Saginaw Power Steering Upgrade - 1974 FJ55 (1 Viewer)

[DoubleNickels]

All right, so here’s the good word: you can install (and be pleased with) a Saginaw gearbox and pump without any major cutting of frame, body, shock mount, or motor mount. Here’s how I did it.

1. With the engine and all body panels in place, I convinced myself that a forward-facing Saginaw box could nest (tight, comfortable, but feasible) just aft of the radiator. Step one was removing all of the goofy OEM linkages and manual box. I had several goals here:
   • Mount the box and its pitman arm as high as possible to keep it clear of objects while wheeling.
   • Anticipate and account for routing of high-pressure and low-pressure (return) lines without excessive length or mounting hassle.
   • Try (as in bonus points) to create a system that uses a single “kit” of Tie Rod Ends to save me or some future sucker from confusion when replacing pieces. Ideally this would be Toyota, but we’ll see.
   • Try (bonus) to keep the angle of the drag link ‘reasonably’ shallow to avoid bump-steer issues.
2. I removed the stock alternator and external voltage regulator (VR), opting instead for an FJ60 alternator (with internal VR) that mounts on the passenger side of the engine bay. I’m a mechanical guy and electrons both confuse and scare me, but I took my time and unwrapped the wiring harness, tracing it back to the fuse block then re-routing along the main bundle that snakes toward the battery. Electrical schematics were my friend here, and I did my best to maintain colors so I or some future schmo could decipher any issues.
3. I ordered a Saginaw gearbox mounting plate from Advanced Adapters. They’re mid-priced at about $85… I think Cruiser Outfitters sells them for less but you have to cut round stock to length and weld it on. I opted for a little more money but less labor. I relied on c-clamps to get the box in an acceptable location, nearly dropping the awkward and heavy box on my face several times. I chose to mockup the steering column linkage using electrical conduit and duct tape. In the end I settled on a two-bar steering column system with a center eyelet support. Without the center support you have too many degrees of freedom, as they say in the engineering world, and the whole system would flop around.
   
   
   
4. The actual steering column components came from Amazon, Borgeson, and Jegs. I welded a Borgeson coupler to the stock joint near the firewall to allow me to retain the telescoping adjustment piece. The coupler has a round hole on one side (welded to the stock setup) and accepts a D-shaft on the other, relying on set screws to hold it in place. The upper D-shaft is a straight shot to the first universal joint – another D-Shaft then spans from here, through the support eyelet, and into the final coupler (universal joint) at the gearbox. I suppose you could keep a rag joint in there but … why?
5. I welded a flange onto the frame’s motor mount to allow me to position my support eyelet. Again this was all roughed in place using clamps until I was confident it would work!
   
   

 

[DoubleNickels]

Now, let’s talk about that box. What box do you think you need? I wanted to have a Four-Hole Saginaw box to assure I could use at least three said holes for mounting. This may not make sense until you try to line it up – due to the jog in the frame you’d be hard-pressed to utilize all four. I’m not saying you can’t, but I found that no matter how I “clocked” the plate I always found at least one hole was right on the edge of the frame. Not wanting to notch and sleeve the frame I opted to just omit one mounting point.

Back to the box – I soon became an expert in Saginaw steering gearboxes. Here’s what you need to know: there are two different diameters of guts (large and small) and two different rotations of guts (standard right-hand worm drive and left-hand worm drive). If you intend to point your pitman forward, which by the way is imperative if mounting the gearbox behind the radiator, you must find a left-hand worm drive box. If you try to point the pitman arm backwards you find your drag link falls directly over the tie rod – it would crash any time you actuate the suspension!

I went to Jalopy Jungle – a local junkyard in Boise - and pulled a Saginaw box from a 2002 RAM van. Any Dodge van, whether a vintage 80’s Astro or a new RAM, will have a forward-facing box and consequent left-hand worm drive. The RAM box was the right diameter (large-cap end) to allow a gut transplant into a different housing. Why transplant anything? Well, the 2002 box had three mounting holes totally different than the adapter plate AND the box was burnt and leaking from every orifice. The donor housing came from a box I had mistakenly purchased from Rock Auto. The box, a Lares 1107, fits a late 70’s J20 and myriad other vehicles. I selected that back when I thought I might point the pitman backward… meaning it was immaculate with fresh seals, four mounting holes, and had 4-turns lock to lock but rotated the wrong way for my needs.

Transplanting gearbox guts is tedious but doable and was fascinating (IMO) to learn about rotary valves and their function. There are some great resources out there in both video and text form (such as this one) and I just followed the directions. Getting the ball bearings back into the worm “channel” will make you frustrated but, again, it’s not impossible. To change a box from one rotation to the other you need to swap the worm, the worm nut, and the front torque rotary valve. I'll try to get some pics up so it makes more sense. If you don’t swap the torque rotary valve you end up with a rather interesting scenario where the steering column mechanically drives the worm one way while hydraulic pressure pushes it the other way, almost breaking your wrist in the process.

