Lotus Europa Community
Lotus Europa Forums => Garage => Topic started by: pboedker on Tuesday,July 21, 2015, 05:48:35 AM
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During the winter, I completely refurbished the front suspension on my Europa, having the wishbones sand blasted and powder coated before fitting all new rubber bushings.
After not many miles, now the right side has developed a squeeking noise, and I find that it is because a rubber bushing has separated, and the suspension arm started to move towards the chassis. The attached photo shows the right side lower front bushing. The inner tube and the rubber is showing, the outer tube is still properly located inside the suspension arm.
I have contacted the parts supplier, who sold me the bushings, and they say that this is typical for having a bent suspension arm, and they have seen this a lot.
I didn't notice anything bent before assembling it, and I did assemble the uprights first, to make sure that the inner ends of the wishbones aligned where they should. I will disassemble the wishbone one of these days, to see how bent the wishbone is.
Has anyone seen this problem before? And was the bushing or the suspension arm the reason for the failure?
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When you assembled the suspension, did you put it at ride height before you tightened the nuts on the shafts? The rubber in the bushing can only take some much deflection so you have to set it up in the middle of the travel. As for the bushing coming out of the A-arm, I think something similar happened to me. I'll take a look but I think I might have put a big washer on both sides of the bushings. For me, at least, it had nothing to do with a bent suspension as my uppers are adjustable ones from Richard (they're pretty beefy), and the lowers were new.
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Similar to the above, I've seen wishbone and other suspension bushes on other cars fail when they are torqued up with the car in the air. The best method is to finger tighten, put the car back on the deck (on ramps or blocks if you need to get underneath) and then torque up.
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To expand on Strawberry's post, I made a set of blocks to hold the front suspension at ride height when I tightened the nuts. It can be really difficult to get to them with the wheel on. Another more expensive option is to get polyurethane bushing as you don't have to worry about the ride height with those.
Theoretically, the rubber bushes contribute to the spring rate - or wheel rate - though I don't recall anybody mentioning that so I doubt it's significant.
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Peter, I had similar failure of my front control arm bushes. During replacement, I noticed that some of my bushes had torn rubber and that the arm had been displaced inward toward the chassis pivot point.
With new bushes installed in the control arm sleeve, I noticed that there is a slight gap between the outer control arm attachment point on the trunnion and the control arm hole. I'm wondering if closing the gap (~3/8" on each side) when tightening the bolt is adding undue forces on the rubber and the sleeve of the bush. Over many miles of up and down cycling of the suspension, the rubber finally fails and detaches from sleeves. I've added a few pictures of my failed bush.
Joji Tokumoto
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Thank you for the answers so far. :)
Yes, I did make an effort of assembling the nuts only fingertight and then driving the car onto a ramp lift to fully tighten and torque them while at ride height.
Joji, 3/8" sounds like quite a lot (I read it like a small gap at the trunnion results in 3/8" at the rubber bushings). Like you, I would believe this to be too much for the rubber, but I didn't see any noticeable gap (or the opposite).
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Peter, you rubber section protruding appears to have just slid out, still looks shiny. Maybe the possibility of a defective adhesion of the rubber to the outer sleeve? My rubber section on the other hands had been torn from the outer sleeve over time.
My rear Spax on the JPS had it's lower rubber bush become detached from the outer sleeve/mount. I had to press it back in and suspect that it will eventually slide off again.
Joji
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I have cycled through a couple sets of replacement rubber bushing failures before settling on the poly bushings.
There are quality and vulcanization issue with the modern rubber replacements. Paying more and receiving the second set in Lotus packaging didn't improve the issues. The center tube on one set was so poorly machined that I had to drill it out to remove an internal seam just to get the bolt to go through the eye.
Even after very carefully tightening the suspension when fully loaded, they would tear out in short order and cause the a-arms to relocate.
After buying and installing two crappy sets, with no warranty return or acknowledgement, I felt it was a safety issues and easily justified the cost of the poly replacements.
