poly vs. rubber control arm bushings

[johnunit]

The torsional bit shouldn't be all that significant. it is a factor, sure, but it probably does more to dampen the spring than actually adding any significant spring action of it's own. Likely you can make up for this easy enough with a stiffer set of shocks.


All this is preference. I have a set on my Towncar front and back and have no complaints about it. Scott dislikes them. I have a set on my Mark VII and hate them. At some point, I will pull those arms back off and change the bushings to rubber. I'm just hoping I can get away with just changing the front back to rubber on that and eliminate that whole kidney stress test thing that it seems fond of doing.

Yeah I'm not super-worried about spring rates and all that because I'll be swapping springs and shocks anyways. It could throw things off to put poly bushings in with your stock springs, but going poly bushings and stock springs seems like an odd compromise anyway.

[gadget73]

well, the Mark has air springs, so you really don't change those. You either ruin the car with a halfass coil conversion, make it a mushpot with the wrong air springs, or build yourself some GTC air spring base adapters to slip over the stock LSC spring base to increase front spring rate. I can't build things with wood to make the GTC adapter mold, so it shall retain the stock LSC springs.

I've had 3 different springs in the Towncar, the only ones that didn't sit stupid were the stock ones. It was either too high or too low, and after that I decided I was too stupid to figure that stuff out and went with standard replacements. It sits normal now.

[johnunit]

well, the Mark has air springs, so you really don't change those. You either ruin the car with a halfass coil conversion, make it a mushpot with the wrong air springs, or build yourself some GTC air spring base adapters to slip over the stock LSC spring base to increase front spring rate. I can't build things with wood to make the GTC adapter mold, so it shall retain the stock LSC springs.

I've had 3 different springs in the Towncar, the only ones that didn't sit stupid were the stock ones. It was either too high or too low, and after that I decided I was too stupid to figure that stuff out and went with standard replacements. It sits normal now.

Yeah I'm fine with the stock ride height at this point, but PI sways, PI shocks, tires wider than a wal-mart customer, and poly bushings all sprung by stock-rate springs seems like a waste.

As an aside, more on topic, I've given up on buying whole arms and am about to pull the trigger on the cheapest shit set of front bushings I can get, and poly bushings front and rear. That way I can put the poly bushings in new shells before tearing the car apart. I have boxed rear lower arms on a shelf, so I can prep those too.

This way all I have to do once the control arms are out is press the ball joints out and in, then out the old bushings however I want and ram the poly ones home. My service manager won't hate me so much for clogging up a bay if the day isn't spent screwing around with 30 year old bushing shells.

[turbo2256b]

Might be better installing the bushings with the rubber first then burn out the poly ones since the poly ones slip in annd out fairly easly. Could end up warping a bushing shell.

Doing uppers removal and install with rubber ones best have the proper tool to get around the shaft.

All teeth shouls be delt with there may be some on the upper arms inner step. Think I installed a washer to stop them from diging into the poly bushing.

[johnunit]

I'm not so worried about having new shells, just about not having to screw around with burning bushings while clogging up a lift at work. Is there really a risk of damaging a shell just from the burn-out and install without having it in the arm? I would think shape wouldn't be that critical because the poly bushing being put in would hold/fix the shape. But I've never seen them without bushing material in them.

[His Royal Ghostliness]

As an aside, more on topic, I've given up on buying whole arms and am about to pull the trigger on the cheapest shit set of front bushings I can get, and poly bushings front and rear. That way I can put the poly bushings in new shells before tearing the car apart. I have boxed rear lower arms on a shelf, so I can prep those too.

Still lots of work that way. And if you happen to bend the arms in the process, you're kinda screwed. I'd suggest you hit a junkyard for a set of lower and upper arms, then burn their bushings out and push your poly ones in. Drop a new set of ball joints too, if yours are questionable. Paint as needed/desired. When you get on the lift, just pull your old arms off and bolt the new ones in, then hit the alignment shop on your way home. You'll probably spend on the arms about as much as you'd spend on sacrificial rubber bushings, and you can do all the prep work at home or some place else where you're doing things at your own pace without getting in anyone's way.