Page 3 of 5

Re: 87-96 Rear Axle Suspension plastic inserts

Posted: Thu Apr 28, 2011 11:01 pm
by heavywoody
You'd be surprised how strong plastic can be.

UHMW is perfect for these bushings. Nice material selection actually.

Yes, I'm one of the plastics geeks on this forum.

And FWIW, my delrin steering rack bushings from Jon are working fine.

Re: 87-96 Rear Axle Suspension plastic inserts

Posted: Fri Apr 29, 2011 4:15 am
by KFLO 93 GT
My delrin rack bushings are rocking too - and these rear axle bushings don't really experience the kind of nastiness that I think you're thinking. There are a lot of load bearing points on the rear ends of these cars: springs, shocks and the axle pivot bushings. Being the pivot point definitely requires having resilience to rotational wear, and side to side and such movement. The bushing pretty much gets sandwiched between metal so side to side should be eliminated.

A properly lubed bushing is only going to be moving clockwise and counterclockwise over a small point of it's full 360* possible rotation. So my biggest worry would be wearing from flaws from rough castings cutting into the bushing. A burr cutting into the bushing as it sways back and forth over time. But I think even that chance is minimal.

My only worries on driving use would be cutting hard into corners that have elevation change and a rough pavement surface. These bushings would increase the possibility of snap steer from not deflecting as much under load. Rough ride in general isn't much of a bother, these cars aren't fucking Cadillacs.

Re: 87-96 Rear Axle Suspension plastic inserts

Posted: Fri Apr 29, 2011 6:06 am
by 3X00-Modified
Why didn't someone just post this to keep questions down... Its far from "plastic" as we categorize it typically.
UHMW




Ultra High Molecular Weight (UHMW) Polyethylene is often referred to as the world’s toughest polymer. UHMW is a linear high density polyethylene which has high abrasion resistance as well as high impact strength. UHMW is also chemical resistant and has a low coefficient of friction which make it highly effective in a variety of applications. UHMW can be crosslinked, reprocessed, color-matched, machined and fabricated to meet most customer requirements.

Features:
Meets USDA,FDA, 3-A Dairy guidelines
UHMW is 6 times more abrasion resistant than steel.
No cold embrittlement, works from -155ºF to + 200ºF.
Impervious to marine borers and barnacle resistant.
Custom colors available
http://en.wikipedia.org/wiki/Ultra-high ... lyethylene

Re: 87-96 Rear Axle Suspension plastic inserts

Posted: Fri Apr 29, 2011 8:17 pm
by ErichZ26
I was at my dad's shop today. He has several different plastics on hand. Then there are metal's different grades of brass and bronze..and some aluminum.

Liljon: people like fancy names that they read about in magazines and in the movies. Delrin for example...it can cost more than UHMW or HDPE..but it machines nice. All three are good Delrin does not wear as well as UHMW and is easily scraped. Savings can be machining. This joint could be replaced with ball bearing or roller bearing cartridges...but that is overkill and won't allow much give. My dad had some unidentified blue plastic on the rack that is used for making gears.

The price is probably going to be $48 a pair. I am looking into metal insert.

Control arm bushings can be made as well. Steering rack mounts. About 6 years ago he made me a UHMW mount insert for 90-94 Quad4 and 92-93 Getrag's but there was little interest. It was for race only.

Re: 87-96 Rear Axle Suspension plastic inserts

Posted: Fri Apr 29, 2011 9:40 pm
by woody90gtz
Control arm & sway bar bushings would be a great application...because there is not supposed to be any flex there for proper suspension operation. I'm not sure about the axle bushings though. How much does the torsion beam itself actually flex?

Re: 87-96 Rear Axle Suspension plastic inserts

Posted: Fri Apr 29, 2011 9:46 pm
by ErichZ26
woody90gtz wrote:How much does the torsion beam itself actually flex?

Quite a bit. Going from FE1 without the welded in bar to the Addco made a significant difference. I also noticed a lot with my FE7 GTZ.

Weba might get these bushings next week depending on service.

Re: 87-96 Rear Axle Suspension plastic inserts

Posted: Fri Apr 29, 2011 10:49 pm
by SuzukiGhostRider
I'll take you up on that sample Eric. I want to see this stuff first hand. It seems I'm not the only one with concerns at least.

I'll PM you my mailing address if you were serious.