I haven't noticed any difference in harshness.
Dean
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If poly is the answer, the Autobush poly bushes are not so costly - http://www.autobush.com/Lotus/Elan%20Twin%20Cam.htm (http://www.autobush.com/Lotus/Elan%20Twin%20Cam.htm)
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Mark,
I assume the Elan front wishbone set (AUB5101) is compatible with the Europa, right?
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Yes, I used the same bushes on both cars, but that posting of Mark's is a good find. (thanks Mark)
I didn't realise they were so cheap, the last time I looked they were more than twice the cost of Lotus bushes. I might try a set at that price. Not so much for the performance aspect but getting away from the "torque up at ride height" thing, it would just make maintenance one step simpler.
Brian
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The bushes, yes. Arms, no.
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My first thought was, like Dean writes, that the bushings were of a bad quality. New china rubber, and all that. But I'm not so sure that it isn't instead my suspension arm(s) that is bent. I will return with the result, following a dismantling of the parts later this week. :)
The autobush bushes look really interesting, I think I'll order a set already now.
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OK, so it's definitely the suspension arms that are bent. :headbanger:
I've dismantled the two lower arms on the right side, which is where the bushing popped out. And then I have measured them, as described in the workshop manual, section C.3, figure 17. The dimension '4' should be 58.7mm (I can't for the moment measure that more precise than 59mm)
As can be seen from the attached photo IMG_Right_Side_Lower_Front_5a.jpg, the arm with the ruined bushing is measuring 48mm, that is 11mm too little! The rearmost arm is measuring 57mm, 2mm too little. Of course these measurements are again not very precise, the arms can wobble a little since they are a little rounded on the flat part, and also the flat area for the trunnion is a little indented so the true measurement point is hard to get to. But it's good enough for government work, as they say.
I lined up the 2 arms (photos IMG_Right_Side_Lower_1a.jpg' & IMG_Right_Side_Lower_1a.jpg) and got to the total of 105mm (48mm+57mm). This is 13mm shorter than the 118mm it should have been, and the 13mm corresponds almost to the 15mm that the bushing has moved.
I take this as a very clear indication, and will take a look at the lower left side also at a later time. The top arms are harder to get to with the rod going into the cabin and all, so I think I will just loosen up the nuts and see if the bushings are jammed in any direction, i.e. if there is a similar problem.
Where did I do wrong?
I think that it was a mistake to assemble the outer ends to the uprights by hand and then believe that the dimensions were correct. It was probably first when I torqued it all up, including the outer ends where the shock bushings has a lot of rubber to compress, that the wrong (bent) dimensions came into play.
So, what to do now?
Since the front arm is definitely bent, measuring it by adding a washer (1.5mm) will bring the measurement to 57mm also, see photo IMG_Right_Side_Lower_Front_6a.jpg. The washer will sit between the shock bushing and the suspension arm,so that when the trunnion and shock bushings are both torqued, the a-arms will keep their proper locations.
Does anyone see a problem in doing this?
Oh, and BTW if any of you who has experienced similar bushing problems have the possibility to measure the dimension '4', it could be interesting to hear what you find.
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Oh that must be annoying Peter, those arms look pristine and I'd have done exactly the same in just putting in bushes and assembling on the car.
Now you know there's a problem I think I'd assemble with new bushes and firmly mount the arms on the car without the upright or damper assembly in place. I'd imagine that would put the arm/bush in it's neutral position as far as twist goes, so you could measure exactly the dimensions where the damper, lower trunnion and upper ball joint should fit. I'd probably have loose components and feeler gauges to determine what, if any, shims were needed.
With any luck the gaps will be too large and washers or shims as you describe will sort the problem. I'd have no problem in packing the gaps but I'd probably aim for stainless washers/shims so it's a fit and forget solution.
If it's too tight.... hmmm. that would be "swear box" time in my workshop !
