As said, swap your top wishbones over first of all, that may fix it. They may not be symetrical
[Edited on 4/7/15 by blakep82]
Hi all,
My car failed IVA because the steering won't make any attempt at returning to centre. Since the test I've tried to toe the wheels out,
adjusted the suspension height so the steering rods are level, and increased the tyre pressure to 35psi. Despite a number of adjustments and
subsequent testing there's been no change and the steering remains in the position to which it is pointed.
I'm unable to adjust the camber/caster so my options are rather limited.
This is the only problem I need to resolve for a retest, however, after a couple of frustrating weeks trying to fix it, I feel that only an all
powerful wizard it going to be able to sort it out. :-(
Thanks,
Steve
No you just need new front top wish bones with at least 7 deg of castor. What car is it ?
Silly question - have you got the top wishbones on the correct side? Try swapping them?
Where are you? Someone close should be able to help...
I know this may be a sticky plaster but what friction is in your steering... I have helped my self centering by replacing the std Sierra column
plastic bearing with a proper bearing vastly improving the steering feel, drag and stiffness....
Dave B
quote:
Originally posted by Dave Bailey
I know this may be a sticky plaster but what friction is in your steering... I have helped my self centering by replacing the std Sierra column plastic bearing with a proper bearing vastly improving the steering feel, drag and stiffness....
Dave B
I will have a look later today....
Simply bearings...
Products Each Total
1 x SBPFL205 Oval 2 Bolt Pressed Steel Bearing Housing with 25mm insert
Option's £7.74 £7.74
The plastic triangular core bush presses into the bearing. The bearing outer race is spherical which allows the bearing to align with the shaft and
the angle of the bulkhead...
Dave B
I've built a Series 2 Lotus 11, this is with an original spec chassis and suspension components. I'm not sure what car the top links are
taken from, I'll find out. They were also used on the Lotus MK14, and I suspect numerous other Lotus cars from the 1950's/60's. The
roll bar hooks into it and making something to replace it is way beyond my capabilities.
I'm located in Welwyn, but taking the car to anyone is problematic.
[Edited on 3/7/15 by SteveDown]
Take the track control arm out at both sides and check for free movement / pivot of the upright, it it is all new there may be some resistance to
overcome that is causing problems. I had it, took mine apart reassembled and torqued up again and all was fine, except i did discover that my new
balljoints were causing a problem and were junk. Replaced them with good quality versions and all was fine.
Castor is the key to it though as has been said.
I had this problem on my trike and I dod a lot of work to try and fix it before it went to MSVA. My advice is not to cheat to get it through the test
but to fix it properly. Self centring is an important part of steering feel. A lack of self centring gives a lack of feedback and confidence in the
car.
As said above, I'd check for friction in all the moving parts. The self centring force generated by the wheels has to overcome the friction to
move. Light weight cars don't make much force so need minimal friction to work properly.
quote:
Originally posted by SteveDown
I've built a Series 2 Lotus 11, this is with an original spec chassis and suspension components. I'm not sure what car the top links are taken from, I'll find out. They were also used on the Lotus MK14, and I suspect numerous other Lotus cars from the 1950's/60's. The roll bar hooks into it and making something to replace it is way beyond my capabilities.
I'm located in Welwyn, but taking the car to anyone is problematic.
[Edited on 3/7/15 by SteveDown]
Pre IVA I jacked my car up, placed axle stands under the front wishbones and sat in it.
Then for quit a while I just wound the steering from side to side to 'exercise' all of the
New components. I could do it easily with one finger after a while.
I second everything that's been said. I found that a good clean and oil of the steering rack helped a lot along with a bit more air in the tyres than usual.
The steering rack is from a Mini (it's lighter) rather than a Morris Minor and has been professionally shortened. It's in tip top condition and the steering operation is super light with very little effort required.
That Mr Wasa in reply number one is a clever chap.
Those that suggest that making sure everything moves freely do no harm at all.
Screwing in loads of this or that and pumping tyres to non usable settings isn't the road to happy motoring.
I made my bones wrong, bit the bullet, and made some more.
Paul G
quote:
Originally posted by SteveDown
The steering rack is from a Mini (it's lighter) rather than a Morris Minor and has been professionally shortened. It's in tip top condition and the steering operation is super light with very little effort required.
I don't know how to measure the caster, visually however, it appears to have none. The top ball joint is sitting directly above the trunnion.
Castor is measured by making a line through the centres of the top and bottom ball joints, the angle of that line away from vertical is the castor
angle
As said, swap your top wishbones over first of all, that may fix it. They may not be symetrical
[Edited on 4/7/15 by blakep82]
Thanks for the diagram, I'll go measure it. I've posted a couple suspension pics in my Photo Archive.
quote:
Originally posted by SteveDown
I don't know how to measure the caster, visually however, it appears to have none. The top ball joint is sitting directly above the trunnion.
Oh wow, that's way more than I have. I've just been out to the garage and hung a plumb line. There is some caster there, but's a tiny amount in comparison to yours.
Steve,
I had a quick look at the drawings I have, and both the Seven S1 and Eleven S2 should have 5 degrees of caster. But, you might have less if the
swaybar has pulled the upper link forward (it happens under bump and droop). I would have a look at how tight you've compressed the bushings
that the swaybar passes through on the upper link. Also, see if there is any binding in the steering column, you may have to rotate the rack a bit
to allow the column U-joints to work freely, provided you have the original type column with it going between the pedals etc.
Rod
Hi Rod,
The steering UJ's are free of any binding, as you correctly stated, twisting the rack up slightly resolves this.
I'll loosen the sway bar tonight and see if I can get some movement out of it.
Ta,
Steve
BTW, your car looks very nice.
I tested the car yesterday, still no change unfortunately. I feel that passing IVA is going to be impossible and I have a very expensive pile of scrap metal sitting in my garage.
quote:
I tested the car yesterday, still no change unfortunately. I feel that passing IVA is going to be impossible and I have a very expensive pile of scrap metal sitting in my garage.
Its more than just caster that needs to be checked/adjusted. The kingpin inclination (sai), wheel offset, camber can all have noticable affects.
Hi Steve
just noticed a very old text from you about self centering
Something worth trying - if your top wishbone has two sets of mounting holes onto the chassis, try mounting in the inner holes not the outer as this
alters the King pin inclination angle and will assist the self centering.
cheers
Tony
Hope he hasn't gone 2 years without sorting it!
I've gone through 5 iva test now 4 mks and 1 sonic7 uno turbo powered car have always got the steering somewhere near but just to help it I've always fitted some valve springs inside the rack yeah it hinders your lock slightly but it certainly returns the steering wheel
All sorted thanks... got it through with the valve springs fitted, worked a treat.
Im intrigued how a valve spring can self centre a steering defect
as in my mind self centering will happen at any point, ie 5 or 10% off central (the spring is not any were near being touched)
and if self centering is required, it MUST be from any point in the steering, not only from lock to lock
or am I missing something here
steve
The car is tested on full lock , the steering wheel is then released and the car has to be seen to show at least some self centring or at least that's how I remember it.
Same here only tested full lock to lock yeah its not ideal but we do what we can to get that pass and number plate
Ok, noted