Castor shims

[ashcloud]

Happy new year!
I have restored the front suspension to better then new condition but ran into 1 problem: the manual says there must be 1 spacer block and 8 (eight) shims for castor adjustment. I found the spacer and 5 shims and now with the new upper bump stop (1mm shorter hole spacing) I can barely fit 1 spacer and 4 (forcefully maybe 5) shims.
The spacers/shims are of the 1.6mm size as stated in the manual.
What is wrong here?
Bernhard

[piman]

Hello Bernhard,

there is no 'correct' number of shims, they should be as required, i.e. you need to measure the camber and caster and use shims accordingly. I don't know if you have the tools to do that or not? However if you find you do need more than you say you can fit, is it a matter of longer bolts to allow that. I don't know how the upper bump stop affects the shims but it's been a while since I've had a close look at the front suspension.

Alec

[ecosselynx]

Hi

I think Bernhard is referring to the fact that once he has the noted shims installed the bolt centers on the upper arms no longer align with the holes in the bump stop.
However Alec is correct in that there is not really any correct number, the number given is a reference, reality is what you need to have the car set-up correctly.
What you need to do is bolt it all up as it was before you stripped it down, go and get the castor and camber checked. Once you have these reading you can then see about making changes.

John

[oldtimer]

Hi Ashcloud,
Pleased that you have managed to restore the front suspension, guess it's all looking smart.

I've just had a look in the book as a reminder an age since I last did that job.

You are understandably complicating a simple job.

The top radius arms mounted on rubber bushes will stick out and find their natural position.
During the process of installing the top ball joint, shims and spacer it is important not to induce any side load on the arms, neither pulled apart or squeezed together. With the radius arms in this natural position the bump stop bracket holes should all align, screw in the retaining bolts finger tight. (do not tighten at this stage)

Now the top ball joint and spacer can be inserted into the gap between the two radius arms and the bolts can be inserted. You will note that a gap still exists, this gap has to be filled with spacers which at this stage should be fitted one at a time either side of the top ball joint. The overall number of shims quoted is an arbitrary quantity. I can't remember if the bolt holes in the spacers are slots or holes!

With the remaining space is filled with spacers tighten the top ball joint securing bolts gradually, checking that the bump stop securing bolts remain free to move. If you feel the need, a thin spacer can be inserted to relieve the side load on the bump stop bolts

The purpose of the spacer is to allow adjustment in the vertical plane between the top and bottom ball joint to achieve the desired castor angle setting. One 1/16 or 1.6 mm shim = 1/4 degree caster angle change.

Caster angle change is achieved by removing one shim and moving to the other side of the ball joint ensuring that the total number of shims is neither increased or decreased.

I'm sure you are well aware that Caster Camber and track will need to be set after all this work.

I hope this helps

Oldtimer

[ashcloud]

Thanks Gentlemen
Since I am not a mechanic, I am a "by the book" guy and that said, I quote:
A packing piece and 8 shims must be always fitted between the wishbone levers and the ball joint.
Now for me the term MUST made me think that there is something wrong on the way mine was put together (I have found too many things that had been done wrong)
It does make sense what You say that actually there is only one correct way and that is with the wishbone levers on and the upper bumpstop mounted handtight the two faces of the upper wishbonelevers must stay paralell, else it will introduce unnecessary tension.
My packing piece is almost 8mm thick so it does fill one side and on the other there are 4-5 pieces. Now I think I will have this machined to half its size and fit some shims on both side for easier adjustment (the packing piece can only be removed with the screws out while the shims slide in and out with the screws just loosened)
The setting for castor and camber have to be re-done from zero since the adjustment was so odd that I did some brainstorming.
First the car was riding high, about 4 inches between the tire and the frontwheel arch, so I got the shorter coilsprings from Derek Watson and installed them. Surprise NO CHANGE?!?!?!?! Talked to Derek and we all where clueless. Here my decision was made to take the whole thing out, and I found that when they previously worked on the car they must have tightened the wishbone/bushing when the car was lifted up and not under load, so even with the coils out I could not rotate the lower wishbones to be level and they swung right back down. Now with the car facing skyward all castor/camber settings where made (balljoint full forward, shims all in the rear to counteract the "rocket" setting)
When I put the suspension together next week (I get the new outer bearing races pressed in on Monday) I will set everything into a neutral position and have the car measured, then make the necessary adjustments afterwards.
Also I made up a template to set everything into the correct position with the suspension still on the bench (lower wishbone --> level!) to tighten everything before being installed.
But I do have one more question: does any one of You have torque values for the wishbone/Polybush and the shocks and the mountingbracket?
The only sad thing is that the "new suspension" looks so nice it would make a good decoration (wife says NO)
Thanks Bernhard
PS: I will post some pictures soon

[ashcloud]

Here are some pictures of the mess. I did get the Coppercraft Brakes which would normally go against my idea of originality but in Germany the old brakes are enough for backroad driving but at Highway speeds if any new car does an emergency stop ..... You find that You have a problem. So the original Dunlops are being cleaned and stored for a refitting if desired.

