HowTo -> Overhaul a ZF steering box for M60 engine

[Hyper]

Doesn't seem likely.

I did not observe that the worm was anything but continuous from end-to-end, although I suppose it could be a two-piece {edit: duh, has to be 2-piece, otherwise we can't sense and react to torque}.
Once the control section is affixed (someway/somehow) to the shaft, the control section and thus the entire worm assembly is constrained by a torrington...


...and a ball-in-race...


...keeping the control section chambers centered on holes in the housing.
We would not want the chambers moving with respect to these housing inlet/outlets.

So your only hope is if the control section can be re-positioned along the shaft (someway/somehow).
This hypothetical procedure would require complete disassembly of the entire box down to bottom level components and therefore couldn't be called "an adjustment".
*****
I'm an analytical thinker and use the word "guess" if I am merely 99% certain.
The hazard in disabling with the assumed piston stop is that, if hydraulic pressure is not killed at the end of travel, then the piston attempts to force the case apart with (hydraulic pressure x bore area ='s) perhaps 3 tons of pressure.
Going the other way I'll guess there is some comparable fail safe, possibly the end of the worm shaft popping yet another check valve inside the piston.
****
Others have mentioned that if one runs out of sector/output shaft adjustment, then one might consider swapping imperial balls for the original millimeter.
Can't comment on that problem or solution, especially in this thread about seal replacement.

[ZesCoupe]

Hallo Hyper.

Had the same mysterious problem with the lack of steering assistance and also braking assistance on my '86 E24, although occasionally on my way home after it started it would suddenly all be there again. Initially changed the pump as it was worn, also tried a replacement accumulator which didn't help either. Sounding familiar? I found this thread after a discussion on bigcoupe.com and avoided the rather expensive regulator replacement. Although slightly different to my steering box the internals look more or less identical so the strip down was a breeze. having said that I did spend a day removing the pitman arm. Looks like only a nut holding it in place (E24/28 model) but mine was so tight that a typical puller ended up twisting itself out of shape. I had to construct a steel cage to support the whole box suspended from under the pitman so I could press the shaft out on my hydraulic press. When it eventually freed there was a crack like a gunshot, scared the crap out of me.

So OK - the inspection. The white piston seals looked remarkably similar to yours, plus I found more residue in the rack chamber. I'd earlier found residue in the reservoir so that wasn't really a surprise. One advantage of the stripdown is that I was able to flush all the old contaminated fluid from all corners of the box. Now there used to be a repair kit (oem 32131126887) which I presume included all the various o-rings and piston seals but as of January this year it is NLA.

The problem: I noticed that there had been one or two other requests (also in the other post in the E32 section) for the source of the 2 kits used for the write up but there had never been a definite answer except maybe the rather cryptic response (fantasy world?) but I'm not quite sure what was being implied. I have ordered the gasket kit (oem 32131126888), although I, like you, had no external leaks, and have been looking for sources for the square section piston seals without much luck. I have been unable to even ascertain the type of material they are made of, that would be a start anyway. What I did find still available from BMW are what looks to be the same sets of 3 o-rings/piston seals (control valve section) but as fitted to a number of older vehicles. Couldn't find any definitive size details but other parts have the same sizes, it looks like certain things are reused in design improvements. I ordered them and if they aren't correct it is only a few dollars (euros) wasted.

So the question is (again) where did the seal kits come from? Were they the same or similar to the kits I mentioned as there is nothing listed for the E31 or E32? I got the idea from an earlier post that maybe Max Lumens was involved in some way. It was suggested that he was rather knowledgeable in this area so maybe he could help if he reads this.

Thanks for a great write up anyway (as far as I got) and I'm sure that if I can find the rings the assembly will be just as easy. Worse case scenario is replacing the underlying o-rings and giving the piston seals a clean-up with some fine scotchbrite.

Regards,
Martyn
Netherlands

[Hyper]

...So the question is (again) where did the seal kits come from?...

The answer is (again), the kits referred to in this thread from years ago were bootlegged out of the rebuilder supply channel in spite of the factory thumbing their nose at owner/operators.

