Rear Beam Problems

[jamie_st200 1]

Hi,

 

recently i upgraded a rebult non gti 309 rear beam to gti spec..

 

in doing this i obviously had to remove the torsion bars..

 

Once i had the beam on the car i tried to set both trailing arms at the same height but i just cant do it..

 

it always seems to be around 10mm out...

 

now i know that there are more splines on one end than the other but say when you locate the torsion bar in the end away from the trailing arm... if you dont get these both in the same place then the trailing arm side will never sit eqaul..

 

im having trouble explaing myself here...

 

say the splings are 1. gaps 0

 

 

10001000100010001 END FURTHEST FROM TRAILING ARM

11111111111111111

are the splines on a ratio like above where it doesnt matter where the torsion bar sits in the furthest location

as it will always line up with the other trailing arm

 

or is it like

10001000100010001 END FURTHEST FROM TRAILING ARM

10010010010010010

so if both torsion bars are sitting in different places at the furthest end then i will never get the trailing arms equal..

 

i know this must be really hard to understand..

 

but one of you expects must get where im coming from

 

cheers, jamie.

[Daz_C 8 1 Cars]

Have you removed the Anti Roll bar ? This may be your problem if I read your question correctly

If you are refitting the torsion bars after removing them completely then you Will be able to re set them within one 8th of an inch of the desired height ! Just pull it back off the spline and turn the bar one way or the other and slide back in to raise or lower to the desired height.

[jamie_st200 1]

yeah the anti roll bar is out..

 

one side is at the height i like so all i try and do is line up the other side but it always seems to sit a lot higher or a lot lower.. not 35mm so im guessing its the side with the most splines is not in the right place...

 

but i was thinking that if the other torsion bar is not located the same way then i will never line them up...

 

im sorry i cant explain

[Daz_C 8 1 Cars]

Are you removed the torsion bar completely from the trailing arm or are you just pulling the arm and torsion bar off together and lifting/lowering it then pushing it back in ?

[jamie_st200 1]

i am totally removing it. the way i understood it is that if you revmoved the trailing arm with the bar still attached and moved it round a notch on the far end you would higher/lower the car by around 35mm.. its not that far out...

[Daz_C 8 1 Cars]

Maybe it wasn't level to start with ?

I would remove the torsion bar from the arm and start afresh. turning the bar a spline at a time when your close to what your after and you'll get it spot on.

[jamie_st200 1]

but you reckon i should get it with 1/8" so whats that in mm about 2-3mm?

 

how do people normally measure each side.. i normally go from the top of the arch to the hub..

 

cheers for your help..

 

jamie.

[Daz_C 8 1 Cars]

but you reckon i should get it with 1/8" so whats that in mm about 2-3mm?

 

how do people normally measure each side.. i normally go from the top of the arch to the hub..

 

cheers for your help..

 

jamie.

 

I know you will !!! Yeah here or there abouts.

I know some people use dummy shocks. I measure as you say. I've never had a problem doing it this way and I've done a fair few over the years.

[jamie_st200 1]

ok cheers mate.. ill have another look when i get another bump stop.. it done the usually and fell off and i cant be bothered to get dirty twice anyway..

 

thanx again,

 

jamie.

[pug_ham 242 3 Cars]

You are measuring it wrong!!

 

Have you got both ends of the torsion bar free?

 

The best way to measure to get both sides even is to measure between the bolt centres for the shock & then fit the torsion bars when they slide home smoothly without any force required. I measure the distance I want on a piece of wood & then drill the bolt holes through it & set each side using that. Even after setting it this way I have a different measurement from the arch (trim) to the hub.

 

Slightly more indepth description here.

 

Graham.

[Daz_C 8 1 Cars]

I disagree Graham.

I can't see and never had any problems from measuring from the edge of the arch trim to the edge of the centre of the hub. Unless the car has had a back ender of sorts and the shell is twisted then your method would obviously be the prefered option. Generally the distances are the same both sides before stripping the torsion bars out with the odd exception.

