Replace Steering Box

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Replace Steering Box

Postby albaran » Mon Apr 23, 2018 6:57 am

When I built the car years ago, I used an old VW steering box. I cut an access hole to enable the adjustment screw on top of the box. I can't get any more adjustment and the play in the wheel is excessive , so I want to replace the box. It seems the replacement box everyone sells is a TRW unit. I guess I have to move the gas tank out to get to the steering column and tie rod ends. Then I guess I have to remove the drop arm and reinstall it on the new box.
If anyone has gone through this, maybe they could comment.
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Re: Replace Steering Box

Postby EEricson » Mon Apr 23, 2018 5:09 pm

Should be accessible from underneath though. I'd put it up on the rack, loosen the pittman arm, loosen the steering box (metal tabs on the nuts), then look at the coupler. Might be gettable from under there too.

If not, yeah, through the top; the gas tank is in the way, so four bolts.

Assuming you've checked them and they're good, I'd try to leave all the tie rods & such alone. Just twist the new box up in there, screw it in loose, line up the pittman arm again and then tighten it all up, making sure it's still in a straight line to the steering shaft.

OK so here's me being the guy who doesn't actually know anything but who heard something: Don't fool with the new steering box adjustments.

Years ago I came across a guy who rebuilds these boxes all day, every day. Says a lot of VW people think it's good to screw with that center adjuster on top to "take the play out" and they end up ruining the box, because setting that adjustment is not for beginners. You get a nice tight steering wheel for a bit, and you wear out the center of your worm gear with too much lash. Something like that.

Bob Hoover had a similar rap. https://groups.google.com/forum/?hl=en# ... KpmTCCzUgJ

"Your steering gets sloppy because of accumulated wear, mostly in the
steering gearbox. See that little adjusting screw on the steering box?
LEAVE IT THE HELL ALONE. That governs engagement of the roller
with the worm and odds are, it's okay.

"Most of the slop in your steering gear is due to wear on the shim at the
upper end of the worm gear and is adjusted by loosening the large lock-
ring on the bottom of the steering gear box then turning the deep multi-
point socket-type adjusting nut. Odds are, you don't have the wrench for
the locking ring nor the socket for the adjuster. But you can make both
of them."

etc...
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Re: Replace Steering Box

Postby albaran » Tue Apr 24, 2018 6:13 am

thanks for the info.
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Re: Replace Steering Box

Postby albaran » Thu May 10, 2018 5:46 am

Just finished replacing the old steering box with the new TRW unit. What a difference! I never realized how bad the play was until I did this. The play now is minimal as it should be. A few points to comment on:
The job is definitely easier with the gas tank out.
I took this opportunity to replace the red urethane coupler that everyone says is dangerous with one of those German rubber ones that has the reinforcing thread running through it.
The old coupler that was on the steering box got mangled in the attempt to take it off the old box so I got one of those new chrome ones. That was also extremely tight so I opened up the hole with a 41/64th drill and that allowed it to slide onto the new shaft without beating on it.
The Pittman arm did come off easily but was very difficult to align on the new box. I did end up taking one of the tie rods off and that made it easier. I used one of those Harbor Freight ball joint removal tools that didn't damage the boots.
There is always something to do on these cars.
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Re: Replace Steering Box

Postby DannyP » Thu May 10, 2018 4:40 pm

My new car has a TRW box in it. After 1000 miles, it had a little over an inch of play in the wheel at center.

If you're going to adjust the box, you'll need a few things. You'll need a 41 mm open-end wrench for the big nut, I found one for $18 on Amazon.
Then you'll need a 12-point(or 6-point) kind of like trans drain plug(only a LOT bigger) to adjust the worm lash. I made one from a 15/16" nut(close enough to 24mm) and a piece of flat steel 1" x 1/8" x about ten inches. You could cut the top and bottom off an old oil pressure switch and use that instead of the nut. Pictures on Samba of what people have done as far as tools.

