How to build a narrowed adjustable Bus beam (tutorial)

[jeremyrockjock]

This is a tutorial on narrowing a bus beam with avis adjusters for both split and bay buses. The beams are so similar that there are only a few differences between the king pin and ball joint beams. However I would like to say upfront that you must plan for the type of setup you want to run. For instance I am running a ball joint narrowed beam in my 59. Ball joints weren’t standard on buses until 1968. I cut my side plates to fit the ball joint tube which are larger in diameter and further apart than the 67 earlier king pin beams. Also the mounting bolt pattern changed in 1970 so that also must be considered. I must say that this is merely how I have done it and that there are other methods that are just as correct too. There are a lot of other people here on Samba with a lot of experience in this matter and can give tips and other ways of doing this so don’t feel like you have to follow this guide to the T. I will say that I am not responsible for anyone building their own beam and that you do this at your own risk. With that said lets begin.

When I first heard of narrowing a beam I had a little experience with the bus front end. I had done a disc brake conversion on my 70 Sportsmobile and knew the anatomy of a beam and how it attached to the bus. However I was confused because I thought how in the world do you shorten the axle without cutting the frame of the bus. Someone explained that the stamped structure of the side flange is where the narrowing takes place and when I climbed under my bus to look at the beam again after so many years the light came on.
This is a model of a basic stock beam

The side flanges (the piece that bolts to the bus frame) are approximately 2 inches thick worth of stamped reinforced heavy gauge sheet metal. They are made of two halves welded together and are hollow. These will need to be cut off but you must do a few things first. General disassembly of the beam is required before you start any cutting.
Starting with the spindles, tie rods, sway bar and shocks already removed: There is a grub screw on the front of each trailing arm.

On one end of each tube loosen the jam nut (19mm or ¾" wrench) and then remove the grub screw (8mm allen wrench)

The reason I only remove one is that I use the trailing arm to remove the torsion bars later. It makes it easier than pulling on those greasy leaves.
Remove the trailing arms off the one side and keep them protected as to not damage the bearing surfaces.

Then loosen the jam nut on the back/lower center of the beam (19mm or ¾”) and remove the grub screw (8mm allen wrench).

You can then pull on the remaining trailing arms and slide the torsion leaves out. The upper one may require some persuasion due to that it still has force on it against the bump stop.

You then must remove the outer bearings. If you don’t the heat from welding will cook them. Yes even the ball joint steel ones will get cooked. I know because I made this mistake and had to replace them all. I made a puller for the roller type bearing that uses a washer and a piece of threaded rod and a piece of pipe. (I will get some specs on my puller and post then soon) It worked quite nicely. I haven’t had any luck pulling the bakelite bushing out of an early beam so I just cooked then out. (Basically burned them with a torch and they fell out)
There are a total of eight bearings in a beam but if you are careful you will not need to mess with the inner ones (Again this is how I do it)

On a ball joint beam there is a rubber seal and a cup on the end of the tubes. They will pop out with a pry bar and then you can pull out the bearings.

Remove the center steering knuckle and the steering dampener mount(not shown) and the brake booster mount bracket (71 thru 79 beams). Use a cutoff wheel to cut the welds. These will need to be saved to reinstall.

You then will need to cut the flanges off of the tubes. I have used a torch and I have used cutoff wheels. The wheels are a lot of work but do a cleaner job. Do not damage the tubes and remove all of the material from the stock flanges so that you are left with two tubes.

Here is where it gets more complicated. Depending on how much you want to narrow is how you have to calculate your cuts. I will try to explain this as simple as possible. Because you have to reinstall the adjusters in the center of the beam I didn’t want the weld to be in the center and cause the torsion retainer to bind. The torsion retainer is a small, round piece that holds the torsion bars at a fixed position in the center of the beam tube. This is what it looks like. (except they are covered in grease and arn't chrome but it sure is pretty huh)