When putting the balls back in, you alternate colors. The balls are either black or silver and differ by a few ten-thousandths of an inch in diameter. Alternating diameters allows the small balls to “idle” in their channel between the larger balls, preventing the balls from galling against each other. It’s brilliant, yet at first blush makes no sense. Think about it and marvel at the ingenuity.

Let’s talk Pitman arms. It turns out you can order a Pitman arm “blank”, meaning it is flat with no hole for a tie rod end. I got mine from WFO for about $70. Procuring a blank meant I could drill the tie rod hole to a Toyota taper (which, for your reference, is 1:10 taper, also called 1.200” taper per foot, and available at some local machine shops). See where I’m going with this? Making that arm accept a Toyota tie rod meant I could match my steering arms … it’s all a ‘standard’ FJ55 TRE kit at this point . Note that you could easily ream the pitman and steering arms out to a larger diameter (same taper) if you desire the beefier FJ80 TRE’s – I may do that in the future.

 

[DoubleNickels]

Three steps remained: final drag link fabrication, mounting of the Saginaw pump, and plumbing of the lines. For not a lot of cash but considerable patience I got my hands on a set of RH and LH tie rod end taps and drag link taps. It took some research to confidently determine the size, then even more patience as an Amazon order was shipped from good lord knows where in Asia. In summary:

• Pitman Arm and Drag Link End: M17 x 1.5
• Tie Rods: M21 x 1.5

So about that drag link. The stock drag link is too long, meaning you could shorten it by chopping down the end with the RH thread then just re-tapping that side. You could also cut out the “middle” and rejoin the two threaded ends by sleeving them with a different tube. I decided to just build a new one entirely. Fabricating and tapping a new drag link was incredibly easy. I bought a four-foot section of 1” OD x .1875” Wall DOM tubing from a local metal shop. That wall (.1875”) is pretty burly and, best part, results in an inner diameter (ID) of 15.875mm for that tube. Guess what the recommended pilot hole is for an M17 x 1.5mm hole? About 15.5mm! One less thing to have to fabricate! I took my time and tapped both ends, one LH thread and the other RH as is prudent, then slotted the ends with an angle grinder cutoff disc. I sourced a couple of locking collars off Amazon and called it good. I’m mighty proud of the result:

Mounting the pump was straightforward, as I ordered the old “Downey” bracket from Georg at Valley Hybrids / Cruiser Brothers. You have options there but I chose this because it sits low and out of the way and doesn’t require tying into head bolts. I originally tried to mount the pump lower on the bracket and ended up hogging out a bunch of metal to make things clear. Bad move, don’t do that. In the end the shown orientation is great and plenty rigid. I went with tying the front (slotted) bracket into a water pump bolt which is also recommended. I'll upload another pic.

It’s worth calling attention to the pump/pulley setup used here. The pump is a regular ol’ Saginaw pump with a ¾” taper per foot spindle, pretty sure any make and model will work as it has the same mounting configuration. The pulley can be a challenge, however, if you’re anal (like I am) and want to find a pulley wide enough to accommodate the Toyota belts. The stock pulley is set up for narrow belts… but running a narrow belt will squeal and slip on the stock front engine pulley. Running a wide Toyota belt on the skinny pulley might work… at your own risk (it might wear funny and/or jump the groove). By far your best move is to get a wide pulley and locking bushing from Grainger. I found some of this tech in the 40/55 section but the part numbers were obsoleted, so here is the new beta:

• Grainger Pulley: 5UHE1
• Grainger Bushing: 5UJA2

 

[DoubleNickels]

Final stop was the plumbing. The return line is low-pressure and can literally be scabbed together with a section of hose and some pipe clamps. For the high-pressure input I decided to have a custom line built. I did this primarily because everything I found at the local pick-and-pull was wrong; either the port adapter pieces came off at the wrong angle or the lines were the wrong length. With Saginaw boxes, there are differing threads for the high- and low-pressure ports. AND, to further convolute things, the thread dimensions and fitting type (flare vs. o-ring) changed somewhere in the early 80’s. I just took in some fittings I verified by hand to a local hydraulic hose shop in Boise and said “please make me a hose with these ends that’s this long”. Here was the result:

Final assessment: dig it. Transplanting the guts from the 2002 box meant I’m only 3.5 turns lock-to-lock instead of 4+ as originally intended. There is some misinformation out there regarding fewer turn boxes, people claim that this results in a “twitchy” steering scenario. That is 100% bull**** as the rack and pinion has a varying pitch, meaning the steering response only increases as your wheel angle increases. Make sense? Picture a helix/screw that has fine threads in the middle and coarse at the ends. This is very desirable for me – there’s really no value in having to crank the wheel more than needed. The biggest rock one could throw at this swap is my drag link angle; relative to the axle, it is more obtuse than I’d like – I’ll watch for excessive tie rod end wear but really don’t expect to see anything adverse.

