Found another one of the housing without the magnasteer in it. You can see the little depression where the stock o-ring for the control wire is held in place by pressure from the magnasteer. He put a seal in there as normal, but added the extra one as a secondary protection against leaks instead of just jamming it with epoxy from the outside. That's the source of the majority of the complaints of steering rack leaks. He did put some epoxy around the joint as protection for the wire protrusion, but not really for leak prevention.

You can also see that the fingers don't really engage anything. The whole thing was held in with some epoxy on the perimeter and compression from everything else in the housing.

He also did use a small amount of epoxy inside the housing to put the magnasteer unit back in.

 

This thread needs a master video to show / describe some of the process in detail for the plebians like myself among the audience.

 

Thanks for the extra info and picture! Still on the fence about removing the magnasteer actuator and opening that can of worms (it wasn't leaking before to my knowledge). Then again, while I'm in there...

In due time, haha. My current plan is to put together something along the lines of this awesome BMW E30 guide: https://classicbimmerbits.com/e30-ho...-rack-rebuild/
If I made a video it would probably just be a slideshow version of the written guide.

 

Yesterday I got 2 packages: the 4 replacement teflon scraper rings from the ebay seller (they were very generous, also sent me some promo items like T-shirt), and the Edelmann 8786 PS rack rebuild kit, pictured here:



A bunch of the parts in the Edelmann 8786 kit are the same as the C5 rebuild kit, but there are some differences.
First off, it looks like the 4 teflon scraper rings are the same (measured them with calipers as well). Light blue are from the ebay seller and specified for the C5, darker blue is the Edelmann 8786 kit rings:



For compressing the teflon rings I actually used the previous looser tool to do the initial compression, and then switched to the new tighter tool to further compress the rings. I've left it sitting since last night so don't have any final compressed pictures.



Lastly, the C5 ebay rebuild kit didn't include the tiny O-rings that seal the fluid hard lines at the pinion body. However, the Edelmann 8786 kit DOES include them, and those O-rings look like they should work to replace my C5's original ones. New on bottom, old on top:



Hoping tonight to make further progress on the rebuild.

 

Automatic transmissions use very similar Teflon sealing rings. I cut up a 1 liter pop bottle, wrapped it around the rings with hose clamps. Let it sit overnight. Worked fine!

 

Good tip! My engineer brain can't let me do something that simple, but I'm sure somebody else can benefit from this knowledge. Assuming I get around to putting a DIY guide together I can include this.

 

My engineer brain is cheap, and I dont have a 3D printer, so I would very much do something similar to the pop bottle!

 

More progress.
For starters, this is the compressed state of the teflon rings after my last picture with the tighter tool:


I went ahead and test fitted the pinion assembly into the rack body. First I lubricated around the teflon rings and the cylindrical surface in the rack body where the rings sit, using my power steering fluid (which is Valvoline ATF +4). The picture below is after removing it. You can see some staining on the rings, but I am happy to report they didn't smear and get damaged this time!


Insert rack rod into rack body. Not shown was that I used blue painter's tape over only the rack teeth so that the teeth wouldn't tear up the middle rack body seal as the teeth went through it. Seemed to work pretty well, and the tape didn't show any signs of having torn on the way through.


Grease up the teeth. For reference, I am using a lithium-based moly grease. My research led me to use this type of grease.



Next up I greased the pinion teeth. I wiped up excess grease beyond the diameter of the teeth, as the teeth pass through a seal and I wanted to avoid/minimize any grease getting on the seal.


Tightening the pinion nut to draw the pinion all the way through.
Here I'd like to point out that it took a couple tries to get the right alignment between the rack and pinion teeth. You can kinda see my blue line mark at the bottom of the picture. For my C5's rack, the orientation of that blue line correlates to the rack rod being centered on the rack body (equal amounts of rod sticking out either end of the rack body).
As the pinion is inserted, it will rotate and the rod will push to one side, so this has to be compensated for prior to the rack & pinion teeth engaging. I found that shifting the rod to the right about 5/16" with my blue line in its correct orientation set the right alignment.


