Types of Saginaw Steering Gears

[captspillane]

I've never understood the details surrounding steering gear switches. There is alot of people suggesting lower ratio gearboxes and confusion regarding variable ratio versus non variable ratio boxes. I hope this thread can clear some of that up.

I also hope someone who has rebuilt one in the past can shed some light on how the internal locks work and whether they can be removed or adjusted. Steering box ratios are often given in terms of "lock to lock" but I don't know how the locks work internally or if they are even present on all boxes. I can spin the steering wheel on my Red SX4 without hitting any locks no matter how many turns I make (the pitman arm and all other steering components are removed right now except the steering wheel, shaft, and steering box). On my Scrambler there is an internal stop that prevents me from turning to the left. The pitman arm and steering gear are able to turn further and the set screws that prevent the wheel from turning too far have inches of space before contact.

[captspillane]

This is a post on the CJ forum by "JeepHammer" in response to someone asking what the difference is between variable ratio and fixed ratio steering gears:

Single rate steering box only allows one type of power assist.
You get the same pressure/assist even if you are making slight corrections going down the highway, which can make the steering seem 'Twitchy',

And you get that same assist when you are making big, fast moves of the front wheels, like when you are trying to turn around or avoid large obstacles you have to drive around.
That will make the steering feel 'Sluggish' or hard to get the wheel to turn fast enough.

Variable boxes allow for a 'Two Stage' assist, Minor corrections get a little assist so things don't seem Twitchy, and when you pull harder and farther on the wheel, you get a second pressure/volume boost to help with big turns.

Full size Jeeps and J-20 Pickups used Variable rate boxes, where smaller CJs didn't.
Using a variable box lets you make big corrections easier when 'Zig-Zagging' through obstacles, and also lets you 'Finesse' on fine corrections on the highway without jumping or feeling 'Twitchy'...

The internal of the Variable boxes are also stronger, and the ones I've used have the same output as CJ's so the pitman arms off the CJ's seem to work fine.
I know there are some of the Variable boxes have 'Issues' with Pitman arm sizes, but I haven't run into that.

You can change to your CJ Pitman arm,
Or you can install a Tie Rod End that matches the FSJ pitman arm on the steering link... Either one will work, but if you use the FSJ Pitman arm, don't forget to adjust your stops!

Since variable rate boxes usually have higher VOLUME pumps, (Same pressure, just larger delivery rates) I's usually a good idea to upgrade the pump and hoses to the larger FSJ size when you install an FSJ box.

It's not 'Required', but you might get a 'Sluggish' feel when trying to make big steering movements with the lower volume pump that came on the CJs most times.
And small hoses can make for restrictions also...

If you want a real bruiser of a which, use the higher volume pump with a Hydraulic Winch!
No such thing as pulling that sucker down or overheating it with a high volume pump!

You kind of have to watch some of the parts stores,
They will list the same pump for both CJ & FSJ, and it's usually the lower volume pump...
They do that because most people will never make such large steering movements they will notice the difference (Jeepers DO!),
And they only want to stock one kind of pump,
So when I get a variable steering box, I usually swipe the pump, hoses, brackets, everything for the switch.
Helps with keeping costs down and performance up.

[captspillane]

I have found out that our Eagles use Saginaw 800 steering boxes, which are pretty standard among all GM, AMC, International, and Chrysler vehicles. All manual Sag 800 steering boxes use the same spline count, but the power boxes use one of two spline counts. There are two different three bolt patterns and a four bolt pattern to all saginaw boxes. Its been suggested that the tabs for the same four holes are on all steering boxes, but some only have three bolts drilled and tapped. Our Eagles have a three bolt pattern. According to Rockauto interchange information it is the same three bolt pattern as a Jeep Cherokee, which is in turn compatible with the three bolt pattern on a 98-99 Dodge Durango steering box. The Durango box is a Saginaw "808", so it has a larger piston bore but is otherwise identical.

