Hi
When I refitted the rear suspension to my buggy I used the original settings I had marked before stripping the vehicle. I knew I would have to reset the suspension to its final position once the lighter buggy body was in place. But I now think this might be too tight. Even standing on one side at the rear of the chassis doesn't compress the suspension at all.
I wouldn't be able to fit the rear axle tube boots as there isn't enough clearance.
Should I adjust the suspension now while everything is off and then again for the final time later on when the engine and body are fitted.
If so any idea of a good starting point.

Boots are easier to fit with box out but not nessasry 
do the axel shafts move freely with resistance  before you put box on chassis
and try lower by one outer spline as a starting point 

Boots are easier to fit with box out but not nessasry 

Only draw back is that they can get  damaged against the frame horns when the box is refitted......ask me how I know this 

I would do one inner spline now as it is easier access as is it may come out about right
final settings depend on weight and wheel width and the chances of getting it spot on first time is slim.
fit the boots with the joint at 3 or 9 0'clock they last longer

Mmmm,

Just my thoughts, but one spline either end will drop it about 50mm, for me its a job
best left until all the work is done and the total weight is final...

Its not that difficult once the principle of whats happening is understood, when you do get to
wanting to fine tune it and set the final height this may help...

The VW torsion bars resolve to have a minimum adjustment of 5mm chunks either way, up or down...

http://www.manxmaniac.co.uk/toolsAndIdeas-1.php?album=SallysRearEnd

Thanks for the advice.
I will back the spring plates off one spline and see the result

I have never tried moving the inner splines in case I cant get the torsion bars back in ?

What is the best way to do this ?

Is this difficult to do ? as I have only ever done the outer splines.

Thanks

I have never tried moving the inner splines in case I cant get the torsion bars back in ?

What is the best way to do this ?

Is this difficult to do ? as I have only ever done the outer splines.

Thanks

You will have no difficulty just scribe a line onto the rear casting along the top of the spring plate when it is free and not sat on the lower cast stop so you know the original setting
then applying a twist on the spring plate start pulling and wobbling it you should see it pull out the torsion bar as it moves. you can always paint/mark the plate inrelation to the bar before moving it.
applying more grease to the inner end before refitting can cause an air lock and make pushing in fully difficult by hand but a tap with the hammer and a block of wood to save damage will force the air out.

Cheers, how far does it come out before you are able to turn it ?

The same as the outer end ?

Thanks

never measured it 50mm at a wild guess as the splines are not very long but if the spring plate is on bar and the plate marked you can put it back in the same place then do it carefully the second time

Moving the inner splines is easy, you just need to concentrate on what you are doing...

The torsion bars and splined hub inside the frame have quite heavy chamfers, so all you need to do
is get comfy and just ease the bar out, all the while twisting gently, you will feel the bar clear the splines and move.
Stop pulling it all out at this point and keep twisting the bar with a little 'inwards' pressure until you feel the spline re-engage on the next one round...

Check out the link to Sally's rear end I posted here previously...... I hope it explains the principle of more splines one end than the other and why, with explanation of the minimum resolution the spline adjustment gives, the minimum up or down is a 5mm height change.

Where as one spline either end will give a raise or drop of 50mm

Peter

Cheers Peter

I know a lot of people like to stick to 1 inner or 1 outer, or one of each for varying reasons - ease, fear, lack of understanding, etc, etc.

The only thing that you really need to be careful of is not removing both torsion bars at the same time - they butt up against each other in the middle and if there is no bar on the other side, the bar can push through the central splined section, or at least you can end up with one sat too far in and one too far out.

I personally have never counted splines inner or outer, but gone with what looks right for my buggy and duplicated with the angle finder on a spirit level for the other side.

Aftermarket torsion bars are much stiffer than stock, so if you try applying the same starting points you will never twist the bar enough to do up the torsion cover, or if you do, the suspension will never move

Even when returning to a new set of stock bars, I simply lined up the spring plate with my 'saved' scribed line (taken against the top of the spring plate against the chassis when unloaded) by changing inner/outer splines until it was dead on.

With new bars, you have no reference point to move from, so this is really the only method that works. Sure you can calculate the difference from where you are to where you want to be with inner/outer splines, but trial and error works just as fast with no paper or maths and you soon get a feel for what is required.

Maybe 8 inner clockwise splines and 9 outer counter clockwise splines is the perfect adjustment for your car:
inner splines as shown in the above table are 9 degrees/spline
outer splines as shown in the above table are 8 degrees 10 minutes/spline
(8 * 9 degrees clockwise) - (9 * 8 degrees 10 minutes counter clockwise)
= 72 degrees clockwise - 73 degrees 30 minutes counter clockwise
= 1 degree and 30 minutes counter clockwise overall
if 50 minutes = 5.5mm as shown in the above table, then 1 degree and 30 minutes = 9.9mm
5.5mm / 50 minutes (or 0.8333) = 6.6
multiply this by 1 degree and 30 minutes (or 1.5) = 9.9mm

You can see from this calculation that you are not restricted to multiples of 5.5mm changes and in fact much finer resolution is possible, but the maths associated with it is somewhat long and drawn out, and without a table showing all the possible combinations, trying to work backwards from a number of mm to an inner/outer combination would be a nightmare, hence why the trial and error method will get you where you want to be much faster.

The method is as follows:
Decide what you think will be a good angle and mark it on the chassis, move an inner spline, then see if any outer spline is anywhere close (pretty obvious when you try and attach the spring plate - only 1 or 2 splines are worth trying, one will be too high and the other too low), move to the next inner and repeat, maximum of about 20 goes to get it right, usually found in a lot less. Take a sprit level with an angle finder place it on the spring plate and zero the level, take this to the other side and repeat the procedure until the same angle is located.

A few other factors that comes into play for the final seating position of the vehicle:
The age of the torsion bar, such that when loaded up again it does not give the same drop on a car with new bars as one with old bars
The weight of the car - a heavier car will deflect the bar further than a lighter one for the same angle of change in splines
The more a torsion bar is 'wound' up/down the less/more it will deflect for a given weight of vehicle - leading to stiffer/softer suspension and potential change in total suspension travel.

Also don't forget to roll the car forwards/backwards after resetting the spring plates before checking the final stance to remove the artificial raise given by the wheels 'tucking in' whilst the rear end of car was off the ground.

The only thing that you really need to be careful of is not removing both torsion bars at the same time - they butt up against each other in the middle and if there is no bar on the other side, the bar can push through the central splined section, or at least you can end up with one sat too far in and one too far out.

Just to add to Zebethyal's excellent post, don't under any circumstances remove both (old) torsion bars and then refit them
on the opposite side to that from which they came...

As, over the years they will have been working in one direction taking the loads and they will have taken on a changed 'state', if they are refitted on the opposite side the risk is run that they may fracture and sheer across the bar...

Peter

If you have no reference points to start with what would be a good angle to set for a swb buggy with 70 profile tyres?