Camber Compensator Installation Issue

OK, I have bump steer! White knuckle bump steer! My car is a 2003 VS Widebody and I greased the front torsion tubes, replaced the steering damper and added a front, anti-sway bar. While these things helped the car still tends to dart around and when driving over 65mph it seems to have a mind of its' own and even tries to change lanes without my input. I just purchased a rear, camber compensator because in reading this forum several folks have mentioned that it helped with their steering issues. The problem is that there are some sort of mounts directly in the locations that the compensator pads go and I can't install the spring. See photos. Does anyone have any idea what these mounts are for and what I need to do to install the compensator? Do I torch the mounts or what?

Thanks, Rich

Presumably your car is lowered to the point that the tie rods are no longer horizontal. Have you flipped the tie rod ends and mounted from the bottom? There is a kit to reverse the taper to do this and will help with bump steer.

The car is not lowered. Any iedas on the camber compensator?

Rick, I had similar issues in the beginning that turned out to be related to caster adjustment. In my case it was caused by me asking Carey to raise the rear of the car to avoid dragging the exhaust on my driveway. That was enough to negate the caster that was built into the front end geometry, and it made the car a bit scary sometimes. Luckily it was easily fixed by bringing the rear end back down. If you car is level, you might want to look into caster shims.

Those mounts are for a "Z bar" which is basically a rear mounted sway bar.

This shows it:

http://books.google.com/books?id=rWTbIiTcRk8C&pg=PA19&lpg=PA19&dq=vw+beetle+z+bar&source=bl&ots=5aKFztlqke&sig=WA2jniyY0Ub7OWYSl5QnqE0BkYw&hl=en&ei=ZP-LSrDDLsLOlAe3vui7CA&sa=X&oi=book_result&ct=result&resnum=5#v=onepage&q=vw%20beetle%20z%20bar&f=false

What you're describing is not "bump steer"

Bump steer occurs when your suspension moves up and down. When that happens, the tire steers in a direction other than where it was originally pointed. Proper front end geometery, caster, camber and toe in play a huge part in controlling bump steer.

As Lane pointed out, I'd start with some caster shims.
What you have described sounds more like an alignment issue so, start and a good alignment and shoot for at least 1/2 degree of negative camber, 3 to 4 degree's of caster and 1/8" toe in (1/16" per tire for a total of 1/8".

I had both the front and rear ends alligned two weeks ago. I don't have the print out with me but the line up shop assures me that both the front and rear are where they need to be. What effect will caster shims have if the allgnment is correct as is?

Rich

Jeff/Anyone,

Do you think the fact that my swing arm originally had a Z-bar that was deleted during construction of the VS could cause the darting my car is experiencing? Would you recommend adding back the Z-bar or could I simply cut off the mounts and install the camber compensator?

Rich

Those tabs I do not see on my '66 Ghia swing axle nor do I see it in a picture in the Chilton manual. Could it have been added (tacked on). My Speedster is IRS.

As far as the car jumping around in the front you need to check (you say alignment was done), toe (I have my tires pointed inwards a tad), loose wheel bearings (this greatly makes the car dance around) or bad bearings. Bad suspension in the front or no suspension in the front. Before the shock comes into play are you sure that the leaves in the beam are creating the proper torsion in the upper and lower arms? Frozen leaves from lack of grease is common and it's easier to change the beam.

Also check for loose bits in the steering. I had a veeeeery slightly loose pinch nut on the pitman arm that allowed just enough movement of the arm on the steering box shaft that it felt weird. You really need to make that one TIGHT. Leon Chupp recommend a two-foot pry bar attached to the wrench.

Bump steer is inherent in the VW/Porsche front suspension design. All one can do is minimize by arranging ride height etc so that the tie rods are horizontal (preferably with simulated normal load). The short rod is the most critical. Work it out by simulating the geometry and seeing what happens when a wheel goes up or down.

Also, of course, full careful alignment (again with simulated normal load) is vv important. Lokely a touch of extra caster is a good idea.

StanS, Binghamton, NY

Appears from Jeff's linked article that the Z bar was a one year thing - guess you got "lucky". Sure looks like it will be a pain to grind it off.

I don't believe you can add a Z bar because it utilized a part of the original steel body as an attachment/pivot point. The fiberglass body of your VS would never handle that stress. So if you want to install the camber compensator you will have to carefully remove those mounts.

I agree with others about the caster shims though.