I hope this helps someone, anyone, out there. I admit it took me some time to get everything rounded up, mocked up, and fabricated, but if I did it again I’d know which parts to source and how. Please chime in if you have questions and I’ll share whatever knowledge I have. Cheers.

 

[RocketCityCrzrs]

Holy well written article Batman! I've been struggling putting PS in my piggie because I didn't want to cut the frame. This is a wonderful discovery, thanks man

 

[scrapdaddy]

Good job!

 

[Ol Yeller]

Great info! Really like that you chased part #s down too.

The only thing I noted that wouldn’t pass a vehicle inspection here is welding the streering shaft, but it’s very common to do.

Have you driven it much?

 

[DoubleNickels]

Hey there, thanks for chiming in. Yes I've driven it significantly. You may have seen in the pictures that A LOT was changing concurrently during the power steering upgrade - I pulled the engine out of the way as I doubted my ability to weld in a tight corner, though a more skilled individual could get by without this, I think. I was also upgrading suspension and the drivetrain (H55... woot!) so I did everything at once.

The steering feels very stable and, true to the Saginaw reputation, turns my 33's with a pinky finger. I'm a Toyota guy through and through... with the exception of steering. Saginaw nailed it. Re the welded shaft, you definitely don't have to weld it at all - you can readily find couplers (from Borgeson or JEGS or anywhere) that use set screws/bolts instead. Being Idaho, this vehicle is old enough to not require smog or inspection.

I also threw in 6-degree shims when I upgraded the suspension to account for the caster angle - highly recommended if you have any sort of lift. Hope that helps!

Calvin

 

[DoubleNickels]

Agreed the reverse steer are more rare, but that's my point above - I think every RAM van from the 80's to now has a reverse box. I'll need to confirm, but that's my impression.

I did realize that, no matter what, you're going to make some sort of concession if deviating from stock/OEM to aftermarket (this applies to every upgrade, not just steering). I opted for less fabrication but some would argue a more radical tie rod angle. This seemed a great trade off in my opinion - hacking through the frame and mounting the box out by the front bumper is wacky.

 

[OldBeachBob]

Great build document. Looks like an excellent upgrade. Thanks for documenting and sharing!

 

[DoubleNickels]

The impression I got from your post is that you took the front half of one PS box and put it into another PS box(servo???) in order to get the reverse turn and not just using a factory box. If it was a factory box, I'll back out my objection

I am the king of hating cutting up the front cross member for a traditional Saginaw conversion... so absolutely no argument from me on that.

You are correct, I ended up doing a lot of shuffling, but it's because I bought the wrong box from Rock Auto. I went back and forth on forward- vs. rearward- facing. The newer RAM boxes have 3-mounting holes... if left to do it over, I'd use one of these new boxes and fab up a 3-hole adapter plate.

Clear as MUD!?

 

[onemanarmy]

Awesome!

Next time I have my engine out, I'll get the PS installed.

 

[J Mack]

I am the king of hating cutting up the front cross member for a traditional Saginaw conversion... so absolutely no argument from me on that.

Is there a cross member that gets cut when installing a Saginaw Scout or FJ60 steering box on a FJ55?

 

[WarDamnEagle]

In a related question, was '79 the only year that factory PS was an option for an FJ55?

 

[J Mack]

Here is 'typical' Saginaw on a 55:

Aha, now I'm up to speed. I didn't realize that was a thing and didn't see the point for all the trouble Double Nickles went through to add power steering. It's all clear now, thanks.

 

[wngrog]

That’s a ton of work to versus a 60/Scout type setup. I don’t understand why you went this route.

Glad you did. It’s the first time I’ve ever seen it done and I actually understand what you did.

Just don’t know why.

 

[DoubleNickels]

That’s a ton of work to versus a 60/Scout type setup. I don’t understand why you went this route.

Glad you did. It’s the first time I’ve ever seen it done and I actually understand what you did.

Just don’t know why.

Unless I'm mistaken, that 60/scout setup lil John shows still required some modification and fabrication. Maybe the shock tower? Maybe cutting the sheet metal within the wheel well? Lil John can fill us in, help elucidate the trade offs. Personally, I worried the Scout boxes are becoming rare and don't love the feel of the 60 boxes compared to Saginaw.

 

[wngrog]

A good 60 box is expensive. Not as powerful.

True.

The Scout box is rare too but not that bad.

The amount of fab you did to put the plate and unit bearing is no more than relocating a shock.

 

[DoubleNickels]

Probably true! I came at it with Saginaw in mind. I knew there just had to be a way to do it without boring through that frame crossmember.

I often fall victim to doing something the hard way, as a result of trying to find an easier novel method...

 

[RUSH55]

The GM Saginaw PS conversion has been carried out for ages. Man-A-Fre used to sell a kit for 40’s owners, probably adaptable to 55’s. One of the old local 55 owners in my area converted to the Saginaw box sometime in the 80’s without a kit. Most of these conversions are a hacked-up cluster f*€k, but @DoubleNickels here did a fine job, a fine job!