H1 and Other Steering Box Choices for a Jeep CJ

[RareCJ8]

The power steering gear is the last frontier for my 81-- about everything else has been R&Rd.  With low gears, big tires and an ARB up front this OEM part may be on borrowed time.  Reading a hummer H1 box is a near exact drop in.  Cardone 1 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.  This sounds like a mixed bag as for lock to lock ratios.  For me, fewer turns the better.  It has the right bolt holes and correct o ring couplings.

I have done the drill out trick on the pump already.  Better performance at low RPM.  

I see others that simply go with the napa generic unit.  rebuilt or new?  Agr?  Psc?  These are spendy.

also note the access to CJ  box components, hoses, etc very tight.  I see some add a coupler mid line for easier servicing, etc.

is there a suggested schedule to flush and fresh fill ps fluid?  Never thought about that.

if a newish box, does it make sense to have it ported for eventual hydro assist?

Thanks guys!

 

 

 

 

[Moses Ludel]

RareCJ8...I'm totally in agreement that you want a slow turn (4-plus turns lock-to-lock) gear for both vehicle control and long service life.  Slow turn means more reduction in the box and less load on the gear and pump.  More powerful, however, does mean more load on the Jeep frame, especially with large tires, and you need to drive/trail and brace up the frame accordingly.  I've witnessed stock Jeep CJ power steering gears rip themselves cleanly from the frame with oversized tires bound up in the rocks and a white knuckled driver wrenching on the steering wheel...Albeit, there are aftermarket steering gear braces available.

Be aware that the power steering gear is essentially a "hydraulic power tool".  The stock power steering gear and pump pressure have been enough to tear many AMC/Jeep CJ steering gears from the frame.  Brace the gear and frame accordingly, especially with the higher pressure pump and heavier duty Saginaw power gear.

I've been at this for a very long time, and the best OE conversion gears in my experience have been the G.M. Big Cars of the mid-'60s into the '70s.  They use the large piston size without the penalty of "sprint car" steering ratios.  Shorter wheelbase Jeep 4x4s have always been a handful with their quick 3-turn gears and smaller diameter steering wheels. 

I used the 4-bolt mount pattern big car 4-plus turn "constant ratio" (not variable ratio) gear on a Toyota FJ40 magazine project vehicle in the 'eighties and believe you'd be happy with this gear.  Verify the input shaft spline size, you will likely need aftermarket adaptation parts.  There are options of aftermarket improved steering shafts, running from the top of the steering gear to the column's splines at the firewall end.  

Note: You likely have the OEM sliding/collapsible steering shaft now.  Borgeson and Flaming River have focused on these shaft conversions for many years, and they offer upgrade double-D shafts and other solutions.  Advance Adapters has some pieces, too.

As for Cardone, if you use the G.M. big car part numbers, you should be able to find a slow-turn, big piston gear.  The four-bolt mount is a clue.  You currently have the AMC/Jeep three-bolt frame mount.  

If you or anyone else is interested in rebuilding their Saginaw power steering gear, they can follow my one-hour detailed rebuild video currently available for free at:

http://www.4wdmechanix.com/rebuilding-saginaw-integral-power-steering-gear/

The prototype gear in the video is a typical 800-series, specifically from a 1987 Jeep YJ Wrangler.  This has features common to many of the Saginaw rotary valve power steering gears.

Curious to hear others' experience around the popular OEM retrofit and aftermarket steering gears that you mention.  Cost-versus-return on investment might be worth discussing, some of these products get very spendy...

Moses

[RareCJ8]

i have all the beefy bracing in place from box to pass frame.  All guessed up.  Driver frame beefed up too.   Running the burgeon shaft from box to firewall, then rebuilt the entire tilt column.   The box does not leak and i have made from time to time slight adjustments on top using the allen head tool to take up some slack. Perhaps on borrowed time? 

From what I can see mine has the 75 stamped in the case.  Sag 800?

Model 800 4 bolt # 76 casting gear box claims a  13/16 x 36 spline input shaft. Supposedly AMC was using these on many CJ models throughout the 1980's.  The Hummer H1 has a 16/13:1 variable ratio gearing. almost identical to the OEM Jeep box at 17:1.    H1 has a 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 on Scrambler.  Research shows the H1 box is also 4 bolt with the 76 cast mark.

 

The Variable gear --in the middle and faster out towards the edges.   Or stay constant all the way is the Q now.  

dooming a rebuild is not for me.  I'd rather install a new box and keep the old for a spare.  

next challenge is to find a replacement pitman arm.  (i like redundant spares) When this heep was originally cobbled together in 1999  we used (if i recall correctly) a GM firebird arm.  It is a bit longer than the OEM.  Sadly casting #s are too worn to read.  This longer arm was to accommodate the full size axles and cross over steering, etc.  

other than sourcing a spare arm, i am at a crossroads.  just leave it be or replace with ? and have a spare.  i saw a guy locally that due to the tight clearances for the steering fluid lines added a coupler mid-way.  it is really tight in there.  At least on the YJs they moved it around for better access.  

 

 

[Moses Ludel]

Interesting information, RareCJ8!  See my red comments below...

