rear suspension inner toelink

[TimMullen]

Originally Posted by milcher

Distorted thread locknuts, nylocks, locktite and double-nutting are not considered foolproof solutions when safety is a concern. The portion of the stud on the rod end side has anti-rotation features, therefore this seems to be a perfect example for mechanically locking using safety wire or using Nord-Locks (if applicable).

None of them may be of use if the problem is that the metal it is clamping to yields (squishes). Using lock nuts, safety wire, etc. may cause a sense of false security in that case - the nut can't turn, so it must be tight (when in fact it may not be) so you don't bother checking the torque.

Is the problem caused by the nuts unscrewing? Or the metal yielding?

[Stan]

Originally Posted by TimMullen

None of them may be of use if the problem is that the metal it is clamping to yields (squishes). Using lock nuts, safety wire, etc. may cause a sense of false security in that case - the nut can't turn, so it must be tight (when in fact it may not be) so you don't bother checking the torque. Is the problem caused by the nuts unscrewing? Or the metal yielding?

Right, assuming Lotus knows a thing or two, it's just not that hard to follow their instructions.

From the wheel well with the wheel off, tool in hand this is about a one minute torque checking effort. They suggest doing this before track days. It's also easy to do from under the car if you have the panels off for some other reason.

Here is the nut:



Here is a retorquing, 15 mm socket, 50 Nm / 37 lb-ft, seen from driver's side rear corner. Each side of the car has the same setup.



The ball joints need to be phased at 90 degrees to one another. That way they can pivot without trying to unwind the toe setting at the tube. In the pic below, note that the toe link can be rotate as shown by the two wrench positions...this is important. It also demonstates the ball joint action which needs to occur without binding.

[Dro]

Mine were loose. I just ordered replacements.

A117D0090S: Ball Joint, inner, LH thread, M10 x 1.25 x 60 stud
A117W3189F: Locknut, flange, cleave, M10 x 1.25, inner toe link fixing

Total cost for 2: $95.67

[TimMullen]

Originally Posted by Dro

Total cost for 2: $95.67

Hmmmm... It might be nice to have a set of them sitting on the shelf - just in case.

[ChrisH]

Originally Posted by Dro

Mine were loose. I just ordered replacements.

A117D0090S: Ball Joint, inner, LH thread, M10 x 1.25 x 60 stud
A117W3189F: Locknut, flange, cleave, M10 x 1.25, inner toe link fixing

Total cost for 2: $95.67

Now you will need to give us details on replacing them.

[David]

Stan,

Others have already expressed this, but I want to add that I really appreciate the information you're providing on this thread. This is very valuable, potentially life saving. I'm one of the lucky ones who takes my car to be serviced by Don at Newport European, but even though--thanks.

[®ob]

I'm not to clear here...if the problem is the nut/bolt getting loose, how does the suspension brace/heim joints fix the issue?

[Stan]

Originally Posted by ®ob

I'm not to clear here...if the problem is the nut/bolt getting loose, how does the suspension brace/heim joints fix the issue?

* You still need to check bolt torques on a braced car before track days. And periodically for street use.

* All of the braced setups I have seen use a double shear concept which is inherently more stable and tolerant to abuse. The stock single shear arrangement wants to be properly torqued, phased, and periodically inspected in order to perform to it's potential.

* The inner joint is a piece that does a few things at the same time. The braced setups use separate parts to replace the all-in-one joint. This provides potential design / implementation benefits.

* Got a new Elise/Exige? Well make sure that your dealer checks this particular bolt torque for you before you take delivery, at the 1000 mile check up, and so forth. They are supposed to do this! DIY is nice here, this is not a hard thing to do.

[Stan]

Originally Posted by David

Stan, Others have already expressed this, but I want to add that I really appreciate the information you're providing on this thread. This is very valuable, potentially life saving. I'm one of the lucky ones who takes my car to be serviced by Don at Newport European, but even though--thanks.

Thanks for the kind words David.

I'm grateful that this thread has not been closed, moved, spindled, or mutilated. Which happened to a similar thread in the past.

[TimMullen]

Originally Posted by ®ob

I'm not to clear here...if the problem is the nut/bolt getting loose, how does the suspension brace/heim joints fix the issue?

The ball joint stud on the tie rod end is in single shear - the loads are "trying to slice" the bolt off at the surface of the chassis. Additionally, the pulling and bending of the tie rod attempts to bend the bolt back and forth - which can lead to the fatigue cracking shown in the earlier photos.

The brace changes the loading to double shear - twice the amount of metal to resist being "sliced" and more importantly reduces the bending load on the ball joint stud. The ball joint is replaced with a Heim joint - this allows a bolt to pass through the brace, then the Heim joint, and then the chassis. The motorsport version of the brace attaches to the chassis in the middle and makes a very rigid structure. The later brace connects the right and left joints together and transfers some of one side's forces to the other side's attachment. Probably not as strong/rigid as the motorsports version, but probably good enough for track days (as opposed to out and out racing).

