Sorting is fun: front beam rebuild

It started with a low brake pedal. It ended with a complete rebuild of the front torsion beam.

The Spyder was driven, by me, for several kilometers on public roads and seemed to handle well. The brakes worked too, although the pedal went too far toward the floor for my tastes.

Bleeding more did nothing.

The kit came with several two-pound residual valves and I looked into installing these to pump up the pedal. But of course that meant also buying an assortment of M10-to-NPT adaptors that apparently don’t exist.

At some point (after parts were ordered) Carey Hines of Beck Special Edition let me in on a trade secret: the master cylinder I had in there was too small. The secret is to look for “DD” on the end of the part number cast into the body of the MC. Mine had just the one D. Not enough d’s. Not enough diameter.

The new 20.6mm bore MC came and I installed it with some considerable swearing. Then my lovely wife volunteered once again to pump the brakes while I opened and close bleeder screws all around her. After an hour or so we had a good pedal, and I endeavored to reattach the front wheels and get a move on. And then…

(Link to video of me swearing)

Turned out, the inner bushing holding the upper trailing arm on the driver’s side was gone.

This set off a three-week odyssey of parts orders, parts returns, and steep learning curvature. Also, grease. Here’s the tech:

The VW beam is two parallel steel tubes held together by gussets and the shock towers which are welded on the end. Inside them are torsion springs consisting of 10 leaves, stacked and fixed in a collar that’s held in place by a grub screw in the middle of the beam. The four L-shaped trailing arms—one upper, one lower on each side—are inserted into the ends of these tubes. The foot of each L is hollow and keyed to accept the torsion leaves, held in place by a grub screw on each end.

The outside of this L foot is round and rides on a needle bearing that’s pressed into the end of the beam tube. About five inches inside that is a bushing, also pressed in, so the very ends of the trailing arms are kept snug in their bores. Both the bearing and bushing are immersed in grease.


The inner bushings were originally bronze, fixed in a plastic (Bakelite) carrier. Later iterations were Micarta. Typically these parts lasted the life of the vehicle and then some, so there are VW hobbyists who have never encountered them.

I was such a hobbyist. And this despite having changed a beam and swapped and modified spring packs on two other cars.

With the driver’s upper trailing arm so loose in its bore I could push the top of the tire in and out two inches, I pulled the trailing arm out. Then I dragged the inside of the tube to find the inner bushing, and couldn’t find it.

So it was down to replacing that bushing. I ordered a new set of bearings and bushings and loosened the set screw in the middle of the beam so I could slide the spring pack away from the work area and gain some room.

The springs would not budge.

Pulled and pushed them, tapped and hammered them. I sprayed Liquid Wrench through the adjuster slot on the off chance some rust had formed over the decade-plus the new car had sat. Nothing would bust these springs loose.

Eventually I learned that the height adjusters Thunder Ranch uses have a second grub screw holding the torsion pack in, and it’s buried inside the housing. The trick is to remove the first grub screw, then rotate the spring pack until the second, hidden one appears in the slot!

By this time my new bronze bushings had come and I learned that their Bakelite carriers were no longer sold.

So I sent them back.

There are companies that sell urethane sleeve bushings to replace both the inner bushings and outer bearings. I considered these, but they’re more a sand rail item: Excellent for occasional use in deserts and dunes but squishier than ideal for a road car.

The other option was white Delrin.

Delrin bushings are much more durable than urethane. They are what Beck uses, ever since a half decade ago or so when the company got tired of replacing failed micarta inners. So apparently, at least for a time, the manufacturer of micarta bushings for VW beams wasn’t managing quality control very well.

Understanding this I realized there was no option but to replace the inner carriers on all four corners. I ordered the Delrin and disassembled the rest of the beam, discovering that the inner bushings were absent in all but the upper passenger side tube.

The Delrin is highly recommended but is said to require reaming with a 37 mm ream. I as fortunate to have a neighbor who runs a big machine shop; he delivered this rare and somewhat expensive tool the same afternoon.

Then it was down to pulling all the bearings and (that one) bushing out. I made a puller out of some threaded rod and washers and stuff. A piece of tubing a littler bigger than the beam diameter gave me the stand-off I needed to extract the bearings (shown here on a spare beam I dragged from the inky shadows of one corner of the shop).

The new full length upper bushings went in pretty easy. I did have to remove them to drill holes for the grease fittings.

Before inserting the lowers I drilled holes in the bottom tube and socked in a couple of sheet metal screws to act as positive stops. There are dimples already peened into the beam but I wanted more.

The inners went in with a little persuasion.

The outers popped in with the palm of my hand.

Amazingly, none required any reaming. after re-setting those buried central grub screws I greased the trailing arms and slid them in. Well, three of them. The driver’s lower needed a few whacks to get home. Once in they rotated freely with none of the slop I had before.

I re-tightened the grub screws and hung the spindles and brakes back on the car. Then wheels and test drive around the block and set up to re-check and adjust the alignment.

It wasn’t too hard to get the camber pretty close to .3 degrees negative on both sides, but for some reason the tie rods fought me on the toe-in for like two days. Eventually I got it very close to 1/8 inch and that held after a 5 kilometer drive up the way and back.

Pumped quite a bit of grease in there and I’m calling that job done.




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