For $15.00 (shims and bolts here: http://www2.cip1.com/ProductDetails.asp?ProductCode=ACC%2DC10%2D4190 )

and maybe 1 hours work you would have a pretty cheap fix. They are super easy to install.

In all likelihood I think some extra caster will help out alot in regards to the darting issue.

The camber compensator is still a great addition though.

The Z-Bar was only 1967. Actually its not that bad, because it came with softer front torsion leafs.

Mike,

To clarify, the car is not jumping around in front, it tends to dart. By this I mean that moving down a straight road at say 65 mph the car swerves to the left or right. It is easily compensated for but is rather surprising if you are not paying attention. I just replaced the front bearings and races when doing a brake job and the tubes were greased at the same time. I have also installed an anti-sway bar. The mounts/tabs appear to be factory and not added on.

Rich

Larry Jowdy's post near the top has good numbers in it. It really does sound like caster.

Jeff,

Are caster shims to allow additional caster over what is normally avaialable? My front end tech has 40 years of experience and he assures me that both front and rear are set properly. Does anyone know what the desired caster, camber and toe settings are for the VS?

I just spoke with the line up shop and he gave me the following information: Caster is at 6 deg Right, 5.5 deg Left, 1/32" toe in and 1/8 deg negative camber. None of this means anything to me but it might to you.

Rich

Lane,

Will caster shims give me more or less caster? I have 6 deg R and 5.5 deg L now.

How was your rear raised and lowered? I am not the original owner of this car and while it looks level to me, it may have been raised slightly from it's original stance.

Rich

Dude this is all over the place......

I'd better let Larry or someone else step in, because I'm not an expert. That sounds like plenty of caster to me. Adding shims gives you more caster.

The rear of my car is lowered or raised by adjusting the screws on the spring plates. It's a very easy 5-minute change, but ONLY if you have adjustable spring plates. Otherwise it's a bitch.

Mike,
Not sure I understand what you mean by all over the place. I started this topic looking for information on the swing arm/camber compensator installation as this was one of the possibilities that may be contributing to the darting issue. I will remove the Z-bar tabs and install the camber compensator so this issue is closed.

However, in one of the responses it was stated that the darting could be due to caster settings.

Rich

Where are you located? If you're in SoCal I'd recommend taking the car by VS and asking them for advice. I've heard nothing but good about Kirk and Mary Duncan, so I'm sure they'd help. I'm beginning to think you need a professional. Your car, I mean ;-)

rich - caster shims give you more caster. at 6 degrees - you already have too much. it's be stable at highway speeds, but a bear in parking lots.

I have a silly question. How about an alignment all the way around before worrying a lot about camber compensators and the like? It sounds like you have toe out rather than toe in, and that can be either front or rear, or both. And,some alignment shops do not really know to align one of these little beasts. And they may tell you it is aligned and it is not. Don't ask how I know this but I do. Doing a "string alignment" could pretty quickly tell you if you are in the ballpark. Alignment should be made with you (or you equilivant weight) in the drivers seat? Just food for thought..... and oops, regarding camber, you said caster? Camber needs to be "right", standard VW camber adjusters may not give you enough range to adjust to slightly positive camber on both sides. Caster is set with shims, most of our cars need at least one on each side (assuming the car is lowered from stock, and who's is not?)

Rich, Check to see if there any caster shims on your car. Like said above you need a caster shim on each side. The difference will amaze you.

~WB

Wow, I'm amazed at all of the help and I do appreciate it! Let's take these in the order received.

Lane-I'm in Portland, Oregon so stopping by VS is not an option.

Jim-As stated earlier I just had a full alignment front and rear a couple of weeks ago. Toe in 1/32"
"

Paul-If I already have 6 degres of caster, how would I go about reducing it?

Wild Bill- If I already have 6 degrees of caster, how would more help?
Rich

My comment and question.... if you had an alignment by a specialist and you are concerned that you may have too much caster....are we close to realizing what the problem is???? Not trying to be negative but this is like 24 posts and points to.............alignment.

I don't mind.... but hey!

Mike,

I think you are reading things into my responses that aren't there. It isn't that I'm concerned about having too much caster. It's that it has been mentioned that I need to increase it. I merely asked what the benefit of adding more caster would be if I already have 6 degrees and the consensus is that 3-4 is ideal. I am concerned about the way the car drives and was just asking those with more knowledge than myself for help. I wasn't aware that there was a limit on the number of questions that could be asked to get to a resolution. Just saying.

