Playing with steering boxes. SPA S fixed ratio, SPA AF variable ratio. Firebird 12.7

[tony-muscle]

I also had an issue with a "pro". Lee (not longer in business) remanufactured my steering pump. First it was leaking between the housing and body because the housing was out of round. Granted it was not his problem the housing was bad but they should have cough it and told me. I eventually did get another housing and fixed that leak. Then a year later the pump failed foaming and making a big mess.

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[Stanglover]

Geoff,

I don't know if I would swap out just balls, safer bet would be the entire ball screw assembly.   I have not found a source to get new parts, Midwest Steering is a strong maybe, if you do find someone be sure to post where you found parts.  That is pretty crummy that the "pro" you used screwed up that bad.  Did you try setting up the thrust bearing preload like shown in the Saginaw paper?

 Reading the Ford manual, the pre load is a very low inch/pound number. I've not been able to find a suitable needle torque wrench for that. I did set the input shaft as described by tightening then reversing the nut 1/2". Seems to be pretty close by feel.

I would tend to agree on replacing both screw and balls, but again my manual refers to just going to a larger size ball if the pre-load is off. I don't have the manual in front of me to actually quote it, but that's pretty much what it says. The thing that got me is the ball diameters are given to 5 decimals. As a machinist, I have never needed to go more than 4 or to the 1/10,000", nor have I seen a micrometer that will read to that accuracy. Don't forget, this manual was written 47 years ago. Today with CMM tech, it is probably quite easy.

There is a company near Toronto that does custom rebuilds on Saginaw boxes, so I may give them a call. Maybe they can offer up some information.

Another problem I noticed on the parts box I have is the bore for the rotation valve is worn quite a bit from the Teflon seals, far more so than on the "good" box. I have no idea if this can be recut and or sleeved. I would think that just honing the bore would not be an option, so I guess that casting is junk. I'm hoping that the box currently in the car will give me a usable casting, but I won't know until I get it changed. I would like to build a 12:1 ratio, but that depends on the availability of good parts.

 

[92GTS-R]

Wow, just found this thread, great info, just need to get my head around it.  My current 71  steering box is leaking fluid out of the top where the locking nut locates and the steering coupler joins onto the splined shaft, looks like its way more complicated than I thought it would be  

 

[Stanglover]

Wow, just found this thread, great info, just need to get my head around it.  My current 71  steering box is leaking fluid out of the top where the locking nut locates and the steering coupler joins onto the splined shaft, looks like its way more complicated than I thought it would be  

It is possible to buy a seal rebuild kit and do it yourself from RockAuto.com. The trick is getting it back together and set up correctly. If you have doubts about doing it, overall it might be better to bite the bullet (again) and buy a new or rebuilt PS box already done. If that were to be the case, you might want to get one that is converted to fast 12.7:1 ratio. I've done my own V/R boxes, so have no experience with companies like Red Hat or Powersteering.com I think it is. If you decide not to get a fast ratio, I would definitely get the variable 16 to 13:1 box, SPA-T or V. While you're in there, do the pump as well, then add new H/P hose and return hose. In other words, do it all, do it right.

 

[92GTS-R]

I have just done the seal replacement on my Eaton pump, But I do require new lines and now it seems a new steering box    

Being in the UK the problem is going to be the weight of the unit and shipping  

 

[Stanglover]

I have just done the seal replacement on my Eaton pump, But I do require new lines and now it seems a new steering box    

Being in the UK the problem is going to be the weight of the unit and shipping  

 There are some good, some not so good videos on YouTube for rebuilding Saginaw 800 steering boxes. If you do not have excessive free paly at the steering wheel or more importantly, a leak at the bottom of the sector shaft, a rebuild / reseal is doable. The kit(s) I use from RockAuto are Edelmann EDL 7860 and/or Edelmann 7858. From the price, I think this is the one that has all the bearings. From my experience, I would buy both because the hardest seal and easiest to break is the feflon one on the rack piston and you only get one per kit. It's a bi*ch to get into the body without breaking it. There is a fluid return hole that tends to have a very sharp edge, but there's a trick for this. If you decide to give it a go, between our friend Bentworker and I, we can probably get you going. I have a lot of pics to explain things.

Unfortunately you wont know how bad the old box really is until you get it stripped. At that point, it's either rebuild it or buy another. There are several factors we can go over at that point before you order a new box. To get the pitman arm off, you may need to go see your favorite garage and have them blow it off with a good impact wrench and puller. Those suckers are on there!!

 

[92GTS-R]

Thank you very much for the info  :thumb:

 

[Fabrice]

Ordered that rebuild kit at rockauto, it's very complete. My box is fine, but it would be silly not to service it after 50 years and their affordable pitman puller that did fine too.  

 

[Stanglover]

Something else I looked at without success so far, is finding the correct size teflon seals and "O" rings separately, especially the rack piston seal. I have at least two partial kits that now, are no use for much. I have a spare casting that has a .005" deep groove in the rotation valve bore at the outer most seal ring that I'm sure, if I could find an "O" ring slightly thicker cross section than stock, I could put that box back into use. That .005" deep groove is enough for that seal to leak, causing poor performance.  Boring and adding a sleeve is just way too expensive and not worth it. Way cheaper to look for another casting. It's a shame because it is/was an otherwise good casting. Oh well, I have another V/R box ready to go, I just like playing with "stuff".