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

[Stanglover]

Ah my friend, now I have a better idea of what's what. Doing a 'simple' seal replacement, one would not get into this area. Obviously you have a well equipped shop where you can work on this... lucky you!! I liked your spanner tool to set the torque on the input shaft. Virtually impossible otherwise, no way to attach a torque wrench. All I did was by feel, tightened till hard to turn by hand and then backed off till I got free but firm movement. Hope it will be OK, won't find out till I get it running.

I for one, will be bookmarking this thread for future reference. I am sure your diligent work will help others attempt a rebuild/upgrade rather than paying big bucks for the same thing. Again very well done and thank you for your time and input.

Geoff.

 

[Stanglover]

Thanks for posting this, there's some great information here, some of which can only be gained by experience. I know I've learned from it (old dogs CAN learn).

Maybe one of the Admins can move it into the tutorials.

Yes I agree. Admin, please move this to tutorials. Excellent info here for all to benefit from.

Stanglover.

 

[Bentworker]

I finally got the rag joint / steering coupler done.  It was a pain to make one I was satisfied with.  I used the splined part of a Chevy rag joint (The one from the lares 200 would have also worked)  the disk from a Lares 200 and made my own 9/16" and 5/16" pins out of some 303 stainless.  The pins were turned to be about .002 larger than the holes in the splined section.  I pressed it all together on an arbor press then used some high quality button head 10/32 screws to retain the pins.

I tried some other things first like the "Help" brand rag joint repair kit, it is total junk.  The disk only had reinforcement in one direction.

Also tried the Ingalls engineering poly rag joint kit, the disk seemed a little soft like it would deflect a lot easier than the stock reinforced rubber ones.  It came with nicely machines pins but they were a little small for all the splined castings I had. Also the pins has to be swedged to retain everything and I already tried that with some other ones I made and ended up breaking the casting trying to swedge the ends of the pins.

We'll see if it was worth the trouble.

Pin, drilled .375" deep for 10/32



Top of pins, one 9/16" OD, the other 5/16"



Mustang spine on top, Chevy on the bottom



It's done!



The bone pile...



Retaining screw.

 

[Don C]

Nice looking work. You can always tell when someone takes pride in their work, little touches like the chamfers on parts that, if it weren't for the pictures, no one else would ever see.

 

[Stanglover]

Again, more good work and information on upgrading the crappy steering box ratio. I'm certainly going to keep this thread for future reference.

I finally got my engine in and fired up yesterday and was more than pleased to find that MY attempt at rebuilding my SPA-T box was successful. I still have about 1.5" of play on my steering wheel that I can't adjust out. That's the same as it was before, so I can live with it. I now know I can rebuild a steering box, so maybe when I get time!!, I may attempt a mod to change the ratio.

Again good work and thanks,

Geoff.

 

[Bentworker]

I cut and pasted some of the steering box application sheets below, since you never know how long that other site will host them for. I just put down the 80's Camero / Firebird and the 90's Jeep Grand Cherokee since they are both plentiful and cheap in self service wrecking yards. Not all of the Camero/Firebirds had the 12.7 box, be sure to look at the information below. It seems like if the car had a V8 it has the desirable steering box. Also keep it in mind that the Camero / Firebird "XH" boxes have the largest torsion bars for steering effort and feedback, you just have to make a hybrid rag joint like I did.

Keep it in mind that the 12.7:1 ball screw will always have the two lines between the "threads" If you look at the first post you can see the picture. At the wrecking yard you can always remove the sector shaft and cap on your parts box, then turn the input so that the piston is at the end of the bore to expose the ball screw. If it has the two lines you have found the desired 12.7:1 box. It is a good way to be certain.

Also, a good pitman arm puller makes junkyard shopping much easier. I use a Snap-On CJ119B.