I used the Bentley manual procedure. I ended up tightening the adjuster less than 1/8 turn and it took some of the play out.

Then I moved on to the top adjuster, for that you'll need a 17mm box and a right angle screwdriver. That went in at least a half turn and took away almost all play with no binding anywhere from lock to lock. Much better driving experience. When you do this, if it's too tight your wheel won't self-return. The road test is crucial and you may have to do the adjustment more than once.

Glad you got yours swapped Al, it doesn't look fun.....
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Re: Replace Steering Box

Postby egrant5329 » Fri May 11, 2018 3:54 am

The steering is another area that I am surprised the spyder manufactures haven't addressed. I would have thought the first priority would be to fix the cars to run modern sized tires so there are no rubbing/clearance issues followed by moving to a rack and pinion steering setup. We don't have the dunebuggy scene in NH, but don't a lot of those run R&P setups?
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Re: Replace Steering Box

Postby albaran » Fri May 11, 2018 4:37 am

Danny, Thanks for the reply. You will notice in the picture that I made the adjustments accessible from the top. While I did the swap, I made that opening even bigger by taking more off the bottom. Now, if I have to make the adjustments you describe, all tools will fit from the top.
Are you planning to be at the Porsche corral at Lime Rock this Memorial day weekend?
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Re: Replace Steering Box

Postby DannyP » Fri May 11, 2018 12:37 pm

No Al, we usually do the Vintage Festival on Labor Day weekend(Saturday). See you there maybe?

Next weekend we'll be in Carlisle(17-20).

I like your access panel. Greg's new body allows a little more room above the steering box than the old mold did.

Ed, you are right. Maybe somebody will modernize the Spyder some day. SE/Beck is doing a mid or rear engine coupe or Speedster with full tubular frame, rack and pinion, and coilovers and A-arms in front. Rear is semi-trailing arms. It looks great. Ready for prime-time next year.
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Re: Replace Steering Box

Postby egrant5329 » Fri May 11, 2018 1:05 pm

I love my spyder, but a 356 (especially a coupe) would be much more practical in NH. I have always liked the look of the coupes. If they weren't in the $45K+ range I would probably be ordering one and send my spyder to Canada since it is a 1986.
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Re: Replace Steering Box

Postby sjgharib » Wed May 16, 2018 11:21 am

I designed and built a custom rack & pinion steering setup for my car. It works really well - quite happy with the way it feels.
See attached presentation. It's hard to see once it's in the car, i wish i had taken pictures as i did it.

Long story short - combining a rack and pinion with the trailing arm front suspension is a tricky business - you have to carefully place the rack at a location that doesn't induce a lot of bump steer or toe-out during braking.

I modeled the dynamic components in 3D CAD and measured the bump steer along the suspension travel. Then I chose a location that basically made it toe-in slightly under heavy braking. Then I had to fabricate and weld in the new mounting system in the right place to hold it correctly.

The other trick was finding a manual rack where the linkages came out of the middle (sort of like a super beetle rack, but you cant use that because it's a front steer rack and it would be backwards). Mine came from a 1980's chevy, but I had to heavily modify it to make it work.

Finally I had to fabricate custom tie rods and a steering shaft with some U-joints to get it all to line up properly. Since I follow Carroll Smith's rules, I never trust any welded components in the steering path, so the shafts are splined and pinned, and the tie rods threaded ends are welded and then taper pinned.

It was a big job, but the result is excellent steering response and a rock solid feel, even under hard braking...

Simon
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Re: Replace Steering Box

Postby Larry Jowdy » Wed May 16, 2018 2:26 pm

Good work on the rack and pinion Many years ago when I ran VW front ends on my sand rails, (really old days LOL) I had a friend who owned a Foreign car dismantling yard. He let me rummage around looking for various parts. I found a Rack & Pinion from a 911 Porsche and he sold it to me for $5.00. I was able to use that R/P for my sand rail with just a little bit of modification. Today I have "A" arms on the front of my long travel car and it has a power rack and pinion steering unit.
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