Like all things, there is a downside. Heim joints tend to wear quickly and are usually difficult to lubricate (and/or need lubrication often) they are not usually sealed to keep the dirt and grime out. That's why you usually only find them on race cars that will have lots of maintenance and replacements. But if they wear out, the tie rod still will be "trapped" and you won't completely lose the control of the rear wheel.

[TimMullen]

Originally Posted by Stan

I'm grateful that this thread has not been closed, moved, spindled, or mutilated. Which happened to a similar thread in the past.

Stan, that post was closed, not because of technical content, but because of the personal attacks that were occurring directed toward a couple of people. That thread is also back (with some of the attacks removed). I know this really bothered you at the time, but it's time to let it go. It's dragging you down too much - with all your really useful posts on this forum you help a lot of people, so seriously, let it go.

[Surferjer]

Stan-I was with Steve Snow when we adjusted the toe setting, and tighten both ends without issue (phased, no problem). But we never checked the one nut you are referencing. I'll look at when I change tires at Peru.

Thanks for the pics. I will definitely do this without removing the diffuser.

[Stan]

Originally Posted by TimMullen

Stan, that post was closed, not because of technical content, but because of the personal attacks that were occurring directed toward a couple of people. That thread is also back (with some of the attacks removed). I know this really bothered you at the time, but it's time to let it go. It's dragging you down too much - with all your really useful posts on this forum you help a lot of people, so seriously, let it go.

There is much more to it than that Tim. Part of my expressing my view of what occured then and at various other times has helped things like this present thread, IMO.

[®ob]

I got it now. Thanks, wasn't thinking clearly. I've seen heim joint boots, which may be worth looking into for a street car.
That being said, I've seen ball joints and TRE boots crack and wear out plenty too. Damned if you do, damned if you don't.

[Randy Chase]

Originally Posted by Stan

There is much more to it than that Tim. Part of my expressing my view of what occured then and at various other times has helped things like this present thread, IMO.

Not really. Not at all in fact.

[bmwtmx]

Was this rear end problem solved with the optional track pack in 2006?

[MattG]

Originally Posted by Stan

I'm grateful that this thread has not been closed, moved, spindled, or mutilated. Which happened to a similar thread in the past.

No worries Stan, this thread is great and incredibly useful! Such a nice change of pace from the last time we discussed this issue.

As an owner though, I'm still a little confused about what to *do* about this. I'm not concerned about the part breaking, I'm concerned about having to check the torque often (though I realize the two can be connected). From what I'm reading here, the suggestion seems to be that if you install one of the two brace options, the bolt should be 'less likely' to loosen. Any quantitative, or even guesstimates, about how effective it'd be at that? If that modification meant not having to always check that bolt torque, that'd be a really strong selling point to me.

[powerbookguy]

great thread, appreciate all the info and photos of what to check on this issue. special thanks to stan, tim and other engineer-minded folks.

are there similar torque etc concerns for the front suspension?

TIA.

[scottyb]

Stan checked my torques last night and we found the passenger side up to spec, but the drivers side was between a 1/4 to a 1/2 turn loose. It was a PITA to check without dropping the under-tray.

[Stan]

Originally Posted by MattG

No worries Stan, this thread is great and incredibly useful! Such a nice change of pace from the last time we discussed this issue.

Thanks, Matt.

As an owner though, I'm still a little confused about what to *do* about this. I'm not concerned about the part breaking, I'm concerned about having to check the torque often (though I realize the two can be connected). From what I'm reading here, the suggestion seems to be that if you install one of the two brace options, the bolt should be 'less likely' to loosen. Any quantitative, or even guesstimates, about how effective it'd be at that? If that modification meant not having to always check that bolt torque, that'd be a really strong selling point to me.

You're stuck with checking bolt torques or at least wrenching them before track days anyway.

A pretty much bullet proof and extra abuse-resistant strategy could be to use the next size larger fastener, say 12 mm rather than 10 mm. This would require changing out an a-arm bushing though. As Marc's race shop friends suggested.

The torque is not that hard to check. Lotus does use a locking nut there BTW (per the description of the nut on the parts list, I have not removed it to check). I think that part of the issue is the old FUD bugaboo - fear, uncertainty, and doubt. And that some things like this might not be properly checked at the the various scheduled inspection periods. You can do it with just a wheel off but there is not much range through which to move a 1/2 drive torque wrench. It's extra easy to do from under the car at oil change time. Once properly tightened and checked once or twice, the joint should stay stable for it's lifetime. Any car should be gone over from front to rear before track days - that is a good idea anyway.

Lotus says that the various torques need to be checked before track events. The torque on the stock or aftermarket joints should each be stable. I think that if you check it per the Lotus schedule you will be fine. (hmm...kinda repetitive here..)

This is one of those things that may require more time during which to build confidence. A series of torque checks with stable readings would be reassuring. From what I can see, it does appear likely that MarcW's link let go because it was not fully tightened. We need to be careful not to knee-jerk the situation, yet be safe and happy. I have heard of at least 3-4 joints that have let go on very low mileage cars. Marc's, some at the McQueen events, etc. It would help a lot if we had closeup pictures of other failed joints so that we can see what happened. Like other things in life, a little more light on this subject would help.