Re: 87-96 Rear Axle Suspension plastic inserts

Posted: Fri Apr 29, 2011 11:25 pm
by 88_GTU
If you guys look up globalwest you'll see the bushing kits they make and just how well they work. I found an old hotrod article where they had Globalwest make them a set for an 88 beretta gt that they built up. They loved the quaility and handling feel they got from these. I called them a year ago hoping to find a set sitting on the shelf but no one even rememberd the project so I gave up and had a buddy make me some. I just haven't got to throw them on yet as the car is in pieces. Those pieces Erich had made look really sharp. I hope he makes more.
J

Re: 87-96 Rear Axle Suspension plastic inserts

Posted: Sat Apr 30, 2011 3:23 am
by KFLO 93 GT
I'd like to give a set of them a chance when I get around to doing a rear disc install. So count me in if we can get a group buy rolling.

I'd like to hear some thoughts on using a sleeve for the bolt. Given the posted info - it seems like it would be unnecessary and possibly be weaker than a bare bushing by itself. But, my gut wants a sleeve because that's how I'm used to getting bushings. So... thoughts?

Re: 87-96 Rear Axle Suspension plastic inserts

Posted: Sat Apr 30, 2011 5:24 am
by weba
I am going use sleeves on mine, taking them from stock bushings. I just 'feel' that it's better that way. And that's the way most, (if not all?) after market racing bushings are.

In thought level, there can be differences in load balance, wear (I think there were actually treads on stock bolt inside the sleeve, I don't want them to touch the bushing)
Depending of the material, can also make it more silent (for example, poly bushings do 'squeak' in some cases) These will be quite sandwiched there, but still there is still movement,

Re: 87-96 Rear Axle Suspension plastic inserts

Posted: Sat Apr 30, 2011 11:04 am
by woody90gtz
ErichZ26 wrote:
woody90gtz wrote:How much does the torsion beam itself actually flex?

Quite a bit. Going from FE1 without the welded in bar to the Addco made a significant difference. I also noticed a lot with my FE7 GTZ.

Weba might get these bushings next week depending on service.

That's a good point. I noticed a huge difference with my Addco as well. But an Addco and these bushings wouldn't be too much?

Re: 87-96 Rear Axle Suspension plastic inserts

Posted: Sat Apr 30, 2011 12:39 pm
by Cliff8928
weba wrote:I am going use sleeves on mine, taking them from stock bushings. I just 'feel' that it's better that way. And that's the way most, (if not all?) after market racing bushings are.

In thought level, there can be differences in load balance, wear (I think there were actually treads on stock bolt inside the sleeve, I don't want them to touch the bushing)
Depending of the material, can also make it more silent (for example, poly bushings do 'squeak' in some cases) These will be quite sandwiched there, but still there is still movement,

I was thinking that same thing too... Isn't the sleeve also slightly longer so that when you torque the bolt down, it clamps on the sleeve and not on the bushing?

Re: 87-96 Rear Axle Suspension plastic inserts

Posted: Sat Apr 30, 2011 7:52 pm
by MY91GT(Z)
i wouldnt mind sample set as i have my rear opened up as we speak for springs and rear disc now

Re: 87-96 Rear Axle Suspension plastic inserts

Posted: Sun May 01, 2011 9:13 am
by Barry
Cliff8928 wrote:
weba wrote:I am going use sleeves on mine, taking them from stock bushings. I just 'feel' that it's better that way. And that's the way most, (if not all?) after market racing bushings are.

In thought level, there can be differences in load balance, wear (I think there were actually treads on stock bolt inside the sleeve, I don't want them to touch the bushing)
Depending of the material, can also make it more silent (for example, poly bushings do 'squeak' in some cases) These will be quite sandwiched there, but still there is still movement,

I was thinking that same thing too... Isn't the sleeve also slightly longer so that when you torque the bolt down, it clamps on the sleeve and not on the bushing?
Yes. Just the bushings clamped on the mounts would bind and squeek

Re: 87-96 Rear Axle Suspension plastic inserts

Posted: Sun May 01, 2011 7:23 pm
by KFLO 93 GT
I must've missed this earlier - but Cack if you'd make some steering rack mount bushings, I'd totally buy a set.

What I really want - is a quality upper strut mount, solid would be perfectly fine with pressed bearings. I'm getting tired of the noise my relatively low mile kyb ones are making. If engineered properly a bit more reduction in rideheight could be gained too.