Steering shaft alignment

[Melb-Mike]

I tried to search for prior postings on this and came up dry. It's possible I don't know what I'm doing.

My problem is getting the alignment of the splined yoke onto the steering rack correctly. My MK4, which I recently purchased but had no part in its assembly had a leaking power steering rack. So I bought a replacement unit. Getting the old rack out wasn't a big deal since the car is on the lift. However installing the new one proved to be a PIA. Working alone, I managed to get the splined yoke on the rack input shaft but it's out of sync with the steering wheel. Point is the flat portion of the rack input shaft is not aligned with the set screw on the yoke. There is no play or slide available on the car's steering shaft so pulling the steering shaft off to reset it can't be done without removing the steering shaft from inside the car. To make matters worse, the self aligning bearing on the firewall is mounted outside so it's not going to slide in. I'm looking at this as a design malfunction but perhaps I'm not seeing something more experienced guys like you may know.

I'm tempted to cut the shaft between the firewall and rack and modify it for easier servicing. Of course I would have to remove the shaft going to the steering wheel in order to machine the double D ends on both ends I cut in order to use a double D coupler for final assembly. I would machine a longer portion on the car side of the shaft to allow the coupler to slide all the way up to clear the bottom shaft, maybe add a spring on the upper side to maintain down pressure on the coupler as a safety measure.

But maybe there is an easier way that you guys know. And no, I'm not pulling the rack back off to attempt correct alignment.

[edwardb]

You're describing two conditions. Been there/done that with both.

It's quite common that the flat on the rack input shaft doesn't align with the set screw on the adapter. The solution has been debated a lot. But I'm three for three (1) Centering the rack, (2) Centering the steering wheel, (3) Determine where the adapter set screw hits the input shaft, (4) Grind a new pocket in the input shaft at that location using a die grinder or Dremel, (5) Assemble the adapter and set screw with a liberal dose of blue Loctite making sure the set screw drops completely into the new pocket. Thousands of miles with that approach on multiple builds.

The other issue I just experienced with my most recent build. I too had a power steering rack that apparently the input shaft was slightly longer than previous builds. The steering shaft U-joint was fully against the self-aligning bearing on the footbox and would not allow me to fit the shaft onto the adapter on the steering rack input. Because it was early enough in the build to change things a bit, I put the self-aligning bearing on the inside of the footbox. This provided just enough clearance to get the steering shaft on/off the rack input. It wouldn't be fun to make this change to a completely assembly car. But strikes me as a simpler solution than modifying the steering shaft. Once the bearing were moved, you should be good with the existing parts you have.

[Boydster]

I experienced the same thing with the rack and steering shaft. I installed the rack, torqued and all, then there was no way the shaft would go in. I removed the rack (outer tie-rods still attached) and was able to manipulate it enough to get it to go together as the rack went back into place. Not easy by any means. Also a very difficult way to grind a new flat as edwardb describes. I like his idea of moving the bearing inside...

[michael everson]

Just did the same thing on a very new build with power steering. No way to assemble once rack was mounted. I moved the bearing to the inside and was able to install the steering shaft to the rack.
Mike

[rich grsc]

Just did the same thing on a very new build with power steering. No way to assemble once rack was mounted. I moved the bearing to the inside and was able to install the steering shaft to the rack.
Mike

The bearing should be placed on the inside. I know kind of difficult to change, but is the best solution.

[Melb-Mike]

I kind of came to the same conclusion. However since the rack is installed and the shaft is on the rack's input shaft, the only way now to remove it is to pull the rack off. There's no physical way to disconnect the steering shaft now other than removing the rack or cutting the shaft. Putting the bearing inside would come after this. What intrigues me is why FFR would continue with such a design when servicing the rack once the car is assembled is such a PIA. This whole thing would be easily solved with a slip yoke shaft at either end. I used to design and build PTO shafts and this would be an easy solution. I looked at Flaming River products and apparently they don't have long slip yoke/shaft components. Thanks to all of you for your input. Great forum !

