FYI - Several threads on different forums talk about different set ups this concept would be fine. Most are 30-60 years old and we don't know what these cars have gone through. Accidents, heavy drivers/passengers, used as a work truck, on the back roads anything is possible.
When starting your project you really need to measure your car to find out if it is crooked. Measuring from the ground to highest point in the fender arch will help determine this. Check out this article to get a better grasp of what I mean.
The best way and only way in my eyes is an angle finder under a load. Place an angle finder on the lower portion of the spring plate. Make sure to write down what the degrees are for both the left and right.
Normally a notch will lower the vehicle about 1.125 inches. So when we did our 58 recently I went two notches and assembled everything back together including the tire and jacked up the shock mount to put the car under a load. If I liked the look I measured the angle and wrote it down. Now all I have to do is make the other side match under a load. If I wanted it higher or lower I would remove the spring plate and torsion bar and rotate the bar to grab another notch and replace the spring plate to try it again.
It is time consuming but to get it right it means everything. No crooked stance and piece of mind if it's dialed in correctly.
This procedure is written for a swing axle model but the principle is the same for the IRS - double joint - rear axle there is just a bit more hardware to remove/install.
In this article the word "rear" means rear-of-car. "Front" means front-of-car.
Description of Parts:
Torsion bars - Round bars which twist under load providing the "spring" for your suspension. Mounted crosswise and horizontal forward of the axles just under the back seat area of the floor pan.
Cover plates - These cover the outer ends of the torsion bars and hold the torsion bars in place using large rubber bushings.
Spring plates - These large flat spring steel plates connect the axles to the torsion bars. On the newer IRS models these plates simply move up and down but on the older swing axle models the swinging motion makes the spring plate twist as they work up and down.
Axle assembly - This is where the spring plates bolt to the axle and they also hold the brake assembly in place.
Tools - You'll need a good jack (this job can be done with a hydraulic bottle jack or screw jack but it will take more time) axle stands (preferably 4 of them for front and rear) box wrenches a file or cold chisel two extra large screw drivers or a set of tyre levers and a lazy afternoon.
Please understand that this article shows you how to lower the vehicle with nothing else purchased, just labor.
- Raise the whole car off the ground (measurements are easier with the car level and you need some working room under the rear). Make sure it's well supported - you need to do some pushing and pulling at the back. Axle stands under the front and rear torsion bar tubes work best.
- Remove the rear wheels.
- Examine the spring plate ends where they meet the fitting on the axle end. The spring plates have elongated holes so you can set the rear suspension toe-in. You might even find an alignment mark on top of the axle fitting (mine has one). Make a mark across the axle fitting and top of spring plate so you can line it all up again on re-assembly. If you use a cold chisel or a file you'll have a permanent mark for next time (in about 10 years) when you have to do it again!
- Check to see if your car has had adjustable spring plates (after-market item) fitted. These have an adjusting bolt and an 'additional' short plate nearer the torsion bar end of the spring plate - front of car end). If you don't have these additional fittings you have the original non-adjustable type which must be rotated. (No guarantee the adjustable type would give you enough adjustment anyway it's really a 'trimming' device to even up the two sides).
- Remove the three bolts holding the spring plate to the axle assembly. These are large bolts and have a lot of torque on them and not a lot of room around the bolt heads. You need good box wrenches (ring spanners) rather than the open-end type or you risk rounding the bolt heads. The spring plate is 'twisted' as the suspension moves through an arc (swing axle models) so you'll see it 'untwist' as you undo these bolts. This keeps the bolts under some tension - they don't just come loose and spin off. There is probably a rubber bump-stop attached to one of these too - take note of how it's mounted so it can be replaced the same way. 67-70 manual transmission swing axle models also have an anti sway bar linkage attached to the axle with these bolts too - remove this mounting. You should then be able to maneuver the whole axle towards the rear of the car free of the spring plate without loosening any of the brake lines etc. You might need to tie it back clear of the spring plate. If it won't move back far enough you may have to loosen the hand-brake cables. Do this from inside the car - pull up the rubber boot over the hand brake and remove the horizontal balance bar between the two cables. Now the axles can be pulled back and the cables will pull out of their sheaths slightly as they follow the axle.
- Now look at the front of the spring plate. There is a cover plate with four bolts. Remove these and pull off the cover. There is a large rubber bushing underneath and you should now be able to see the splined outer end of the torsion bar.
- Now comes the interesting part. The spring plate is still under considerable tension and will be sitting on a stop-lip - a lip just to the rear of the torsion bar. If you try to lever the spring plate outwards it will fly downwards with a big thump (breaking any arm or leg in it's way) so it's better to ease it down. Place the trolley jack (or a bottle jack will do) under the axle end of the spring plate and jack up the spring plate just enough so it is just free of the stop-lip.
