Rear Steering Rack Rebuild

[Jimvr4]

Checking in ASA it looks like there never was a kit for rebuilding the rear steering rack. Are they sealed units or can they be taken apart and refurbished? Looking at the system diagrams I don't think the rear rack could be all that complicated. It looks it just works off the hydraulic pressure generated by the rear steering pump. I can't imagine it having more than a few O rings inside.

I see you can buy them on Ebay but it looks like they're just used units from wrecked cars.

Anyone try to rebuild them? If so what size O rings did you get?

[Bloodlust182]

Not sure on the o-ring sizes, but I do have a good condition rear rack if you are looking for one?

[Jimvr4]

Can you have a close look at it and see if it looks like it can be taken apart?

[Unlogic]

If I'm not mistaken there was a member on the GTOOC forum or the 3000gt.se forum which fixed his leaking rear steering rack. I'll see if I can find the post.

[Jimvr4]

Not sure on the o-ring sizes, but I do have a good condition rear rack if you are looking for one?

No leaks? How much do you want for it?

[Jimvr4]

If I'm not mistaken there was a member on the GTOOC forum or the 3000gt.se forum which fixed his leaking rear steering rack. I'll see if I can find the post.

Let me know. The shop manual doesn't show any ability to service them....

[Unlogic]

Sorry for the delay Jim, I managed to track down the post on the Swedish forum (http://forum.3000gt.se/viewtopic.php?f=48&t=2413&start=80#p23774) from a member with a similar problem.

http://pics.unlogic.se/3000gt/leaking-rear-steering.jpg

Unfortunately he didn't open it up but instead opted for a used replacement so I didn't yield any more information on how to service the rear steering rack.

[Unlogic]

However I found this post on 3SI which sounds encouraging:


i took the rack apart and got the stock seal out of it and went to a shop that makes rubber seals and o-rings etc and they got me one from the shelf just by measuring up the old one and it cost me $3 or something and fixed it

rear steering rack rebuild - 3000GT/Stealth International Message Center (http://www.3si.org/forum/f12/rear-steering-rack-rebuild-412114/#post4805542)

[Jimvr4]

Thanks Robert :)

I had found that at one point and then forgotten about it. I'll have a look at it this weekend and see.

[hyper3000gt]

when these units go on our cars is it worth it to replace them? I know many people that just remove them instead. just how much does the aws help in cornering situations?

[Jimvr4]

Not debating that here. For a few bucks ill put in new seals and keep the feature.

[hyper3000gt]

that's cool if you can fix it for that cheap

[Bloodlust182]

Hey Jim, sorry I did not respond for so long. I got caught up at work with a project and forgot about the pics. The rack came off a 91 from Cali with 119k on the clock. It could use a outer tie rod end on one side, but other than that it looks great! No tears in the boots.

http://i289.photobucket.com/albums/ll203/bloodlust182/20140729_012426_zpsty8av1kd.jpg (http://s289.photobucket.com/user/bloodlust182/media/20140729_012426_zpsty8av1kd.jpg.html)

http://i289.photobucket.com/albums/ll203/bloodlust182/20140729_012410_zpsidv4e8ci.jpg (http://s289.photobucket.com/user/bloodlust182/media/20140729_012410_zpsidv4e8ci.jpg.html)

[Elderloc]

Jim,

If you get your broken down and repaired please let us know what you find. There can not be that much to the thing I bet it's just a handful of ORings. Ask Hans to look into this when he has time.

[Jimvr4]

I received a rear rack from a part out and got the tie rods off the cylinder. From here it looks like a special tool is needed to remove the end cap. The needed tool would be 37 mm diameter with two 3mm pins located at the edges of the cylinder (two pins spaced at 34mm C-C). So far the only thing I've found that might be close are the brake tools that rotate the pistons back into the cylinders. Ideally the tool would have a 1/2 inch square hole in the center to accommodate a 1/2 inch drive.

[Jimvr4]

Success!! I found the tool and ordered it. Wasn't easy to find because almost all the tools in this space have bigger pins.

[Swisstec]

Mine is leaking pretty bad. Very interested in fixing instead of deleting.

[Jimvr4]

I will know more soon. The tool has shipped already.

[Jimvr4]

Tool came in but pins were too short to reach the recessed location so no go. I've also tried a big ass pipe wrench on the end and it doesn't budge so I have my doubts the tool would be strong enough. I might find a shop to look at how to disassemble it. I'm either missing something or it is welded shut :(

[Street_Chally73]

That sucks! At least you tried, though.

On a side note: do you think it would be possible to have a fabricator/welder make one up based off the dimensions you're able to get?

One would think that between getting all of the correct dimensions & creating it in a 3D AutoCAD program, you'd be able to get a custom tool made up...It's been a while since I've used 3D ACAD design tools for objects, but it shouldn't be too hard to recreate with the appropriate dimensions that are needed.