In order to have the center weld off center you must calculate how narrow you want your beam and offset the weld by at least one inch. I wanted 4 inches narrower so I measured the overall length of the original tube. Mine was 34 ¾” so minus 4 “ is 30 ¾” Since I want the weld off center by 1” I divided 30 ¾” by 2 which makes 15 3/8” then added 1” from one side of the tube and subtract 1” from the other end. I cut the tube in half at 16 3/8” making sure not to cut through the center torsion retainer. I then cut the other end of the tube to 14 3/8”. Take these cuts from the center of the tube and not the ends. The reason I do it this way is so I don’t have to mess with the inner bearing locations. They are where they need to be in reference to the outer end of the tubes. Okay so 14 3/8” and 16 3/8” equals 30 ¾” so I have gone 4 inches total from 34 ¾” now you have to slice the center tube section to remove the torsion retainer but don’t cut too deep. Now take your large half of your avis adjusters and they will need to be modified to fit the larger bus beam. There are two ways of doing this. One way is to heat it up and flatten it out in a vise a little. Another way is to grind the outer, back edges until it sit nicely against the beam. It won’t need as much work done if your building a king pin beam because the tube OD is approx 2.30 inches and the adjusters are made for a 2 inch bug beam. The ball joint beams are approx 2.5 inches OD.

Okay so once the adjuster sits nice and flush against its intended tube you must figure out where it will sit. One thing to take into consideration is the zerk fittings(grease fitting) locations. You want them to be where you can get to then easily when the beam is all together and in the bus. I try to put them as close to the original position as possible which looking at the beam from the drivers side of the bus would be about the 4 o’clock position. This is about where the bottom of the adjuster would sit so I lay out the adjuster location. On the longer tube half I find the true center which would be 15 3/8” and I center the slot of the adjuster at that point. I then scribe the slot and the out side of the adjuster on the tube, I then cut out where the slot was on the tube without cutting outside the outer perimeter of the adjuster location.

I then side the torsion retainer in and push it in as far a possible while I weld the tubes together. I use a long piece of angle iron and clamp the tubes in the valley of the angle while I weld the tubes together to hold them inline with each other. Make sure you have good penetration on the welds. Remember the weight of the bus and YOU are on this. Once the tubes are welded grind down the weld where the adjuster will sit and slide the retainer back to the center and assemble the adjuster using a new longer grub screw (14mm x 1.5) to hold the adjuster in position while welding.

Now you need the new side flange plates if you haven’t made them already. Here is a list of options depending on what you want.
1. 55 thru 69 bus mount bolt pattern with king pin beam.
2. 55 thru 69 bus mount bolt pattern with ball joint beam.
3. 70 thru 79 bus mount bolt pattern with king pin beam ( not sure why you would want this one)
4. 70 thru 79 bus mount bolt pattern with ball joint beam.
The mount bolt pattern can be made universal simply by drilling the side flanges for both patterns.
I make my side flanges from 3/8" steel plate and use a template to cut and drill them to which ever setup I am building. Here is a set we are building out of 3/8” steel diamond plate.

You must take into consideration the mount bolts interfering with the shocks when building a 4 inch narrowed beam. This is why you see the shock towers so far back on a lot of narrowed beams. I offset my upper shock mount hole back about 2.5 inches and it clears the mount bolts. It can vary depending on how your setup is so keep it in mind when designing the side flanges. You will have to drill the shock upper bolt hole location according to your setup.
I have a jig I use when welding the tubes to the side flanges. It is a section of a 62 bus frame and it holds everything in place while I tack the tubes in position. Another good method is used your bus as a jig and after you tack weld it pull the beam back out and finish welding it. If you are running the brake booster you can align the bracket location while the beam is in the bus too. Weld everything really good.

Reinstall the steering knuckle and steering dampener mount bracket.

Reinstall the bearings. You may need to work the bore with a sanding wheel and die grinder due to warping from welding.

You then will need to cut the torsion leaves to match the new shorter length of the beam. If you went 4 inches on the beam then cut 2 inches off each end of the torsion leaves. Use a chop saw or something that can cut them all at once. You then need to make a new dimple for the grub screw on the torsion leaves.

Reinstall your trailing arms and grub screws to the right torque.

