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HOW TO RAISE OR LOWER YOUR REAR SUSPENSION
BY DREW VROMAN
This article will describe the procedure for adjusting rear torsion bar preload allowing the raising or lowering of the rear suspension.
WARNING: THIS PROCEDURE CAN BE EXTREMELY DANGEROUS IF ALL PRECAUTIONS ARE NOT FOLLOWED PRECISELY!!!!
The VW rear suspension is centered around the use of torsion bars (spring-like steel splined at both ends) on both the swing-axle and IRS. There is a torsion bar for each side and they are "preloaded" to help the suspension absorb road shock. By resetting the splines you can change the preload thus affecting ride-heigth.
You will need the following tools: Floor jack, 2 jack stands, 6' of tow-chain, several large and medium-sized screwdrivers, Protractor, and metric wrenches.
The first time you do this procedure it will probably take the better part of a day to complete, but with practice it can be accomplished in an hour or two.
Start off by jacking up the rear of your bug or bus and setting it on jack stands. Make sure it is secure. Remove the rear wheels and shocks. Disconnect your emergency-brake cables at the interior handle. Use a scribe, awl, or screwdriver to mark the position of the diagonal arm where it bolts to the spring-plate to assure proper realignment in the elongated spring-plate holes (the elongated holes in the spring-plate are the way in which the rear toe in/out alignment is set).
Remove the bolts holding the diagonal arm to the spring-plate. Pull out a little slack in the emergency-brake cables. Pull the wheel assembly backwards and clear of the spring-plate twisting it so that it is fully clear. Do one side at a time so you can see how the parts fit back together.
Use a length of rope to tie back the wheel assembly (you can wrap it around the end of the axle and tie it to the rear bumper). On IRS cars you may need to tie another length of rope around the lower shock mount. With everything tied back you have free access to the spring-plate.
Remove the four bolts that secure the spring-plate hub cover and remove the outer rubber bushing. WARNING: THE SPRING-PLATE IS STILL UNDER EXTREME LOAD AND CAN SLIP OFF THE STOP WITH A DANGEROUS FORCE. KEEP ARMS AND LEGS CLEAR!!!
Place a FLOOR JACK (not a bumper or screw-jack) under the end of the spring-plate. Loop a heavy-duty length of chain under the jack and secure it to the upper shock mount using the shock bolt. The chain should be snug but not tight. This will tie the jack and the car together so that the car doesn't lift off the jack stands when you jack the spring plate off of its lower stop.
Raise the spring-plate off the stop far enough to see part of the hole in the rear suspension submember. It's just in front of the raised area that is the spring plate stop. When enough of the hole is expo9sed, insert a medium-sized screwdriver under the plate and about an inch or two into the hole. The screwdriver will hang down at about a 45 degree angle.
Slowly release the jack. The screwdriver will guide the spring-plate smoothly off the stop. If the spring-plate binds on the screwdriver shaft just jack it back up a little and then release it again.
What we are trying to do here is move the spring-plate out far enough so that it is off the stop and unloaded, but still connected to the torsion bar Make sure the torsion bar stays splined to its center socket. This will allow you a point of reference (the original setting). With the spring-plate hanging down in the unloaded position, scribe a line along the top edge of the plate onto the submember.
Use your protractor to get a degree measurement of the unloaded spring-plate. Next get a degree measurement on the door sill. Figure out the difference between these two angles and you arrive at the present preload setting. Now you are ready to make the adjustment. Slowly pull the on the spring-plate to disengage the inner or outer splines (it doesn't matter which, but you must do the same splines on each side of the car and it seems like it is usually the inner splines that come loose easiest). When you feel the splines disengage, rotate the spring-plate one spline (down to raise the car, up to lower). Reengage the splines completely and center the torsion bar in the hub (you may need to hold it in position). Use your protractor to take a new degree reading. It should have changed by about 9 degrees, write down this reading so that you can get it the same on the other side. The inner splines are 9 degrees apart and the outer splines are 8.1 degrees apart, so if there is a difference from side to side in the final setting it can be compensated for by mo0ving the outer splines on one side and the inner splines on the other. The object is to get the final spring-plate degree reading equal on each side.
If you are raising the car, do not go beyond an additional 9 degrees from the original setting with stock bars as any more tends to stress them beyond their limits leading to breakage. If more preload is desired you should get heavy-duty aftermarket torsion bars.
When lowering the car is the desired outcome, you can go as far as you want, -9 degrees will lower the car 1-2 inches.
With the spring-plate set for torsion-bar pre-load that you want, put the outer bushing in place. If you're using stock bushings, make sure the word "oben" is at the top. Bolt on the spring-plate hub cover( these can be a real bear sometimes, use a punch to align the holes if necessary). Snug all four bolts, but don't tighten them.
Jack the spring-plate so that the lower edge is just above the bottom stop. Evenly tighten the cover bolts to suck the spring-plate into position. With a lot of preload (raised suspension) you will have a hard time getting everything to line up, jack the spring-plate up and down as you tighten the bolts to help with alignment. Remove the chain and jack.
Now you're ready to reassemble the wheel assembly. Untie the ropes, swing the bearing housing into position and loosely tighten the bolts connecting it to the spring-plate. Now align the bearing housing mount with the scratches you made earlier on the spring-plate and tighten the bolts securely. Reinstall the shock and repeat all procedures on the other side. Put your wheels back on and admire your handiwork!
