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Unhealthy Movement

Posted: Fri Oct 06, 2006 11:57 pm
by wanderinstar
I have some rather strange movement at front of car, when driving. If I suddenly lift off throttle the car twitches to O/Side, when I floor accelerator it twitches to N/Side. There is a bit of play in track rod ends, but not excessive. Have ordered some new ones.
But in the meantime has anyone else had this and if so what was the cause?

Posted: Sat Oct 07, 2006 7:52 am
by jonathon
Have a look at the tiebar and its bushes, if they are loose then this could be your problem. Check also the eyebolt nut for security and wear in the top/bottom trunnions. Another might be loose bolts or worn lever arm dampers. :wink:

Posted: Sat Oct 07, 2006 9:06 am
by rayofleamington
My first guess would be to check the rear axle - that is the most likely cause of torque steer on a Minor. Turning leftt on accelleration could well be a poor location at the left spring mount.

I had one where you could change lanes on the motorway just by using the gas pedal! This turned out to be the rear axle not seated on the leaf spring spigot, allowing a few mm of movement. That was easily fixed by locating everything properly.
I wonder how on earth the previous owners had managed to overlook that, or maybe that was why they'd stopped using the car.

As everything appeared tight it had passed the MOT the day before I took it out for a 50 mile shakedown. Using a crowbar on the axle it was possible to see where the axle could move relative to the spring.

Once the axle was fixed, the car drove great (this was the 'pimp my ride car').

Posted: Sat Oct 07, 2006 9:22 am
by bmcecosse
Look hard at the front brackets where the tie bars attach to the chassis - if there is rust - or fatigue cracking - they could be coming away. The other tips are all good too - and you have just changed the rear springs ??? A broken main leaf could also give similar movements.

Posted: Sat Oct 07, 2006 10:11 am
by wanderinstar
Yes Roy, just changed them about a month ago. The tiebar bushes are Poly. Will give everything a good check over when I fit new trackrodends [hopefully today].
One thing I did notice was that the eyebolt on the o/side seemed to be screwed up more on this side thsn n/side. About 3 threads showing on o/side as opposed to 1 thread on n/side. It has had new chassis legs before I got it. Is it possible someone was overzealous while tightening o/side up.
Is there spacer tubes inside leg to prevent legs crushing.
Parts have just arrived, good old ESM.
Ian.

How much is too much, re trunnions?

Posted: Sat Oct 07, 2006 11:35 am
by rayofleamington
Is there spacer tubes inside leg to prevent legs crushing.
yes. The main strength of the chassis leg at the eyebolt is inside where you cant see - there is a thick steel section and a cross tube. The outer steel is pretty flimsy in comparison.
Are both nuts the same or does one side have different washers?

Posted: Sat Oct 07, 2006 12:22 pm
by wanderinstar
Ray,
I will have a good look this afternoon, but I think they are both nyloc ones.
Ian.

Posted: Sat Oct 07, 2006 5:56 pm
by nebogipfel
rayofleamington wrote:My first guess would be to check the rear axle
So would mine :)

Check that the "U" bolts are tight and are not stretched so that they appear tight but aren't. (I've had that before - dead tight but not actually holding anything!)

Posted: Sat Oct 07, 2006 7:55 pm
by bmcecosse
The eyebolt nuts position will depend on how many washers/spacers have been fitted on the outside face of the leg - these spacers set the amount of negative camber for the front wheels. Mine are set for 1 degree negative - standard setting is approx 1 degree positive. The chassis legs are also famous for developing ' fatigue' cracking - inspect very carefully. But DO inspect the brackets where the tie bars meet the chassis - some say poly bushes here are too solid - and lead to cracking and eventually breaking away of the bracket. For this reason I have retained rubber bushes on the tie bars.

Posted: Sun Oct 08, 2006 5:41 pm
by wanderinstar
You were right Ray. U bolts seemed tight but I could move rebound rubbers round axle. Retightened everything up, see what its like tomorrow.
Fitted all new seals to front suspension as well as trackrod ends. What a job it was to undo jubilee clips on inner ends of steering rack boots. Must have taken as long to do that as doing rest of work. Even contemplated taking rack out.