Steering rack overhaul and Delrin caps

[RichardM912]

I have just overhauled the rack on my 69 912 (same as 911). I found the earlier posts on this very helpful and confirm that it is pretty straightforward. The bearings and oil seal are available from standard engineering suppliers and cost less than $50. A couple of hopefully useful tips from my experience:

1.If you are keeping the eyelet ends on the rack (not switching to turbo tie rods) you can get their angle correct without the factory jig. Leave one eyelet on the rack and use a couple of lengths of threaded rod to line the second one up (see photo). If replacing both eyelets, do them one at a time and align in between.

On pulling out my rack I found that the two eyelets were at slightly different angles (again, see the photo). This was not a concern as I was going to turbo rods but I found it easy to find which eyelet was correct by drawing the required angle on a large piece of card and sighting the threaded rods on to it.

2. The manual says check the pinion for end float on assembly and shim as necessary. The pinion is a pretty tight press fit and it shows no end float. It is necessary to either measure the gap between the upper pinion bearing and the circlip and shim this gap or - easier because of the difficult access for the measurement - add shims at assembly to a thickness where you can only just get the circlip into its groove.

Finally, I had the Delrin cap for the metal pressure block made professionally. This is a wear item but is no longer available from ZF. I have a few spares which I would be happy to pass on at cost (see photo). Please send me an email if interested.

[RoninLB]

I'm in for one part and I sent the e-mail


thx again

[hesaputz]

E mail

[Canada Kev]

Yeah, I'm in, too.

[Evans, Marv]

If there are enough, I'd like one too. I was wondering about these and if I would ever find one.

[77carrerabt]

send me one also.
Thanks
bgblocks@yahoo.com

[chris_seven]

I think that there are two type of pressure blocks.

Early racks had a steel pressure block with a Delrin contact surface and racks of this type have a dust boot seat on the steering rack housing. These racks are quite rare and I thought they had been replaced as early as 1968.

Later racks - without the dust boot seat have a solid Delrin pressure block which now has a 914 part number - 914.347.018.00.

I don't know if they are still available as we have been replacing them with a machined bronze bush for some time .


Both of these types of pressure ring were fitted to racks with the 'threaded nut' for adjustment of the force applied to the pressure pad.

Later racks always used the solid Delrin pressure ring and the force was adjusted by the use of a shim pack between the housing cover and the pressure ring. The spring force being increased by reducing the thickness of the shim pack.

I think the torque required to turn the rack with the tie rods disconnected should be a maximum of about 100-120 ozins

[RichardM912]

Chris-seven is right. I have been pointing out to those who have contacted me that there were two types of pressure blocks, as he describes, and sending a parts diagram. I do not know how late in the model runs this type of metal block with cap was used. Mine is a 69 car and the rack is stamped/cast as 68 by ZF. I bought a spare rack off ebay, also stamped 68, and it had this type of pressure block. I gave a cap to a guy on the 912BBS who was helpful in my overhaul. He has a 68 car and it has this block style. But pls check your car if you can.

I might pass on one of the useful tips that the 68-owner gave me. On dismantling, it is common to find that the Delrin cap has split around its circumference, along a line that coincides with the outer edge of the metal block it is sitting on. This probably happens when applying the very high torque needed to remove or install the tie rod eye bolts on these racks (the locknuts). This torque is taken by the pressure block. To save the cap you need to hold either the rack or the eyebolt in a vice so that it takes the torque. Difficult to do if working with the rack in the car!

[RoninLB]

Originally Posted by RichardM912

I have just overhauled the rack on my 69 912

Finally, I had the Delrin cap for the metal pressure block made professionally. This is a wear item but is no longer available from ZF. I have a few spares which I would be happy to pass on at cost (see photo). Please send me an email if interested.

Greetings Rich

I received the part a few weeks ago all well and good

sorry so late to acknowledge but have been overloaded with remnants of hurricane crap

[micheloaks]

Richard you mention the oil seal is readily available, do you have the pt numbers for these and can you let me know what your rack number is

[Chuck_Costello]

Greetings Richard,

This is a long shot, but if you have another Delrin cap for the metal pressure block...I would like to have one. Mine has cracks around the edges.