- Now carefully lever the spring plate outwards about 1/2 inch using very large screw drivers or tyre levers top and bottom working at the torsion bar end. Once clear of the stop-lip you can then lower the jack and the spring plate will drop a lot lower past the stop-lip (this is why you need the car up off the ground).
- Leave that side and attack the other side now so you get both spring plates hanging free on their torsion bars.
- Measure the distance between the ground and the axle ends of the spring plates so you can judge the effect of the adjustments. VW recommend an inclinometer here with different angles for different models but you can get it pretty good just by taking note of the height from the floor to the rear end of the spring plate. The torsion bar has 40 splines on it's inner end and 44 on it's outer end. VW designed it this way so you can make fine adjustments to the angle of the spring plate (ride height of the rear end of the car).
- Now working on one side or the car at a time you pull out the spring plate WITH the torsion bar until it is free to rotate (about 1 inch or so). Might be a bit fiddly as the assembly might stick a bit on the inner rubber bushing around the torsion bar end. Then rotate the whole spring plate AND torsion bar downwards by one (inner) spline and push it back in. This increases the spring plate angle by 9 degrees which is too much so you now pull the spring plate off again but this time push the torsion bar in (you can see the end of it remember) so ONLY the spring plate comes loose. Now rotate the spring plate alone upwards one (outer) spline. This decreases the spring plate angle by 8.1 degrees for a total angle increase of 0.9 degrees. The axle end of the spring plate should now be a little closer to the ground (which of course raises the car on it's wheels).
- Do the other side similarly. You'll have to judge how many times to do this rotation trick But usually one "rotation" is enough. Two rotations might be needed for a really sagging rear end. If your spring plates were hanging at similar heights before you started (point 7 above) it is easier as you simply match the rotations side for side. If they were at different heights you'll have to decide which setting you like on one side and then match the other side to it. It is ESSENTIAL to get the sides matched fairly closely in height otherwise the car will 'squat' on one side. (Adjustable spring plates are useful here as it is then easy to fine-tune the angle of each side). Note: The spring plate angle should be about 20-21 degrees but this does vary from model to model.
- When you are happy with the settings bolt the cover plates back over the torsion bar ends (pulling it in evenly with the bolts so the rubber bushing is not distorted). Be careful here as you need to pull the spring plate up just snug against the stop-lip then jack up the axle end until the plate is higher than the stop-lip then tighten the cover plate fully so the spring plate will rest on the stop-lip when you release the jack. DON'T try to jack the spring plate up before you start fastening the torsion bar cover plate - the plate must be partly secure BEFORE the spring plate is raised or you'll never be able to start the bolts in the cover plate.
- Then remount the axle assembly at the rear end - being careful to line up the toe-in marks you made previously. Don't forget the bump-stop and any other attachments at the axle end.Note: Don't forget that the spring plate will be 'twisted' again as you do the bolts up (swing axle models) - I found it easier to install one bolt (where the spring plate and axle assembly are closest - bottom bolt I think) first and tighten it up to start the 'twist' and you'll then be able to spin on the other bolts on a little easier. Lining up the toe-in marks might require some hefty wacks on the brake drum nut with a rubber mallet or block of wood (DON'T use a metal hammer please) as snugging the bolts up twists the spring plate and makes it quite a tight fit even before you tighten the bolts completely. Don't forget to reattach your hand brake fittings inside the car and adjust the horizontal balance bar between the two cables so the hand brake pulls evenly up 3 to 4 clicks.
- Once the car is back on it's wheels you have to roll it back and forwards (or drive it a few yards) for the swing axles/wheels to move into their 'natural' position and you can then check the height of the rear end. The axles should be close to parallel viewed from behind - perhaps just a slight wheel-end-down angle (slight positive camber) with the running boards parallel to the ground (assuming that the front suspension has not been altered).
- There is the possibility that you will need to do it all again if the suspension angle is still not right.
If you want to do it right, there is a list of parts that will make it perfect.
- Lowered Shocks - Once you have lowered the vehicle the travel in the shock has changed. Getting the right shock means no more bottoming out because the travel is limited with the shock.
- Adjustable Shocks - Ride quality, MyFit - My fit - Your idea of soft is this and my idea is this. With an adjustable shock, your fit is available with a twist of a knob.
- Lowered Adjustable Spring Plates - When lowering your vehicle the track increase and decreases depending on the amount of drop. Your toe changes drastically as well. With Airkewld's adjustable spring plates, that is easily remedied.