been improvements made to urethane.But,I had a wandering problem with a`71 K/20.After replacing every part involved in the steering it was still all over the place.I had someone work the wheel while I watched underneath.The whole assembly of springs and axle were racking back and forth.The 3 year old poly lift kit bushings were all cracked up.

[70cst]

Originally Posted by Classic Heartbeat

Weld the body to the frame... Just kidding. The only real way to stop the sqeeking perminently is to go back to rubber. WES

Geeeee...I am sure glad WES sold me rubber bushings. The bushings that was taken off my 70cst were the original bushings...at least that is what I was told. The only squeak I want to hear is one from a mouse.

[dfwright]

Now I'm confused. Should I plan to put rubber everywhere, or rubber in the cab/engine mounts and poly in the suspension parts?

[70cst]

Originally Posted by Classic Heartbeat

Polyurethane is bad for body mounts, and engine mounts. They defeat the purpose that the manufacturer used the rubber for. Rubber mediates movement, and vibrations. Polyurethane does not do this, at least not effectively. The chassis on these trucks are "C" channel chassis, designed to flex and move with the conditions of the road. (This is why they are bolted and riveted together. Bolts and rivets allow for flexibility) Unlike the bodies and their parts witch are spot welded together and can not move like or with the chassis. This is why GM used rubber mounts and did not bolt the bodies directly to the frame. The flexibility of the rubber is needed to preserve the body by absorbing at least most of the movements that the chassis does under normal circumstances. Same goes for the engine, it torques, flexes and vibrates, so it is mounted on rubber mounts so the vibrations and movements are not translated throughout the vehicle. Causing problems in the chassis and body. The long and short of my point is poly is good for suspension, but that is all. It is good for suspension because it tightens it up so the vehicle handles better. WES

Originally Posted by dfwright

Now I'm confused. Should I plan to put rubber everywhere, or rubber in the cab/engine mounts and poly in the suspension parts?

Well...I used 100% rubber in my resto ... but WES knows his trucks so if he says poly in the suspension is ok...thats good enough for me. Soooo I would either go 100% rubber or all rubber except the suspension and use poly in that application. JMHO

[Zeke]

Go to Lowes or Home Depot and get some plumbers silicone grease, looks like the same stuff sent with some poly kits only cheaper. You'll have to disassemble the mounts and put wherever the poly touches the metal. Don't know how long it will last but should take care of the squeak.

[leddzepp]

The rubber used nowadays is nowhere near the quality of the rubber manufactured 40 yrs ago. The fuel filler gaskets are a good example of this. I would also guess that this would hold true with any rubber piece made today, including the cab mounts. I am thinking that it has something to do with EPA regulations....no wait, they are made in taiwan now...ok, that explains it! Even so, I would still opt to use rubber for the cab mounts simply because they will not squeak and will give you a smoother ride.

[c10addict]

Silly as it may sound I brush Anti-seize on Poly bushings/ mounts before I install them.. Seems to work... I agree that rubber is the best way to go.. Yes poly is better for suspension but always seems to start to squeak... For a street car/truck and not a track car/truck go rubber... And if you want to hear noisy meet up with me and I will take you for a ride in a track prepped BMW M3 with solid aluminum bushings! Now thats noisy!

[Classic Heartbeat]

After seeing how long my "repop" fuel filler neck grommet lasted, I just couldn't make myself try repop body cushions. I just invisioned all those cracks!

First off all of the "repop" fuel filler neck grommets are poor quality. We inform our customers of this and at least for the 67-70 2" filler grommet we sell Genuine GM only. Sadly we can not get the Genuine GM 71-72 1 1/2" grommets anymore so we reluctantly affer the "Repops". However we are working with an OEM supplier to manufacture grommets exclusively for us. These grommets will not crack like the reproductions out there now, but will come at a cost. They are probably going to be two to three times the price of existing repop grommets.
Secondly, fuel filler grommets are exposed to the weather degrading them a lot quicker (UV rays are bad on everything) The body mounts are only exposed to water and dirt, so they will not degrade nearly as fast.

The rubber used nowadays is nowhere near the quality of the rubber manufactured 40 yrs ago.

Partialy true, some of the Taiwanese rubber is bad, however there are other companies manufacturing rubber products that are actualy better than they were 40 years ago.

Now I'm confused. Should I plan to put rubber everywhere, or rubber in the cab/engine mounts and poly in the suspension parts?

If it were me, rubber body mounts, rubber engine and transmission mounts, urithane rear control arm bushings, and urithane pan hard bar.

Well...I used 100% rubber in my resto ... but WES knows his trucks so if he says poly in the suspension is ok...thats good enough for me. Soooo I would either go 100% rubber or all rubber except the suspension and use poly in that application. JMHO

Thanks for your confidence in me.
Any anti-seize or grease will ware away and have to be reapplied time and time again. Rubber bushings are installed and forgotten for many years to come. WES

[dfwright]

Originally Posted by Classic Heartbeat

we are working with an OEM supplier to manufacture grommets exclusively for us. These grommets will not crack like the reproductions out there now, but will come at a cost. They are probably going to be two to three times the price of existing repop grommets.

If it were me, rubber body mounts, rubber engine and transmission mounts, urithane rear control arm bushings, and urithane pan hard bar.

Wes, Thanks for the advice. I'll save this for future reference. Sign me up for one of the new grommets when they are available. I don't want to have to replace it once installed.