HOW TO RAISE OR LOWER YOUR REAR SUSPENSION
BY DREW VROMAN
This article will describe the procedure for adjusting rear torsion bar preload allowing the raising or lowering of the rear suspension.
WARNING: THIS PROCEDURE CAN BE EXTREMELY DANGEROUS IF ALL PRECAUTIONS ARE NOT FOLLOWED PRECISELY!!!!
The VW rear suspension is centered around the use of torsion bars (spring-like steel splined at both ends) on both the swing-axle and IRS. There is a torsion bar for each side and they are "preloaded" to help the suspension absorb road shock. By resetting the splines you can change the preload thus affecting ride-heigth.
You will need the following tools: Floor jack, 2 jack stands, 6' of tow-chain, several large and medium-sized screwdrivers, Protractor, and metric wrenches.
The first time you do this procedure it will probably take the better part of a day to complete, but with practice it can be accomplished in an hour or two.
Start off by jacking up the rear of your bug or bus and setting it on jack stands. Make sure it is secure. Remove the rear wheels and shocks. Disconnect your emergency-brake cables at the interior handle. Use a scribe, awl, or screwdriver to mark the position of the diagonal arm where it bolts to the spring-plate to assure proper realignment in the elongated spring-plate holes (the elongated holes in the spring-plate are the way in which the rear toe in/out alignment is set).
Remove the bolts holding the diagonal arm to the spring-plate. Pull out a little slack in the emergency-brake cables. Pull the wheel assembly backwards and clear of the spring-plate twisting it so that it is fully clear. Do one side at a time so you can see how the parts fit back together.
Use a length of rope to tie back the wheel assembly (you can wrap it around the end of the axle and tie it to the rear bumper). On IRS cars you may need to tie another length of rope around the lower shock mount. With everything tied back you have free access to the spring-plate.
Remove the four bolts that secure the spring-plate hub cover and remove the outer rubber bushing. WARNING: THE SPRING-PLATE IS STILL UNDER EXTREME LOAD AND CAN SLIP OFF THE STOP WITH A DANGEROUS FORCE. KEEP ARMS AND LEGS CLEAR!!!
Place a FLOOR JACK (not a bumper or screw-jack) under the end of the spring-plate. Loop a heavy-duty length of chain under the jack and secure it to the upper shock mount using the shock bolt. The chain should be snug but not tight. This will tie the jack and the car together so that the car doesn't lift off the jack stands when you jack the spring plate off of its lower stop.
Raise the spring-plate off the stop far enough to see part of the hole in the rear suspension submember. It's just in front of the raised area that is the spring plate stop. When enough of the hole is expo9sed, insert a medium-sized screwdriver under the plate and about an inch or two into the hole. The screwdriver will hang down at about a 45 degree angle.
Slowly release the jack. The screwdriver will guide the spring-plate smoothly off the stop. If the spring-plate binds on the screwdriver shaft just jack it back up a little and then release it again.
What we are trying to do here is move the spring-plate out far enough so that it is off the stop and unloaded, but still connected to the torsion bar Make sure the torsion bar stays splined to its center socket. This will allow you a point of reference (the original setting). With the spring-plate hanging down in the unloaded position, scribe a line along the top edge of the plate onto the submember.
Use your protractor to get a degree measurement of the unloaded spring-plate. Next get a degree measurement on the door sill. Figure out the difference between these two angles and you arrive at the present preload setting. Now you are ready to make the adjustment. Slowly pull the on the spring-plate to disengage the inner or outer splines (it doesn't matter which, but you must do the same splines on each side of the car and it seems like it is usually the inner splines that come loose easiest). When you feel the splines disengage, rotate the spring-plate one spline (down to raise the car, up to lower). Reengage the splines completely and center the torsion bar in the hub (you may need to hold it in position). Use your protractor to take a new degree reading. It should have changed by about 9 degrees, write down this reading so that you can get it the same on the other side. The inner splines are 9 degrees apart and the outer splines are 8.1 degrees apart, so if there is a difference from side to side in the final setting it can be compensated for by mo0ving the outer splines on one side and the inner splines on the other. The object is to get the final spring-plate degree reading equal on each side.
If you are raising the car, do not go beyond an additional 9 degrees from the original setting with stock bars as any more tends to stress them beyond their limits leading to breakage. If more preload is desired you should get heavy-duty aftermarket torsion bars.
When lowering the car is the desired outcome, you can go as far as you want, -9 degrees will lower the car 1-2 inches.
With the spring-plate set for torsion-bar pre-load that you want, put the outer bushing in place. If you're using stock bushings, make sure the word "oben" is at the top. Bolt on the spring-plate hub cover( these can be a real bear sometimes, use a punch to align the holes if necessary). Snug all four bolts, but don't tighten them.
Jack the spring-plate so that the lower edge is just above the bottom stop. Evenly tighten the cover bolts to suck the spring-plate into position. With a lot of preload (raised suspension) you will have a hard time getting everything to line up, jack the spring-plate up and down as you tighten the bolts to help with alignment. Remove the chain and jack.
Now you're ready to reassemble the wheel assembly. Untie the ropes, swing the bearing housing into position and loosely tighten the bolts connecting it to the spring-plate. Now align the bearing housing mount with the scratches you made earlier on the spring-plate and tighten the bolts securely. Reinstall the shock and repeat all procedures on the other side. Put your wheels back on and admire your handiwork!