On 2/15/2017 at 0:29 PM, RareCJ8 said:

i have all the beefy bracing in place from box to pass frame.  All guessed up.  Driver frame beefed up too.   Running the burgeon shaft from box to firewall, then rebuilt the entire tilt column.   The box does not leak and i have made from time to time slight adjustments on top using the allen head tool to take up some slack. Perhaps on borrowed time?

These boxes are rugged, so are your frame and steering shaft upgrades.  No leaks is always a good sign.  See my troubleshooting video for in-chassis quick tests, you may know some already from your comments:  http://www.4wdmechanix.com/saginaw-power-steering-gear-in-chassis-troubleshooting/.  A couple of "minor adjustments" would be the limit.  Any wear beyond this point is time for a rebuild and reseal...Your OE gear is a testimonial to the stamina of these gears when considering the driving venues and age. 

From what I can see mine has the 75 stamped in the case.  Sag 800?  

By design, your box is in the 800-series category.  You can break it down from there.  The casting number does offer application and year sorting details.

Model 800 4 bolt # 76 casting gear box claims a  13/16 x 36 spline input shaft. Supposedly AMC was using these on many CJ models throughout the 1980's.  The Hummer H1 has a 16/13:1 variable ratio gearing. almost identical to the OEM Jeep box at 17:1.    H1 has a 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 on Scrambler.  Research shows the H1 box is also 4 bolt with the 76 cast mark.

Good for AMC/Jeep if true.  They may have standardized since the J-trucks and Grand Wagoneers most often were fitted with power steering.  The gear you describe is that caliber.  Piston head size is easy to determine with a caliper measurement at the gear's end cap.  The piston bore is approximately the same diameter as the gear casting's inner lip measured outside of the retainer ring.

The Variable gear --in the middle and faster out towards the edges.   Or stay constant all the way is the Q now.

Variable ratio was a Saginaw breakthrough.  The sector's middle teeth are deeper than the outer teeth, with a match on the power rack teeth.  The result is more control or firmer "feel" over center (slower ratio) and quick outer steer for parking the vehicle.  This was popular on big cars like our 1972 Buick Riviera (owned in the early 'eighties).  As for your application, in my view, I'd want the constant ratio for less stress with the big tires that you run on your CJ-8.  You're in the rocks a lot, and that fast outer ratio is nothing but inertia and added load.  In the rocks, you would hardly care if the steering gets faster off-center...

dooming a rebuild is not for me.  I'd rather install a new box and keep the old for a spare.

Okay...That's a call and understood... 

next challenge is to find a replacement pitman arm.  (i like redundant spares) When this heep was originally cobbled together in 1999  we used (if i recall correctly) a GM firebird arm.  It is a bit longer than the OEM.  Sadly casting #s are too worn to read.  This longer arm was to accommodate the full size axles and cross over steering, etc.

A longer pitman without your cross-over ratios would simply speed up the turning.  Sometimes there is room for a choice around the length of the arm.  Most often, the arm's length is governed by the tie-rod clearance and preferred angle of the draglink.  Likewise, this is the case with a dropped pitman arm, which is often installed to prevent or reduce bump steer on a lifted vehicle with a sloped drag link/tie-rod.

other than sourcing a spare arm, i am at a crossroads.  just leave it be or replace with ? and have a spare.  i saw a guy locally that due to the tight clearances for the steering fluid lines added a coupler mid-way.  it is really tight in there.  At least on the YJs they moved it around for better access.

Share how that looks...Hard to visualize where he put the coupler... 

 

 

 

[RareCJ8]

tnx moses for the notes.   i am on a quest to find a spare pitman arm.  it is straight not dropped.  i obtained a period correct CJ arm and it was far shorter than the one now in use.  New custom drag link from ORD too.  if i get to doing a new box i will have it in hand for easier shopping and side by side comparison.  

the drag link and tie rod are in perfect level planes.  the beveled steering arm on pass side knuckle makes that easier.  now the end rests at 90 degrees, not stressed to the limit just for everyday use.

on jeep jambo last year noted a very common type of breakdown on newer jeeps is a busted sector shaft.  going to massive drag/tie rod suggests the weak link is moved upstream.  Such a breakage can be a real headache to fix in the field.    i'd rather straighten out a bowed tie rod than deal with the gear box.  

 

will look for more info on the mid-line coupler.   i recall it was with AN hardware and put together  by a local hose shop.

[Moses Ludel]

RareCJ8...There are lots of hose options if made from scratch.  Many of the NAPA stores could make hoses and couplers from scratch, using Weatherhead fittings of every kind and popular fitting angle.  (See a Weatherhead fittings catalog.)  I took advantage of this at Yerington where the agricultural equipment makes the hand-built option practical.  

At Reno, there is Reno Hydraulic, they make hoses and fitted couplings for any kind of hydraulic application, popular for mining, construction, heavy equipment and heavy-duty automotive/trucks.  They can make the right hose with couplers and fittings.

As for pitman arms, I've seen recycling yards with barrels full of pitman arms, this is dense metal that gets saved for scrap.  You might try some of the Reno/Sparks yards, even Pick-n-Pull, for ideas and a possible pitman arm solution.  The spline size is fairly common, as you suggest, it's getting the length and outer tapered hole size for the tie-rod or draglink ball stud.

Moses