Brian
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I'm not convinced they are bent. First, they don't look bent. The TC/TCS workshop supplement says the lower arms for the S1/S2 are the same as for the TC/TCS and it is incorrect. It might be that dimensionally, they are equivalent, but I would need confirmation. The TC/TCS have the tube for the shock bolt that yours has but the S2/S1 does not. Without going through a long story, my car ended up with a pair of S1/S2 lower arms and whether it was because of them or something else, I could hardly move the suspension at all. It was a long time ago and as I say, there were other variables so it is possible that they are interchangeable but as I say, without confirmation I wouldn't do it.
According to the parts manual, there are two different arms for the TC/TCS. It's possible that you have two leading arms on one side and two trailing arms on the other or maybe some even more complicated combination. For that matter, I may also! Yikes!
If someone can give the proper dimensions, that would be a big help.
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Peter, your little problem got me thinking on the straightness my control arms. After I get my electrical issue fixed, it looks like I'm going to have to go back and visit my front suspension again, and I thought I was done with the mechanicals on 1098R. I also have a TCS with it's front end up in the air for brake work. I'll have a look at it's control arms and see what it measures. All this will be in a few days, I need to get the blinkers and brake lights working on 1098R first.
On the S2, to compensate for the huge gap between the control arms and the mounting holes in the uprights and shock, I used washers and I offset the bush slightly on the inner sleeve of the control arm where it pivots on the chassis point. Probably not recommended but I was out of options at that point.
Joji Tokumoto
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BDA, as far as I read the parts manual, the lower arm pairs ar interchangeable, i.e. the trailing on the one side becomes the leading on the other side ande vice versa. That's why it needs 2 of each of the CA20 and CA21. These have parts numbers from the type 65, so they could very well be different on earlier models. I will dismantle the left side now, to make sure that they aren't bent too, but I believe they should measure 59mm as the workshop manual says.
The upper arms are 4 different ones, the leading two with a S1 part numbers, the trailing two with type 65 part numbers. The trailing ones are those that moved from 'inside the chassis' to 'outside the chassis' during production run. So only the leading arm measurements from the workshop manual can be valid, since the manual is showing early S2 dimensions. Yes, measurements that are definitely TC/TCS valid, could be really nice.
Thanks, Joji, I appreciate all the measurements I can get. And if nothing else, this might be a heads up to others to measure the parts properly on reassembly before pulling the bushings apart as I did.
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Oops! Sorry for the brain fart about the two different parts! :-[ But it is a relief that I didn't put my front suspension together wrong! :)
From your measurements, Peter, I would think that something that far off would be obviously bent. I don't see that from your pictures. Hopefully Joji's measurements will shed some light on this.
I know I remember posting about this issue to the yahoo group and finally found my post and an explanation of what was happening. Here it is:
Jim Grunewald wrote:
> I found
> driver's side leading lower A-arm was pushed toward the rear about a
> 1/2". The interior metal sleeve is proud of the rubber part which is
> proud of the outer metal sleeve. The outside metal sleeve is properly in
> the A-arm (I took some pictures that hopefully show what I'm talking
> about in an album entitled "Interesting bushing failure").
This is a relatively well-known issue, and there are two independent
possible causes. The first one was documented in an early issue of ReMarque.
I've brought it up on the list in the past. This problem is most often
caused when aftermarket dampers are fitted. Typically the lower mounting
bushings of the replacement dampers are shorter than those on the OEM
dampers, the result being that there is a clamping force that tends to
deform the inner bushings. Konis are known offenders here. The solution is
to add spacers to the damper lower mount bushings. I measured the space that
had to be filled with the suspension fitted less dampers, then added the
necessary spacing to the lower damper mounting bolt during reassembly.
The second issue is caused by reaction to braking force. If this is the
cause of the problem, you will see both halves of the lower A-arm shift
rearward at the inner pivots, with associated deformation of the bushings. I
placed washers at the rear of both inner bushings to prevent this motion,
and it has worked very well.
