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Grand Cherokee box into 71-73 Mustang?
#1
Heh, fun never ends...

Driving home, car was running horrible, again. Was running sooo nice on the way to work, too. Turned out I had another bad vacuum cap which caused the bad idle, again.

While walking around the car to fix this, I find a trail of fluid going down the driveway and into the street, where I had just driven to park. Turns out I have a serious leak in the output shaft seal of steering box... Grrrr.

So, long before joining here I new that the Mustang box looked the same as the boxes in my Chevelles and Monte Carlos, Saginaw's all. And I have recently done the Grand Cherokee steering box swap on my Chevelle wagon. Very nice. So, thought about doing this to the Mustang if the box castings (mounting ears and such) will allow one to be installed.

After joining here, I have seen some others here have considered this, especially Jeff/droptop73. So, has anyone proceeded completely to try fitting one of these JGC boxes to a 71-73 Mustang mounting?

I know I can reseal the box I have, and may be doing that out of time necessity. I also know I can buy a nice shiny new box that is guaranteed to fit and be faster ratio, but I'm cheap, and dig on junkyard upgrades.

So what is known about this at this time? Anyone? Bueller?

Thx
Tom
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#2
Hi all,

Bumping this up, as I will have to do something soon. Car leaks sooo bad it is undrivable.

Don't mind being a test subject, and not afraid of anything required to do such a swap (have access to a machine shop), just would like to avoid any missteps that may have already been made.

Thx
Tom
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#3
From the little that I know, the Grand Cherokee box is essentially a GM Saganaw power steering box (Saganaw 800?) with an improved ratio - externally the same thing that is in our cars from factory.

So long as the input and output shafts have the proper splines, and the box itself has the three mounting holes in the same spot, it should work. I put a Mach 1 quick ratio box in my '78 Lincoln Mark V, and would have probably been better off trying a GC box.

-Kurt

[Image: satellite-valiant-mustang-license-tags-signature.png]
How to buy a '71-73 Mustang:
Rule #1: Assume all classic car sellers are guilty until proven innocent.
Rule #2: No classic car dealer is ever innocent; thus, they are all guilty.
Rule #3: Buy from trustworthy people: Fellow forum members. Visit 7173Mustang's For Sale forum.
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#4
If it fits, it fits. No way to tell until you compare mounting hole alignment and everything.

On a second note about the stock box, I noticed that mine stopped leaking once I installed an appropriately sized fluid cooler. I had been running without one for quite a while, but the proximity to the header was doing the system no favors. I installed a nice stacked plate cooler for the steering fluid and my leaks diminished considerably. Just a thought.

1971 Mustang fastback: 10.3:1 C90E 408W hydroller - CDAN4 EEC-V w/EDIS8, girdled, lowered and caged
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#5
I remember reading an article about the swap a while back... briefly skimmed through it... didn't save it in my bookmarks. Figures Undecided

A half hour google search turned up nothing notable.

Pete - MotoArts Decals and Signs
'71 Sportsroof 351C-4V/4-speed - FINALLY under construction - no, wait, on hold again...
'90 Mustang 7-Up 5.0 ragtop, rolling beater
'66 Sunbeam Tiger Mk.IA, survivor
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#6
Bump to see if anyone has any more insight on the swap.

Pete - MotoArts Decals and Signs
'71 Sportsroof 351C-4V/4-speed - FINALLY under construction - no, wait, on hold again...
'90 Mustang 7-Up 5.0 ragtop, rolling beater
'66 Sunbeam Tiger Mk.IA, survivor
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#7
I read that they are totally compatible, cant remember where though. I was considering getting a new one because mine had about 6'' of play until I found out they were adjustable. You can get a shiny new one, but not for cheap.

I've heard that there are a few parts that are compatible from jeep to mustang, Steering box being one of them.

If you don't have time to do it right the first time, you sure as Hell don't have time to do it right the second time.

Dutch uncle
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#8
kidwithfastback=fast;202692 Wrote:I've heard that there are a few parts that are compatible from jeep to mustang, Steering box being one of them.

Mainly as both are GM (!) Saginaw parts.

Same applies to the spam-can power steering pump found on later Fords, and Hydroboost braking systems (found on Ford and Mopars equally at times). I may be overlooking a few other GM-sourced parts too.

-Kurt

[Image: satellite-valiant-mustang-license-tags-signature.png]
How to buy a '71-73 Mustang:
Rule #1: Assume all classic car sellers are guilty until proven innocent.
Rule #2: No classic car dealer is ever innocent; thus, they are all guilty.
Rule #3: Buy from trustworthy people: Fellow forum members. Visit 7173Mustang's For Sale forum.
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#9
Haven't done much cuz the car is parked with a steering box leak and I haven't had time to even push it around...

What I have found:

GM-used boxes and the Jeep GC boxes use a 4 lug mounting system. So does the 72-up Torino, I believe. Seems some Torino owners have swapped (or looked into swapping)in the JGC box, threads link on this forum allude to that. The 71-73 Stang box is a 3 lug mounting, also discussed on this forum, I believe. I have a spare GM 4 lug box box, am trying to get a Mustang 3 lug box back from a friend so I can figure out mounting possibilities. I have a couple of ideas, one involving an added bracket between 2 ears on the box, converting it to a "3 ear" mounting, and the other involving welding a mounting lug to the chassis rail. For me, this is OK as my car isn't concours. For restored cars, probably won't fly.

The JGC needs the Lee inserts to convert from flare hoses to O-ring box. There are also Weatherhead fittings that may work for the Mustang application better than a GM application as the Ford hoses come straight up out of the box. Not concerned about adapting hoses to this.

Pump will be used as-is. If it isn't quiet right, I'll deal with it later.

A rag joint coupling is needed for the new box to the column, I believe the same one I used on my Chevelle wagon will work here. Converts from the later size input on the box to the standard style end on the intermediate shaft on a Chevelle, which I remember looking much the same as on the Mustang.

As work won't give me time off now, and I am having a surgery the week before Thanksgiving (with recovery over that holiday week) I don't think I'll get to the junk yard to hunt up a steering box until December. However, If I can get the sample Ford box back from my friend, or pull my leaker, I will see what needs to be done to fit the Jeep box to our cars. Also afraid of what other fun stuff I will find with the steering (tie rods and linkages) while I'm working on it. Always something...

Best,
Tom
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#10
Update:

Got tired of a car that was non-useable, and had not had time (still don't) to go to the junkyard for a JGC box, so pulled the Mustang box to reseal, and was then able tp compare it to a Chevelle box, which has the same mountings as the Jeep box. Remember, I am not worried about minor mods to my car, but at this time the Jeep box is too different in its mountings to be as easy a swap into a Mustang as it is into a Chevelle.

Mustang box:
[Image: IMG_4346_zps95fdedf8.jpg]

Chevelle, and therefore Jeep box:
[Image: IMG_4349_zpsba10b89a.jpg]

Mounting lugs appear to be in the same plane, so if an adapter bracket could be fabbed it may still be a bolt in. But not for me, not at this time.

Also going to try to contact a Saginaw steering guru who hangs out at the Chevelle and Corvette forums, see if he has any input on taking the guts out of a Jeep box and putting them into a Mustang box.

Happy Hew Year to all,
Tom
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