The 700/900 ZF steering rack rebuild thread

Just got my hands on this good core ZF rack after searching for a couple of years. "supreme 940" saved my bacon on this one - and was an amazing seller. It looks to be in nice enough shape that it would probably be fine to run as-is for a bit, but I'm going to rebuild it before I install. Hoping to document it all here as I go. Very pleased with how things look after pulling the boots back - no water intrusion/rust on the shaft.


The nice thing with these racks is the OE Lemfoerder tie rods/ends/boots are still available.
Next up is ordering a seal kit. Please chime in if you've rebuilt a rack and put some miles on it to give your impression on the seal kit you used.

I'm trying to decide between:
Gates brand rack rebuild kit $
VP autoparts kit (https://vp-autoparts.com/en/artiklar/seal-kit-steering-rack-740-940-zf-83-92.html) apparently put together by a company in Sweden$$
Kit from Volvo $$$$$ who knows if it's actually an OE one at this point or just an aftermarket set of seals put in a Volvo box.

If you find the time to continue this thread it would be appreciated. Hope your rebuild goes well.

I would chose VP autoparts. I've had good success with everything I've gotten from them. You could also try checking the Volvo price at Tasca.

940 16 valve said:

Just got my hands on this good core ZF rack after searching for a couple of years. "supreme 940" saved my bacon on this one - and was an amazing seller. It looks to be in nice enough shape that it would probably be fine to run as-is for a bit, but I'm going to rebuild it before I install. Hoping to document it all here as I go. Very pleased with how things look after pulling the boots back - no water intrusion/rust on the shaft.

The nice thing with these racks is the OE Lemfoerder tie rods/ends/boots are still available.
Next up is ordering a seal kit. Please chime in if you've rebuilt a rack and put some miles on it to give your impression on the seal kit you used.

I'm trying to decide between:
Gates brand rack rebuild kit $
VP autoparts kit (https://vp-autoparts.com/en/artiklar/seal-kit-steering-rack-740-940-zf-83-92.html) apparently put together by a company in Sweden$$
Kit from Volvo $$$$$ who knows if it's actually an OE one at this point or just an aftermarket set of seals put in a Volvo box.

Click to expand...

I like the volvo factory seal kits, but that's all I've ever used (ZF, TRW, CAM). No problems.

So I checked and the Volvo seal kit for the ZF racks is NLA, so I've ordered the VP kit.

I got to disassembly. First I made sure the rack was centered so I could make note of the orientation of the pinion for reassembly


Pulled this cover which holds a spring and piston

Next remove rubber cover on top and remove snap ring

This part was a bit nerve wracking cause the cover is NLA. I lightly tapped around the perimeter until it started to back out.

Hold pinion while undoing nut from under that cover

Another snap ring holds the bearing at the base of the pinion in

I gave the pinion the lightest tap and it came out very easily

She's out!

Bearing on the upper part of the pinon

I was thinking I would replace the bearings, but after inspecting them I can't feel any play or notchiness so I'm on the fence. The lower one is available (NTN6001) but the upper one looks like it would take some more digging to find.
A ring on the other side of the rack holds in the seal and it's carrier.

The main shaft out

And finally I drove the lower bearing for the pinion out - there's a tiny recess at the lower left that gives you a spot to tap it out without damaging it.

Bagged and tagged to keep everything clean and sorted until reassembly. Now I've got the bare rack housing to clean. It has what looks to be some undercoating on it, so I've got to figure out how I'm going to deal with that (maybe see if a machine shop can hot tank it?). Better than a bunch of corrosion though I suppose. I'm impressed with the condition of everything internal so now it's just waiting for parts!

First I ginerly tapped off this cover - its NLA as well.

Thanks for posting the progress of the rack rebuild.

dl242gt said:

Thanks for posting the progress of the rack rebuild.

Click to expand...

Totally! I know this is the type of content I always appreciate others sharing.

Finally got some time (and seals!). When the seal kit arrived I was initially disappointed when I saw it was pro parts sweden. I have no experience with their parts, but usually I'm let down by anything that isn't a brand I know is OEM for some euro carmaker. On closer inspection I'm impressed, the seals looks like the ones I took out, and you can see where they the brand name has been shaved off of them - which is usually a good sign.