[edwardb]

What intrigues me is why FFR would continue with such a design when servicing the rack once the car is assembled is such a PIA...

Little bit of a tough characterization there. The manual rack from FFR fits fine. The steering shaft can be removed with the rack in place. I've used them twice with no issues. One power steering rack, not from FFR, also was OK. Again, the steering shaft can be removed with the rack in place. On my last build was the first time I couldn't fit the steering shaft unless I reversed the bearing as mentioned. The power steering rack wasn't from FFR. I traced the difference to a variation in the output shaft from the power steering rack. Same brand rack (Unisteer) but the outputs were different.

Unfortunately, the standard design can't always accommodate the wide variety of parts that are used. Every build has these kinds of issues on occasion. I'm not saying the design is perfect. I've been left shaking my head on multiple occasions. But this isn't one of them IMO. You've painted yourself in a bit of a corner here. One way or the other you're going to have to unbolt the rack enough to get the steering shaft back off. Do it once, reverse the bearing, and problem solved. I don't know where you're at on your build, but I'm willing to bet there are bigger challenges ahead than this one. Happens in every build. :p

[CraigS]

So remove the rack to re-position the shaft-no big deal. Pull the two bolts and move the rack as far to the passenger side as you can. It IS a pain in the a--, but after a few cycles you will find you can get it loose in about 3 minutes. Don't actually remove it, just move it away from the steering column. When you do it, either have a helper or use a ratchet strap to hold the steering wheel from rotating. The hardest part is making a one spline adjustment. The last one I helped with I think we moved it 6 times. 2 of those were bogus because it turned out I actually hadn't moved it at all.

[rich grsc]

Every slip joint introduces slop in the steering shaft.

[michael everson]

BTW if you move the bearing to the inside, t will interfere with the Wilwood pedal box mounting bracket. Just make a note of it and clearance the bracket. Or you can modify the bearing retainer.
Mike

[Boydster]

BTW if you move the bearing to the inside, t will interfere with the Wilwood pedal box mounting bracket. Just make a note of it and clearance the bracket. Or you can modify the bearing retainer.
Mike

Yeah, I was looking at this last night. Might need to take a bit off the lip of the bearing retainer...

[Melb-Mike]

Unfortunately, the standard design can't always accommodate the wide variety of parts that are used. Every build has these kinds of issues on occasion. I'm not saying the design is perfect. I've been left shaking my head on multiple occasions. But this isn't one of them IMO. You've painted yourself in a bit of a corner here. One way or the other you're going to have to unbolt the rack enough to get the steering shaft back off. Do it once, reverse the bearing, and problem solved. I don't know where you're at on your build, but I'm willing to bet there are bigger challenges ahead than this one. Happens in every build. :p

What I had in mind was a slip sleeve between the firewall and the rack. This could be in the form of a double DD outter sleeve with a double DD shaft inserted and fitted with a spring to keep the tension downward on the rack's input shaft. This could also be energy absorbing in case of an accident. Yes, I realize they have that incorporated in the upper section inside between the firewall and the dashboard. My power steering rack is from Cardone and I can tell you there is no way for even King Kong to remove the shaft once the rack is in position. Also, the input pressure line fitting is riding high enough that even if I remove the two anchoring bolts and try to slide the rack towards the passenger side, it won't clear the upper tube of the frame. I like serviceability, I like to be able to fix the thing without taking the whole car apart. Keep in mind I didn't do the assembly of the car, I bought it already assembled. It would have been easier during the build to mount the bearing inside vs. now. I didn't have that opportunity. Now I'm having to deal with what I bought. I will get this straightened out but it will be a chore.

[CraigS]

You could cut a section out of the middle of the steering column and then splice it back together. I don't have a mKIV to measure the OD of the column but let's assume it is 3/4 inch. Cut an inch or two out and use a piece of the .188" wall tube from here.
https://www.mcmaster.com/#steel-hollow-rods/=173c595
Slip it into position and drill a 5/16 or 3/8 hole though the tube and column at each end of the tube. Use grade 8 bolts and Nylock nuts. Get a bolt length so the solid shank is inside of the tube and the threads start outside of the tube. You may need a few hardened washers to get this just right. Cut off the excess threads. Tighten the nuts tight enough to collapse the tube to take out any free play. McMaster has tube in many different IDs and wall thicknesses if my guess isn't correct.