A couple other sidebar notes...
* The square section rings are commonly referred to a "lathe cut" and there are suppliers that can deliver to your specs, providing the bottom line of the deal is big enough to include NRE and production setup. Once you've paid for 1,000 of each seal in the box, you will then sell a dozen per year while the remaining rot with the passage of time.
* What is missing from our DIY bench is any performance specification, and any means to test whether a box conforms to the specs. This could become a big deal if we are on a quest to source seals that may or may not work properly. Our current method of testing is to spend the time to install the box and then see whether we can properly get down the road. Besides the time involved, it is not a pure test of the box, because there are other questionable components that go into the higher level system. IOW's the box has not been sufficiently isolated with all other variables removed.

[rjjablo]

This is what I just used, Does not come with the White Square Rings, Way to expensive for what it is but it had what I needed. Mine was just seeping and I don't think I had any internal Leaks

https://www.ecstuning.com/b-genuine-...t/32131134768/

[ZesCoupe]

Thanks for the reply Hyper. I thought that was more or less what was implied, maybe I need to try and find a contact at ZF in Delftland, Netherlands. I get the point about special orders as well, I have seen Google results with this sort of offer. I'll have to try plan B and reuse them with new o-rings underneath which I have been able to source. I seem to have now flushed out all the old fluid and any contaminants so maybe that should help, it did seem to be somewhat intermittent.

Also Rjjablo, as I mentioned in the post I have a gasket set (for the E24) on order at present from the local dealer. Mine, as far as I had seen, was not leaking but having opened it I thought it would be best to replace the external oil seals and anything else supplied in the kit.

[petejk]

As I understand it, there is a lot of similarity between steering boxes from the e31, e32, and e34.
From reading this thread, and others, there seem to be 3 kits that could be sources of components with which to completely reseal/rebuild.
Of course, if I'm barking up the wrong tree, please let me know

BMW directly - kits are apparently still available

32131134768, e31/e32 with servotronic
Attachment 694501

32131134714 e31 without servotronic
Attachment 694502


The above are external seal kits only


...and aftermarket kits.

From ebay I saw two kits which might prove to be sources for the white internal seals referenced earlier in the thread:

Both kits are from the same Russian supplier, but the second picture in each auction shows a pretty complete looking kit. They are listed as for the e34 box, but there is potentially commonality with some or all of these internal seals between the e34 and e31/32 boxes.

Firstly https://www.ebay.com/itm/164183975606 - e34 steering box with servotronic

Attachment 694498

and https://www.ebay.com/itm/164553883861 - e34 steering box without servotronic

Attachment 694499

and then finally, a well known source for bearings and recirculating balls

Attachment 694503
http://duesenklinik.de/uberuns/proje...w-850i-ci-e31/

[Goodguyili]

There is a lot of play in my stearing, thanks for sharing petejk, im pretty certain the ball bearings in my stearing box are worn so that last kit is a must for me. Do you know how to overhaul and remove the box itself?

[affa]

Yes the bmw kits are just seal kits. They don't include the Teflon seals (those white rings) and back up o-rings to do a thorough job. Depending on your box's condition the recirculating balls and bearings might or might not need to be replaced.

The way i look at it if I'm getting in there then they're all getting replaced. What you found in the last pic looks very interesting indeed...

iirc for the full bmw experience (lol) i did mine with the seal kit and the E28 rebuild kit which has the internal wear parts, but no bearings or balls...

Thanks, that's a good find. I have a csi box on the healing shelf. This find might come in handy.

[petejk]

There is a lot of play in my stearing, thanks for sharing petejk, im pretty certain the ball bearings in my stearing box are worn so that last kit is a must for me. Do you know how to overhaul and remove the box itself?

Sent from my SM-G970U using Tapatalk

I removed the original steering box from my car, when I had the engine out, so it was a much different experience from what my future experience will be replacing it again from the under the car.

The process as I understand it is to remove the X-brace, along with the center link, idler arm and pitman arm and then to unbolt and remove the steering box.

As far as overhauling my old box goes, I haven’t crossed that bridge yet, but I’ll be making use of Hyper’s reference photos to do so.

It looks like the e28 bmw repair kit mentioned above that included the white rings is now NLA, which is why the Russian eBay kits caught my eye. Who knows how long they will be available for..


Sent from my iPhone using Tapatalk