This is the method I used to lower my own Peugeot 306 GTi-6. I would like to point out that the torsion bars had previously been removed, cleaned & greased & refitted. The o/s torsion bar was seized into the trailing arm, which is very common if they've been in for a few years & needed a 10 tonne hydraulic puller to free it. I would suggest you make sure both bars move freely before making any adjustments.

Also, this is only a guide & may contain errors. If you follow these instructions to adjust your own suspension & it all goes horribly wrong, it's not my fault. You have been warned.

If possible, position the car on perfectly level ground & take measurements of the wheel arch heights for future reference. Don't be surprised if they're slightly different from side to side (up to about 5mm)....nothing's perfect.

Jack up the rear of the car & support it on axle stands, remove both rear wheels & release the handbrake.

Disconnect both shock absorbers from the trailing arms.

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Remove the anti-roll bar end plate fixing bolt (13mm spanner) from both sides of the car. The plates can then be rotated out of the way to allow access to the ends of the torsion bars. If the plates are very difficult to turn, they may need to be removed to allow the trailing arms to rotate independently. To separate the end plate from one end of the bar, remove the platic plug & screw an M12 bolt (Ford wheel bolts are M12) into the hole where the plug came out & keep tightening until the plate pulls off, see below. This can be done from either side. You'll need to prevent the plate turning as you do this, so loosely re-insert one of the fixing screws.

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Remove the Torx head countersunk screw from the end of the torsion bar.

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This is what the screw looks like, in case you were wondering. It's purpose is to adjust the length of the torsion bar & hence the clearance between the trailing arm & the seal in the end of the beam tube.

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Position a jack under the hub & raise it by 5mm. This will take the weight of the hub & remove all tension from the torsion bar.

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Pull the torsion bar out of it's splines in the trailing arm....

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Jack up the hub by the amount you wish to lower the ride height. The new measurement will be the figure you wrote on the tape, minus 5mm, minus the lowering amount. i.e. if you're original figure was 420mm & you want to lower by 25mm, the new figure will be 390mm.

Re-insert the torsion bar. If it doesn't slide in first time (it probably won't), rotate the bar & try again. Eventually you will find a position where both ends of the bar will just push in. If you left the slide hammer in the end, it'll be easy to do this on your own, otherwise you'll need someone under the car aligning the other end of the bar with the fixed bracket.

Remove the slide hammer.

Now do the same for the other side of the car.

When that's done, temporarily refit the wheels & lower the car to the ground to check the height. Bounce the car a couple of times to allow it to settle.

If all's ok & you're happy with the ride height, get the car back on the axle stands & remove the wheels.

Refit the offset washer & tap it into position, aligning the hole with the torsion bar.

Before fitting the countersunk screw, refit the slide hammer through the washer & pull the torsion bar hard up against the washer. Then, remove the slide hammer & fit the screw.

Check the clearance between the trailing arm & it's bearing seal & adjust it to 0.5mm using feeler gauges, tapping the arm in or out with a mallet.

At the other end of the torsion bar, turn the screw anti-clockwise until it just stops against the end cap. Refit & tighten the nut & washer, then re-check the trailing arm/seal clearance.

Re-attach the bottom shock mountings. You may need to jack up the hubs slightly to get the bolt holes to line up.

Refit the torsion bar at one end & loosely fit the hexagon headed fixing screw. From the other end, push the other plate on the end as far as it will go. Screw in an M8 screw with a nut & washer on, through the plate, into the anti-roll bar & tighten the nut to draw the plate onto the bar until there is 1mm between the plate & the trailing arm.

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If the torsion bars aren't seized, yes it is that simple