Removing the anti Roll Bar and the shocks obviously. Leaving the trailing arms and torsion bars in and measuring it at this point - then removing the torsion bars (completely) and re fitting at the desired distance. Original measurement minus the 30-35mm or whatever you want. (Both sides can be refitted at exactly the same height and no force is required either !)

Obviously everyone has there own way of doing things but for the life of me I can't see why this way would be Wrong if the outcome is the same ?

Or should I do a recall on the 100's of Pugs, Citroens and Renaults that I have lowered this method ? As stated I have never had any probs doing it this way and I ALWAYS get it EXACTLY the same both sides with the torsion bars sliding in relatively smoothly considering the Rust and alike on the splines. Obviously a Good Scrub with a wire brush and a clean in the splines then copper grease up but a smooth slide in is rarely achieved unless an hour or so is spent cleaning the edge of each spline with a sharp implement !

[jamie_st200 1]

thanx for your help guys, although measuring the ride height is not my main problem..

 

it just seems that when i get my trailing arm at the height i want the splines do not line up so i have to go slightly higher or lower...

 

although i must confess i have not tried taking the bar right out, and sitting the trailing arm where i want it and sliding it back in...

 

 

jamie.

[Dj_mini 7]

I did saxo yesterday i got the bars out reset one side no problem went round the other side to reset that the same i just could not get it the same i have done over 50 beams and never struglled so much to get it even but after half an hour of twisting the bar and measuring pop in it went where i wanted it you just have to keep trying untill it sits right. Doing it this way you can normaly get it 2-3mm either way of where you want it. I have also found that if you use a dummy shock after you remove it the swing arm will sag slightly changing the amount you have reset it i always now measure from the arch to the top of the hub and have never had a problem.

[pug_ham 242 3 Cars]

Daz, I didn't mean it was totally wrong doing it this way just that I'd had bad experiences trying it by the method on my car that, afaik, hasn't been in a rear end prang or got a twisted shell. Arch trims can be sat a few mm different each side quite easily & I prefer to set it against two more unchangable points.

 

Measuring between shock bolt centres is the most exact way to do it but this is only strictly possible with the torsion bars removed completely.

 

Using the spline method (which it seems Jamie is doing) shouldn't be possible to set them to far out unless the beam has been built badly previously & the ride height was different to start with.

 

One large spline each side should give the same change in ride height, as long as you have disconnected the same end on both bars & not the arm end on one & beam end on the other.

 

Graham.

[jamie_st200 1]

i wasnt using the spline method, i was leaving the torsion bar fixed at the furthest point away fron the trailing arm, pulling the trailing arm away so it leave the torsion bar sitting in/on the axle then holding the arm where i want it and trying to push it back onto the t-bar. but it either goes on to high or to low..

 

i know it this end that is wrong because it does not sit 25mm out more like 10-15..

 

but this bring me back to my 1st question..

 

i know there are more splines on the nearest end of the torsion bar but is it say on a ration of 1:2 because i can think that if it isnt and it has say 18 one side 23 the other then maybe it because i have both of the torsion bars fixed in different places... if you get my drift

[Dj_mini 7]

Remove the bars completly and set the swing arms much simpler and easyer to get the swing arms set at any height you want and level.

[pug_ham 242 3 Cars]

Splines on each end are 30 one end, 32 the other.

 

Setting it this way you'll never get them both the same imo, you need both ends free to set it that right now.

 

Graham.

[veloce200 3]

Just done one myself and you can change the distance 1mm at a time on each side. If you need to decrease the distance you go clockwise one spline on the 30 spline end and then anticlockwise 1 spline on the 32 spline end (thanks to who counted them as this is a much easier way to refer to each side) Hey presto 1mm at a time. The trick is to actually move one spline clockwise and one anticlockwise.