Torsion Bar Ride Height Adjustment

[welshpug 1,657]

step 1 loosen wheelbolts then raise and support the rear end of the car,

a well padded trolley jack each side is best

 

step 2 remove wheels

 

step 3 use a wire brush and small screwdriver to clean all bolt heads and exposed threads, then spray penetrating oil on the aforementioned areas, as well as the inner ends of the torsion bars.

 

Step 4 Unbolt the handbrake cable bracket on both sides and turn the ARB end plate as shown -

 

Step 5 on one end of each torsion bar there is a slotted stud and 13mm Nut, clean and lube the threads of the stud, then place a ring spanner on the nut and hold the stud in place with a large flat bladed screwdriver, undo the nut!

 

Step 6 remove T40 torx bolt from opposite end of the torsion bar, and impact driver is handy here.

 

Scrape away any corrosion and dirt from around the offset washer then tap it to the middle of the hole and remove it, when the end of the torsion bar is exposed spray some more penetrating oil in there.

 

 

Step 7 remove the shock absorber, then measure the shock bolt centres on the trailing arm with its weight supported (place a trolley jack underneath, and lift it about 5mm or so) the std measurement is Circa 330mm (on a 306) fit the dummy shock absorber at this setting.

 

 

Step 8 mark the visible end of the torsion bar with a punch/scribe/tippex and mark the side of the hole as a reference.

 

step 9 attach a slide hammer to the end of a torsion bar with an M8 bolt (preferably a High tensile steel one) and withdraw the torsion bar.

 

step 10 set trailing arms to desired height with the dummy shock absorber. (every 3mm change in ride height is a 2mm difference in damper bolt centres)

 

Edited September 3, 2008 by welshpug

[welshpug 1,657]

step 11 screw the threaded studs fully into the end of the torsion bar (not tightly, they are quite fragile) then insert a well lubricated torsion bar into its place (both torsion bars have identifying marks, the RIGHT bar having ONE coloured ring painted and the LEFT one having TWO rings painted on)

 

The torsion bar may not slide fully into place so you need to rotate the bar one spline and try again until it slides into place, drive the torsion bar into place.

 

 

step 12 fit the offset washer, then pull the torsion bar back against the washer with the slide hammer then refit the Torx bolt.

 

 

step 13 insert a 0.05 feeler gauge between the trailing arm and the crossmember seal and push the trailing arm against it, you may need to use a wooden/rubber mallet to strike the trailing arm.

Once in place unscrew the shouldered stud in the end of the torsion bar until it contacts the cup (do not force the stud), refit the washer and 13mm nut, holding the stud in place while doing so.

 

 

 

Repeat process for the opposite sides torsion bar.

 

 

step 14 Check the ARB end plate to Trailing arm clearance, should be 1mm (0.5mm per side) if its greater than the specified dimension remove both plastic plugs from the Plates, and fix the Left hand end of the ARB with a bolt and washer.

 

Insert an M8 threaded rod/bolt with a nut and washer on it in the right hand end of the ARB and draw the end plate onto the anti roll bar until there is 1mm between the trailing arm and the plate (place a spacer or feeler blade between the end plate and the trailing arm.

 

 

step 15 refit shock absorbers and wheels.

 

step 16 lower car to ground and check the ride height is equal to within 10mm.

Edited September 3, 2008 by welshpug

[welshpug 1,657]

As rightly pointed out by Anthony who has done far more rear beams than I have, this is an idealistic guide so please bear in mind that your average 205 309 and older 306 will require a bit more force to strip the torsion bars out.

 

I have read that the Pullers Made by Tom Fenton are far more effective than a slide hammer, I've yet to try this method myself, this is just how I do it.

 

Another point raised is that the ratio in movement between the damper eye bolts and ride height is closed to 3-1 than 2-1, I think its actually 2.5-1 but I have mislaid the measurements from my last lowering.

 

If anyone has any damper eye bolt measurements and consequent ride height dimensions feel free to add them

Edited September 3, 2008 by welshpug

[All Praise The GTI 3]

h mate. how can this be done if i dont have a dummy shock?

thanks

[welshpug 1,657]

just support the trailing arm on a trolley jack and be accurate with your measurements

[Tom Fenton 1,541]

h mate. how can this be done if i dont have a dummy shock?

thanks

 

Length of wood with two holes drilled in it at appropriate centres.

[timmsy19 3]

good guide welshpug

 

voted to be made a "sticky" as it gets asked all the the time