[Jimvr4]

I have no doubt I could draw up the needed tool in AutoCAD. I just think the small (3mm) pins would break off before anything would turn on that end. Either something interferes with turning the end cap or it's welded shut. There's a right angled block with a hydraulic connection so I was thinking that piece was threaded in to the cylinder housing and might be blocking the end cap from turning however the right angle piece doesn't budge either.

[Jimvr4]

Well, I didn't use a big enough BF pipe wrench after all :)

I found a hydraulic shop today and brought in the power cylinder. They used a really huge pipe wrench and opened it up and replaced the shaft seal for FREE !!

It was already completed when I returned and I asked him how he did it and he demonstrated that it functions properly and has no leaks. So, my core unit is fixed already and I have the one on the car to take out and fix. If this core unit can be cleaned up enough I might put it on my car.

I didn't get the PN of the seal they put in there but I do have the one they pulled out. It states SKY-18N on the seal but google returns nothing on that. Anyway I'll probably take mine down there and see if I can get it done for free too! :)

[Toni]

Ask if you can get seal PN info! That would be awesome for those looking to do the same in the future.

[Jimvr4]

Ask if you can get seal PN info! That would be awesome for those looking to do the same in the future.

Yes, I will try. The seal is kind of similar to what we have for the cams and transmission shafts, not like an O-ring at all.

I was thinking the way to open up the power cylinder is to do it on the car when it's still bolted to the subframe. It takes a pretty huge vise to hold it otherwise.

[Toni]

Do you think it's similar to anything in the front rack? I've rebuilt those a couple times but I imagine they are different pns.

[Jimvr4]

Nope, just looked at the front rack rebuild wiki and nothing there looks like the seal in the power cylinder. I'll get the info on it next time though.

[Unknownvr4]

Good info. I don't plan on deleting my rear steering, so any info to rebuild them if needed in the future is gold!

[Jimvr4]

I have all the details on the seal :)

I went back to the hydraulic shop and found out what the original seal is and what the replaced it with. I bought a couple of seals so I have one for my power cylinder and I have a spare one. Haven't been able to locate an on-line source for these though. I may go setup a group buy on these seals.

[Jimvr4]

What I know is the original seal is Nitrile Rubber (aka NBR or BUNA-N) and the dimensions are 18mm inner and 26mm outer and 5mm thick. Essentially a small rubber doughnut.

The profile of the seal is called SKY.

The shop I used installed new seals of a different profile. The ones they used were Polypak Type B which is similar to SKY but capable of higher pressure sealing. The Polypak technology uses what they call an energizer ring kind of like an O-ring to support the lips that seal against the rod and the bore.

I bought two extra seals from them and plan to take my power cylinder apart and replaced the seals. I plan to leave the cylinder mounted in the car and use a large pipe wrench to unscrew the end cap after removing the tie rods.

I never could open the old cylinder because I don't have a vice and couldn't get a good grip on the end cap.

Anyway if you have a southern car that isn't rusted to shit there is a way to keep AWS and its fairly inexpensive. Just replace the seal(s).

BTW nitrile rubber is very good at sealing hydraulic cylinders however it is not expected to retain its properties for 20 years. I don't think we could fault the designers one bit for using it.

I've googled extensively for metric rod seals and have come up empty for on-line ordering. What I have found so far is:

CRC Seals: MPP-018.0x026.0x05.0B
Hydraulicseals.com.au: SKYM-018026-05

I haven't tried contacting them by phone.

[Unknownvr4]

This should be stickied or something for the future!

[Jimvr4]

I'll add pictures to this thread once I get going on the rear end rebuild

[Elderloc]

Interesting so you found a shop that could rebuild the rack?? Or did I read that incorrectly? What type of work does the shop do, maybe I can find someone around Michigan. I mean rather do they rebuild racks or are they just a general hydraulic place?

[Jimvr4]

No you read it right :) It was just a general hydraulic repair shop. They replaced the seal(s) in like 5 minutes. I can probably get more seals from them if anyone needs them.

[Bloodlust182]

No you read it right :) It was just a general hydraulic repair shop. They replaced the seal(s) in like 5 minutes. I can probably get more seals from them if anyone needs them.

I need a full set of seals for the rear rack!!!

[Jimvr4]

Pm'd you back. I just don't have time to visit that shop right now. I can't give you anything as I'm not sure what I need to repair my rack with.

You could help me if you could list out the steps to drop the rack. I think it starts with dropping the exhaust and then at least lowering the subframe a bit. Can you confirm?

[Bloodlust182]

you need to drop the sub frame to get to the rear rack. Gotta disconnect the brake lines, e-brake cables, power steering lines, drive shaft, and struts.