I am putting a '73 PS system into my '66. Got everything bolted in and added new lines and then did an initial fill of the PS fluid. Noticed some slight leaking out of the top of the PS gear box so I took it out today and replaced the top end with a new seal kit. Had a friend stop by to make sure I wasn't doing the wrong thing to get the original dust boot seal out, and then he checked the box for wear. On the output shaft there is essentially no side to side nor up - down movement. Virtually none for the input shaft either. However, I have the pitman arm attached to the output shaft, and you can move it/rotate it by hand maybe 1/8 of an inch total before you can feel it fully engage the internal gears.

Is this normal movement, or should there be NO rotational movement at all? Is this adjustable with the adjustment nut or is that affect something different? The forum search on this topic talks about all the other items that need to be inspected fixed for "loose steering syndrome" (should we call in "LSS"? ) like rag links and steering column bearings and tie rods and wheel bearings and pivot bushings, etc, but they don't apply here since I have this gear box detached from the truck. Is there suppose to be some slight rotational movement or not and is this what the steering adjustment is suppose to compensate for or not?

Thanks! Hope I didn't spend a whole afternoon of labor and the cost of a seal kit on a steering box that needs to be replaced!

 

With a worn box there will always be movement. While you can adjust that movement out with the adjustment screw the box will bind up in other positions. VERY DANGEROUS! There are torque tests for the adjustment screw in the repair manuals that can be used when the box is out of the truck.

 

Thanks Eric for the reply. I'll assume you meant to say "worm" box? I thought there might be some amount of movement along the rotation axis, but the guy that came by yesterday says there should be zero movement!? I believe the manual states something along the line that there should be about 11-15 inch-pounds of torque required to start movement of the input shaft from the centered position without anything (linkage, steering column) attached, but I don't know how to test this without a special nut to fit over the geared i/p shaft (or maybe I can get a socket fit it)? How much movement is within spec? Thanks.

 

Bummer - I just called Redhead Steering and talked to Harvey. Great guy! I explained what I'm doing and what I've got and this slight movement, and he said there should be no lash movement! The adjustment screw IS for this type of movement/wear, and gave me directions on how to set it up and test to make sure it will work OK or if I need a rebuilt unit.

FYI, I talked a bit about the shop manual procedure to set the preload to 11-15 in-lb, etc, and he said that procedure is NOT good for used gear boxes with miles on them! I'm to adjust the screw with 1/8 to 1/4 turn max and then see if the lash is gone. Then by hand test the input shaft for any movement. 1/2 turn is basically the limit on turning that screw if I understood him correctly.....

Bummer

 

No, I meant worn, as in not new, worn out, used, etc.

And NO, -if you set a used or worn box for zero lash you will crash when the steering binds up. Many people here have tried that and ended up with steering that would not return to center.

The box is worn the most in the center where most of the action is. If you adjust to zero lash at that point you will end up with less than zero or an interference or bind or whatever you want to call it outboard of the worn area. Steering that binds up is very dangerous!

A person needs to test for steering effort at all points across the operating arc of the steering. If at that point the play at the center is unacceptable then the box or the worn gear parts must be replaced.

 

The looseness you are probably experiencing is between the teeth of the sector shaft and the rack block. These pieces are machined so that they are tighter in the center of travel than to either side. This is because the vehicle is driven 99% of the time in a straight line and needs this tightness to keep the box tight so it won't wander going down the road.

However, the difference between the tightness at center and the tightness off center is very slight. Typically, you have a certain amount of measurable drag when turning the box (when not hooked up to anything) that accounts for bearing drag and friction from moving parts against the case. This is usually only about 6-8 inch/pounds (depending on the vehicle and steering box design). When the box comes up to the center of travel, this reading should increase about 4-5 extra in/lb and then go down again after center. This is a very small amount of drag and must be measured with an accurate torque wrench.

This is enough center gear mesh drag to keep the box tight at center, but not enough to cause binding or excessive wear. If the gears will not produce a "high spot" at center, or has tight spots at either end of travel, then the gear teeth are worn and will have to be replaced.

 

That "tight spot" in the middle experiences the most wear and as it gets loose there is impact loading also which makes it wear faster. Kind of a no win situation. At least you have the box out so you can measure the torque. To measure small amounts of torque usually requires what is called a "torque watch".

 

thanks Eric and stanger53 for the comments. Warren from Redhead Steering did suggest I can try the adjusting screw, but no more than 1/2 turn total. He also said that once these steering boxes get enough miles on them then the torque setup procedure is not very accurate/useful (again on a used box, not a completely rebuilt one). He said that after I tighten the adjustment screw clockwise about 1/4 turn, check output shaft play and if that is gone then check for ANY movement on the input shaft and if so, it needs to be rebuilt. So, there must be some success in using the adjustment screw otherwise I would thing the lash adjustment would be made more "permanent" from the factory... He also said that the shafts themselves are made of very hard heat treated metals and he rarely has to replace them - it's the bore in the casing itself that wears (more oblong) that causes this slop - thus his modification of re-boring the casing and installing rollerbearings on the output shaft fixes most.

 

As DaggerNC was told, it makes sense to upgrade to roller bearings on these Ford steering boxes - some rebuild shops do it routinely. I was told that if you do moderate to serious off-roading, the upgrade is essential. Expect to pay more for an 'upgrade' rebuild - up to 50% more than for a GM Saginaw box rebuild.

 

Not being familiar with the various steering boxes that come in Ford pickups, I am assuming that the steering box in question is the typical Saginaw-style integral box like used in many passenger cars?

If so, I know the output shaft uses a needle/roller bearing on the bottom, and the top of the shaft is supported by an aluminum bore made into the bottom of the top plate. Is the wear you are talking about, and the roller bearing conversion being discussed, the modification of this aluminum bore and the insertion of a needle/roller bearing like is on the bottom of the shaft?

 

My assumption after talking and reading on this topic is that these integrated PS gear boxes do NOT have a roller needle bearing on the bottom of the output shaft? That is mod that I believe Redhead Steering does (are there other sources?).

 

The Ford boxes are not Saginaw, Ford decided to make their own steering boxes.

 

Correct me if I'm wrong...but certain Broncos had a true GM Saginaw power steering box. Most Fords of course had Ford design boxes that had much longer 'sector shafts' without roller bearing support at the bottom of the output shaft. The OEM regular bearings (bronze?) used were a weak point.

Yes daggerNC, there are other shops that install roller bearings in Ford boxes as part of their rebuilds. "Steering Solutions" in Surrey, BC do it for $349Cdn exchange Toll free 1-877- 513-9813 or (604) 513-9813

 

Mr. Fixit - sounds like it's a west coast thing!

 

An update: I decided to try adjusting the set screw on this PS gear box as Warren from Redhead Steering suggested. Interesting results. I mounted the box in the truck and connected the lines but did not add any fluid (some left in the lines/pump box). Connected the steering column/steering wheel and then centered the wheel (no steering linkage attached). With only about 1/16 of a turn clockwise, there is virtually no movement at dead center, but when I move off center by about a turn then I can move the pitman arm ever so slightly. I then put the steering back to center and put a in-lb torque wrench (analog) on the steerwheel nut looking to make sure there was less than 20 in-lbs effort to move the steering wheel. To my surprise it only took maybe 5 in-lbs to start moving the wheel off center!?! I rechecked the pitman movement at dead center and none really. Turning the wheel all the way left and right I don't feel any mechanical binding but I do feel/hear fluid pressure resistance from the fluid still in the gear box.

Think this is OK to try out?