The Most Comprehensive Guide to Lowering the Peugeot 306 Torsion Bars

By 306-Swanny, with edits from Welshpug

Well I've recently lowered my 306 using various guides from various forums all of them very good but with something quite complicated like lowering the back of the 306 I would have liked quite a comprehensive guide so along my way I took lots of pictures and have decided to make a good guide for many people to use instead.

We encountered probably every problem you could so hopefully this will be the most comphrensive and helpful guide.

This guide will show you how to lower the back of your 306 using the torsion bar method, not the notch method.

I would just like to say I don't take any responsbility for anything going wrong If your car was as stubborn as mine, be prepared for lots of swearing, fustration, so my first tip, probably buy a punch bag before lowering your car as you may need it

Right lets get down to business, first off the back (I would advise a few days before soak the trailing arm in WD40, it will be your best friend throughout lowering the car.)

Make sure you car is on some clear level ground, loosen wheel nuts, chock the front wheels, jack up the rear with a trolley jack via the rear beam.

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Remove the rear wheels.

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First thing to do is using an Impact Driver (torx screw T40) remove the O/S screw.

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Then head over to the N/S and it should look like this.

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Remove the N/S handbrake cable and ABS bracket.

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Repeat on the O/S

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Then in the middle of the Anti-Roll Bar plate there will be a black plastic plug, remove this. Then you need to take this plate off. These are often seized so you'll need to get an M12 x 1.5 bolt and screw it in. NOTE: This is considered a Fine thread as the standard M12 bolt is usually a 1.75 pitch. An XU10 or XUD headbolt is ideal for this, nice and tough and long enough.

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It should work it's self off.

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Repeat the process on the O/S. Again it's probably seized so used the same method to get it off.

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The plate and anti-roll bar should come out together.

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At each end of the anti-roll bar there are 2 different seals. You should replaced all 4 and clean up the splines on the ends.

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Now without the anti-roll bar plate off you on the N/S you can see the end of the torsion bar. There is an encentric washer that needs to be removed, just get a small screwdriver and give it a waggle and it should come out. Do the same for the O/S torsion bar.

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Then come back to the N/S and there will be a small nut holding in the O/S torsion bar, simply remove it.

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You then need to release the bottom of shocks on both sides, it's just a single nut and bolt to remove from each side.

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Now measure the distance from the top of the arch to the hub on both sides. Note the use of masking tape for marking and recording purposes.

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Alternatively to set and adjust the height it is best to use what's called a dummy damper, this can either be a simple piece of wood with two appropriately sized holes drilled so the trailing arms are set at the exact same height.

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Or it can be an adjustable tool to aid with lowering, or raising the ride height, measuring from the bodywork is not best practice, measuring between the damper bolts is the most accurate method of ensuring both sides sit at the same height.

330mm between bolts will give standard ride height on 20mm torsion bars, 322 roughly 25mm, 320 - 30mm drop. I don't know any further figures as I don't lower cars any further than that.

When re-fitting the torsion bars you need to hold the trailing arms firm, hence the use of the dummy damper, you do not move the arm at all to make the torsion bar go in, this will guarantee that the ride height will not be what you intend it to be, nor will you be guaranteed to have it the same both sides. You rotate the torsion bar till you find the splines that will slide straight in with firm finger pressure.

Now take the weight of the torsion bar by jacking up both trailing arms by 5mm, this takes the tension and weight of the trailing arm off the torsion bars, making it easier to come out.

Then screw in the slide hammer where the enectric washer came out of and hammer the torsion bar outwards.

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As one side was so seized our first slide hammer broke. So we had to get a bigger slide hammer and it still wouldn't budge, infact when using the slide hammer we used so much force the whole O/S trailing arm came out. Which is never a good thing. So if this happens to you, disconnect your brakes from the disc and if you don't want to bleed the brakes again just thread them through the trailing arm.
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With the torsion bar seized firmly into the trailing arm it failed to budge with the slide hammer, WD40 and even heat. Hopefully you won't have all this trouble but if you do, the final step that worked for us was a huge hydraulic press. You will then have the torsion bar, finally out of the trailing arm.

