There is an enormous amount of info out there about installing a set of Avis adjusters on a Beetle beam. Before I started, I did a bunch of research and found what I needed, however, it took a bunch of digging. You can think of this as my interpretation of how to do this. I am sure there are many more ways, if so, let me know!
For this project, I started with the 67’ ball joint beam that was stock from my car. My beam was in great shape and I didn’t want to replace the needle bearings with urethane, or Delrin; the stock needles are working great.
First off, I stripped the beam of everything but the needle bearings and cleaned the beam up so the main chunks of old crud were scrapped off and I could handle it without getting all nasty.
Now, here is where it got fun! My Brother-in-law, Steve, stopped by and brought along a spare beam, you know, because everyone has one for just such an occasion. We bench engineered for about 20 minutes and decided it would be easiest to cut sections out of the donor beam and use these to install the center retainers. Remember, I was worried about saving the bearings, and beating the center retainers loose with a big pipe, or rod and a sledge hammer just didn’t seem like a good thing to do to the bearings. So cut we did!
Now, the main tubes for the Beetle beam are much thinker than I thought, it’s .160” (4mm) thick and took some work to cut it. We used a sawzall and ran it nice and slow while Steve dribbled Tap-Magic (the best stuff on the planet by the way) on the cut while I sawed away. Worked great. We took about a 3” (75mm) section out of the middle of the upper tube to start with. It works really nicely to cut and install the adjusters in only one tube at a time, that way you don’t loose alignment of the tubes.
We placed the curved serrated piece of the adjuster kit on the section of tube we just extricated from the donor and scribed marks to show us where the slot would need to be made. I center-punched the end holes and drilled those out with a 5/16” (16mm ish.) drill bit.
Next I cut the rest of the slot using the sawzall method again.
Being of the "chicken" variety, I made the slot a bit narrow and I opened it up using the angle grinder.
This slot is not critical and could be made a couple of mm oversize and not hurt anything. We reinserted the center retainer and the grub screw to put any fears to rest about a good fit prior to welding. All was well.
I welded the ends of the serrated piece to the beam and cleaned everything up nicely. A little note of caution here, the center retainer fit perfectly prior to welding, however, it was too tight after welding! As you can see, we were getting really good penetration with the weld.
We needed to hone out the inside of the beam section a bit and go after the center retainers with the disk sander to remove a few thousandths for that nice happy fit.
With this completed, we cut a matching section out of the good beam. This is a bit disconcerting, but measure twice and have at it.
Since the intent of adding the adjuster for me was to lower the car, I positioned the adjusters so I would only have a little bit of additional up in the adjustment (about 1/8” from the grub screw to the stop point) from the stock position, and all the rest of the adjustment would be in the down direction. I figured if the springs ever got a bit weak and I wanted to run the car at a stock height, I could make that happen.
Once all was aligned and ready, I taped the threads of the grub screw and the slot with masking tape so no weld spatter would get where it wasn’t supposed to. I then welded the new center section in place and cleaned up the weld.
As a side note here, all the welding was done using my cheapie Century wire feed mig welder with flux core wire. Take your time and this is a very easy welding project. This is the kind of metal they give you in welding class the first day you start welding because it’s so easy to weld on.
After celebrating our success of the first beam section, we got to work on the lower beam. As you can see in the pics, this portion of the job went quite well and the second tube goes much faster than the first because you know what the heck you are doing.
Now since I am in the middle of this restoration/mod of this car, there is no way for me to tell if any of this work will perform it’s job as intended. I can’t see any reason why not, but I can’t see lots of things!
Some lessons learned along the way: The Avis adjuster kit comes with two screws. One small grub screw which looks like it is supposed to go in the center retainer and wedge into the leaf spring stack, and the longer screw that is supposed to pass through the beam and pinch the retainer to the serrated section of the kit to keep the center retainer from spinning. This doesn’t work in practice however. In order to install the small screw, the springs need to be inserted. Once you tighten this screw, it separates the leaves and opens the center retainer slit and locks it into the beam. Now, being unable to rotate the center retainer, you cannot adjust the beam. It makes no sense to install the screw and leave it loose, so I ground the 45 Deg. point onto the longer screw and that will both, wedge the leaves open, and serve as the lock screw.
The only thing I can think of here is that the small set/grub screw is just a temporary screw used to push the center section into the beam to get it aligned with the slot. If you then removed this small screw and replaced it with the longer bolt, that would make sense. However, since we made new center sections, we did not need this part.
Another thought for anyone attempting this that does not have the luxury of a helpful brother-in-law and a spare donor beam, I am thinking it would still be possible to use this method using only one beam. If you mark and cut the first cut about one inch to one side of the original beams grub screw, and the second cut about 2” to the other side of the grub screw, you can remove this “off center” section, clean it out and beat the original center retainer out with the pieces up on the bench where it is easy to work on.; Now flip this section end for end and drill and cut your slot in the nice smooth portion of the tube. When you weld it back in, just make sure it is flipped. The new center retainer will be on center and the location of the old center section which is now banged up a bit from pounding out the original center section is off center by one inch. You would need to weld up the original grub screw hole to seal the beam up nicely.
Good luck with your adjusters,
Hope this helps someone.
Camper