I spent forever cleaning the rack in mineral spirits and scrubbing, and then painted it.

I lightly honed it just to brake up the glazing and hopefully help the new seals seat.

New seals


and more still

New seals on the main shaft.

You can see on this seal where the brand marking is removed

New bearing for the bottom of the pinion

Installed pinion back in and the bearing circlip and pinion bolt on.

Shiny repainted cover on (with some sealant around the perimeter in case.

Shaft back in and packed with grease

In goes the piston that holds tension against the main shaft


Washer and spring


Shiny new cover and hardware

I considered cleaning the old hard lines, but decided if I've come this far I should splurge on new rust-free lines.

Just need to put on some tie rods and boots and it's install time!

Damn, I'm impressed! I've seen a lot of rebuilt racks, and have rebuilt more than my share. I'm a stickler for clean, and get it done right, but a new paint job! You could have a future in the rebuild world, but I think you'd have to charge an arm, and a leg to make any profit. Good for you, not many people left in this world that have that old school sense of pride in your work, and do it right just because. Thanks for the post!

Excellent work and documentation pics! I never knew that there was a ZF rack for the 7/9 series... I've got a 2 series core in my basement shop for my future 242 build.

Will have to inspect my 90 745 once she's home to see if I scored a ZF on that one. If anyone knows the year range the ZFs were made for this application, would be a worthy addition to this thread.

Thanks for the kind words! I've always had a meticulous streak, and now I'm trying to do each job as thoroughly as I can. Given that I daily this beast I figure if I do everything properly, it'll help the car not gradually feel like it deteriorates in a death by 1000 cuts kind of way.

Got the rack installed shortly after my last post. The old rack was really leaking out the ends and into the boots, not to mention it didn't have full power assist turning right (which I actually liked, I always felt like it was too much assist.)
This side wasn't so bad

But the drivers side was really wet, and could could actually see drops of red ATF.

Checking to see if I could use the steering limiters from Ben, but they only fit the other style rack.

Out with the old

I gave up on getting OEM boots (used Febi stuff which I find is variable for quality) FCP then showed stock, then said they didn't have any after I ordered, and then somehow one boot shows up in my order. Dang.


Man do I love the feel of this rack though! When I first did my engine swap, using the 960 power steering pump I really felt like there was more assist than my old 940 had (same pump I know, but maybe a pulley size or pressure spring difference?). Anyways with the failing rack I liked the amount of assist it had turning right - the side where I suspect a seal was failing on. With the ZF rack I feel like it has noticeably less assist (even both ways however) and I'm very happy with it. Of course it's newly rebuilt and not fair to compare it to the TRW/Cam one, but I'm happy!

Hey 16V,
You should be happy, got good results, and that "I did it right" feeling. Great job!

tbrcktch said:

Hey 16V,
You should be happy, got good results, and that "I did it right" feeling. Great job!

Click to expand...

Thanks! Probably most of the people in the world who would appreciate a project like this are on this website!

I forgot to mention, I bought orings for the 2 steel lines from Volvo and they turned out the be just a hair smaller than the ones off the old rack/ ones that came with the pro parts kit. They wept fluid and I ended up pulling the rack again to figure that out. Keep a close eye if you're rebuilding a rack!

Left is the seal that came on one side of the new volvo lines (they only included one side) middle is the one from the rebuild kit, right is what volvo sent me and is what they list as the correct oring)

Good news! The 2nd 7/9 ZF rack in North America has been found......



Never thought I'd ever see one of these. My recently purchased 745 has a seeping reman. rack which needs replacement. I was in Pull-a-Part South Atlanta and decided to inspect a forlorn 90 740 Sedan. Boy, am I glad I did. Nice and tight, no leakage from inner tie rods. Just cleaned her up with kerosene and I'll know soon if she's AOK. All I know now is she's tight.... no lost motion at either end and operates smoothly from lock to lock. I may end up having to rebuild..... but hopefully that is later.

For 700/900 posterity, some numbers to hopefully help others:

Thanks for writing this up- very helpful, I’ll refer to this thread when I wade into rebuilding a leaking rack in the near future