a-arm bushing issues

[jbcollier]

My brand new a-arm bushings were not actually bonded to the outer sleeve.  As I drove along, the lower a-arms slid backwards on the bushings.  This did not improve the handling.  I pressed them back in place and used washers to hold them while new bushings wound their way here.

Here are the old bushings:

https://jbcollier.smugmug.com/Lotus-Europa/i-W7cTbNb/A

You can see the rubber has just slipped out.

Here is the new bushing next to a dud one:

https://jbcollier.smugmug.com/Lotus-Europa/i-w226Q9N/A

https://jbcollier.smugmug.com/Lotus-Europa/i-dCM2Bf6/A

The new bushing looks to be bonded: the rubber looks “poured” rather than bulging out as though it’s pressed in.  The ends are rolled as compared to just straight tubing.

Just something to watch out for.  I can’t say for sure but the duds either came from Banks or Rdent.

YMMV,

[blasterdad]

Thanks for the heads up , they are on my parts/to do list.

[HealeyBN7]

I could not find an OEM set that stayed together.  Didn't matter if it had a Lotus logo on the bag or not.  I had several that I ruined before I even got them near the car, as they had to be de-burred.  I could not slip them over the a-arm bolt even before I pressed then in the arm.  Just took a light touch with a deburring bit and the centers debonded.  If they didn't tear out immediately then they would after a hard drive. 

Decided to pop for the poly set that Ray (RDent) sells.   This is from his web site:

Front Wishbone Bushes
for all Europa


Polyurethane bushes with stainless steel sleeves.  Directly replace original bushes with no loss of ride quality and improved life expectancy.   Easy to install; no press required.  Please note that a total of eight bushes are required per car (two sets of 4).

Ref. 36RC6004PB - $145.00/set of 4

Must say that I am happy to have something that works.  Wallet got lighter, but wasn't that Colin's mantra.

Dean

[BDA]

I think I had the same problem as you, John. I don't remember, but I think I had the same bushings as your new ones, but then it's been a long time. That was not an uncommon problem. I changed the bushes and added big washers to try to retain the bushing as best I can.

Did you torque your A-arm nuts at ride height? This is important because if you tighten them at full droop (or bump), the angular displacement will be enough to tear or separate the bushing. When I did mine, I set the body at the proper ride height and propped up the hub so the spindle was at half the tire/wheel height. Then I torqued the nuts. Having said all that, it's something you have to do but I'm not sure it is the solution. I think I went through all that when I originally put my car together. I haven't looked to see what it's doing now. I'm almost afraid to look!

Of course, if you use poly bushes, you don't have to go through all that. Another supplier for those bushes is here: http://www.autobush.com/Lotus.htm. I don't have them, but I understand the Elan and Europa bushes are the same so they should work. They will be my next call if the problem re-emerges.

[jbcollier]

After the work is done, I leave the a-arms a wee bit loose, lower the front onto ramps, bounce the front and turn the wheel and then crawl under and tighten the a-arm nuts.

[BDA]

You can't do better than that. The rest is up to the Europa gods. I figured you were up on that but I thought it didn't hurt to mention it in case someone else didn't know.

[EuropaTC]

Hmm. I've fitted new arms to the Elan this summer and used new bushes from SJS. I compared them to the old ones and they looked identical with the rolled ends, but now you've got me wondering if there isn't another "rubber problem" about to rear it's head.

I must put that on the check list, thanks for the heads up.

Brian

[pboedker]

As I found out a year ago it is possible to bend the lower A-arms, since they are the weakest part of the front suspension. If the wheel takes a whack from something, the pair of A-arms can be deformed so that the trunnion point is moved e.g. to the rear while still maintaining the correct dimensions where the arms bolt to the chassis. This will not be a problem to the bushings.

If the suspension is dismantled and the A-arms mixed between the two sides - possible, since there are only 2x2 mirrored parts - the inner dimensions will be now be incorrect and the bushings under a pushing or pulling stress when torqueing up the suspension. This will not be visible upon reassembling but will after some time with the combination of pull and rotation.

Maybe the new bushings are not good enough, but having the wrong dimensions doesn't help either. 

