Strange "jerk" in the steering

[Robbie693]

Could it be a sticking damper/shock absorber?

Robbie

[collins_dan]

When the jerk of the wheel happens, do you notice anything else? Does the car actually start going to the right, or is the steering wheel just transmitting a shift that is not happening at the wheels? If it seems isolated to just the steering wheel jerking, then it would seem to be just related to the steering, not the suspension... Are you driving straight when it happens, or are you steering? Did you check all the various clamps that hold the steering column in place? Just more things to check before tearing apart the rack. Good Luck, Dan

[chris_uk]

I think it less likely to be a shock absorber as it only happens once on a journey and does not seem related particularly to going over uneven road surface or bumps.

When it occurs there does seem to me to be a slight jerk to the right which I have to adjust for in the steering (i.e. 1-2 degrees left hand down a bit). It have usually happened on the straight when I'm going 50-60 about 1-2 miles into the journey. Although on the last test it did not occur until I was on the last tight right hand turn into the drive travelling at about 5 mph (just when I was thinking I must have inadvertantly cured it!).

Chris

[rgh0]

have you checked the slip joint clamp in the steering column to ensure it is not moving?

cheers
Rohan

[ricarbo]

Yes, but you haven't answered my question. When the jerk occurs, does the steering wheel need a different position? i.e. is the down spoke of the steering wheel pointing more at your left leg, whereas it was previously pointing at your gonads?
regards
richard

[chris_uk]

Richard,

Yes that was the "I have to adjust for in the steering (i.e. 1-2 degrees left hand down a bit)." Troutbridge reference in my previous response. Although I have to say any change is pretty minimal so I could be fooling myself into belieiving there is any at all.

"Slip joint clamp" - another thing on the list to check!

Thanks.

Chris

[robertverhey]

Mate, humour me and check the rear!!!!!!

Would hate to think you're driving a car with a broken rear a-frame mount or something else awry back there.

Just pulled the body off mine and one of the rear a frame mounts had come almost completely adrift from rust.

At least lets exclude the rear as a possible cause.......

[paddy]

Unlikely, but might it be a loose caliper? You brake when you're reversing leaving home, and then it resets itself to a forward position when you're driving?

Paddy

[512BB]

Chris,

Your comment about turning into your drive and feeling the click, is symptomatic of a VERTICAL LINK, pulling out of a trunnion. That is the brass thing at the bottom of your front suspension, on both sides. Very dangerous if it is that.

To test, jack the front of the car up just enough for the front wheels to be off the ground. Wedge a tyre lever or similar under the tyre, and lever the tyre up and down, vertically.

Observe where the threaded part of the vertical link goes into the trunnion. There is a black dust cover there. If you can see either the vertical link or the trunnion, moving INDEPENDENTLY of each other, ie. the vertical link can move in and out of the trunnion, even minutely, then either the upright or the trunnion, or both, are knacked, and would need to be replaced.

Leslie

[ricarbo]

That sounds to me like the rack is moving relative to the chassis. Should be easy to check by having a look while an assistant winds on half a turn of lock one way, then the other. The loads doing this are greatest when the car is stationary (hitting kerbs excepted!!), so you can expect a bit of flexing of the rubber mounts, but when the assistant stops pulling the rack should be in it's normal place.
atb
Richard

[chris_uk]

Thanks, for more thoughts (especially useful for a tyro elan owner like myself if they come with detailed instructions for how to perform the test!) . I'll update when I've looked again but it won't be until next weekend at the earliest that me and car are reunited again!
Chris

[chris_uk]

Hi,

It's been some time but thought I would update on this. I finally got to the bottom of it I think. It was a combination of factors that I guess are unlikely to happen to others but I guess it's worth closing the thread just in case others encounter something similar. It was due to these factors:
Tyres wider than original spec (175 width).
Anti-roll bar an imperfect fit widthwise to the front suspension and not torqued up to the damper as much as it might be.
Backing out of the drive on full righthand lock.

What happened was that in reverse on full lock the tyre contacts the roll bar on the drive's side and moves it compressing the rubber bush and allowing the ARB to be pushed down and out of correct alignment where it is fixed to the lower end of the damper. The ARB subsequently clicks back into place sometime during the first mile or so of driving causing the strange jerk. Avoiding full lock and torquing the ARB bolts up slightly has removed the problem for the time being. I should either replace the tyres or change the steering stops at some point. I'd prefer the former option as I prefer the look of the narrower tyres and wider ones make the steering feel a little heavy at slow speed (and I could then get the spre into the well in the boot). But replacing 5 near brand new tyres (on the car when purchased) goes against the grain a bit ....

In any event thanks for all the useful comments - I learnt a lot about Elan suspension and what can go wrong with it!

Chris

[billwill]

There was a thread on the forum somewhere recently about missing stop-fittings in the steering rack.

Perhaps that is your fundamental problem.