Outer Limits 4x4 Board

Finally bolting the old Surf back together.
My problem is this..................
Front axle is in place, engine and box etc is in place but my front driveshaft angle is too steep and the double carden joint is binding up.
It only does it in one place per revelution, its as if its not syemetrical.
Any ideas?

At this stage the body is still off the chassis hopefully it will sit down abit with that back on.

run an 80 series front diff?
lower it?
I've heard that double cardan joints acutally do not permit more angle than a single uni, only less vibration and an out of phase shaft, so maybe a single uni with a clearanced yoke?
move the front axle forward?
rotate the axle up @ the pinion?
Double cardan @ both ends? ( I have seen this done, I'n not making that up)

I think that the problem is the fact that when I changed to coils I cocked up the caster angle, seeing as I used Rangie control arms I don't have any adjustment. I'm not keen to use castor correction bushes as they look like they would restrict articulation.
I'm looking for a sneeky fix as I built the front axle so it wouldn't break and the only way to fix the castor is to grind off the mounts.
Maybe I should ditch the Rangie arms and go to a four link seeing as I seem to be a glutton for punishment.

ok i spose you have put a lift in it? the body should weigh it down a fair bit i would use gearbox packers i had the same prob on my shorty packed the gearbox about 30mm some guys do it by more but wait till the body goes back on and play around

pics?

I seem to recall seeing some photos of the back end being done - It looked pretty high. My idea would be to go 4 link. At least the caster will stay the same through the whole range of travel then.

Also, I am willing to bet you will have WAY more roll stiffness in the front than the rear, so getting away from the rangie arms will help this no end. see the "measuring balance" thread for some info about the compromises of Rangie arms with low roll stiffness in the rear.

Yes, I think that caster bushes will make the artic. and roll stiffness worse, plus, I am guessing that you need more correction than this.

Is the gearbox end too high or the diff end too low ?

If it is the gearbox end then i would recommend you put some packers on the mounts. If it is the diff end, then it definitely would be the castor angles, have you tried a 3 degree caster bush or plate ?

This is the best pic I have of the problem. I borrowed the camera so I can't get a better one at the moment. Sorry.
Since I started this thread I've modified the x member and the problem seems to have gone away and when I put the body back on it should be even better.
The stiffness balance shouldn't be too bad (I've put alot of thought into this) the front springs are a whole lot softer than the rears.
Also I tend to agree that I have made the thing to high. So my plan is to get it going and see how it turns out, then I will sort out the gremlins which I think will be easier than trying to engineer them out.
If it is too high once finished then I redo the panhard rod and put much softer spring all round.
At the moment I will stick with the Rangie arms but can see a 5 link in the very near future.

The x member that I made is designed too lift the gearbox 40mm.
The Supra motor never sat flat, my reasoning was that this would help this problem (45mm body lift aswell) I neglected to think about the driveshafts

If it is only binding in 1 place is it the grease nipple?
60 series cardins apparently have more missalignment
J Top

Is it binding at the gearbox or diff?

If its at the diff cut and rotate the knuckles to get back to factory castor this should solve all probs oh yeah dont forget to fill the old fill hole in the diff and drill another one so the oil is at the correct level in the diff .... either that or fill it on a really steep hill

If its at the gearbox cut and turning the knuckles will help however you may need to lower your gearbox/engine as mentioned above.

It was binding at the g/box. but I rebuilt the x member abd it solved my problem.
Another thing that forgot to mention was that I moved the chassis mounts for the contol arms up 50mm which gained about 7-8 degrees positive castor.
I think it is all sorted now guys thanks for all your help

chimpboy
Posted: Fri Jul 23, 2004 9:16 pm

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pics?

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