[Melb-Mike]

Well I got it done. No cutting. No splicing. No relocating the steering shaft bearing. I recalled seeing steering shaft adapters in the FFR parts catalog. After looking at the end of my steering shaft, I noticed two small set screws on opposite sides near the U-joint. The shaft had a DD end with a female DD to 3/4-36 spline adapter. I removed the two small set screws and after removing the power rack's two anchoring bolts I was able to remove the shaft off the adapter. After that I gently tapped off the spline coupling from the rack. It's a lot easier to install the spline adapter to the rack and then install the DD end into the adapter than mess around trying to line up the spline. My spline is very tight and requires it be tapped on and off. After a couple of slight misalignments, I got it dead on centered. It's pointless to install the large screw into the rack's input shaft since there is no physical way to remove the shaft without removing the rack first. And with the sharp edged stainless cover plate on top of the radiator, I also managed to slice my left forearm. Am I having fun yet ?

Now the Wilwood brake upgrade comes next. Hope it goes smoother.

[Boydster]

Glad you got it! I'm going to have to try your way when it comes time to align the steering wheel. I tried moving the bearing inside the footbox yesterday. It took some grinding on both halves of the bearing retainer, and it wasn't enough. I put in a 1/8" stack of washers to move the bearing further in, and still not enough to remove the shaft with everything installed. I'm not going further than that.

[Boydster]

Hey Melb-Mike, just wanted to drop a note in your thread. I wasnt able to separate the shaft from the adapter with the bearing on the outside. I put it on the inside, had to grind on it a bit, and I can now separate them when it's turned just right. Thanks for the tip. And you're right... you dont need a whole new flat because once those 2 set screws are in, there's no way it's coming apart. And it's easy to check at normal inspection time.

Bravo!!

[Melb-Mike]

Glad I was able to shed a little light on this. You are correct, with the steering rack installed, you can't separate the shaft end from the shaft. I removed the two hold down bolts on the rack, slid the rack towards the passenger side about 1" and then the shaft end would separate. What really surprised me is nobody mentioned the removeable adapter end of the shaft while they mentioned moving the bearing inside. I wonder if this is such an unknown bit of info ????

[edwardb]

Glad I was able to shed a little light on this. You are correct, with the steering rack installed, you can't separate the shaft end from the shaft. I removed the two hold down bolts on the rack, slid the rack towards the passenger side about 1" and then the shaft end would separate. What really surprised me is nobody mentioned the removeable adapter end of the shaft while they mentioned moving the bearing inside. I wonder if this is such an unknown bit of info ????

It's not unknown. I thought that's what you were talking about. It's pretty common to put the splined adapter piece on the steering rack, lock it down, and then take the steering column on/off with the two set screws and the square drive fitting. Since I'm posting, I'll also go ahead and say I personally wouldn't leave the large set screw off the splined piece either. Along with a good dose of Loctite on the splines and the set screw. I hear you that it can't slide off the end once the steering column is installed. But you also don't want to take any chance of it being even slightly loose and introducing slop in your steering. When it comes to steering I want belts, suspenders, and whatever else I can find. :)

[Melb-Mike]

Thank you for your input. In order to use the large set screw, I would need to remove the rack from the car and on the bench drill a hole into the splines so the set screw would penetrate into the input shaft by more than two threads. Also, in order to even get the splined adapter onto the rack's spline input shaft I had to apply anti-seize compound on the splined and drive the adapter with a drift and hammer. To say the thing is tight is an understatement. I understand your desire for safety but when I said King Kong couldn't yank it off, I meant it literally. The only way it could be more secure is if I welded it on. And I'm more apt to tack weld it with my MIG than use a small set screw of limited grip.