Front spring fouling chassis

[ESM]

This is an odd one. I had a track control arm (front lower wishbone) break on my red car. It was scary for a second but I got it parked without too much drama and had it recovered to my local garage. Bob Brown very kindly sorted me out with a pair of good second hand parts that were cleaned up and hot zinc sprayed (I though it wise to replace both sides). The garage has now fitted them but they say the springs are now catching on the chassis on both sides! They also made some daft comments like "it must always have done this". They didn't remove the spring, shock or top wishbone as part of the job.

The only thing I can find is the instruction in the service manual that says:

Tighten the wishbone pivot bolts and damper to lower wishbone fixing bolt ONLY with the car at normal ride height, otherwise the bonded bushes will be preloaded, resulting in degraded ride quality, premature wear and increased ride height.

I asked them to slacken off those bolts and re-tighten with the suspension loaded. Any other ideas?

[DeeAitch]

Alan, did you replace the bush which the yolk bolts too? Last time I enquired these were on back order at Lotus so maybe a pattern part is in there -and not pressed in quite central?
Can you get a picture showing where it is catching?

[RayD]

It is odd Alan,

It’s hard to imagine any amount of wrongness in the tightening up procedure would cause it on its own.

Presumably the springs are touching at one of the points indicated on the diagram making it appear the bottom of the unit is too far forwards or backwards?

Mine are clear by about 10mm either side.

Ray

[bobbrown]

The lower wishbones were a pair I purchased second-hand a while ago and they were complete with the raft assembly and upper wishbone, I only sent the lower wishbone (both halves) and it all appeared to be OK. I did get them sandblasted and hot zinc plated to at least give then a chance to last longer. The bushes and ball joints were shielded when they were cleaned up as they looked and felt in a usable condition.

2a.jpg

[Specky]

Just thinking outside the box...

The longerons changed several times through out there life as did the yokes on the dampers, is it possible the lower wishbones changed subtly as well !

I have the same question as Ray, is the spring fouling front or rear, or on the inboard section?

I'd say not torqued on the ground.

Just thought, can you spin the lower part of the damper round, this may orientate the fork further inboard.

All very strange...

TTFN

[Specky]

I'll have a look at a few pairs of dampers and see what's what after tea...

TTFN

[Specky]

No you can't as an assembly, they also look even.

TTFN

[wayne]

Don't know if it's related but I recently replaced my front dampers and noticed that the springs were both very close to the inboard side of the chassis.
I also found a washer on the top of both side inboard top mounting stud??

I assumed that it ws there to shim out the strut to stop it fouling??? so I just put them back. There is no indication of fouling but I do remember thinking it was close!! As far as I am aware the dampers I removed were the origional. (especially looking at the bumper stops and knowing the history of this car for about the last 10 years or so.)!

Hope this helps

Wayne

[RayD]

… is it possible the lower wishbones changed

I removed a similar sentence from my post Dave … thinking someone would have come across it earlier

The distance from the sides seems too far for the springs to reach with all the bolts in place … now Wayne has pointed it out, the lack of clearance at the back sounds more likely.

I’ll have another look.

Ray

[RayD]

I’ve had another look albeit by lamplight and while the clearance is slightly less than the 10mm I said earlier it appears to be the same all round and parallel.

Is it worth people checking the TCA measurements just to make sure they are all the same … or has there only ever been one part number?

Ray

[Specky]

This is straight off the top of my head....

Lotus part numbers, the last letter is the modification standard or variant. So if it's an "A" it's original, subsequent letters are minor changes. Some variants never made it into production, whilst others did.

I don't know what the part number is for this item as my books are in the next room and I'm in bed.

TTFN

[Specky]

Good point Wayne,

And if the washer was then incorrectly refitted, that would double the error, Time to check the IPC .


TTFN

[bobbrown]

Problem is to quote "They didn't remove the spring, shock or top wishbone as part of the job" so just a replacement of the lower wishbone"
As I understand it both sides are the same, and only one was broken!

Puzzled of North Essex

[ESM]

Wow - lots of responses. Thanks guys.

I've just been and had a look and I've taken a few snaps. First off the spring is clear fore and aft it is rubbing on the inboard face of the turret. I can't see any radical problems anywhere - the rollbar was on the bottom of the pivot bolts instead of the top (just about the only thing, I can think of, that could be put on the wrong place). We corrected that but it was never going to move the spring positions. The floor isn't perfect but it doesn't look grossly deformed and the 'diamond' plates that mount the raft to the longeron look undeformed too. They have slackened and retightened the bolts at the correct ride height with no apparent effect.

The car had new shocks and spring all around a few years ago (all Lotus parts: standard springs, S2 front shocks and SE rears) no rubbing before or after that. It had a TCA replacement a few years back as well with no issues. The floor was recently off for some engine work (crankshaft shells) but it was fine after that too.

As a bonus we found a crack in the lug on the hub carrier where the steering arm connects

Pictures can be seen here

[Specky]

If you took the car for a quick spin, do you think the suspension would settle ?

Is it worth putting the old TCA back on and see if it also induces the spring to contact the longeron turret?

All very strange...


TTFN

[saska]

Very long shot but since it is the inner part of the spring to turret that is fouling, I'd loosen the 4 yoke to bottom damper wing bolts, loosen the 3 top turret mounting bolts, lever the damper/springer assembly outboard, maintain that pressure and re-tighten all seven. As Wayne noted the tolerances are close so may be worth a try.

[ESM]

The washer on the top of the shock is interesting to know about. The shocks weren't removed though.

The TCA part numbers are still prefixed with A100 in my parts manual, although I think at the moment only aftermarket alternatives are available.

I didn't drive it. I don't really want to go anywhere with the springs rubbing against the chassis and a cracked hub carrier! I doubt it would fix itself but it's always possible I suppose.

It is puzzling that even the side that didn't fail touches with the replacement TCA. I just can't see where a short TCA would come from, never mind a pair of them.

The options I have so far are:

1) Stick on a new prongeron (it is a little bent). There is a picture on John_W's site that shows one that seems a bit flatter.

prongeron comparison.jpg

2) Put on alternative TCAs on to see if anything changes.

3) Loosen it up and lever it out (but this seems a bit bodgy to me)

[bobbrown]

Here's a thought, if the spring/damper assembley has not been changed maybe a slight twist has been introduced in the yoke bush when it was tighted up causing the spring/damper assembly to be pushed more towards the chassis. Easy to see if this is the case just slacken back the bolt and see if you get a clearance and with the bolt loose is it possible to move the damper away from the chassis and then retighten it.

Bob

[ESM]

I did have them loosen and retighten the bolt through the yoke bush already (the tighten at the normal ride height thing). I doubt they tried to move the shock further out when it was loose but equally I would expect the weight of the car to push it out if there was play available.

[Specky]

Another question?

When you say it's touching on the inboard... Is the car on the ground or in the air?



TTFN