I'm planning on replacing all the rubber suspension components on my '81 F-150's front end (Twin I-Beam, 2wd), and I'm considering getting a polyurethane kit. But before I make a decision, I have a couple of questions...

1. How well does the polyurethane hold up compared to rubber?
2. What's the average lifespan for polyurethane in this application?
3. What difference will using polyurethane have on ride quality, if any, compared to rubber?

My truck is mainly street driven, though I do plan to use it to haul things now and then. I don't take it out mudding, so the suspension probably won't see too much excessive flexing.

 

1. How well does the polyurethane hold up compared to rubber?
Poly bushings last longer

2. What's the average lifespan for polyurethane in this application?
Don't have a answer for that, but will probably outlast the truck

3. What difference will using polyurethane have on ride quality, if any, compared to rubber?
Poly bushings give a harsher, stiffer ride.

 

Will they help with how the truck handles?

Thanks for the quick answers!

 

Yes, they stay stiffer than rubber, allowing the truck more stability.

 

I had a 96 Sebring that I replaced them all with and was pretty surprised how the 30-something bushings tightened up the ride. They don't break down like rubber. The softer rubber flexes more eventually tears. Rubber seems to dry out as well, but I haven't seen a 30 year old poly bushing lol.

 

Yes, they are good when used/installed correctly as they operate differently to rubber bushes. With the original rubber bush, the inner tube is clamped tighly to the chassis and cannot move in relation to it. The outer side is clamped tightly to the suspension component and cannot move in relation to it either. All the suspension movement is taken up by the flex in the rubber, there is no lubrication needed as there is nothing sliding/moving against anything else.

Poly bushes work totally differently. There is not enough flex in the poly to have it fixed to the chassis and to the suspension arm, there has to be some sliding of components and there has to be lubrication. Like the original rubber, the inner tube supplied with the new bush must be clamped tightly to the chassis so that it cannot move. Likewise the outer part of the bush needs to be almost a press fit in the suspension arm. The movement point is between the inner hole in the poly bush and the inner tube. This must have the lubricant supplied applied there. If the outer part of the bush can rotate in the suspension arm then it will wear away the steel! It is surprisingly abrasive stuff.

The most common mistake, and I found it EVERYWHERE in my truck (previous owner), is that the inner tubes were not clamped tight enough to the chassis and thus they were turning on the bolts. Most of the suspension bolts were dangerously warn away

Also, if you own an older Ford with the original Mustang/Falcon style front end, never ever use poly bushes where the radius arm bolts to the chassis. The poly bushes are too stiff and don't allow enough flex as the radius arm moves up and down. This makes the radius arm (instead of the bush) flex and eventually snap off, usually around the rear nut.