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Posted: Wed Dec 15, 2004 3:49 pm
by professor
The plastic is almost certainly UHMWPE. Also I don't think there are numerous suitable pastics, the beauty of the UHMWPE is a combination of very low friction, huge wear resistance, and virtually unbreakable nature. Also, since the MW is so high, it really doesn't exhibit a sudden melting point, and will hold form for brief excursions up to 400F and above.
Teflon would be low friction but wear resistance is not as good and it cracks fairly easily.
Yes the Energy one-piece bushings can be a bear to get into place. The ones for the endlinks and the lateral links present the same problem. I tried the c-clamp press and the damn bushings distort so easily that I still could not get them in.
But I have secret...
Freeze the bushing thoroughly to stiffen it up. Then quickly heat the side you want to fit through the hole by setting it in shallow hot water, then dip the flange in soapy water, and quickly, with your already-set-up c-clamp assembly, jam it through the hole. This is easier with a small arbor press to be sure.
I use that freeze technique also to machine soft urethanes to a nice finish. I took a bit of the flange off of several by spinning them up against a belt sander. It works well.
Posted: Wed Dec 15, 2004 4:12 pm
by greg donovan
so you cut one of those rings off of one side to make it fit in better?
Posted: Wed Dec 15, 2004 6:12 pm
by BAC5.2
Greg - Yes. There is a rounded side, I just trimmed it back. Not flush, mind you, but there is about a 2mm lip.
You'll see what I mean when you buy the bushing.
Professor - That's very interesting. Good idea! What bushing kit did you get?
Posted: Wed Dec 15, 2004 6:56 pm
by skid542
I am far from certain that it is UHMWPE. Just about all UHMW polymers exhibit a high initial resistance to heat. You have to impart enouh energy to the material for long polymer chains to start to break down. Having an undefined melting point is a characteristic of all UHMWPs, they will exhibit a plastic region first where deformations will be permanent if allowed to cool. Most of them will never become a liquid no matter how much heat you put to it, it'll burn first. That's one of the things that makes UHMWPs nice. You can work the material like you would glass, I've blown pieces out of polycarb this way. Teflon while it isn't great for impact resistance would work just fine for this application. The wear resistance won't really matter since it is being used as a bushing on a smooth surface (or should be smooth). As long as you didn't whack it with a hammer a lot trying to get the bushing in there'd be no issues. Nylon, while Phil's piece isn't, would make a good choice selection too. It is readably availabe, expecially 6-6, easy to machine, impact resistance, good friction qualities, and it's temperature range would easily fall within what a shifting linkage will be. In fact, I can personally atest to using nylon for a situation like this. I had to do work on my shifting linkage and fabricate a few ball joints on my old Colt Vista when the shifter fell to the floor one day while driving. There are definately a lot of material options that will meet specs beautifully, it's a matter of price and availabilty. Just my .02 and not meant to distract from the purpose of the thread or anything.
Posted: Wed Dec 15, 2004 7:05 pm
by professor
I bought the WRX "Master Kit" from
www.suspension.com for $120 shipped
It has the afore-mentioned shift bushing, four endlink bushings, 10 of the 12 rear link bushings, and both front and rear A-arm bushings, and four sway bar mounts, of which the front set only fits the later Impreza mounts, for 20mm bar, but the 19mm for Impreza rear worked on my front bar beautifully.
Posted: Tue Aug 26, 2008 4:36 pm
by TrueBlue
Bump. Beautiful write-up. This is one of the "must do" mods for my '94, as the shifter has absolutely ridiculous amounts of slop, in gear - feels like it's in neutral all the time. Tough finding third and scary finding 4th!
Nice job.

Posted: Tue Aug 26, 2008 7:15 pm
by n2x4
Have you done this mod yet? Another member and I just discussed fixing shifter play:
http://bbs.legacycentral.org/viewtopic.php?t=36952
If you want to make it 100% you're going to want to replace bushings in the linkage and shift "knuckle" and make sure your return spring isn't rusted away.
Posted: Tue Aug 26, 2008 9:36 pm
by TrueBlue

Thanks for the link - PM sent to DerFahrer.
Posted: Fri Aug 29, 2008 1:22 pm
by BAC5.2
I should add to this How-To. DO NOT USE REDLINE 75W90NS. After a few thousand miles, it was back to the horrid shifting transmission.
Posted: Fri Aug 29, 2008 8:27 pm
by 93forestpearl
^ I second that. Several years ago, I had my 5 speed rebuilt. Two years on the 75W90NS and my syncros were crap again.
Re: Shift like a pro...
Posted: Wed Nov 10, 2010 6:40 am
by scottahicks
Um.... Can you change your original post and put the pictures back up on a new photo host? would be nice to see the original pictures.
Re: Shift like a pro...
Posted: Thu Nov 11, 2010 5:40 pm
by n2x4
Those pictures have been gone for quite a while, I don't think I have any copies saved anymore either. Was there anything in particular you wanted to see for clarification? I might be able to help.