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To make sure it doesn't seize like this again make sure you clean off all of the rust and tidy up the splines.

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Before refitting the trailing arm pack it with grease and thread the brake cables back through for refitting.

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When the torsion bar is refitted you must ensure the double ended stud with the slot is screwed fully in, fit the offset washer and torx screw.

Then place a 0.05mm feeler blade between the arm shaft seal and the steel cup it slides against, push the trailing arm home against the feeler blade but not with excessive force, you should be able to slide the feeler blade out easily. Now you need to wind the stud out till it stops against the cup, don't go forcing it as you will open up the gap between the seal and the trailing arm you have just carefully set. Fit the serrated washer then the 13mm half nut.

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Refit the brakes if you removed them.

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Take out the N/S torsion bar, first go to the O/S and release the nut. Then using the slide hammer take out the N/S black torsion bar (should be easier than the O/S)

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Now everything is out give the splines a clean and a general clean up and paint.

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Now both sides should be jacked up by 5mm and both torsion bars are out.

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It's time to set your ride height, basically take away however much you want to lower your car. I wanted a 45mm drop at the back so using some sicssor jacks, jack up both trailing arms to the desired height. Simply subtract the drop from your original measured height, in this case one side 344mm - 45mm = 299mm. Each side may have started at different heights, so make sure you subtract the drop from each. Then use the new height independently for each side or you will end up with a lopsided car. Or use the dummy damper method. Transferring it between side of the car as you go.

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Once both trailing arms have been put to the new ride height, it has to be put together. These were the new seals/nuts/screws you should replace.

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Everthing is cleaned up you can get back to putting things back together again.

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So far your best friend to this point has been WD40, for this next part it will be grease, if you want to lower it again, you don't want the hassle of everything seized up again, so pack everything with grease!

So starting back with the O/S torsion bar grease up both ends of the trailing arm and both ends of the torsion bar.

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Thread the torsion bar back through the trailing arm splines. You may have to jack up the trailing arm a 1mm or 2 to get the splines to match up. Once it is fully in and poking out the other end grease up the new off centre washer and slide it in.

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Align the off centre washer and screw in the new torx screw and pack some more grease in there.

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Now go round to the N/S and screw in the nut to hold the O/S red torsion bar in place... and more grease!

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That is the O/S new ride height completly set!

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Now, the same with the black n/s torsion bar, grease up both ends of the bar and the trailing arm.

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Refit O/S the torsion bar. It is a bit fiddley so we used the slide hammer to push it back in, making sure the splines fit same as before.

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Again slide the new off center washer back into place, fit the new torx screw and pack with grease.

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Then screw in the O/S nut into the N/S black trailing arm to keep it in place... and add grease.

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Now the shocks have to be screwed back into the trailing arm. Grease up the bolts and refit the shocks on both sides.

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Grease up both trailing arm faces and both of the anti-roll bar faces, splines and seals.

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Insert the anti-roll bar back into the trailing arms.

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Grease up the other faceplace and refit ensuring the splines line up.

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Take the ARB with its left hand end plate still in its fixed position, remove the plastic bung and stick a short M8 bolt and washer in the hole, this is to ensure the ARB doesn't pull out of the end plate when setting the clearance to the seals in the following procedure;

Fit arb through the middle of the beam from left hand side, fit the M8 bolt into the trailing arm.

on the right hand side place the removed arb end plate onto the ARB, if both trailing arms have been successfully set at matching heights the hole in the end place will align with the M8 hole in the trailing arm, if it doesn't you need to adjust the ride height till it does.

When the ARB end plate lined up nicely, fit a long threaded stud in the end of the ARB, and wind the plate on with a jut and suitable washer.

Before fully drawing the plate on place a 1mm feeler blade between the arm and the end plate, now draw the plate up against the feeler blade.

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Refit the handbrake cable and ABS sensor brackets.

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Fit the new black plastic plugs on both sides into the anti-roll bar plate.

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Well done. The job is now complete. Time to refit the wheels, get the car off the axle stands and admire your handywork.

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