Steering Boxes: VW vs. TRW; VW Teardown & Rebuild

[ataraxia]

[OKType3Tim]

Ray,

I like your idea of using the button head screw. I had considered the same issue you mentioned of the set screw falling into the inner workings. E.G. If things came loose due to vibration over time.

Finding a solution that has a 1.0 pitch would be better, since the majority of the hole is already drilled out to the proper size for tapping a M10X1.0 thread. (M10X1.5 might be a bit loose when tapped.) What are your sources and do they have a M10X1.0 solution?

As ataraxia noted, the Type 1/Type 3 steering cases lids are either magnesium alloy (early) or aluminum alloy (later). So drilling and tapping will not be as challenging as it was for you on the type 4 steering box.

Now, since the lid is 'not' steel; using a stainless steel screw would be preferable from a long term perspective of keeping the two dissimilar metals from corroding together.

ataraxis and I are both working on the shim issue. My next post will highlight the challenges with the shims
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'69 Squareback restoration
'69 Fastback restoration
'66 Type34

[OKType3Tim]

So picking up the disassembly:

I cleaned all the parts in my parts washer and remounted the main housing back on the fixture. The arrows point to a couple small nooks where it is easy to not get all the old grease out of:

Then I pulled the old seals out. They were made of the "blue colored" material, that to me indicates they were original.

I'm using a standard seal puller, available at about any tool or automotive store. Due to experience, I'm careful to pull on the seal and not dig the tip of the puller into the metal surface that holds the seal. Pull gently on one spot, move over and pull gently a 1/8 inch over, move back to the original spot. Gently, back and forth between two spots and the seal should tip out. Also, a little KROIL squirted around the edge of the seal/metal interface will help loosen the seal up from being stuck to the steel for these 50 or so years. Since I know that I can get replacement seals I didn't have to be careful about not damaging the seals.

When you get the small seal out, you look in and see the shim,

Note that this shim is forming the "Bottom" of the seal area. I.E. when the seal is installed, the shim is where the seal bottoms out at. (Which means you can't install this seal until the shim is installed.)

And the shim is backing the upper bearing race which is still in place.

_________________
'69 Squareback restoration
'69 Fastback restoration
'66 Type34

[OKType3Tim]

So how to get the shim out without destroying it (completely):

My first temptation, on a previous unit, was to do this:

DON'T DO THIS!!!

Here is what you are trying to remove:

From the outside looking in:

From the inside looking out:

Side View:

The shim is thin and has no structural strength when unsupported, so you are needing to catch the part of the shim that is in contact with the back side of the bearing race. But the bearing race has a chamfer, and the socket is going to fall right into that chamfer. First hammer blow is going to destroy the shim....all the way around, in one blow.

[Yes, there is a reason I know this.]

So.. you might be tempted to do this, BUT DON'T:

The shim is so thin, that the force of a square edged punch is going to cut right through the shim.

So I used a smaller diameter socket (10mm and 8mm 1/4" drive) with a rounded edge that I could work my way around the shim/race; and hopefully not damage the shim to much.

So after a bit of tapping: I have started to move the race, but I have also clearly created some damage to the shim. If I didn't catch the back of the race perfectly square, the socket would slide off into the middle of the shim, causing the shim material to be stretched.

You can just start to see the back edge of the race beginning the clear the notch in the housing.

All I can do is continue as best I can until the bearing and shim are out:

So how bad is the damage:

Let's see If I can fix the shim. I'll use some body work/metal work techniques. First some gentle taps (hammer and dolly) to repair some of the damage.

Then to shrink the metal that has stretched, a propane torch and quench with cold wet cloth.

I wish it was better, but it is what it is, and I think it would be serviceable if I can't find a source of shims.

Um, actually doesn't look to bad from this perspective.

With everything apart:

Clean again and then blast it completely clean. I use 40-60 grit glass beads in a small blast cabinet. Now everything has been degreased, paint and rust has been removed.

So now, on to evaluation and figuring out what I have that can be reassembled into a serviceable unit.
_________________
'69 Squareback restoration
'69 Fastback restoration
'66 Type34

[raygreenwood]

[Chochobeef]

[ataraxia]

FYI: The number of notches in the shim is supposed to indicate the thickness of the shim.

[raygreenwood]

So.....just getting this straight in my head.

So although the seal rests/bottoms on the shim...it could just as easily bottom on the bearing race. So...the shim is there....primarily to set depth in the bore of the bearing race?