Compiled by Jim Shea, Posted

1982-93 Camaro Power Steering Gears

YEAR

ALPHA CODE

APPLICATION

GEAR RATIO

EFFORT

T-BAR SIZE

TRAVEL

1982-83-84

WN

F Level IV

14:1

24-30

0.204 Dia

35 deg

WP

F Berlinetta

15-13

14-20

0.175 Dia

35deg 15min

WS

F Level III

12.7:1

24-30

0.204 Dia

35 deg

1985

WN

F Level II

14:1

24-30

0.204 Dia

35 deg

WP

F Berlinetta

15-13

14-20

0.175 Dia

35deg 15min

WS

F Level III

12.7:1

24-30

0.204 Dia

35 deg

XH

F Level IV

12.7:1

28-34

0.210 Dia

32 deg

1986

WS

F Z28 w/o FE2

12.7:1

24-30

0.204 Dia

35 deg

XH

F V8 w/FE2

12.7:1

28-34

0.210 Dia

32 deg

JL

F-Base

14:1

20-26

0.195 Dia

35 deg

1987 thru 93

WS

F Z28

12.7:1

24-30

0.204 Dia

35 deg

XH

F w/FE2 Level IV

12.7:1

28-34

0.210 Dia

32 deg

JL

F-Base

14:1

20-26

0.195 Dia

35 deg

1992.5-1998 Jeep Grand Cherokee

1992.5 -1993 AL or BT Jeep Grand Cherokee 12.7:1 20-26 0.195 Dia 43deg 45min

1993 MN Jeep Grand Cherokee 12.7:1 20-26 0.195 Dia 43deg 45min

1994 AL,BT,PD,ZJ Jeep Grand Cherokee 12.7:1 20-26 0.195 Dia 43deg 45min

1995 JH Jeep Grand Cherokee 12.7:1 20-26 0.195 Dia 43deg 45min

1996 KD Jeep Grand Cherokee 12.7:1 20-26 0.195 Dia 43deg 45min

1997-98 WK or BT Jeep Grand Cherokee 12.7:1 20-26 0.195 Dia 43deg 45min

 

[Bentworker]

Just happened to come across this video on YouTube. They do an excellent job of explaining how a power steering box works. The guy is a little dry, but the cutaway and animation of how the valve works are both awesome.

In the video they refer to the torsion bar as the metering rod. So with that bit of translation you can get a pretty clear picture of how the box in the Mustang works, and see why you won't get increased feedback without swapping in a larger T-bar / torsion bar / metering rod.

 

[Stanglover]

Now, that gives me a better idea of how it works! Good video, but you're right, the guy is a bit "dry". Thanks for posting.

 

[Bentworker]

800 series box3.pdf

Found this today, it shows the adjustment procedure. This came out of a GM service manual and is for the 800 series Saginaw box. The pdf picture quality is a little better than the scanned photo I posted before.

 

[Bentworker]

I edited most of my posts, added descriptions to many of the pictures and tried to make the whole process a little clearer. I did not remove any wording, only added. Hopefully this will help someone on the forum to tackle their own quick ratio conversion. Really it is a pretty inexpensive and rewarding little project if you have some time and want to tackle it. Plus who does not love a trip to the self service wrecking yard?

 

[Bentworker]

More donor applications cut and pasted from Jim Shea

1983-96 SAGINAW 800 FAST RATIO (12.7:1) POWER STEERING GEARS

(Not including F-Car)

YEAR ALPHA CODE ORIGINAL APPLICATION GEAR RATIO EFFORT T-BAR SIZE TRAVEL

1983-84 Olds G YA Hurst 12.7:1 24-30 0.204 Dia 39deg 15min

1985 Chev G (MC) YA Monte Carlo SS 12.7:1 24-30 0.204 Dia 39deg 15min

Olds G " Hurst " " " "

Buick G " Sport Coupe FE3 Turbo " " " "

1986 Chev G (MC) YA Eurosport 12.7:1 24-30 0.204 Dia 39deg 15min

Olds G " V8 " " " "

Buick G " w/HO " " " "

1987 Chev G (MC) YA Monte Carlo SS 12.7:1 24-30 0.204 Dia 39deg 15min

Olds G " V8 " " " "

Buick G " w/HO " " " "