Then the pinion end cap with bearing and seal was lubricated with PS fluid. Note that I wouldn't recommend greasing this bearing because it is subjected to PS fluid during operation, and you don't really want grease to enter PS fluid.


Installing the end cap. I lubed the O-ring a little so that it wouldn't go in dry which should reduce any damage it would otherwise incur.
With it initially seated against the rack body, I used a really deep socket (actually used a separate ring under the socket to gain more depth, my sockets weren't long enough) and tapped the end cap until it was fully seated.



Time to install the end cap retaining ring. Get one end started, and work it around into the groove.


Shown above is the new retaining ring that came with the ebay kit. Unfortunately, it seems this ring was too long and I couldn't get it to seat (the ring overlapped itself...). So I just reused the old ring that seemed to be in satisfactory condition.
Note the picture below is the original ring reinstalled, and the ebay kit ring I couldn't use:


Moving toward installing the rack rod end support/seal. I added some grease to the bushing only. Not a lot, and this might not be necessary, but I figure it can't hurt. In the long term I'm sure this grease will just wipe away and become useless.
The grease is only shown as a glob to highlight which surface I applied it to. It was evenly spread around as a thin coating.


Next I lubed the O-ring on the rod support bushing/seal support body, and installed it:




Then the retaining ring gets installed. As with the pinion end cap ring, for this one too you'll get one end started and work it around. Have some tool like a screwdriver or punch to help push the ring around.


Moving on to the plunger assembly, which is what applies preload to the rack rod to ensure a proper engagement between rack & pinion teeth. Improper preload (or a worn plunger assembly) can cause backlash in the steering system and make the car's steering feel vague and/or uncontrollable.
Grease up the plunger, and also make sure the rack rod is thoroughly greased up on the backside. I greased the ends of the preload spring since those see metal-to-metal contact.




There is a procedure for tightening the plunger adjuster plug. You can check that out here: https://www.corvetteforum.com/forums...djustment.html
And for reference this is the procedure:

1. Turn the adjuster plug clockwise until the adjuster plug bottoms in the gear assembly.
2. Turn the adjuster plug back 50 to 70 degrees (one flat is 60 degrees).
3. Install the adjuster plug lock nut (1) to the adjuster plug.
4. Hold the adjuster plug stationary while tightening the adjuster plug lock nut (1) 68 N·m (50 lb ft).

Pinion nut cap goes on, just use a proper size socket and a mallet to knock it in place.


O-rings on oil lines. So... I initially used the new O-rings that came with the Edelmann kit posted about previously. Lubed them up and installed the oil lines. On the 2nd one, the nut had a weird feeling as I was tightening it, almost as if the fitting threads stripped. After pulling the line back off, the new O-ring was oddly flattened and obviously damaged. The other already-installed line's O-ring was similar. WTH!! Went ahead and re-used the original O-rings, fingers crossed there... at least they looked okay. Also let this be a note that these oil lines really don't take a lot of torque to tighten.



And then the steering rack rebuild is complete! Pending testing to make sure it doesn't leak, of course.



One other thing I want to point out that may be apparent to some: I didn't mess with removing & resealing the Magnasteer actuator. To my knowledge it wasn't leaking before and so I left it alone. @bradleyss14 shared some really awesome info that ought to be enough to help others out with that aspect of this rebuild.
If in the future mine leaks there, I'll tear apart the rack again and document my attempt at resealing it.


As far as testing the rack in-car, my current plan is to situate it back in the car and only hook up the PS lines and steering column shaft, then fill with fluid and bleed (as much as can be done without firing the engine). Next up, fire up the engine very briefly and refill fluid, and repeat as needed. Then bleed with engine running, turning lock to lock. Finally after bleeding and verifying [hopefully] no leaks attach the tie rods with boots.