[captspillane]

I am writing this thread as I research. I hope that someone who knows more than I do will read it and correct or add to anything that I find. I would like to know what the stock ratio is for the steering boxes in CJs, TJs, XJs, and Eagles because those are vehicles I've driven the most. I found this quote online:

"Conventional power steering gearboxes were originally manufactured with a wide ratio. Depending on the manufacturer, most were in the range of 16:1 to 24:1, requiring four to six full turns of the steering wheel from stopping point to stopping point (wheels locked from the extreme right to the extreme left, commonly referred to as "lock to lock"). Many of these units were also designed to have slow steering response around the center point, with improved response as you approached the ends of their maximum range; these were termed variable-ratio. Quick-ratio gearboxes will reduce the steering wheel lock-to-lock range to as low as 2½ turns."

I also found this statement regarding a replacement gearbox for a CJ8 Scrambler like mine:

"Spec one out for a '96 Hummer H1, A1 Cardone part number 27-7595, it's a bolt in for the stock CJ P.S. gear it has the larger piston for less effort with a faster turning ratio (variable 13 to 16-1 vs 17-1) with 13/16" input splines and metric fittings as original to Scramblers"

[Whuntmore]

I was having the steering box in my '99 grand am replaced.  the mechanic told me it was a variable ratio.

So when you're driving down the highway at 110 kms (or 70 mph) the steering is more 'gentle'.    That's about the only thing I know of.

If you get to the point where you know the exact steering box (say GM Product) that are a direct bolt in, keep us all posted.

[captspillane]

What I am concluding so far is that the driving experience in my beloved SX4 was in part because of a variable ratio steering box. Driving straight forward there is a soft area where its easy to steer with your thumbs and there isn't a drastic impact on steering wheel motion. I'm guessing that soft area has a ratio of 16-1 or 17-1. Then when I want to make a U turn, I only need to turn the steering wheel a slight amount before the car responds instantly to my steering inputs. I'm guessing that harsh area has a ratio of 13-1. As I understand it, the tightest steering ratio available in Saginaw units is 12.7. Some people rave about a 12.7 fixed ratio steering box, but I would not want to have that sensitive of a steering system while driving on the highway. I also would not want a sluggish 17-1 constant ratio like stock CJs have. It looks like the stock Eagle variable ratio steering box is the best box available for these cars in my opinion.

One time on my way home from college route 80 near the G. Washington bridge, only two lanes were plowed. The third lane had about 6 inches of undisturbed snow and lots of random chunks of snow thrown on top from the plow trucks in the adjacent lane. Traffic was moving at 15 or 20 mph bumper to bumper in the plowed lanes. I drove my red SX4 into the unplowed lane and sped past literally hundreds of cars at speeds of 45 to 55 mph. While driving through the unplowed snow the steering wheel was shaking mildly but the car body itself was relatively still. Every time I hit a chunk of ice, the wheel and car would get jerked toward the chunk. I could give one quick stab of the steering wheel and and instantly correct for the jerks. The steering was forgiving enough to react reasonably aross such a rough surface but responsive enough to maintain control easily. I could not have gone that fast without the CV shafts, low center of gravity, all wheel drive, and steering characteristics. I had my own lane entirely to myself and it was awesome.

[captspillane]

At this point I think that anyone replacing their steering boxes in an Eagle should use the variable ratio unit available at rock auto. A 12.7 box is available from camaros, firebirds, and even a ZJ jeep application but I don't recommend it when our steering box probably has a 13 ratio when it matters in tight turns and also has the 17 ratio for gentle highway steering.

For those of us who love to upgrade to bigger and better, there are larger diameter pistons available. I don't recommend any of us getting those because the larger pistons probably operate at the same hydraulic pressure but at a larger volume of hydraulic fluid. To install a bigger steering gear you should also upgrade with a higher capacity power steering pump like those found in J20 trucks. This is a route I will try in my 401 SX4, since that engine actually came from a J20. As I understand it the larger "808" size saginaw pumps are available with our three bolt pattern in a 98-99 Dodge Durango. I also think that the four bolt pattern saginaw pumps share three of the same bolts as our three bolt units (I can not confirm this until I fix my CJ8 later this winter) so we have an option of a 96 H1 Hummer unit or a J20 Jeep truck unit as well. Those are the variable ratio boxes with the large piston like the Durango has I've read about so far.

All saginaw pumps are pretty much fair game for installation except that you have two different spline counts on the input shaft. I think its 3/4 inch versus 13/16 inch. I do not know which our Eagles came with. Adaptors are available.