Ray

[OKType3Tim]

[OKType3Tim]

Um. Strike my previous comment about VW tool 423 (which the bentley manual suggests you use). I went and remeasured. A 21.5mm drift is going to completely destroy the shim and pass right through the middle of the bearing race. The only way VW423 would work, is by turning the shim into a mini puller. Doing this by wedging the tool and shim into the id of the bearing race; thus pulling the bearing race from the housing.

In fact! If you install a bearing into a VW housing without a shim; you will have a very hard time getting it back out. The shim does in fact act as a bit of a ledge for you to tap on as I described above. Without the shim, there isn't enough of the bearing race back exposed such that you can actually get some good force onto it.
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'69 Squareback restoration
'69 Fastback restoration
'66 Type34

[OKType3Tim]

Here is something to comment on regarding the search for shims:

How critical is it to have the exact same 7 shims that VW originally used?
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'69 Squareback restoration
'69 Fastback restoration
'66 Type34

[raygreenwood]

The one good thing about these shims....is that they are just shims.....spacers. They just need to be uniform. So they are not being used as precision ground flat thrust shims like would run against the balls of the bearing....right?

So assuming that Vw was anal and that .25mm means .25mm...and not its closest inch size....then you can just buy unhardened shims of the neareat thickness higher and lap them to exact thickness on a sheet of glass. Ray

[OKType3Tim]

Correct, they are just spacers used to shift the center point of the worm shaft. This shift is part of the adjustment to make sure that the "free of play range" between the worm and roller, extends equally from turning left, to turning right.

And correct, they do not run against the balls of the bearing.

Pretty sure that they didn't use inch equivalents. But I also think that the thicknesses spec could have been +-.01 mm. My example is that I have a shim that I extracted with practically no damage. It is marked/notched to be a .30 mm shim. But it actually measures .31 mm.

So... maybe US measurement shims are close enough. No lapping required.

And
What if you made the adjustments using a "6-Shim" US set; instead of a "7-Shim" metric set?
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'69 Squareback restoration
'69 Fastback restoration
'66 Type34

[KTPhil]

You only use one shim, right? So it doesn't matter if you throw away 5 or 6 extra shims.

[OKType3Tim]

Correct, you only use 1 shim.

But it does affect the cost of producing a shim packet.
_________________
'69 Squareback restoration
'69 Fastback restoration
'66 Type34

[air-h2o-air]

while this is all great info..isnt the most common wear item the worm gear in the straight ahead position? It gets hammered flat which renders it useless?

[ataraxia]

[OKType3Tim]

[KTPhil]

[OKType3Tim]

EVALUATION:

I set down with some measuring tools to evaluate the 6 units that I've torn down. I didn't use the electronic calipers much as they tend to have me "Over Measuring", looking for accuracy that isn't actually there.

The parts have been cleaned and sorted:

I obtained these from various sources, so some had steering worm flanges, but not all:

Some had drop arms, but not all:

There are 3 late model drop arms, 1 early model drop arm. Here are the differences; late on the left, early on the right:

Note the markings on the base, "311" vs. "311A"

The main components laid out:

Left to Right:

Note the slight difference in the shape of the main housing casting between the 3 different sources. I think that the markings of "+GF+S" vs. "+W&E" could indicated different OE manufacturers contracted by VW. Maybe someone can provide enlightenment on this regarding whether it means subcontractors, divisions, labor unions, or something else. In any case, the "+GS+F" units come with clearly marked casting dates. (although someone messed up at the foundry and put a year of "19" in the mold on January 22nd.

And, so here are the measurements:

There has been discussion and concern about how to know if the bushings are good or bad. From this sample, I think the spec on the main housing bushing was an I.D. of 23.85 mm. And none of these units show any appreciable wear on this bushing.

I think the spec on the bushing in the cover lid was 23.9 mm. As noted, wear of +.2 will be enough that you can physically detect the side-to-side play of the shaft in the bushing

The spec on both the top and lower bearing surface of the roller shaft appears to be 23.48 mm. (Although the shaft in unit#1 appears to have made it through QA with a bit of out-of-roundness.

And, as noted in a post above, the real wear point is the roller needle bearing, and the roller surface and worm surface interface. This wear dependent on getting the proper "play" set on
1st: the Steering Worm [where the ball bearings are],
2nd: on the top adjusting screw for the roller worm interface,
and 3rd: the axial play on the roller (needle bearing).

.
.
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AH yes grasshopper--that is what the Bentley manual says!
_________________
'69 Squareback restoration
'69 Fastback restoration
'66 Type34