3D printing is one of my big hobbies (also have gotten into it quite deeply for work), and I really enjoy being able to design & 3D print stuff for my automotive hobby. My plan is to share the CAD files for the teflon ring compressor tool, and also I don't see why I couldn't lend my tools or print additional copies.


EDIT: Got the rack situated back onto the car, with just the PS lines and steering shaft hooked up. Tie rods are still disconnected so that I can have a visual on potential leaks from the rack ends. Have done some bleeding and ran the engine briefly a few times as part of that process. The last time I ran lock to lock with the engine on, probably for about 30 seconds. It seems to be bleeding nicely and I can't discern any leaking fluid yet... fingers crossed it stays that way! Think I'm ready to proceed with reassembling everything else.

 

Just some additional follow-up:

• I'm slowly typing up a DIY guide. Will be using all the same pictures as posted in this thread, just with a ton of writing.
• In true DIY fashion, I aligned the front toe. The car got a full alignment only 13 months / 3,500 miles ago and front toe is all that should have changed since then. Didn't want to spend $95+ to get it done professionally again, although I spent $19 on bungee cords & matching tape measures (which can also be used for other things). Already had 2 suitable levels. I "wasted" a BUNCH of time on the alignment process, but it's been a neat experience and I can do it substantially faster now that I know what I'm doing (i.e. I can make quick iterative toe adjustments without raising the car, removing wheels, etc.).
• There's just about 3 degrees of rotational "free play" in the steering wheel when it's centered (+/- 1.5 degrees). Pretty sure that's new since the rebuild, or at least it's a lot worse than before. My gut is telling me I just need to increase the preload tension which supposedly can be achieved without rack removal per this post: https://www.corvetteforum.com/forums...post1603946132
  Thinking I should be able to dial in an adjustment since I can quickly verify improvement by jiggling the steering wheel (engine off).
  • The free play is a bit surprising considering I followed the factory procedure, but maybe it's just a result of worn parts? Fingers crossed it's not something like excessively worn pinion or rack gear teeth.
• The rebuilt rack has 18 miles on it so far. I haven't [yet] noticed any leaks and power steering seems to be operating as expected.

 

 

Over the weekend I did some disassembly to access the preload adjustment; it is very doable without rack removal. I should snap a picture, but I only removed the sway bar and undid the EBCM from its bracket so the bracket could be moved out of the way (couldn't actually remove the bracket).

Admittedly it seemed like I was able to tighten the preload adjuster more than the ~60 degrees I set it to, but in the tight space constraints with rack in the car my perspective may have been skewed.

I wound up tightening the preload adjuster completely to lock the rack rod in place. This allows me to try turning the steering wheel and check for play in the steering system without needing the tires on the ground.

Aaaannnddd.... there's definitely play in the steering, such that the steering wheel can be jiggled back and forth a decent amount. While doing this I can see movement in the steering shaft that translates into the steering rack input (no perceivable play in the steering shaft/joints, all connections are tight). So even with rack preload @ 100% it kinda seems like there is a little play in the rack/pinion gear teeth.

Now, having researched power steering rack & pinion design prior to disassembling my Z06's rack, I'm aware that some play is expected in the pinion assembly itself as this is how power steering works:
When you turn the steering wheel, this applies torque to the pinion shaft. With that torque applied, a part called a torsion bar [internal to the pinion assembly] deflects a little bit, which opens up a small port/channel [in the rotary valve] that allows pressurized fluid from the pump to be directed into the rack body, where the fluid can apply pressure to the rack rod... thus powering the output of the steering. Some good info here: https://auto.howstuffworks.com/steering4.htm

What I don't know, is, how much torsion bar deflection is normal. For example, what I'm suspecting is play in the rack & pinion gear teeth might just be 'normal' torsion bar deflection.

Crossing my fingers that things will be okay if I just go ahead with re-doing the preload adjustment procedure and reassemble. If not? Might mean that correcting the issue would require a different rack.

