View Full Version : Poly Bushings

04-22-2002, 07:45 PM
Somebody mentioned in a previous post not to put the poly bushings in the front lower control arm as they bind up. I got off the phone with OPM, didnt ask if it was Tom or the other guy, and he was saying not to install the ES poly bushings either. Is the first advice the same source as the second? Can anyone comment further on this?

Also, for the rear trailing arm bushing, I havent checked yet in much detail, but I'm pretty sure mine are shot or in bad shape. How was the install for the Prothane bushing? Im leaning towards the Mugen hard rubber, because I think I remember Caroll Smith commenting on the fact that rubber bushings allow flexing around the center shaft which act as a small bit of spring action, while poly bushings simply rotate around the center, which may not be ideal. Maybe this is the same reason why OPM doesnt recommend the ES poly bushings in general. Anyone care to comment? For anyone who has installed the Prothanes, how difficult is it? OPM said the Prothane doesnt come with the dogbone which makes installation a pain, but the pictures seem to show it as a complete unit.

I finally cleared out my garage and am ready to put the CRX on stands for a while to rebuild my whole brake system and suspension, and hoping while its up, replace the needed suspension bushings as well.

04-23-2002, 02:15 AM
Tyson, You either spoke with Tom or Blake when you called OPM. Both are great people to obtain information from. When I spoke with Blake, he recommended that I not use Prothane bushings as well, but I went ahead and did it anyways. My stock ones were shot, so I said what the hell and went with the Prothane kit. The install was a major PITA! Luckily, I have a friend that has a machine shop and had done the bushings on his car, so he basically did all of the work. I would say it took him a good 4 hours to do all the pressing. He had to machine pieces that enabled him to press out the sleeves. This is what took most of the time. If I have any problems with the bushings binding, I will just take them out and replace them with OEM pieces, but I wanted to give them a try. As far as the trailing arm bushings go, I went with the Mugen pieces that OPM sells. The install for these was pretty easy. Simply press the OEM sleeve/bushing out and press the mugen one in. I dont know about your CRX, but on mine, both trailing arm bushings were torn. I have yet to drive the car, but from the looks and feel of the Mugen bushings, there is a noticible difference. IF you do not have access to someone who can "hook" you up with the help on pressing the bushings, I wouldnt recommend trying them out. First off, they may not be better than the OEM pieces, even if the OEM pieces are worn, and secondly, a machine shop would probably charge you an arm and a leg to press the bushings. The ones I would recommned are the Mugen pieces. I have spoken with numerous people that run them and none of them have complained. Maybe try out the radius rod bearings instead. You can either get these from OPM or Progress. I spoke with Bernardo (ITA CRX driver in Socal) and he told me that the Progress ones are much better than the Vitek ones that OPM sells. well, fingers are tired. Maybe I'll see you out at laguna this weekend if you are driving. I'll be there as a spectator.

Jon Nelson
04-23-2002, 09:33 AM
I "heard" the comment about poly bushings and binding, too, but I don't think it's a problem. Of all the bushings in a CRX that MIGHT bind, the only one I'd worry about is the lower outer control arm at the rear. It carries vertical load and side load simultaneously. At the front, this is carried by the lower ball joint.

Poly bushings require maintenance, IE, lots of lube, but it's a good excise to take everything apart and inspect every couple of weekends.

I'd recommend the prothane bushings over stock. If you've ever driven a car back to back after even doing just the lower control arms, you'd agree.

I too, spoke with Blake about poly bushings, his reason for not doing them was that it is a lot of work to install them.

As for pressing them out/in, burning the old ones out with a torch is the easiest way.

more later,


04-23-2002, 10:34 AM
Jason- Thanks for the info on the Mugen pieces. I was just looking at my trailing arm bushings this weekend...

Regarding the front lowers: Doesn't a more solid mount, i.e. Delrin bushings or a bearing, make more sense for the front lower control arm pivots than a Poly bushing? Jon made the point that other parts in the front carry loads that allow the front LCA's to pivot on their axis without strange loading, so a more positive mount seems to make sense. Deflection is bad, right?


Jon Nelson
04-23-2002, 12:09 PM
If cost is no object, yes, deflection is bad.

Progress sells spherical bearing kits for the lower control arms for the CRX, at a price, I think 179 a pair, although you might get them cheaper from a distributor.

I would guess the biggest benefit in reduced deflection would be seen by doing the front lowers and rear, lower, outer. May as well do the front radius arms, too.... but it will get expensive!!


04-23-2002, 12:20 PM
Another OEM part that should be replaced is the engine mounts! Fresh/new mounts make a world of difference.

For my '87 Si, the only choice is OEM. I filled my motor mounts with a tube of polyuerathane glue (let it harden for 24 hours before reinstalling). BIG improvement.


04-23-2002, 02:25 PM
Thanks guys for the input. I guess the anti-poly platform is being originated from OPM. Actually, I think they confused the Prothane and Energy Suspension rear trailing arm bushing kit, as the Prothanes come as one solid piece and the ES bushing is only the poly and needs to use the stock metal, which then makes the bitch of a job of separating the stock metal from the rubber.

yes, i do have a source with a good hydraulic press.

can anybody with carrol smiths book look up the chapter in bushings and remind me what he said about poly vs rubber bushings? I know he had something important to say... i want to confirm. maybe ill have to go to the library (barnes and noble) for this myself.

as for engine mounts, i know for certain mounts MUST be rubber as stated in the rules, so filling it with poly or using the poly inserts would be illegal. however, anyone know if you can fill em with real rubber? (this was already posted in the Rules Forum as well)

04-24-2002, 11:55 AM
I have an H3 (Honda Challenge - basically an ITS car) GS-R with the ES kit, purchased from OPM. It was a good deal of money to install, and yes, you should disassemble stuff and lube it every so often. But it really helped the feel of the car. After 100K street miles, the stock stuff was toast...and the Mugen pieces, while nice, were simply too expensive.

I've found that "Moly" grease - the thick, nasty black stuff - works really well with these bushings. And once they're installed...removing them for cleaning and regreasing isn't hard, since they simply press in and out. We should all probably be disassembling parts of our suspension every winter anyway, just to make sure nothing's bent or cracked.

05-08-2002, 12:25 PM
Progress now has the radius rod bearing kits, the front control arm inner pivot bearings, and the rear control arm inner and outer bearing kits - all of them use teflon lined spherical bearings. They have an ad in SportsCar, $649 for the whole car (fronts, radius rods, and both rears)