Printable Version | Subscribe | Add to Favourites
<<  1    2  >>
New Topic New Poll New Reply
Author: Subject: Failed IVA - steering not returning to centre.
SteveDown

posted on 2/7/15 at 09:15 PM Reply With Quote
Failed IVA - steering not returning to centre.

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

View User's Profile View All Posts By User U2U Member
big_wasa

posted on 2/7/15 at 09:23 PM Reply With Quote
No you just need new front top wish bones with at least 7 deg of castor. What car is it ?
View User's Profile View All Posts By User U2U Member
JC

posted on 2/7/15 at 09:38 PM Reply With Quote
Silly question - have you got the top wishbones on the correct side? Try swapping them?
View User's Profile E-Mail User Visit User's Homepage View All Posts By User U2U Member
coozer

posted on 2/7/15 at 09:38 PM Reply With Quote
Where are you? Someone close should be able to help...





1972 V8 Jago

Midlana when I find the space...

View User's Profile Visit User's Homepage View All Posts By User U2U Member
Dave Bailey

posted on 2/7/15 at 09:40 PM Reply With Quote
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

View User's Profile View All Posts By User U2U Member
HowardB

posted on 3/7/15 at 05:45 AM Reply With Quote
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


Dave,

do you remember the bearing number that you used?

thanks

HowardB





Howard

Fisher Fury was 2000 Zetec - now a 1600 (it Lives again and goes zoom)

View User's Profile View All Posts By User U2U Member
Dave Bailey

posted on 3/7/15 at 06:23 AM Reply With Quote
I will have a look later today....
View User's Profile View All Posts By User U2U Member
Dave Bailey

posted on 3/7/15 at 06:33 AM Reply With Quote
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

View User's Profile View All Posts By User U2U Member
SteveDown

posted on 3/7/15 at 06:49 AM Reply With Quote
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]

View User's Profile View All Posts By User U2U Member
CC Cyclone

posted on 3/7/15 at 09:34 AM Reply With Quote
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.

View User's Profile View All Posts By User U2U Member
smart51

posted on 3/7/15 at 12:29 PM Reply With Quote
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.

View User's Profile View All Posts By User U2U Member
MikeRJ

posted on 3/7/15 at 05:09 PM Reply With Quote
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]


Are you using a genuine Lotus 11 steering rack, and if so has it been "reconditioned"? I put that in quotes as there are some horrendously bad reconditioning companies whose idea of reconditioning is to fit new gaiters, wind up the rack preload and dunk it in a vat of black paint. You end up with a rack so tight that car is almost undriveable.

If you jack up the front wheels does the steering still feel tight, or is it free enough to steer with one finger on the wheel?

View User's Profile View All Posts By User U2U Member
avagolen

posted on 3/7/15 at 06:14 PM Reply With Quote
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.





The Answer for everything, but never the last word....

View User's Profile View All Posts By User U2U Member
mistergrumpy

posted on 3/7/15 at 08:55 PM Reply With Quote
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.
View User's Profile View All Posts By User U2U Member
SteveDown

posted on 4/7/15 at 12:06 AM Reply With Quote
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.
View User's Profile View All Posts By User U2U Member
907

posted on 4/7/15 at 05:47 AM Reply With Quote
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

View User's Profile View All Posts By User U2U Member
MikeRJ

posted on 4/7/15 at 12:46 PM Reply With Quote
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.


That suggests that you may be starting with very little castor, which won't help matters at all. Have you measured the castor to ensure it's correct for whatever a Lotus 11 should have?

View User's Profile View All Posts By User U2U Member
SteveDown

posted on 4/7/15 at 02:07 PM Reply With Quote
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.
View User's Profile View All Posts By User U2U Member
blakep82

posted on 4/7/15 at 02:17 PM Reply With Quote
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]





________________________

IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083

don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!

View User's Profile View All Posts By User U2U Member
SteveDown

posted on 4/7/15 at 02:57 PM Reply With Quote
Thanks for the diagram, I'll go measure it. I've posted a couple suspension pics in my Photo Archive.
View User's Profile View All Posts By User U2U Member
907

posted on 4/7/15 at 03:38 PM Reply With Quote
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.






I know this is a 7 and yours is an 11 but looking from directly above caster looks like this.



Rescued attachment bone-fitted-2s.jpg
Rescued attachment bone-fitted-2s.jpg

View User's Profile View All Posts By User U2U Member
SteveDown

posted on 4/7/15 at 03:43 PM Reply With Quote
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.
View User's Profile View All Posts By User U2U Member
cs3tcr

posted on 7/7/15 at 10:09 PM Reply With Quote
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

View User's Profile Visit User's Homepage View All Posts By User U2U Member
SteveDown

posted on 8/7/15 at 11:33 AM Reply With Quote
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.

View User's Profile View All Posts By User U2U Member
SteveDown

posted on 12/7/15 at 08:25 AM Reply With 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.
View User's Profile View All Posts By User U2U Member
<<  1    2  >>
New Topic New Poll New Reply


go to top






Website design and SEO by Studio Montage

All content 2001-16 LocostBuilders. Reproduction prohibited
Opinions expressed in public posts are those of the author and do not necessarily represent
the views of other users or any member of the LocostBuilders team.
Running XMB 1.8 Partagium [ 2002 XMB Group] on Apache under CentOS Linux
Founded, built and operated by ChrisW.