[captspillane]

Here is some pictures from Rockauto. The pictures of a 92 XJ, AMC Eagle, and Dodge Durango are visibly identical. They have the same three bolt bosses. In the second picture is a J20 unit. It has four bolt bosses like CJs and H1 Hummers. I still assume that you could install a J20 unit into an Eagle by using three of the four bolts. I will be buying a J20 unit for my Scrambler soon and confirming this.

[captspillane]

I also found these pictures online from someone installing a J20 unit into a CJ. If you look closely at the other two photos I just put up, the J20 has a protrusion on the input shaft that is not there on the Durango, Eagle, XJ, or CJ inputs. That person just used a grinder to eliminate the protrusion. Photo one shows the unmolested J20 input. Photo 2 shows the original CJ input. Photo 3 shows the red adaptor piece that Jeep guys buy to switch between the 3/4 and the 13/16 input shafts. Photo 4 shows that red adaptor on a steering shaft. I don't know if we can use it on our shafts.

[eaglefreek]

I know very little about the Saginaw boxes, just what I have read on the internet. I prefer a firm steering feeling. I don't want to feel like I'm driving a Cadillac like my Eagle feels now. I'm hoping the Grand Cherokee box I'm going to put in eventually, will take care of that. I read somewhere, but can't find it now, that you can have the same ratios but different total degrees of turning at the sector shaft. So if you don't match the total degrees at the sector shaft, where the pitman arm attaches, you can have either a more or less turning radius depending on what your factory box was.

[vangremlin]

I just looked in my 1981 AMC Service Specifications book and it says the power steering has a ratio of 16:1 on center and 13:1 at full lock.

[Whuntmore]

Here is some pictures from Rockauto. The pictures of a 92 XJ, AMC Eagle, and Dodge Durango are visibly identical. They have the same three bolt bosses.

so if they are identical, I'm assuming you can still get an eagle steering box?

[captspillane]

Yes the stock Eagle gear boxes are still available at Rockauto for 88.79 and 15 dollar core. Advanced has one for 140 dollars and 15 dollar core. They fit alot of other cars than Eagles and will always be available.

What prompted this thread is the enthusiasm some people have for the 12.7 fixed ratio boxes. That's the smallest ratio available. Most production cars had a ratio of 16 to 20 it seems. They make it sound like its a must have upgrade to make our cars handle like real sport cars. I've always felt that my SX4 handled perfectly. I feel alot better knowing that our boxes have a 13 ratio where it matters, so we have no reason to be ashamed of our turning response. I can see why its a must have upgrade for a Jeep, since those came with a fixed ratio of 17:1. On my Jeep CJ8 I will be ditching the 12.7 box for a variable ratio J20 box.

Thank you very much for confirming those numbers Vangremlin. I was only guessing that we had a similar ratio as the H1 gearbox. It turns out we do have those exact ratios with a smaller bore.

I haven't found still a good authoritative description of the available steering boxes. It must exist somewhere to define the part numbers. Right now the only way to know if an alternative box will have enough degree of travel is to buy it and see what happens. I also hope someone here has rebuilt one and can shed some light on what it is that limits the degree of travel internally. This winter I'll be rebuilding one and creating a write-up on what I discovered inside the box.

[carnuck]

Since my wagon will likely end up with 33/9.50/15s, I'm going with an FSJ box with the Eagle arm on it. When I do the front lift, I'll use the '73 and earlier FSJ box 3" drop plate for the steering box (I'll have to make one for the idler arm too) They are steel and not lightweight aluminum like the Eagle uses.

[BenM]

I've heard two arguments for ratios; that a tighter ratio gives a quicker feel, and that a wider ratio prevents over-correcting the steering in low traction conditions. Most new cars are very tight because marketers tell us people prefer that.

The variable ratio boxes do give a better feel, and reduce fatigue on the highway. They are always a popular classic car upgrade weather they are power or manual. Off-road Jeep guys have different demands from steering then regular drivers, so fixed-ratio may be better.
The other advantage of wide ratio boxes on a CJ would be that if the engine stalled or the hydraulics failed you could much more easily steer it. That may have been a concern back in the 50's when the CJ5 came out.