 

great post. i used an INCH lbs torque wrench to set steering lash. i measure drag with nut loose and hooking wrench to where steering shaft normally connects. set steering lash to 18 inch lbs
4 inch lbs initial drag + 12. 16 rounded to 18 inch lbs.

 

Thanks for sharing this. If you don't mind me asking, where did you learn about the 12 in-lbs extra drag value? Also I'm curious what tool (or arrangement of tools) you used to measure torque on the steering rack input shaft.

 

the 12 inch pounds pre load (+ 4inch lbs drag) was gleaned through research.... a long time ago. the fsm instructions i found were too loose which resulted in net zero lash. the car would track everywhere. i simply found a socket to fit the point on the rack where the steering shaft connects. i then hooked up an inch lbs torque wrench / deflection bar style."performance tool" m195. in retrospect i would have set the lash to total of 20 inch lbs. fluid also seems really important. i use motul fully synthetic dexron 3 style.

 

This is why I remain a fan of the forums vs fb. More tech quality information, and it is stored in an easily searchable tome of reference for all time.

 

https://www.dropbox.com/sh/gfd85r11c..._hlh6xSza?dl=0

 

Awesome, thanks. I'm struggling to imagine having enough space to use this style of torque wrench hooked up to the rack input shaft, with rack installed in the car. But it sounds like you did so I'm sure there's a way

The screenshots in your Dropbox folder are from a video I coincidentally found and was going to link to: Pretty good visual of measuring rack input shaft torque/drag.

 

go slow and its doable installed in the car.

 

It seems like I managed to overcome the on-center looseness/play This did appear to be 2 separate issues:

1. Loose steering shaft coupling: the one that holds the steering shaft to the steering rack input. This may have been a thing for a while considering I had the rack out 2 years ago for Harmonic Balancer replacement... With the bolt torqued to factory spec 25 ft-lbs, the coupling clanked audibly while jiggling the steering wheel. Torqueing it further changed it, but there was still some looseness/movement in the coupling.
   • Wound up removing the coupling bolt entirely, thoroughly wire-brushed off the old threadlocker (which I did before also), and did what I could to wipe away any possible debris from the coupling and rack input shaft. An old thread I found through searching suggested trying to hold the coupling tight against the rack input shaft while tightening/torqueing the bolt, even going so far as to use a C-clamp. I just held it tight by hand and put a final torque of 35 ft-lbs (30 wasn't enough). This all seemed to solve the problem!
2. I actually did this first: played with the steering rack preload. In hindsight I wish I had messed with the coupling first as I believe it could have reduced the effort I put in for painstakingly/iteratively adjusting the preload.
   • In any case, below are some pictures I took of the in-car preload adjustment process. It probably ended up on the tighter side as I didn't use @don37 's precise method of setting preload, but I think it has since loosened up so that the drag seems fine. There's no perceivable play in the rack itself now!

Accessing the preload adjustment, what worked for me:

• Disconnect Magnasteer connector. Remove sway bar, in my case it was still resting in the car but unbolted from the cradle and the end links were unbolted/removed from the lower control arms.
• For later years (like all Z06 models), loosen the 2 nuts that hold the EBCM to its bracket and lift the EBCM up and toward the engine. I used a zip tie to hold it up as much as possible.
• Also for later years, remove EBCM bracket bolts and push the bracket up and out of the way as much as possible.

The preload adjustment


The lock nut can be knocked loose (unscrewed) with a screwdriver or punch, when hammering on it to push it in a counter-clockwise direction.

Lock nut removed:


Then I could get a standard 22mm box-end wrench on the preload adjuster.


For me, the hardest part of doing this preload adjustment: when I would hammer the lock nut tight, the preload adjuster moved with it a little bit. So I'd have to anticipate how much the adjuster would move with the lock nut... and it required multiple attempts to dial it in and make the steering wheel have a good feel so that there was no backlash but also no excessive drag.

 

@metalman2 thank you for this well documented subject for the reconstruction of the steering rack, I am interested in the 3d files to make the tools for the Teflon seals can you please share them with me, thank you very much