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Steering geometry

PostPosted: Sat Jun 01, 2019 10:53 am
by axshack
Hi all,
today I found out that my front subframe is out of kilter with the rear!
When I measure the distance between front and rear wheel centres, there is a 5mm difference between left and right !!
No wonder the car wants to pull to the left all the time!! :(
I am guessing that I can correct this by shimming the mounting bolts to bring the front back into line - agree or not?
If not, how do you suggest I go about fixing this?

Cheers

Dave

Re: Steering geometry

PostPosted: Sat Jun 01, 2019 7:51 pm
by johno
Dave, I can't find any information in the works Metro service book about subframes, Haynes does have an illustration which clearly shows there to be elongated slots in the front mounting but not the rear.
Before you set about adjusting this it might be an idea to have the wheel alignment checked particularly if the car is pulling towards the side with the shorter wheelbase. Correct alignment is 0 to 3mm toe OUT.
Because the wheel centre you are measuring to will move backwards and forwards as steering is turned the wheels need to be both aligned correctly and facing forward at the same angle to take an accurate measurement.
If all that checks then I'd set about measuring the diagonal distance between two points on the rear and front subframe as this is a better way of checking squareness. If that shows a miss-alignment then think about going ahead with spacers and adjustment of the subframe.

Re: Steering geometry

PostPosted: Sat Jun 01, 2019 11:05 pm
by axshack
thanks for this johno. Going to give it all a serious seeing to in the morning !

Re: Steering geometry

PostPosted: Sun Jun 02, 2019 1:28 pm
by axshack
well now...had an interesting morning trying to fettle this problem.

After an accurate measurement of both front to rear wheel centres I found that there was nearly 11mm difference between left and right. With the left side being shorter than the right - which of course made the car wander to the left all the time.

So, we loosened all of the subframe bolts (the small ones, not the big ones) and with a bit of push and a shove managed to move the subframe enough in the slotted bolt holes to get the measurements to match up (2140mm and 2139mm), which is close enough for me !!

tomorrow, off to get the tracking done again now that the subframe is sitting more accurately.

I am quietly confident that after tracking the car will perform much better than it has for some time now.

Many thanks for all the pointers here.