Steering Box Overhaul

John Vardanian · Post by **John Vardanian** » Mon Jun 14, 2004 3:48 pm

Has anyone rebuilt a 50's or 60's steering box? Does the worm gear have a center position? If so, is it marked? If not how does one find it?

In other words, when the wheels are pointing straight forward, does the worm gear need to be is a certain position?

Thanks.

john

fest · Post by **fest** » Mon Jun 14, 2004 10:50 pm

steering box on my car is a ZF and
workshop manual contains this info:

Steering Box Alignment Marks

Steering Arm Alignment Marks

if earlier boxes are also ZF, maybe the same?

(apology for crappy pics, camera pissin me off)

John Vardanian · Post by **John Vardanian** » Mon Jun 14, 2004 11:31 pm

AKB,

Thank you. The old boxes are also ZF, but they look a little different from yours. I'm sure the workings are the same. Looks like I'll have to take mine apart again, as I don't think the allignment are right.

john

oldfart3 · Post by **oldfart3** » Tue Jun 15, 2004 7:50 am

One of the first things I did on my Lusso was overhaul the steering box. It leaked furiously, as the seals had acquired the consistency of the plastic that was used to make the old telephone handsets, and it had a lot of play around center.

It's a worm and pin design, which can wear. It's pretty tedious to relap, but can be done with care and finesse. The preload adjustment screw will take up a lot of the play, but may tighten things up too much at full lock left and right, so setting it is a compromise.

Good luck.

John

Post by **330GT** » Tue Jun 15, 2004 8:32 am

For those who are members of the Ferrari Owners Club in the UK, there is a good tech article on rebuilding the ZF steering box from a 365 GTC in the June 2004 issue of Ferrari News on page 37.

Art S. · Post by **Art S.** » Tue Jun 15, 2004 9:48 am

Kerry,

Can you post the article here or on your website?

Art S.

John Vardanian · Post by **John Vardanian** » Tue Jun 15, 2004 12:12 pm

John Tarr,

Thanks for your comment, but let me ask the question in a different way...

For the center position, i.e., the wheels pointing straight, the pin should be in the mid point of the worm gear. Does the worm gear need to be oriented in a certain position while the pin is at mid point?

The question really is, are the spiral cuts on the worm gear exactly the same width and depth througout the length of the worm gear?

john

Matt F · Post by **Matt F** » Tue Jun 15, 2004 9:02 pm

Hi John.

I haven't posted on this thread yet because I've never rebuilt a Ferrari steering box before. The only steering box I ever rebuilt was from a 1930's Ford. It was called a "worm and roller" setup, as opposed to a "worm and peg". I'm not sure that there's a difference. (If there is, I'd really like to hear what the difference is.)

Before I give you some recommendations, I'd like to define some terms, in order to talk about the same pieces in the same language.
Ferrari calls the linkage that goes from the steering box to the front wheels the "leva di comando sull'albero della guida". I'll call it a pitman arm, in American.
Ferrari also calls the "peg" the "albero della guida", which I'll call the sector shaft.

Although I don't know the details of your rebuild, I think you need to center the different components seperately.

Here's how I'd go about centering the steering:
1) Remove the cotter pin and castle nut from the pitman arm.
2) Use a puller tool to remove the pitman arm from the end of the sector shaft. This will allow you to adjust things independently.
3) Adjust the steering box for play, if you haven't already. (It may now be different on its own, without the pitman arm attached.)
4) Find the center of the steering box. Turn to one extreme, and then the other. Mark the center with a permanent marker.
5) Center the pitman arm, based on the wheels pointed straight ahead.
6) Re-attach the pitman arm, castle nut and (hopefully) a new cotter pin. Use the center that you found in step 5.

Everything should now be centered and ready for serious high speed use!

I hope that helps.

--Matt

John Vardanian · Post by **John Vardanian** » Tue Jun 15, 2004 11:40 pm

Matt,

Thank you for going through the process step by step. It explains things very well. I think your American car steering box is pretty like the ZF.