Rich

Rich - From your photos it doesn't appear your car has been lowered - don't see any adjusters. Dropped spindles don't negativeley impact handling like severe dropping with adjusters would. Could it be as simple as maybe your running too much air in your tires? Or add a couple of bags of sand to the front trunk for weight.

Wolfgang,

When I got the car it was running 35 psi front and rear and had a very harsh ride. After reading some posts in the SO.com, I reduced the pressures to 20 psi front and 22 psi rear. Sand bags in the trunk...hadn't thought of that but I'm not opposed if it will cure the darting. I'll pick up a couple of bags at the hardware store and give it a try.

Thanks, Rich

Rich, His numbers may or must be wrong. If your car feels like the front end is light and is hard to keep on the road at speed, you need to try a set of shims. They are cheap and easy to put in. If you do, you may need to replace the bottom beam bolts with the longer ones available, so buy two along with the shims. Hey, it's worth a try. If it don't work, pull'em back out.(and re-sell them here)
Also, do a nut and bolt check on everything on the front end, particularly the bolt that secures the pitman arm to the steering box. That one has to be really tight.

~WB

Wild Bill,

I just got done cutting off the Z-bar tabs and mounting the camber compensator. I also did a nut and bolt check of the front end and found the nut on the pitman arm a bit loose. I got about 4 flats of turn on it. I also found the pinch bolts holding the steering box to the upper torsion tube loose and tightened them as well. After dinner I'll take it for a drive and report back.

Thanks, Rich

Looking at the pics I think I see one Avis style adjuster up top. Not sure if that is how VS does their lowering.

Also, in some of your pictures it looks like I might see the silver glimmer of a caster shim....but then in another picture it looks pretty flat. Then again the lower part of the beam does look a little tilted out at the bottom.

Rich, I think what people are telling you is that, via experience, these cars benefit greatly from caster shims....regardless of what the alignment reads. Maybe its not logical, maybe its tough to understand....but it is true.

Now possibly....and I repeat possibly....you might already have them on there and maybe....just maybe...you have too much caster (as indicated by your alignment report).

So what to do?

I would see if you have them on your lower beam. If you do...take them out and drive it. Better? All done. Worse? Put them back in.

Just one man's opinion.

YOU DON'T NEED ANY SILLY SAND BAGS - YOU HAVE AN ALIGNMENT PROBLEM!!!!!!!

Caster wedges were used by VW for over 40 years because their assembly process (believe it or not) was imprecise. The wedges were used behind the torsion tubes (both top and bottom) to correct alignment problems and were (are) very common.

YOUR problem is, believe it or not, quite common but there aren't very many alignment "specialists" who have been around long enough to know how to properly align a 40-year-old VW, let alone a Speedster based on a 40-year-old pan.

YES, Your car has been lowered from original VW Sedan stock height. If it hadn't been lowered your body would be about a foot off the ground and Kirk would never have shipped it.

YES, you have a very common problem, which is that the car wanders unpredictably due to road surface variations or even cross winds. YOU PROBABLY DO NOT HAVE BUMP STEER. You just have too little caster.

Every VW pan is different as to the amount of total caster it will need (because all pans are different) but YOUR car will need somewhere between 1.5 and 3 degrees ADDITIONAL CASTER OVER A STOCK VW SEDAN. I don't care what your alignment "expert" says, your car will need it (and so says several other people on here). Otherwise, it will continue to wander, especially at speeds over 65mph.

Caster Wedges (they look like curved metal pieces cut lengthwise from a pipe) usually come in two thicknesses: about 1.5 degrees and about 3 degrees. I suspect that you will need at least a 1.5 degree one in there on both sides to cure your wandering, but you need to know what the current total caster is on the front end and on both sides in order to know what to install for shims, otherwise you're shooting in the dark.

Assuming that your alignment guy knows what he or she is doing (something I wonder about) go back and either get your alignment data sheet or have them check it again and make sure it is set to a stock, 1970 VW Beetle sedan spec. If the caster is set to stock (or off of stock), then find out what the caster is on both front wheels and compare it to stock settings. You need to have AT LEAST 1.5 degrees more caster on both front wheels than stock. Maybe even as much as 3 degrees per side to cure it.

