Another article about torsion bar adjustment

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Another article about torsion bar adjustment

Postby Larry Jowdy » Fri Feb 05, 2010 5:21 pm

Note, although this article is about Baja Bugs, it's applicable to a Spyder with torsion bars in the rear.

The rear of a baja is suspended by two torsion bars. Think of a solid bar of spring metal. Twist it, and it twists back with spring force. Torsion, you see.

The torsion bars on a baja are splined on both ends. Lucky for me, Hot VW's magazine printed an article in the February '97 issue, and they tell me it's 40 splines on the inside, 44 on the outside. This converts to 9 degrees per spline inside, 8.18 degrees per spline outside. Street VW folks will use them in combination - turn two splines down inside, two splines up outside, lose 1.6 degrees. My point of view is simpler - gain a spline on either end, as long as it's even on both sides, and your baja will ride like a skateboard.

All this torsion is controlled by a couple of torsion bar stops. Do Not Mess With The Stops! I'll say it now, and I'll say it again in this writeup - we're messing with a whole lotta torsion here! Several hundred pounds per side. Causes major hurt. For awhile, after turning the rear torsion bars, your baja will ride like a skateboard, and hardly ever come off of the stops anyway, just from one tooth. After awhile, you'll beat your torsion bars into a more forgiving state, but don't worry too much about sagging, due simply to the major amount of torsional force we're playing with.

The torsion arm stops are positioned in a fair location, but let it be known: Adding lift is hard on CV joints (IRS) and causes the rear tires to camber in in a rude way (swingaxle rear end). For IRS, look in to either bus CV joints, or Transform shot-peened CV's. Much stronger. For swingaxle, there's this device out there to keep your torsion bar from flexing (twisting), thus limiting the camber problem, but be prepared for increased tire wear. If you're using bias ply tires, you can have 'em dismounted and switched periodically to wear the outside edges twice as long. You can't reverse the direction on steel- belted radials, 'cuz it spins the belts the wrong way and has been known to cause tread separation.


What you'll Need:

- floor jack, preferably not one of those little guys. If it's a little one, provide a stack of short 2x4's. I understand that there's a tool to grab & compress your torsion arm. Latest Rage offers 'em for sale for about $30 - check their ad in Hot VW's or call them at 562-404-5001. Allow several weeks for delivery and hope for the best - latest rage has some people pretty upset at 'em.

- Jack stand (I really mean it)

- a few feet of chain (and I don't mean that wimpy chain - Welded Links!)

- Pickle Fork or other suitable increasing-width tool. Large screwdrivers work, but not nearly as well as pickle forks

- Ruler

- Urethane bushings, both inside and outside varieties

- BFH (Big Friendly Hammer, friends)


Stand one rear corner of the car on the jack stand. Note the position of the jackstand's lift setting - you'll want it to be the same for both sides of the baja. Remove a rear tire. Unbolt the torsion bar from the swingarm or trailing arm.

On the front of the torsion arm, there's this cap-looking thing that holds the torsion bar into the car. Torsion cap? I think. Unbolt it.

If you went through the trouble to find a torsion tool, that gadget to grab & compress torsion arms, use it here to contain the torsion arm. Using the pickle fork, work the torsion arm off of the stop. Prepare for a major release of tension! If your leg is in the way, it will probably be broken - if you plan on putting body parts in the way of the torsion arm here, call an ambulance now.

Measure the distance from the ground to the bottom of the torsion arm in its released state. More details later.

Pull the torsion arm & torsion bar - preferably in one piece (remove the torsion bar from the inside). Not a big deal if the torsion arm comes off of the bar first - but it'll save trouble if you can remove 'em both at the same time.

Install the new inside urethane bushing now. Lube the holy !!!! out of the new urethane bushings! It's a common problem to get rude squeaking later on, so do everything you can to avoid it now. Some bushings come with this little tube of superlube, just for this occasion.

Difficult part #1: Re-insert the torsion arm & bar, just enough to grab teeth. Use the ruler and re-align its position to the same measure you got when you removed it. Now, pull the torsion bar ever so gently, and move the torsion arm down one tooth. When this is accomplished, you can Seat the torsion arm & bar like you mean business.

Difficult part #2: Again, if you acquired a torsion tool, use it here. Otherwise, place the floor jack under the end of the torsion arm. Chain the car to the front axle of the floor jack (tight). If using the wimpy little floor jack, build a STABLE pile of 2 x 4's under the jack - you'll probably need the extra travel. If you use a bolt to connect the chain, use a good bolt - if this puppy gets loose, you'll have a whole lotta torsion arm slapping and baja falling and chain whipping, among other unfortunate occurances!

Jack the torsion bar up high enough to clear the stop. Hammer the torsion bar in farther, until the torsion bar is COMPLETELY on the stop. Release the jack, but again - use caution. That torsion arm can cause a whole lot of hurtin'. Install the outside bushing, and bolt on the torsion cap. Careful not to strip any bolts - for some reason the new bushings make this difficult!

Finally, reassemble the swingaxle/swingarm (torque them nuts on HARD). On my IRS setup, I had a heck of a time with this step, 'cuz the swingarm didn't want to clear the torsion bar, either above or below! I had to remove the swingarm, and reassemble from there. I hope you don't have to do this - remove the rubber bump stop if you have to, but have your giant allen wrench handy. And by the way - if you do have to remove the swingarm, consider having new bushings & inserts pressed in while the durn thing is out!

Install the rear wheel, and do the same treatment to the other side. Be Sure To Keep Both Sides Even! If one side is sagging a bit more than the other, consider new torsion bars - adjusting for it is tricky & is more likely to make your suspension crooked than it is to even it out. It's been done, using inner- and outer-splines in combination for an extra degree, but don't get too happy
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