Along the way, I also found this post to the yahoo group:
jcpeters1@shaw.ca
Date: Wed Feb 25, 2009 9:30 pm
Subject: Banks on Poly - Nylon front bushings
This thread was interesting as I considered going with these bushings last year.
I have modified suspension and my decision was made to stay with stock when I
spoke to Richard Winter (who happens to also sell hard nylon/brass ones). He
indicated that on his team cars he is finding the hard bushings are leading to
too much chassis damage and is not recommending them any more. As someone else
noted the Europa wishbones and chassis are not robust enough to justify the
minor reduction in deflection gained especially on a street driven car. Just my
2 cents worth.
Chris.
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OK, so the left side were also bent: The leading arm was 71mm (+12mm) and the trailing arm was 54mm (-5mm). Of course these measurements are not very precise being done with a ruler on the kitchen table. But they do indicate some difference.
It's not possible to see anything wrong or bent with any of the suspension arms, however holding the mounting plane to the table top the measurements speak very clearly and it is also easy to compare two arms next to each other to see the difference. Inserting a 1mm shim under either hole at the mounting end is multiplied to 4-5mm at the bushing end due to the length of the arm.
Now, when I overhauled the suspension in the winter, the lower arms might have been mixed left/right or diagonally. They can be combined in 4 ways as they should measure the same. One combination of my bent ones gives almost the correct inner width 118mm at both sides with the right side almost within spec. but the trunnion position of the left side appr. 10mm to the rear. My theory (speculation?) is that the suspension arms were originally combined like this, but the left side hit a bump and got bent. I don't know. Pot holes are everywhere.
I've decided to replace the one ruined bushing, and refit the arms, using the 54mm and 57mm ones as trailing arms and with a washer on EACH side of the bushing. This should locate the trunnion at about the correct place, and since the top arms appear OK (I will loosen the nuts and check that the bushings aren't clamped together) the wheel alignment should be OK. Then I will shim the trailing arms at the trunnion/damper to make sure that the bushing in the two 48mm and 71mm arms are not stressed.
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Great work, Peter!! I wonder if this is just a case of poor quality control... In any case, it seems like you have a pretty reasonable solution.
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If I find that mine are bent, I will probably order replacements and I'm still not too clear on which arms are interchangeable with which car, S2 vs. TC.
I'm still trudging along on my S2 electrical issue. I finally got the two relays in the DB10 relay box freed up so they now operate. Now need to move on to the individual lights one by one.
Joji Tokumoto
Fallbrook. CA
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Joji,
I'm not sure if there are any dimensional differences - from Peter's measuring, it seems they are similar - but the TC arms have a tube for the bolt at the lower shock mount where the S1/S2 arms are flat there and don't use a tube for the lower shock mount. To my knowledge, this is not shown in the workshop or parts manual. It seems odd that they would make it more expensive to make a TC arm unless there was a reason for it. It could be that the the lower shock bushing was a bit wider on the TC or something similarly benign. I thought I had spare S2 and TC lower arms, but so far I've only found the TC ones.If I find the S2 arms, I'll try to take some measurements and post the results.
Congratulations on your progress on the electrical front!
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When I get to attacking the suspension of both the S2 and TCS, I'll try to get some photos posted for comparison and measurements. In the meantime, I'll check the KB later on in the week.
By the way, Ray at RDEnt. has new and used wishbones listed on the website.
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This afternoon, I managed to remove and measure the lower right side suspension arms for one of my non running TCS. These are the dimension #4 measurements of both arms.
lower trailing half: 44 mm
lower leading half: 89.7 mm
Just by visual observation, it's obvious that both arms are bent. The front (leading) arm being the more severe. I'm assuming that both arms on one side are suppose to be mirror opposites with the centerline of the holes being parallel to each other. Look closely at the pictures of the inner bushing with the 1/2" bolt hanging off of them. It's obvious that both are bent from the angle of the bolt from vertical. I need to measure a new undamaged front wishbone set to validate my measuring technique. I'll check the right side suspension over the weekend and report my results.