Once you know where it is now, he/she will then need to loosen both lower front beam bolts (he will undoubtedly not know about this process), pry the lower torsion tube away from the mount enough to slide one 1.5 degree shim between the torsion tube and the frame head mount on both sides. You will need one or more on each side, depending on what the original caster setting is. If you need more than one on a side, you'll need longer mounting bolts (100mm long, 12mm by 1.5 pitch, available from cip1 or your local ACE hardware store). Doing that should bring your total front end caster to 1.5-3 degrees more than stock AND cure your wandering problem.

Honest.

gn

Oh....and if you don't believe Larry and me, then go to Gene Berg's site and see what he says about caster shims: http://www.geneberg.com/cat.php?cPath=12_384_2917

And that camber compensator won't help your problem AT ALL.

POST EDIT: Saw your comment on the loose pitman arm nut. THAT can give you a wandering problem as well, just as you described. If tightening that cures it, then you're all set. If not, then check out the caster shims.

gn

Gordon,

Tightening the pitman nut seemed to help a bit but it still darts at speeds above 65 mph. I took a look and I do have caster shims. They are about 1/4" thick so per Mr. Berg's article, I must have the 2.36 degree shims. I'll take the car back to the line up shop and have them verify the total caster and adjust from there.

Thanks Everyone for your help. I'll post once I add/remove shims and see the result.

Rich

Gordon---that last post of yours was another "keeper" ---thanks and keep 'em coming!

How the hell do you know this stuff??---Jack

in berg's article he talks about bent frame horn. what is this and can it be corrected with different size, shims on each side, this is the caster problem iam having. bill

Rich, is your alignment guy a crusty old sort who does it the old fashioned way and who is used by all the local street rodders? If not, find one like that. The modern shops really aren't very familiar with Beetle suspensions, and depend on their computers. If it's not in the computer, you can't be sure that they knew what they were doing.

Bill:

Having unequal caster needs isn't a big deal - in fact it is also common. It's well neigh impossible to weld together a VW Pan with it's 150-200 separate parts and get it dead straight every time, and frames and suspension can take a beating over time on the road so VW designers took the logical way out - they allowed for adjustment post production.

Camber is easy - you just turn a big nut on the upper ball joints to adjust (although speedsters often need more adjustment, as Jack found out) and so Caster is easy, too, but you have to mechanically move the relationship of the top and bottom torsion tubes and, in turn, the angle of the vertical centerline of the trailing arms/spindle to get the correct geometry on the spindle/wheel to make it drive right.

It's been decades, but if I remember right you need to shim link-pin spindles to change camber, only the shims are, of course, smaller. It was enough of a PITA that VW went to ball joints in 1967 or so (and finally got rid of swing-arm rear ends in 1969, improving handling a LOT).

None of this is news - people have known about trailing arm steering geometry since the 1920's or so when it was first used (and then raced).

Still, it's not unusual to have different caster shims on each side. For instance, Pearl has an additional 3 degrees on the right, and nothing added to the left to get them equal, more than stock and feel right. Her difference is probably due to the doofus who built her (me). I've had her aligned three times - the first two guys told me that caster was not adjustable on VW front ends so I straightened them out (although they both had cool print-outs of the results). The last time I did it myself in Beaufort (a car club member runs a body shop with a laser alignment deck) and got it right on, except that I needed more camber adjustment than one side allowed so Jack got me a pair of "extra wide" adjusters that will go in when I get a chance.

On the frame horns, those are the two, big, tapered tubes at the rear of the pan which accept the transmission mounts amidship of the transmission. If the car has been hit on or near a rear wheel of if it's been jacked up repeatedly on the end of one horn, or the horn simply rusts or rots out, the horn can become bent which will throw off the suspension geometry and may require something different on the front end alignment to compensate.

BTW: Some VW drag cars that have been modified a lot in the suspension may require a LOT of added caster (and strange or "different" toe-in settings) to get them to stay on the track the way the driver wants it.

That's it.....I'm going back to working on the "new" old, rotted out pan, which is slowly becoming new again!

gn

Oh, and Jack - I learned this stuff the same way Larry did and my son, Chris, too; Get in there and do things, making mistakes and learning along the way. And also as a way to escape working 80 hour weeks in high tech. Nothing better after a day of high stress than to go home and beat on some metal, rather than beating on co-workers... ;>)

ciao

Thanks Gordon, great post's,,, but,,, I really don't know anything, I just make this stuff up as I go....