[piman]

Hello Bernhard,

my apologies, I had totally forgotten about the top ball joint shims and was thinking of the shims that fit on the tower where the top wishbone cross shaft is mounted.
Looking at my manual confirms what you said about the eight shims and the spacer.
I had stripped a MK 1 front suspension assembly last year and checking today, it's top ball joint only has one spacer (5mm thick approximately) and three shims so again another 5mm total. So possibly there is a change between MK 1 and MK 2 in that area. (I originally was going to totally overhaul this assembly ready for my car until I found out that the geometry was improved for the MK 2 (Different roll centre) so I abandoned that idea.)
Surprising for a factory manual there are very few torque figures quoted so I can't help you on that side.

Alec

[ashcloud]

Ya, I have tried every combination but there is no way to fit 8 time 1.6mm shims and an 8 mm block. The upper bumpstop holes would be 1/4inch to close together and so the only way to do this would mean the spacerblock should be 4.5mm and not 8 thick. So I have to see which way to go but if I can get 6 more shims (SNGBarratt was out of them) I have the spacer ground down to 4.5mm. Normally I would say who cares but more shims allow better adjustment without touching that spacerblock. That 4.mm Spacer would be close to Your 5mm and it might even be the correct one (and the one I have is the wrong size)
Bernhard

[ashcloud]

Oh Alec
About the torque values, I have the values for the XKR and I will compare the bolt and threadsizes and the type of bushings and use just the lower end of those torque values. If any one has a list of recommended torque values for the different brithish theads I would be thankful.
Bernhard

[oldtimer]

Hi Ashcloud,
The photo's look great.
I believe you have been given the answer in respect to the number of shims in each of the previous entries. Lets try again. Measure the gap between the two radius arms with the bump stop bracket screwed in place which could be say 50mm (just a guess) And the top ball joint is about 30mm in width (not going in the workshop to measure one at this time of night) Take 30mm from 50mm = 20mm. Now select 20mm worth of anything it does not matter, just accurately fill the gap. When you get round to setting the caster and camber then you can re-look at the shim arrangement.

Oh course, what we don't know is, who manufactured the top ball joint and has the width altered,
if so, the bit in the Manual that says must fit, suddenly goes out the window.

I don't know the ride height, this is specified in different ways on different models. I'm sure someone will tell us how to measure it. What I am sure of is that the lower wishbone bushes being tightened whilst in the extended fully down position does not have the ability to raise the car considerably above its correct ride height. Installing in this manner will cause premature failure/tear it apart.

Are there any spacers in the spring pan that can be removed? If not my feeling is that you may still have the wrong springs. The 2.4 will have different springs from the 3.8

I will be interested to hear how you get on but hope my bit helps just a little

Oldtimer

[ashcloud]

OK, the latest such measurement left 17mm total space, so 8.5 on each side.
MY spacerblock is 8mm (so it fills one side) and each shim is 1.6mm. that is 9mm divided by 1.6mm -->this is 5 shimms and a thin one. So almost 6 shims.

The ball joints, original and new (Lemförder) are both 41.5mm

About the ride height: I have no more ideas why else it could have been so high, there was only one spacerring above the coilsprings????
Bernhard

[ashcloud]

About the coilsprings: the one that where in there where way too high (I will take pictures) but the Derek Watson springs are shorter and stiffer and drive nicely. It only has printed MK2 on them but since the 3.8 was the heaviest it should be too low with the wrong springs and not too high, or do I see that wrong? I also checked if the engine is the original (Jaguar Heretage Cert.) and all numbers match.
Since all is new now and the adjustments will be too I hope to get a new start on this old problem. I will post any progress and all findings.
Bernhard

[ecosselynx]

Hi Bernhard

Your springs are sitting in the corner in the fully relaxed position, do you know how long they have been like that!
You need to get your front end built-up and back in the car following the information given above.
Once the full car weight has been on the springs it will bring it down, best if you can go for a drive in it, which will then bring it down to their true height sooner.

hope this is of use.

[piman]

Hello Bernhard,

one point is that with the top bump stop bolted in position (I realise now how it affects the situation) and the top links bolted to the cross shaft is that the faces where the ball joint and packers go should be parallel. If not there is a problem somewhere?
The reason I mentioned about the MK 1 bits I have is that possibly Jaguar fitted a narrower ball joint in the MK 2 to give more range of adjustment, could you have an incorrect joint?
I just measured my MK 1 joint and it is 44mm in width with the joint and packers it is about 55mm, the pitch of the top bump stop bolts is 122mm, as near as I can measure with a tape measure.

Alec

[ashcloud]

Actually the balljoints (old and new) are 41,5 and the space left was a total of 17mm between the flanges when all things where positioned correctly and the bushings tightened. So that left 8,5 on the left and the same on the right side.
Now the spacerblock is already 8mm and that left enough space for 5 shims.

I will get the washers from the upper wishbone mounts from the shop and then I will put it together and take some pictures.
At this point I can only think that my spacerblocks are to big. I have found so many items from other jags in mine that I would not be surprised to find out that they are from an XJ6 or so.
Bernhard