Manual to power steering conversion for my new “sportsroof”

[bucketlist fastback]

So...    my cool new 73 Sportsroof has manual steering and I am thinking of making a conversion to power for my first upgrade project.  I have been Scouring the 7173 website and the entire internet for anyone who perhaps has done this precise conversion on a 7173 coupe or fastback.   
     I have seen other projects on Falcons and older 65-69 Mustangs but not 7173’s.    I am hoping not to have to cut or modify steering column for a power steering conversion like this..   I have a pick and pull in nearby philly pa who has three coupes who says he is pretty sure he has everything I need... pump, pulleys etc.    Any expert advice would be humbly appreciated.

 

[Hemikiller]

You'll need steering box, pitman arm, rag joint, pump, brackets & bolts, water pump and crank pulleys, belts, hoses and Type F ATF. 

A 50 year old steering box is pretty much guaranteed to leak, so consider getting it rebuilt (or do it yourself) before loosening a bolt, same with the pump. 

 

[Stanglover]

I agree with hemikiller on the parts list. I did this on my 71 Mach 1. It's really not that hard to do, but I strongly suggest getting all the components together and have them serviced or rebuilt before you even start to pull the manual box. I got lucky to be honest because a friend of mine had scrapped out a 71 Mach 1 and sold me the variable ratio PS box and pump with hoses. The hardest part was finding the water pump pulley and again, I got lucky and found one in BC Canada, date code correct as well!! However, I learned my lesson later on when the old parts started to fail. Long story, but eventually, I learned how to rebuild my own PS box and there are many posts and threads that cover this. Search "Saginaw 800 power steering box rebuild" by Stanglover. Also search by author; Bentworker. He has rebuilt many and done ratio conversions and actually was the person who basically taught me to do it. Much of this is for "down the road" so to speak. For now, I suggest finding the correct ratio PS box OR better yet, buy a fast ratio box already done. Red Hat or Powersteering..... .com (damn, I can't remember the name right now) HELP please!

What you need is a box with a tag SPA-T or V which is 16:1 to 13:1 variable ratio. The "standard" box is a fixed ratio 17.5:1 tag SPA-S or U for 71 to some 73's. Also SPA-AD or AF (VR) 73 from 1/2/73 The pump ratio (pulley size) also changed on some cars with AC If I'm correct. If you can find parts that match your car's year, the better imo. 

Also, what steering column do you have? I assume non-tilt. It could be a whole different ball game as the rag joint needed seems to be illusive if not. The rag joint for the non-tilt can be bought from Rock Auto, Lares 201. Pitman arm I got from NPD and also the Idler arm. I would have to look up the numbers though.

That's enough to confuse you for now, all the best with your search. It will be worth it in the end.

 

[bucketlist fastback]

Thank you Hemikiller and Stanglover for responding quickly.     The “Sportsroof” has been sitting in the garage since it arrived two months ago and I would like to start getting this thing back to roadworthy.      In doing research I came across two different videos of fords that had steering columns cut to fit new power steering box so I was growing concerned.   I have been doing a good bit of research on jobs I want to do to the “Sportsroof” and thought this one wouldn’t be too difficult for my skill level and age (59).  (Getting difficult to lay upside down for long periods of time)..  If the pick and pull has the pulleys and pump brackets I can manage the rest.   I just didn’t want to get into a big fabrication job..   Thank You for your support.   

 

[Stanglover]

Thank you Hemikiller and Stanglover for responding quickly.     The “Sportsroof” has been sitting in the garage since it arrived two months ago and I would like to start getting this thing back to roadworthy.      In doing research I came across two different videos of fords that had steering columns cut to fit new power steering box so I was growing concerned.   I have been doing a good bit of research on jobs I want to do to the “Sportsroof” and thought this one wouldn’t be too difficult for my skill level and age (59).  (Getting difficult to lay upside down for long periods of time)..  If the pick and pull has the pulleys and pump brackets I can manage the rest.   I just didn’t want to get into a big fabrication job..   Thank You for your support.   

73's are not my area of knowledge, so perhaps someone with knowledge can confirm the pulley sizes you'll need. If you can get the complete set-up including drag link, idler arm and pulleys from a Mach 1, all the better. I'm pretty sure the year won't matter if you get it all from 1 car. I do know there is a difference in pulley sizes on the 73's. I'm not sure if a car with A/C makes any difference either.

As far as the mechanical work is concerned, you'll need some help as the weight of the PS box can be a strain on older shoulders when you're putting back in. We can go over that later. You'll need a 1 5/16" socket 1/2" drive to get the pitman arm nut off. I took mine to my buddy's garage and had them blast it off with an impact and puller. It WILL be hard to get off.

More later as you get your parts together. In the mean time, take advice from the guys that know, not the abundance of so-called "experts" who just want to make a YouTube video. Not to say there are not some very good video's, just keep an open mind and pick and chose. I actually learned a lot about rebuilding the PS box from Y/T videos....... after going through about a dozen of "yeah, that won't work" by back yard mechanics.

All the best moving forward.

 

[Carolina_Mountain_Mustangs]

I have 72 & 73 and yes the pulley on the PS pump was smaller diameter on my 73 Mach 1 Q code with AC. Do not know why but it is smaller dia..

 

[Hemikiller]

There's a variety of pulley combinations available that will work. You can get pretty much anything from a 70-73 Mustang with a 302. You can also get them from full size cars, mid size (Torino/Montego) etc. Some 351C and 351W pulleys will work also. The non-AC setup is close to a 1:1 ratio on the water pump, AC cars have a smaller w/p pulley to increase fan speed and coolant flow. 

I have boxes full of pulleys and can build a correct 73 matched set up for you. I may have a few extra 70-73 302 P/S brackets kicking around, I'd have to look. Shoot me a PM. 

 

[bucketlist fastback]

Sportsroof update,     First, thanks to all that added advice to my thread post.     Today I finally scored what I hope will get me rolling on my power steering conversion.    I got the parts from a salvage yard in Philadelphia that specializes in old American iron (classic cars).    Unfortunately I didn’t notice that I didn’t have the rag joint coupling that was suggested to me on an earlier post.     Dealing with said salvage yard was somewhat difficult so I don’t really want to return there if I can reuse the one from the manual box or perhaps one from NPD.     I could possibly use some guidance on replacement hydraulic hoses as ones on donor were short and were spliced with couplings and fittings.    Thx

 

[Hemikiller]

Looks like a good score, haven't seen a 71-73 in a yard around here in years. What's the tag # on the box?

The pressure and return hoses are available from Rock Auto. They are not an exact reproduction, none of the available ones are. Steering coupler is Lares 201, also from Rock. 

Hoping you're planning on rebuilding the pump and box before installation. 

Looks like that came off a car with a PS cooler and AC. You'll also need the spacer to go between the pump and head if your car doesn't have AC. Did you get the support bracket and steel tube for the pressure hose? First impression is the pump bracket is wrong, but it may be the angle - what's the part # stamped into it? 

 

[bucketlist fastback]

No support bracket.     There was a short length of steel tube (6”) immediately off back of the pump….   One end male other female joined to a brass coupling that connected the rest of the length of pressure hose..   I got the small finned cooler but it was bolted to the A/C bracket that’s back on the donor..    The bracket and pump assembly looks just like the diagram in this image….    I am aware about missing spacer because of a/c bracket left behind on donor..     do you know if I can change to a two (2) groove crankshaft pulley once I get things sorted out or is there even such a piece?    I have seen aftermarket aluminum ones but not OEM.