NOS Power Steering Gear Box

7173Mustangs.com

Help Support 7173Mustangs.com:

Joined
Jul 27, 2021
Messages
820
Reaction score
598
Location
East Texas
My Car
1971 Mustang Mach 1 M code 351 4 speed
Would a power steering box have any actual grease in it? I thought that they were lubricated by the power steering fluid and that just the manual boxes used grease. I could be wrong, I have never opened or rebuilt one, when they have gone bad I have just taken them out and had someone rebuild them. On a power steering box the most worrisome part would be the rubber o-rings and seals that are inside it. If the box had some oil in it, and that oil is still there, the o-rings should still be fine. If I was going to try it out I would fill it with ATF (I think type-F is what our boxes require if I recall correctly), and move the gearing around by hand and let is sit for a day or so to get all the seals and o-rings lubricated before I put it on. I would be willing to bet that it still works fine, as long is it was not completely dry on the inside when you got it.
 
Last edited:
Joined
Sep 12, 2015
Messages
6,049
Reaction score
1,045
Location
SW Ontario
My Car
1971 Mustang Mach 1, M code, 4 speed.
Would a power steering box have any actual grease in it? I thought that they were lubricated by the power steering fluid and that just the manual boxes used grease. I could be wrong, I have never opened or rebuilt one, when they have gone bad I have just taken them out and had someone rebuild them. On a power steering box the most worrisome part would be the rubber o-rings and seals that are inside it. If the box had some oil in it, and that oil is still there, the o-rings should still be fine. If I was going to try it out I would fill it with ATF (I think type-F is what our boxes require if I recall correctly), and move the gearing around by hand and let is sit for a day or so to get all the seals and o-rings lubricated before I put it on. I would be willing to bet that it still works fine, as long is it was not completely dry on the inside when you got it.
Wow! Just knowing you have a "brand new" PS box is an awesome find. Also knowing that nothing inside is worn, sector shaft, rack screw and balls or the rotation valve, means that replacing the seals and "O" rings is relatively easy. However, some care, knowledge and specialty tools are needed. There are some good YouTube videos (and some not so good) that show how it's done. Setting the pre-loads is the hardest part. Lots has been posted here too.
However, one question; what is the ratio, i.e. tag letters.?
 
Joined
Sep 12, 2015
Messages
6,049
Reaction score
1,045
Location
SW Ontario
My Car
1971 Mustang Mach 1, M code, 4 speed.
I would be a bit surprised if the rubber input / sector shaft seal hold up after 50 years.
Yeah, I'd want to put all new rubber and teflon seals in for sure. Way too much work to put it all in the car and then find it pukes oil.
 

piper62j

Well-known member
Joined
Jul 6, 2014
Messages
354
Reaction score
18
Location
34613
My Car
1973 Q-Code Mach 1. Full restoration in progress.
The power steering gear box does not require grease of any kind.. Before replacing the seals, fill the gearbox with the appropriate fluid (Type F transmission fluid) if I recall, Work the gearbox by hand thru several revolutions from stop to stop to allow the fluid to work it 's way into the spool valve, worm gear and recirculating balls.. If the unit is free in motion with no sticking, it's good to go.. Factory fresh gear boxes are sealed internally with a fine coat of preservative to prevent corrosion during storage.. That coating dissolves once the unit is pressed into service.
 
Joined
Sep 12, 2015
Messages
6,049
Reaction score
1,045
Location
SW Ontario
My Car
1971 Mustang Mach 1, M code, 4 speed.
The power steering gear box does not require grease of any kind.. Before replacing the seals, fill the gearbox with the appropriate fluid (Type F transmission fluid) if I recall, Work the gearbox by hand thru several revolutions from stop to stop to allow the fluid to work it 's way into the spool valve, worm gear and recirculating balls.. If the unit is free in motion with no sticking, it's good to go.. Factory fresh gear boxes are sealed internally with a fine coat of preservative to prevent corrosion during storage.. That coating dissolves once the unit is pressed into service.
Checking it out as you describe would definitely be worth a shot. That would save a ton of work upfront. However, if it pukes under pressure, you're back to square one. There is the option of test under pressure on the bench if one had a pump set up.
 

piper62j

Well-known member
Joined
Jul 6, 2014
Messages
354
Reaction score
18
Location
34613
My Car
1973 Q-Code Mach 1. Full restoration in progress.
Checking it out as you describe would definitely be worth a shot. That would save a ton of work upfront. However, if it pukes under pressure, you're back to square one. There is the option of test under pressure on the bench if one had a pump set up.
Good point.. However, the spool valve is the only pressurized section within the gearbox. The sector shaft and worm gear are lubricated thru the bleed collar inside the spool valve.. There is no high pressure outside the spool valve.
 
Joined
Sep 12, 2015
Messages
6,049
Reaction score
1,045
Location
SW Ontario
My Car
1971 Mustang Mach 1, M code, 4 speed.
Good point.. However, the spool valve is the only pressurized section within the gearbox. The sector shaft and worm gear are lubricated thru the bleed collar inside the spool valve.. There is no high pressure outside the spool valve.
You are of course, correct. No argument here.
Replacing "O" rings and seals is definitely a job for someone with good mechanical skills, tools and knowledge of how these things work. I generally ere on the side of caution, so for me, I'd probably go ahead and replace, or at least check the "O" rings and seals. The teflon seal ring on the rack piston is a biotch to fit with out breaking it!!
If not, then go ahead and keep the fingers crossed I guess.
 
Top