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.
(http://i1295.photobucket.com/albums/b630/Als_Buggy/007_zpsc15bc8e6.jpg) (http://s1295.photobucket.com/user/Als_Buggy/media/007_zpsc15bc8e6.jpg.html)
Boots are easier to fit with box out but not nessasry ;-)up
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 ;-)up
Quote from: Big Clem on August 17, 2013, 12:37:38 PM
Boots are easier to fit with box out but not nessasry ;-)up
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
(http://www.manxmaniac.co.uk/albums/SallysRearEnd/slides/adjustingRearSuspensionChart.jpg)
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
Quote from: SR Buggy on August 19, 2013, 08:57:43 AM
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 :D
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.
QuoteThe 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?
The profile of the tyres when related to a camber angle will not be used, as the camber is the same whether the tyre is large or not,
though if they are large diameter it might be relevant in that to achieve a 'standard' slightly negative stance may mean the tyres hit the rear wing....
VW specify an angle of the spring plate in a 'down' position below the centreline
of the torsion bar of 21.5 degrees + 50'...
Remember though this is the position that was used on the production line and was determined
taking into account the weight of a fully assembled Beetle, with the quality control of the torsion bars and their heat treatment being monitored closely!
Body weight is the factor here, if you use this VW stated angle as a start point you will have a lot of positive camber on your buggy
due to the weight difference between your buggy and a Beetle, but from that start point you can take a measurement from the top of
the tyre to the body work, or better still, for me...
Drop a plumb line down the side of the rim 12'oclock down through 6'oclock, and then measure the 'gap' at the bottom
to the rim lip.
A little pythagorus will give you the positive camber angle and you can go from there to get to where you need to be...
Peter
Cheers Peter I think I get it. Comes down to quite a bit of trial and error too I guess with regards to the right look.
My Manx is completely disassembled with no reference points so I am worried that I won't even be able to get the outer splines lined up the same on both spring plates.
Don't worry about getting both the spring plates the same, use the angle as a start and then do each spring plate
so that it give you the camber you want evenly on both sides. Or ride height, it depends on what your preference is.
Remember, over time the torsion bars may well be in different states, so all you are doing is 'dialing in' each side to achieve the same result...
Camber or Height, the two torsion bars are NOT linked in any way, they are completely independent from one another ;-)up
Peter
Quote from: Peter on August 25, 2013, 12:17:07 PM
Don't worry about getting both the spring plates the same, use the angle as a start and then do each spring plate
so that it give you the camber you want evenly on both sides. Or ride height, it depends on what your preference is.
Remember, over time the torsion bars may well be in different states, so all you are doing is 'dialing in' each side to achieve the same result...
Camber or Height, the two torsion bars are NOT linked in any way, they are completely independent from one another ;-)up
Peter
So are you saying Peter that its ok for each side to have slightly different settings, ie i'm sure my spring plates are the same angle and number of splines on both side, but the drivers side is 25mm or so lower and will rub on the tyres. I'm thinking this is a result of wear and extra load (driver) over the years. I was going to adjust that side, does it matter that it will be a slightly different angle to the other side or is this all part of the dial in process??
No I am not saying that, and must apologise if I worded it all a bit badly.
I was just trying to show that the camber adjustment is separate and that the torsion
bars are not linked, they adjust each side independently from the other.
You are right about the angle of the spring plate, but I always ingnore that and set up
the 'camber angle' to be the same both sides.
If the buggy is standing on flat and level ground the camber should be the same either side,
eg 1 degree negative.... And the body work should also be the same/level both sides.
In fact its the errors in the body work that always crops up, my Manx is higher on the passenger side,
yet the camber is the same either side. As thats what I wanted to achieve...
Its possible the spring plates wont be at exactly the same angle due to the splines being broached in the hubs
during production without any real referencing to their position...
The KEY thing when setting up, is the CAMBER, as, if you have equal camber on both sides and yet the bodywork rubs on one side only,
then its the body work/chassis misalignment that causing it and the body work will have to be altered to suit...
If one side at the rear is sagging due to years of use, then the camber will be affected too, and there will be more negative
due to the sagging of the torsion bar, you cant have a lower/sagging stance due to ageing torsion bars and no change in camber
as the two components are linked together...
It should be possible, if all the chassis and bodywork is level and square to just raise it back up and restore the camber.
Its IMPORTANT to realise that the VW setup using a protractor was only used to facilitate accurate and quick setup on the production line,
it would have been done before the body work had been put on...
VW would have R&D'd the settings, established a manual way to set the spring plate angle and then applied the results to production, the
protractor enabled the chassis suspension to be set prior to any bodywork being present, so when the finished Beetle finally rolled off at the end,
it sat correctly.
For buggy owners its a different set of rules, as the final weight/stance is unknown.... So we start somewhere sensible and fine tune it from there.
This thread is showing the reason why so many buggy owners use IRS now, as the attitude of the rear wheels is NO LONGER linked to ride height.....
Does this make sense, I am sorry if it doesn't and dont mean to bang on ???
Peter
we put chimps torsion bars in at 16 degrees and it has not been touched since.
they are marked L and R for side fitment.
as said it is old paarts so settigs will vary with wear.
None of this is as bad as it seems at first.
Once you have popped the spring plate on and connected only the cover and rear axle, you
can just drop it down roll it about to see whats happening and alter it again if needed.
I was altering Sally's adjustments in about 10 minutes if I remember...
When you get the hang of it, things are quite straight forward.
Peter
A quick update
I wanted to slacken off the suspension from its original factory setting as I had no movement at all.
I moved the rear suspension 1 outer spline. This made the spring plate sit in this position with the bottom of the spring plate level with the stop. It was about 50 mm of movement as Peter had said.[/size](http://i1295.photobucket.com/albums/b630/Als_Buggy/250820132_zps9535617a.jpg) (http://s1295.photobucket.com/user/Als_Buggy/media/250820132_zps9535617a.jpg.html)
I reconnected everything and the suspension now sat with about 5 mm off the stop so I had movement at last and the axle tubes were no longer touching the gearbox yolks. (http://i1295.photobucket.com/albums/b630/Als_Buggy/310820134_zps5df5e830.jpg) (http://s1295.photobucket.com/user/Als_Buggy/media/310820134_zps5df5e830.jpg.html)
With the engine fitted the suspension dropped about another 5 mm
(http://i1295.photobucket.com/albums/b630/Als_Buggy/3108201310_zps760fb3dd.jpg) (http://s1295.photobucket.com/user/Als_Buggy/media/3108201310_zps760fb3dd.jpg.html)
(http://i1295.photobucket.com/albums/b630/Als_Buggy/3108201311_zps322a88ca.jpg) (http://s1295.photobucket.com/user/Als_Buggy/media/3108201311_zps322a88ca.jpg.html)
(http://i1295.photobucket.com/albums/b630/Als_Buggy/3108201313_zpsd48cfe55.jpg) (http://s1295.photobucket.com/user/Als_Buggy/media/3108201313_zpsd48cfe55.jpg.html)
that looks better and you now know how to do it if it needs fine tuning later when complete and settled.