This thread shows some measurements and photos from my troubles last year:
http://www.lotuseuropa.org/LotusForum/index.php?topic=1127.0

[BDA]

Peter, how big a whack did your wheel take? I knew they were the weakest part of the suspension to save the frame from possible damage so I kept my lowers stock and added Richard's adjustable A-arms on the top. If they are more fragile than I thought, getting tubular A-arms might be on the list for a future purchase.

[pboedker]

I cannot point to a single incident for deforming the a-arms, it could be me or the PO that caused it.

All I know for sure is that the a-arms no longer had the dimensions in the workshop manual and that
A. One of the four combinations gave a close to perfect measurement on the one side with the other side being still OK near the chassis and bent-but-still-correctly-assembled on the trunnion end.
B. The other three combinations all resulted in the inner dimensions being either too wide or narrow. This would pull the bushings apart.

So, my theory is that I had situation A initially, and one of the B situations after reassembly which ruined my new bushings.

[Steve_Lindford]

So - should we be putting washers either side of the bush?? - if so - surely that will slightly move the front and back wishbones apart - which should show at the hub/upright end. The manual doesnt show any...

Has anybody worked out how many degrees of rotation there would be at the bush between the top and bottom of suspension travel?? - cant be much.

Steve

[EuropaTC]

So - should we be putting washers either side of the bush?? - if so - surely that will slightly move the front and back wishbones apart - which should show at the hub/upright end. The manual doesnt show any...

Has anybody worked out how many degrees of rotation there would be at the bush between the top and bottom of suspension travel?? - cant be much.

Steve

My memory is hazy on this one Steve, but I think when I fitted the polybushes to the Europa I only fitted large washers at the outside of the bushes. No pictures I'm afraid, so here's the equivalent 1000 words instead....

As you say, fitting 4 additional large washers takes up space and if nothing else the "inner" ones will disturb the geometry between the arms and the top ball joint & bottom trunnion/damper.   I think what I did was fit a large washer on the outer ends, at the top it was between the bush & Antiroll bar mount.  The logic was that if the arms are bolted firmly on the ball joint or trunnion then they would move as a rigid structure and if either end were restricted this would prevent the whole lot migrating either backwards or forwards.

I haven't seen any obvious movement so far.

As for rotational movement, I agree it can't be a lot.  There's not a great deal of rubber in there between the inner & outer steelwork and only so much torsion the material or bond would take.

[jbcollier]

They came from the factory with three 1" diameter, 1/16" thick washers, one inside each a-arm securing nut.

http://www.lotus-europa.com/manuals/s1parts/c/index.htm

[BDA]

I got a chance to look at my front suspension (since my car is on stands - sigh). After the bushing failure I had (see pictures above), I used one thin washer behind the leading lower A-arm. I know it changed my caster a wee bit, but I haven't noticed any difference. My bushes, on that side at least, seem to be doing ok. I wouldn't want to claim that my washer is the reason though.

This is the best picture I could get - sorry! You can barely see the washer behind the gaiter and in front of the spring.

[Grumblebuns]

I had a different type of bushing failure. Peter, I'm wondering if we both haven't suffered the same control arm/bushing issue. In my case,  I did a bushing replacement on the front suspension my S2 and noticed a lateral displacement of the rubber bush from the outer sleeve of the bushing. From the two pictures, you will see that the rubber and inner sleeve had displaced about 3/8" out from the outer sleeve. It looks like the rubber had torn from the outer sleeve and allowed the control arm to move inwards since the inner sleeve is fixed in place and can't move.

With new bushings pressed in and the control arms installed  on the pivot pins of the chassis there was a very noticeable gap between the trunnion and the flat ends of the lower control arm where the bolts go through. That large of a gap would have taken about four washers to bridge on each side. When I disassembled the lower control arms there was only a single washer on each side. I believed the PO simply forced the ends tight with the bolts without compensating for the gap. This is what I believe caused the rubber to tear and cause the arm to move laterally on the bushing. The control arms looked undamaged but who can tell without measuring the dimensions per the manual.

I also have bent lower control arms on my TCS and since new arms are NLA, I will be forced to buy the tubular aftermarket ones as replacements.