The following post is more of a play by play post as it reflects what's recently done, specifically today.

Power Steering --> Round 2

Talk about deja vu.

One of the spares.

Super... another toxic mess to, well.... unmess.

I'm just painting the case parts this time. They are cleaned and the first coat is drying.

So then I started on this:

Differential

Time to get crack'n on this. I do believe I have all the parts to assemble the third member. The third member case is a Summit Nodular Iron unit. An Eaton Truetrac will reside in it and tethered to that is a set of 3.00 gears. Now for the astute you're probably wondering how 3.00 gears are going to work in a Truetrac that will only accept 3.25 and larger gear sets.

That is a good question. I did some research and just a little machining needs to be done on the face of the pinion to clear the differential body. If that's all, then I think I can handle chucking that up in the lathe and face cutting the pinion. Currie enterprises offers this complete third member with the Truetrac and 3.00 gears. I'm not saying what you see on the table was inexpensive but it's a heck of a deal compared to the Currie ($1600).

I am reusing the 3.00 gear set from the galaxie 500 XL. If I can't get a decent gear pattern I have two more sets of 3.00 gear sets I can try. Now the timing marks are still visible on these gears. For those unaware the gears are machined together and timing marks are placed on the gear sets that are non-hunting and semi-hunting. Therefore it's important to time the pinion to the ring gear when assembling, much like a camshaft timing sprocket set.

My goal for this axle to accomplish similar to the building of the Ford 9" I did for my Chevrolet Caprice Classic. See here for that build up and installation: Converting GM 12 Bolt Rear Axle to a Ford 9 Inch Axle

With that I have the key third member pieces cleaned and the first coat of paint applied (POR 15).

Probably will not be till after Christmas before they are ready to assemble. But I still have an axle housing to contend with and Explorer type disc brakes to adapt to it. It will not be easy.

Power Steering --> Round 2 Continued

Thought I'd continue on with steering gear #2.

All the parts cleaned and painted.

I'll go right to the juicy end since I just covered this.

This has more play than the first one..... Well crap....

You win some and you loose some. But here's my thoughts on all this. But first a simple primer on how these things work for those who may not know. If you do skip this part.

Quick and dirty tutorial:

This is the control shaft assembly. You can see the input shaft on the right where the steering coupler attaches and the worm gear on the left that moves the piston/rack assembly. There is a torsion spring rod connecting the input shaft to the worm gear. It actually runs inside the input shaft and inside the worm gear. Attached to the torsion spring is a mechanism that either moves the spool valve holder up or down depending on the rotation of the twist on the torsion rod bar. If you have vice grip like hands and have enough arm/hand strength you can hold the worm gear in your left hand and the input shaft in your right and twist in opposite directions. Depending on how much strength and grip you have you can feel the torsion spring/rod in there and probably see the spool valve holder slide up or down the long axis.

Armed with that mental visual, how the power assist works is the power steering pump puts out a controlled flow rate independent of engine RPM. The flow rate enters and exits the steering gear. The spool valve takes the input pressure and applies it to both side of the piston/rack if there is no twist on the torsion rod (no steering wheel input). When you want to steer the car, this is what happens. First when you move the steering wheel, you are trying to spin the worm through the torsion rod via the input shaft. The worm tries to move the rack through the ball bearings that recirculate. This produces resistance because the rack is ultimately directly connected to the tyres via the Pitman shaft, Pitman arm and steering linkages (tie rods and such). In other words for a tiny movement of the steering wheel you are trying to move the wheels manually as if there was no power steering. This resistance causes the torsion rod to twist and the spool valve to move in the appropriate direction that starts cutting off return fluid to the pump, thus raising pressure, whilst simultaneously applying that pressure to the side of the piston that will move the rack in the direction you're turning.

So really the power assist works off of the torque differential between the worm gear and the input shaft. The greater the amount of twist (more torque) the more the spool valve moves and the more hydraulic pressure or assist you receive. I hope I explained that well enough, if so cool beans we're both on the same page. The extra play that arises comes from a worn worm, worn rack or worn balls, or all the above. Since the power assist only reacts to the amount of twist in the torsion rod, any play in the worm to rack interface doesn't start to load the torsion rod until that play is taken up. If you have 7 degrees of play before the torsion rod engages that will translate to linear amount of circumference steering wheel travel (depends on the diameter of steering wheel) that effectively does absolutely nothing.

