On throttle, pulls left. Off throttle, pulls right. Causes?

[tigerdog]

Smaug has been driven very little in the last few years, partially because of unsettling behaviour described above. This is not torque steer; rather it's behavior that's consistent at any speed, and happens as readily with light throttle as heavy. I've finally retired from the daily working grind so will get under the car to find out what's happening. It'd be good to see if someone has already fought similar behavior. I'm thinking it could be anything from control arm bushings to ball joints to raft bushings to engine mounts. Who wants to start a pool as to the root cause?

[Dave Eds]

Steering column UJ Doug!

[tigerdog]

Steering column UJ Doug!

Interesting thought - wheel doesn't feel disconnected from the rack, though. I'd expect a bad u-joint to introduce play in the wheel even when the car is stationary. Is this not the case? Also, it was doing this before I had the rack replaced a while back. I'd have thought a bad joint would have been discovered as part of that proces. But it's one more thing to check! Thanks, Dave!

[M100-NC]

Smaug has been driven very little in the last few years, partially because of unsettling behaviour described above. This is not torque steer; rather it's behavior that's consistent at any speed, and happens as readily with light throttle as heavy. I've finally retired from the daily working grind so will get under the car to find out what's happening. It'd be good to see if someone has already fought similar behavior. I'm thinking it could be anything from control arm bushings to ball joints to raft bushings to engine mounts. Who wants to start a pool as to the root cause?

Doug,

Most likely the Raft bushings or Upper Wishbone bushings are worn out (or the retaining hardware has come loose) and allowing the the raft or upper arms to rotate the knuckle when you apply the throttle.

The upper ball joint could be bad or the retaining bolts loose in the arms.

The TCA bushings could also be bad or have loose hardware.

[roy666]

Doug... sounds like my "steering kick" topic trail. Although I solved it with new upper ball joint (LHS) and steering rack joint, I still do have the nudge but very slight.. M

[tigerdog]

Rebuild time, I guess. Raft bushes have failed on left US driver's side, right side not good. Ball joint rubbers torn, so probably time for a rebuild. SJ an OK source for bushes, etc.? They list a couple of "steve's alternative" bushes for items that seem to be no longer available. Good experiences? Any negative?

[dapinky]

Doug,

I got my latest set of bushes from SJs - they still have (had?) rubber ones for the raft front, raft rear and raft top..... and the one bush where the shock yokes attach to the lower arm.

The rest were Poly bushes (top wishbone, inner bottom TCA, inner bottom support bar thingy).

[tigerdog]

The rest were Poly bushes (top wishbone, inner bottom TCA, inner bottom support bar thingy).

Thanks for the quick feedback, Dave. Any negative experiences with the poly? No squeaks? Harsh ride?

[dapinky]

As I've only driven the car for 28 yards (out of the garage, turn round, back in!) it is a bit early to say!!!!

However, I fitted exactly the same combination to my own car 10 years ago and they are fine.

[tigerdog]

fitted exactly the same combination to my own car 10 years ago and they are fine.

What? They only lasted 10 years??? The old ones lasted 30.

[Saltire]

I think Dave’s referring to two different cars. The one he did 10 years ago is his own vehicle, and the one he’s currently rebuilding is his partner’s.

I did mine about 4 years ago using the same combination of bushes as Dave has. At that time the raft bushes were the only ones still available in rubber; everything else was poly only. Personally I would avoid using poly on the raft, because Lotus designed those bushes with a specific compliance and non-OEM is likely to affect the handling adversely.

[tigerdog]

Personally I would avoid using poly on the raft, because Lotus designed those bushes with a specific compliance and non-OEM is likely to affect the handling adversely.

Seems like OEM raft bushes are still available. If I can get a copy, I'll post a link to the video the mechanic took of the old bushes when subjected to load. It was frightening!

[TorqueHorse]

FYI, I just replaced my front suspension bushings and one thing that I had a bit of a stumble on was the "LOWER RAFT MOUNTING BUSH, REAR". For us FED crew, it wasn't crystal clear (at least to me) which version to use. Based on John's input in this post, it seems the optimal one is the S2 versions (E100C6001F). But I don't know where John got that perspective from, because Steve at SJ thought it should be the S1 versions. I ended up going with the S2 ones because I think John knows the FED market best, but it remains something I just couldn't find a lot of data on either way.

[tigerdog]

I ended up going with the S2 ones....

I ordered S1 since that's what the parts guide v7 indicated. I'll update this thread once the parts are here and the work is done.

[tigerdog]

Problem was a truly b0rked raft bushing and failing ball joint(s). Friendly independent shop with patience and great skill removed both rafts, replaced all raft bushes, upper and lower ball joints on both sides, plus a couple control arm bushes that needed fixed. I pulled out my trusty bag of shims from a group buy many years ago and the shop completed a four-wheel alignment including the rear suspension, that had probably never been properly aligned since I bought the car. The results speak for themselves - Smaug is a joy to drive!

PXL_20230914_190710719.MP.jpg

[HJ2]

Wow! You must realy notice that on a spirited drive and finally enjoy the m100 as god intended!

[tigerdog]

Wow! You must realy notice that on a spirited drive and finally enjoy the m100 as god intended!

I even notice it on a tame, old-man-slow drive

[Tuga2112]

i love the amount of green in that picture