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Evening all. I have just fitted superflex (blue) polyurethane trailing arm bushes on my next restoration project. I cleaned up the trailing arms, applied the white lubricant supplied with the bushes and pressed them in without a problem. I then fitted the stainless steel centre tubes and all looked good. I decided to test the bushes by clamping each end one by one in a vice between two plates, simulating its position on the car. The vice jaws clamped the stainless tube as expected and when I push/pull the arm I can see the poly bush twist as it would under cornering load, although movement was easier than expected. However, when I raised or lowered the arm the poly bush was rotating inside the arm and not around the stainless tube as I expected, all four ends are the same. All the rubber ones I have fitted over the years were much harder and you couldn't twist them this much and they certainly would never spin. I can't fit the arms to the car like this, any ideas as to what the problem might be?

Not sure what the problem is (whether it rotates on the shaft or the RTA). I got the blue and yellow ones from UK, not sure of manufacture. I just compressed them with vise and put them in. Didn't over think it.

http://s119.photobucket.com/user/Spit999/slideshow/TR7/Pulling%20Bushings



- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT

Hi,

Got blue fitted my FHC and found no problem, as my learned friend FI Spyder say's it is possible to over think these things, I would put the arm in its natural environment and look again.

Cheers John


LIVE LIFE A QUARTER OF A MILE AT A TIME!

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1979 3.5 FHC(STATUS PENDING!!)

1982 2.0 DHC NOW A 4.6, BUILT NOT BROUGHT !!!!

The bushes, especially in the trailing arms should not rotate. The original bushes would have been tested in 4 axis.
Axial - side to side movement viewed in the plane of the bolt (so movement along the bolt)
Radial - up and down movement
Torsional -IMPORTANT one for the trailing arms (rotate around the bolt)
Conical (up one end and down the other) when you go round a corner and the trailing arms moves to the side (if that makes sense, I am trying to keep this all simple). This is important as too stiff and the car will oversteer.

also don't forget that the bolts for the trailing arms must be torqued up with the vehicle on the ground to set the neutral position so that when the axle moves up or down then the bushes acts conically (tries to twist)and depending on the make up of the bush (shore hardness) will counteract this and help the arm get back to the neutral position.

I am going to look into this in the new year as its something that will interest members who fit after market bushes. I work developing cars for ride and handling.

Paul

Thanks all. Perhaps I am over thinking it but I just want to be sure it's correct. Yes, the load should be on the car in it's natural position before tightening rubber bushes, however with these poly bushes I can't see why that would matter. The steel tube isn't bonded so the bush is designed to rotate around it when in situ, the tube is clamped tight to the body so the bolt and tube shouldn't move. That's the problem, mine don't rotate around the inner tube, they rotate around the area of least resistance which is at the outer circumference of the bush within the trailing arms.
[:(]After a google search it looks like a lot of people are having similar problems and the super pro/flex website isn't much help. It will be a pain but fitting good old rubber ones seems to be the only solution. Having said that, as the poly bushes are wear resistant, or so they claim, and the steel in the trailing arm is obviously harder does it matter whether it rotates on the inside or outside face of the bush?

Did you use lube between the plates your used the clamp and the ends of the bushes?

Darrell Walker
66 TR4A IRS-SC CTC67956L
81 TR8 SATPZ458XBA406206
Vancouver, WA, USA

No lube for testing as it wouldn't have any when fitted, I only used it for fitting the bushes as instructed.

<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by moodyblue</i>

No lube for testing as it wouldn't have any when fitted, I only used it for fitting the bushes as instructed.
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

Then I'm not surprised by what you saw. You have a dry joint between the test plates and the ends of the bushings, and a nice lubed joint between the arm and the bushing.

Darrell Walker
66 TR4A IRS-SC CTC67956L
81 TR8 SATPZ458XBA406206
Vancouver, WA, USA

That's correct, there is no way you can, or would want to, lubricate the ends once fitted to the car. Using the supplied lubricant is the only way to fit them as per instructions so this will give before the area around the tube. I also tried the test using short bolts as spacers ensuring that just the tube was clamped, this produced the same results. So, you need to use the lube to get them in, and if you do they don't work as designed, in the name of creation![V]

You can fit the bushes without any grease, you just need to know how. Very easy to do. Bevel one end of the steel tube and it will push right through. http://www.jclay.me/jclay/TR8_project.html#73

Clay

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I recall a few articles on the web about this years ago when I was looking at using poly bushes for the Saab. Some reckoned that they did not last as long as claimed due to the movement of the bush around the sleeve wearing the bush.
It is surperising if the bush was rotating in the arm rather than around the sleeve as the surface area (and frictional resistance) against the arm is much greater. Although the grease helps insert the bushes I am not sure how long it lasts in the real world. they may tighten up in time.

Alan
Saab 9000 Stg 1 (now passed to son for his family car)
Saab 9000 2.3 FPT Auto (now gone that others might live)
Saab 9000 2.3 LPT Auto
'81 TR7 DHC

Ok guys, I phoned SuperPro today and I was given a contact email address. I will update when they get back to me and with any luck we can resolve this issue.
Thanks.
al

Update - No simple answer to the bush question I'm afraid. After discussing the issue and eliminating possible issues, Superpro UK have passed my comments back to their engineers in Australia to get their view. The design of the latest bushes has changed to allow for crush tube lubrication, although not for the TR7. I will feedback when they get back to us.

Did you get a chance to look into this issue Paul?
I've been trying out a couple of new designs from Superpro with voiding and inner bore Knurling. These are a better design and rotate around the crush tube as intended although the bushes can still be turned in the housing with a bit of effort.
This issue has held up my project for far too long. I have hard rubber bushes on the arms of my other TR7 which I use every day and it handles superbly. The bushes I took out lasted 30 years so I'm thinking rubber hard or soft may be the way to go. Much to think about.
<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Paul_TR8</i>

The bushes, especially in the trailing arms should not rotate. The original bushes would have been tested in 4 axis.
Axial - side to side movement viewed in the plane of the bolt (so movement along the bolt)
Radial - up and down movement
Torsional -IMPORTANT one for the trailing arms (rotate around the bolt)
Conical (up one end and down the other) when you go round a corner and the trailing arms moves to the side (if that makes sense, I am trying to keep this all simple). This is important as too stiff and the car will oversteer.

also don't forget that the bolts for the trailing arms must be torqued up with the vehicle on the ground to set the neutral position so that when the axle moves up or down then the bushes acts conically (tries to twist)and depending on the make up of the bush (shore hardness) will counteract this and help the arm get back to the neutral position.

I am going to look into this in the new year as its something that will interest members who fit after market bushes. I work developing cars for ride and handling.

Paul
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

Fitted SuperPro bushes to a set of rear arms last week and they are pretty tight.
Even with a hydraulic press it took me almost an hour to get all the bushes in.
Also needed the press to get the stainless steel tubes in ...

So, are you sure you have the correct parts?





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