Now we were looking at it from the input shaft side, lets consider what happens from the output side of the steering gear. Say you're holding steering wheel firm or locked trying to drive in a straight line. Now the wheels hit a pot hole or a groove in the road and that tries to force the wheels to turn. That force is translated up through the steering tie rods and such through Pitman Arm into the Pitman shaft and into the rack/piston. That rack will move and spin the worm gear, but you're holding the input shaft (steering wheel) from turning. The torsion rod will start to twist and apply hydraulic pressure which will keep the rack from moving any further and prevent the wheels from following the grooves in the road or a sudden steering event from a pothole.

You can imagine if there is indeed play in the rack to worm gear interface, the wheels are allowed to move a little bit more before the hydraulic system corrects that. So the car will have more of a propensity to wander and of course wider tyres will tram more exacerbating the effect.

How to fix this.....

That's another whole ball of sticky wax. There are no replacement parts at all I can find for this. You have a few choices, some unpleasant; find another steering gear and hope for the best, have a machine shop measure/scan the rack and worm then CNC new pieces then heat treat. That route I'd estimate 2-3 grand for a one-up set. Or if the wear is strictly in the rack and uniform try a bearing manufacturer to see if you could get steel balls in a couple thousandths oversize and see if that eliminates the play.

No matter what you do it's time consuming and pricy.

The problem with finding another steering gear is also wear and then, even finding another steering gear. 1965-1968 are the same and they are all old. I have a theory that the wear problem stems from oil break down due to heat. How many people ever change the power steering fluid? Yuppers not many. Ford uses ATF for power steering and ATF breaks down with heat rather easily. The 3rd gen Fords and some of the 4th gens use Ford-Thompson pumps. Ford Thomspon pumps seem to have a high regulated flow rate. These are the old round P.S. pumps with a metal shell for a reservoir. The high flow rate generates more heat, as a result I have found through looking at these cars every 3rd gen Ford with factory air seems to have come with a power steering cooler, or at least the big block cars did. This latest power steering gear I rebuilt that has even more slop than the first one (and has 1/4 less miles than the first gear I did), came from a car that had dealer installed air but no cooler. The oil was black/brown. This supports that theory, but with a small case sample size it could be coincidence.

With all that said, for now I will run with the first steering gear I did and is already installed on the frame. Granted I'm being picky, the play in this one may not even be noticeable as I do not plan on wide tyres, it will be either 225 or 235 all the way round.

To complete the front end of the chassis I put on some crappy tyres and rims for now. Time to focus on the rear axle and its disc brakes.

Differential

Time to start on assembly.

I ran a flat file over the new differential and the old ring gear to remove any burrs. Next I pressed on the carrier bearings.

I had to get creative whilst not damaging the parts to push the bearing past the differential nose sticking up.

The ring gear can go on next.

If you don't have a decent book on Ford rear axles, I have to suggest this book. It's full of good information.

Now the ring gear should be snug over the differential, but this one was tight. I ran a file on the inside diameter to remove any burrs to no avail. I ended up sanding the ID of the ring gear and test fitting numerous times till it finally felt snug without needing a press to get it on. What should have taken 15 minutes to install took over 2 hours. I see why people go mad and abandon car projects.

Also chase the threads for the ring gear and bolts, use Locktite and torque down evenly. Now to hold the differential I used one of the brand new axle shafts.

The new Moser 31 spline 1541h alloy shafts arrived.

I have aluminum jaw protectors installed and holding the shaft which holds the differential enough to torque down the ring gear bolts.

On a side note sorry for the weird lighting pictures. I had recently replaced the fluorescent's over the bench with soft white LED's retrofit bulbs and whilst it's easier on the eyes, it plays havoc with the camera, especially when there is cool white (blueish) fluorescent's in the main roof of the building. The white balance is set to auto but it's all over the place and the pictures end up funky.

I forgot that the new Summit nodular iron cases have a snap ring to hold in the pinion snout bearing. Didn't need stock retainer after all.

Installed.

A couple things here. First before you remove the end caps mark them so they go on the correct side. I just take a small punch and dot the base and bearing cap (left hand side you can see a dimple on the bottom and on the cap).

The last thing, on these Summit cases, remove that small bolt that secures the lock for the bearing adjuster and toss it right in the rubbish bin. It's garbage. It's so soft you cannot even torque them down to the 20 ft lbs without stripping out the head. They are too soft. Obtain some proper fasteners.

Continued in next post.