You will need to shorten your tie rods to match your beam. I took two of the adjustable tie rods and cut 2 inches off the end with the right hand threaded tie rod and retapped the tube 14mm x 1.5, slotted the end like the original and reinstalled the tie rod.

I will be fine tuning this tutorial so let me know if you need something added or need more info.
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Why buy what you can build.
Step away from the fiberglass and no one gets hurt!!

[rizzag]

jeremy, you are a freak! keep up the good work.

jeff
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flossin, tossin, dippin, and trippin

[Ryan]

Very impressive tutorials!

Thank you!
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The best things in life aren't things.

'64 Standard Bus

[rob_lewis]

Should this be a Sticky?

-Rob

[ratpanel61]

In the tutorial Jeremy mentions that the Bakelite bushings will catch fire when you cut the stock side flanges off. We found this out when we cut mine. If you do a Bakelite beam and burn the bushings, it's not a big deal. McMaster-Carr has bushings that can be used for the outer bushings in a variety of sizes. I read in another post where the guy used their 2 1/4" OD by 1 3/4" ID and said they worked pretty good. We'll actually be getting ones that are little meatier than that and machining them down so he'll show the finished product then.
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- '57 Sunroof Beetle (project)
- '73 THING

[Miroan Werks]

That's awesome Jeremy. Bring on the slammed transporters!!!

I would like to add that you can narrow the lower shock mount very easily to maintain a vertical shock position, opposed to having the top mount offset 2"-3" back.

[KamperKitJay]

just got my beam back today......here she is http://www.thesamba.com/vw/forum/album_page.php?pic_id=77802
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http://www.youtube.com/watch?v=1FUDnVrMNnM

[KamperKitJay]

just got my beam back today......here she is http://www.thesamba.com/vw/forum/album_page.php?pic_id=77802
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http://www.youtube.com/watch?v=1FUDnVrMNnM

[KamperKitJay]

just got my beam back today......here she is http://www.thesamba.com/vw/forum/album_page.php?pic_id=77802
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http://www.youtube.com/watch?v=1FUDnVrMNnM

[Autamataun420]

LOVE the Diamond Plate...Would like to see that one when its Finished...

[j.pickens]

[WesleyWesty]

Nice work Jeremy!

[jeremyrockjock]

[splitpile]

Great plans. Now my question, has anybody caculated the caster change when doing a lowered beam/dropped spindels. I have seen caster compensaters for bugs that bolt on to the lower beam mount. Narrowed, adjustable, lowered spindels are great but I would love to see a bus that steers as original when lowered. I am working on this, but is very time consuming.
Set up stock beam and ran it through it's stroke, made a templete of the travel. Next I am going to swap dropped spindels and run it through the same templete to see the change, then use and adjustable beam in lowered position and measure the stroke, then move the lower tube forward or back to see if I can compinsate for the change. Even on a ball joint beam there is not enough correction in the adjustable cones to get the caster right.
The next problem I have found with narrowed, lowered, dropped spindel buses is really bad bump steer, another problem to address.
Making parts is not really that hard, it's making them work right that is.
I remember when we lowered 356's we would have offset link pin bushings made to help with the drastic caster change
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www.BUSTORATION.com metal and more for your bus
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[jeremyrockjock]

[fastbackerdez]

very good, peice, well written and thought out i do think!!!

just one Q:- which bug avis adjusters do i need??? K+L or balljoint, or does it not matter???
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if theres a gap underneath, its not low enough.

[jeremyrockjock]

[fastbackerdez]

i thought so just wanted to check before i ordered!!

ile post some pics when i get round to doing it.
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if theres a gap underneath, its not low enough.

[holidayken]

I have a 67 splitty myself. I design suspention components for a race company so I can appriciate DIY help. I was wondering how to better the front end of my Bus. I have king P style front w/wolfGang spindles ... NOT LOW ENOUGH! I am planning on tubbing the front sheet metal to fit a set of 17" wheels any suggestions welcome I have incuded a link to the wheels I am going to use http://www.americanracing.com/images/wheels/mega/m699.jpg

[Miroan Werks]

I thought about changing the castor as well. Does anyone have measurements that will help determine the best degree of correction for a maximum drop?

Any thoughts?