Now, let me ask you one thing about the worm. Independent of the rest of the components, does the worm have a center point of its own?

john

Matt F · Post by **Matt F** » Wed Jun 16, 2004 8:52 am

John Vardanian wrote:Now, let me ask you one thing about the worm. Independent of the rest of the components, does the worm have a center point of its own?

I don't think so.

The travel of the steering box is limited at each end by the pie-shaped housing of the sector shaft. The center of that would be important.

The worm itself, however, should rotate freely. It has nothing to stop it, and therefore no center. When you assemble the box, it shouldn't matter where the worm is in its 360 degrees of rotation, as long as the worm engages the peg.

And to answer your earlier question: yes, the spiral cuts on the worm gear exactly the same width and depth througout the length of the worm gear. Or at least they should be unless they're worn.

Post by **330GT** » Wed Jun 16, 2004 9:59 am

John,

At least for the SB on the 330 GTs, the worm is tapered with more play towards the outsides (lock) than in the center. But you can't go wrong. Just put it together. Everything is self aligning. Remember to align the pitman arm (if you took it off) on the SB using its marks. When you have the car aligned, use the marks on the SB and steering shaft to center everything so the SB is centered when going straight down the road.

A warning, most of the wear on the worm is in the center as most driving is straight. Don't adjust the pin down tight and then go for a test drive. You are liable to find the steering to be quite tight as you move off center, possibly to the point of not being to turn the wheel. Don't ask me how I found this out! So after adjustment, make sure that the feel is OK over the whole range. You may have to leave it a little loose in the center so you don't bind going off-center.

Art, sorry I won't post the article due to copyright restrictions. However, I will email a scan to anybody that is interested. Just send me a private message. Include your regular email in the PM so I can send it out to everybody in one email rather than having to answer each PM separately.

John Vardanian · Post by **John Vardanian** » Wed Jun 16, 2004 9:46 pm

Thanks Matt and Kerry,

I will have to take a closer look at the worm gear. It may be worn in the middle, judging from your comments. I would love to have a copy of the article. You have my email address I'm sure. Thanks so much.

john

Colin Angell · Post by **Colin Angell** » Wed Jun 23, 2004 11:16 am

Hi John,

You have already had some good advice, but as I am a newly joined member and also the author of the article mentioned in the UK Ferrari magazine, I thought I might chip in.

Firstly I would be happy to post the article to Tom's site but I can't work out how to do that yet! In the meantime I will send a copy together with some photo's to anyone who sends an e-mail address.

If you imagine the steering box disconnected from the steering column at the top and the steering arm at the bottom and with the peg lifted out, the worm is free to turn round and round. With the peg dropped into place it gets dragged up and down the worm in a slight arc. The middle position is obvious and you really can't go wrong!

In this position you should find the marks scribed on the worm shaft and the steering box line up (as shown in the earlier diagram). If you haven't got marks I would suggest you cut some because when the top is on the box you can't see the centre.

Once in the centre the important thing is to make sure that the steering wheel is centred by carefully aligning the splines connecting the worm to the column. You then have to connect the steering arm with similar accuracy so that the wheels are pointing dead ahead.

In other words it isn't the steering box centre which is difficult to find, it is the relationship between that and the wheels!

Great site

Colin

Post by **tyang** » Wed Jun 23, 2004 1:16 pm

Hi Colin,

I'm glad you like the site!

I would love to post your article to the "tips" section. Send me an e-mail if you need help sending me the files.
tom@tomyang.net

Tom

jcwconsult · Post by **jcwconsult** » Thu Jun 24, 2004 4:51 pm

I worked with manual steering boxes in 122S Volvos in rallying, similar to fest's illustrations. I would echo Kerry's caution about not overtightening at dead center. I did that once and road shock actually bent the upper forging cap under the adjustment screw .. upward into a concave cup. I heard about, but did not see, one example of cracked gears when there was pretension with a bit less than zero play between the gears.

www.tomyang.net