1988-89-90 Chev B WZ F41 12.7:1 20-26 0.195 Dia 43deg 30min

CP FE2 12.7:1 17-22 0.185 Dia 43deg 30min

1991 Chev B CP FE2 12.7:1 17-22 0.185 Dia 43deg 30min

1992-93-94 Chev B CP FE2 12.7:1 17-22 0.185 Dia 43deg 30min

FB Police 12.7:1 20-26 0.195 Dia 40deg 45min

HL Police 12.7:1 24-30 0.204 Dia 40deg 45min

1994 Buick B KL FE-1 12.7:1 17-20 0.185 Dia 43deg 30min

1995 Chev B CT FE2 12.7:1 19-22 0.185 Dia 43deg 30min

DU Police w/FE3 12.7:1 20-26 0.195 Dia 40deg 45min

1995 Buick B FK FE 12.7:1 17-20 0.185 Dia 43deg 30min

1996 Chev B TW FE2 12.7:1 19-22 0.185 Dia 43deg 30min

MX Police w/FE3 12.7:1 20-26 0.195 Dia 40deg 45min

KW FE 12.7:1 17-20 0.185 Dia 43deg 30min

 

[tony-muscle]

Excellent video.... like he says i need to watch it couple times but makes me understand better. Thanks for the link.

1971 M-code Mach 1

 

[Bentworker]

Link to a site with a steering box tag de-coder. Kinda handy to have.

Peter

http://www.stangerssite.com/steeringboxtagdecoder.html

 

[Vinnie]

Thanks for the video! Always wondered how that works.

 

[Bentworker]

Another resource, lots of info at this link. A couple very good scans of the Saginaw manuals including a long version for the 800 box (what our cars have)

https://midweststeering.com/wp-content/uploads/Saginaw-800-PS-Comp.pdf

https://midweststeering.com/service-information/

 

[Don C]

Good find, good trouble shooting information on the entire front steering system in the manual. :goodpost:

 

[Bentworker]

It has been about 2 years since I posted the steering box build, just curious has else has done a DIY steering box?

 

[Stanglover]

Yes, well sort of! This will be a bit of a story but..................

About 5 years ago, I switched my Mach from manual to power steering. I was fortunate to pick up a SPA-T box and pump for a hundred bucks. The hard part was finding the appropriate pulleys. In short, it worked fine for a couple of years, but started leaking. Being capable, I stripped it down, installed new bearings and seals, made adjustments to the sector shaft, but still had too much play at the S wheel.

SO, I sent it to a local steering and brake rebuild company. It seemed to work better, less free play, but it then lost power on right hand turns. I was told the rotation valve was shot. Okay now what. I saw on here that someone else, possibly in this thread, was looking for a "T" box and Don from OMS replied saying he had a couple. I bought on of those, took it back to the shop for them to switch the rotation valve. When I got it back it took me about 2 seconds to realize something was wrong. It only had a little over two turns lock to lock, should be 3 1/8th (according to my Ford manual). So back I went. Now, here is the part that was unbelievable. The so-called "expert" took the end cap off and removed four, yes 4 balls from the space between the ball screw and plug. At this point, I forced myself to shut up when he told me the screw was full still, they must have been "extras" !!! Really? I'm not dumb, I know what happened, but he couldn't admit it, the balls came out of the screw when he pulled the rotation valve out. I took only 20 balls out, so 4 missing.

The old adage "if you want a job done right, do it yourself" is very appropriate here. I have since stripped it and redone it, but not yet installed it. The car has a 17.5:1 fixed ratio box in it at present, so it's drivable and only just out of storage.

The point of this saga is that good people and good parts are hard to find, around here anyways. What I have learned is there are several factors to remove free-play, but getting the parts is my problem. I need bigger balls!!  According to the manual, there are several sizes, but where can I buy these? I tried the local GM dealer, no go there.  Adjusting the sector shaft alone is not going to remove rotational play.

So, after all this, does anyone know where I can buy new or remanufactured parts? I'd like to build up a good spare box just in case, but I do have to consider the dollar exchange rate to make it worth while.

Geoff.

 

[red351]

I had a 5 turn that I rebuilt because it started leaking and ran it for ten years in the 72 mach. Two years ago I came across a 87 jeep wrangler with a better ratio (3 1/2 turns). Took the guts out and put them in an other Saginaw box that I had laying around that also leaked. Again with all new seal kit, but ended up having 4 full turns. I had to use the stop that was in the ford style box to get full pitman arm travel needed. So that's how I ended up with 4 and not 3 1/2 turns. I'm happy with faster ratio.

 

[Bentworker]

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?