Front Suspension Alignment

[David Morris]

Hi,

Measured at the brake drums flat surface, adjacent to the wheel nuts, does anyone know the correct angle that should be relative to vertical? We have fitted rubber-bushed front suspension in replacement for the original metal-bushed type and need to fit the correct thickness of shims behind the top mounting brackets.

Many thanks,

David

[johnairey]

David,
Page 92 of the manual wheels to be vertical to a plumb line. The fixings are awkward suspension to the chassis especially the drivers side.
Cheers John.

[David Morris]

Thanks John. Very useful.

Best regards,

David

[Keith Clements]

One of the other things to check is that the upper link is the correct orientation and parallel with the torsion bar. I have seen three cars (both Jav and Jup) with half shims under the oil box/holding plate to correct any misalignment.
I guess this was perhaps to correct for body/chassis damage but may have been to correct for production imperfection.

viewtopic.php?f=153&t=4206&p=23020&hili ... ion#p23020
The few pictures showing how I did it are about halfway down through this long post.

Renovated front suspension and steering on.
Check on chassis straightness

I made sure the chassis was perfectly level both axially and longitudinally using the frame level gauge between the torsion bars and the bed angle welded under the main chassis tube (main chassis member on Jav).
Then checked top of radiator housing for level on Jup. Using a pair of rods through the two middle bolt holes of an opposite pair of the six housing bolts across the radiator cavity I checked they were both level. This also works on the Jav.

Then created a centre line down the chassis with a line. Using a plumb line I checked the centres of the two rods aligned above this centre line. You should be able to do this more easily with laser alignment and levelling gear.

Fitted half shims to compensate for any misalignment. Note that further shims will be needed for camber adjustment.

If this alignment is not done there may be a change in caster angle between full drop and bounce and probably excess wear.

I do not know the full story on the design of the front suspension but I guess the angle of the torsion bars may have a relationship with the Ackerman angle.

[David Morris]

Hi Keith,

Yes, thanks. The Javelin we are working on has, in addition to the normal set of full shims, a couple of half shims on the forward area of the near side but not on the off side. Like you said, I guess these are for slight post production 'adjustments' ? I am guessing, but Jowett's probably had a jig for this during assembly.

We have been changing over to a set of rubber-bushed front suspensions on this Javelin and although I have found these usually swap over with no headaches, this time the vertical alignment has not gone to plan. At present, the description 'Noddy Car' seems more appropriate, hence my request for advice on the correct settings! I suspect that, during this car's inactive layover of some 15 years, some of the shims have gone missing? As John has mentioned above, some of the bolts, especially on the driver's side are right little piglets to get into place. We found it well worthwhile to use nice clean bolts and nuts during assembly, otherwise the air gets 'blue'.

All the best,

David

[Keith Clements]

If you require shims I have a load.
Having looked at different ages of Jav, I think the early ones could not (easily) be converted to later suspension. The body was definitely changed a long time prior to the fitting of the rubber suspension in preparation for the mod.
There are some pictures comparing the two somewhere in JT!

[David Morris]

Thanks for the offer of some shims Keith, we may need some, but I will let you know. I can remember changing over my second ( or maybe third? ) Javelin for rubber bushed suspension on the roadside outside our flat in Tunbridge Wells. She must have been quite an early one as she had hydromechanical brakes, with that puny rear axle with the small diameter half shafts.These gave me problems later when the very slender Woodruff key 'fretted' in the slot and gave me problems by the time we had moved to Bath. Her registration number was, I think, VMG 177. I sold her to someone in Devizes and never heard any more about her.

Many thanks for your help,

David

[Mike Allfrey]

Hello David,
Jowett Cars Limited did put out a Service Bulletin about fitting the rubber bushed suspension to earlier Javelins. There was mention of welding a piece of key steel (I think) to the spring arm, followed by 'or install the later spring arms' or words that mean the same.
Critical is the clamping of the rubber bushes so that all pivoting movement is through the rubber medium alone.
Regards,
Mike Allfrey.