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Thank you for the update, Joij, your measurements show that something is clearly wrong with that side of the suspension. Sort of the same situation (bent backwards), that I think I had originally on the left side, before mixing the arms. The angles of the bushings can't be good to them either. Could be interesting to see the measurements from the left side arms too. :)
I owe an update myself, because since I refitted the suspension arms to my car and shimmed the trunnion/damper to try to better locate the outer ends, I have seen a very noticeable and better handling of the car. It must be the caster angle that does it, though I still need to confirm by measurement that it is now back within specs. The car is much better at high speeds, and where I before had white knuckles when driving 100km/h and above 120 wasn't really possible because it was all over the road, on the first test drive I now did 130km/h with one hand on the wheel and doing 150km/h was OK with two hands. Also slow speed handling, like e.g. through a roundabout is much more predictable than before. This is definitely something I will examine further, since it has 'put the fun back into motoring', as I think one of the contemporary road tests named it. 8)
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Yep clearly bent, you last pictures shows that very clearly. and might be worth checking the chassis while you are at it, I would expect the arms to take all the hit, based on the amount of deformation, but be worth checking out as you have everything unbolted.
Dave
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If poly is the answer, the Autobush poly bushes are not so costly - http://www.autobush.com/Lotus/Elan%20Twin%20Cam.htm (http://www.autobush.com/Lotus/Elan%20Twin%20Cam.htm)
Resurrecting this thread, I've decided to try a set of these bushes and placed the order this morning. Cost for UK delivery was £45 for a set of 8 bushes with stainless inserts. I'm still bemused by the cost, I'm sure they were much more expensive in the past. My first thoughts were "cheap polymer" but reading their website it would appear not and to be an engineered product.
I'll post how it goes....... good or bad.
Brian
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Hi folks,
A follow up post to the previous one above, as promised.
Well, the bushes arrived from Autobush, kit AUB5101 as for Lotus Elan. You get 2 bags with 4 bushes plus stainless inserts, a tube of grease and an instruction sheet in each bag. I've never used such things before so I don't know if these are good or bad, but they looked & felt quite solid to me. Inside the bore of each bush is a cross hatching which I tried to photograph but failed. Apparently this is to retain grease to reduce noise in operation and as the grease is white you can easily see when it's applied, which seems a neat idea. I had previously assumed such bushes would just have a plain bore, but these have clearly been engineered/designed.
As you might expect, they pop in easily enough. The instructions say "Apply grease, fit the bush into the wishbone then fill the bore and press in the stainless insert." as they say once the insert is in place the bush will expand and then won't go into the wishbone. It's a tight fit as it is so I think this is good advice.
And that's about it. It's an easy job and quite noticeable that you can tighten up the wishbones and still move them easily as the bush rotates on the stainless "crush spacer" as they call it.
I'm no driving god so I very much doubt I'll notice any difference when I get it out next week, but it does look like a reasonable alternative to the OEM rubber bushes, which in truth don't have that much rubber in them anyway.
Brian
Edit to add:
One thing I forgot in the original post, the stainless inserts / crush spacers were slightly different to the ones in the original bushes. Now my wishbones are tubular Spyder ones and were supplied fitted with bushes so I don't know for certain that they were identical to OEM Lotus, but the length of the insert on the Spyder bushes was 34.9mm. On the new Autobush kit, the length is 36.9, 2mm longer because the poylurethane bush is also fractionally longer
The way these are fitted doesn't make this a big deal, I only noticed it because I had thick washers on the upper spindle with the Roll Bar mount and when fitted I didn't get a full nut so I just used a thinner washer ! There wasn't any noticeable misalignment when mating up to the top ball joints, I suspect it's so little that it just slides into alignment on the insert.
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Thanks Brian. Please give us your driving impressions when you get a chance.
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Thank you, Brian, that sounds like a nice kit.
I'm very tempted to try it too. 8)