m38a1 steering

1950 - 1968, M38, M38A1, M170, modifications, sugestions, and ideas, official MWO's and unofficial field mods.
sidewinder54
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m38a1 steering

Post by sidewinder54 » Sun Jul 22, 2007 10:31 am

just rebuilt the steering box on my m38a1 it handles worse than it did before( has about 1 1/2 of play on each side of the steering wheel) i adjusted the nut on the side of the box trying to get some of the play out,it helped a little but also caused the steering wheel to become very hard to turn in certain positions my question is there any steering conversion i could do and keep it looking close to stock?


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Post by Cuz » Sun Jul 22, 2007 2:59 pm

The common upgrade is the Saginaw unit used by AMC on the CJ after 71. Sits right out front between the bumper and grill.

A correctly rebuilt gearbox will leave less than a 1/2" radial play at the rim of the steering wheel when the pitman arm is clamped tightly so it cannot move. If you aren't clamping the pitman arm tightly then you are feeling the slop in the draglink, bellcrank and or the tie rod ends.

Since you mention the steering wheel now being tight at only certain points in it's travel that tells me your rebuild did not include a new cam or worm. This unit wears in the center. When you try to adjust that last little bit of play out it will bind at the far ends of it's travel as the worm grows fatter there. Also did you install and ream to the correct clearance new bushings?
Cuz (AKA Wes K)
45 MB, 51 M38, 54 M37, 6? M101A1, 60 CJ5, 76 DJ5D & 47 T3-C

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Post by sidewinder54 » Sat Jul 28, 2007 5:50 am

i replaced everything in the box but the worm( i guess you mean the steering shaft?) i put new bushings in but did not ream them for clearence
didnt know i had to just put it all back together with new parts and this is what ive got now,( sloppy steering) do you think a new worm(shaft ) would take care of my problem? since everything else is new or do you know of anyone who could take a look at it and correct what is wrong?

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Post by Cuz » Sat Jul 28, 2007 6:49 am

The worm or shaft is the source of your current problem with the steering binding towards each end of the adjustment you made. The middle of the shaft is worn and the only fix is a new worm shaft.

The new bushings are generally an overly tight fit and folks not familiar with rebuilding these units and without the proper reamer will often just open them up with a drill bit and this will leave them too loose. If you attained a good snug fit with your new bushings then you're ok there.

I don't know how much you've spent on your steering box thus far but John at Midwest Military and George at AJP offer government overhauled steering gear boxes for about $375.

Are you using the tech manual TM 9-8015-2?
Cuz (AKA Wes K)
45 MB, 51 M38, 54 M37, 6? M101A1, 60 CJ5, 76 DJ5D & 47 T3-C

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softskin_driver
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Ross box not good for freeway drafting

Post by softskin_driver » Mon Aug 06, 2007 2:10 am

Hi Wes is it possible to install a Saginaw manual box without destroying the frame beyond an easy switch back if someone after I am done with it should deciede to do a factory restoration.
I only ask because I have decieded to build my M170 for driving and I think the brakes and steering leave alot to be desired when on the freeway here in Silicon Valley.
My steering is in pretty good shape but at 47mph on the freeway when a Peterbilt slides passed at 75mph the Ross box need a quick quarter turn (more of a flick to take up slack) left then right when the bow wake goes by to keep the jeep going straight. It is not something I would want to have happen head on at closing speed of 100+ on a two lane road.
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Post by Cuz » Mon Aug 06, 2007 8:38 am

A sharp person could utilize all the existing bolt holes up front to develope a mount bracket for the Saginaw unit and that would make it an easy switch back.

I am surprised someone hasn't developed a rack and pinion power conversion yet.
Cuz (AKA Wes K)
45 MB, 51 M38, 54 M37, 6? M101A1, 60 CJ5, 76 DJ5D & 47 T3-C

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Post by softskin_driver » Tue Aug 07, 2007 2:30 pm

With that said I guess I will start looking for a either a donor CJ or a Junk yard donor.
There was an early rusty CJ-5 in the local pick and pull I will have to go and see whats left I took a lot off of it for my project.
Didn't think about the steering box or brackets.
California has a buy back program they give you $650 for an old pre unleaded fuel (smog) vehicle the local junk yards pick it up and write the check.
So the yards stay full of older stuff but at the same time the steel scrapers are paying $200 a ton so you got to be quick....
My local post office has about 8 old DJ's rotting in the sun I have talked to the post master and she has sent a letter asking if they can be scrapped I noticed on my walk this morning they all have 11 inch brakes and Saginaw manual boxes. Funny thing I was at first looking on the wrong side and could not find the box then I looked inside and the steering wheel was on the right Duh!!!
Stupid is as studid does!
But I learn quick!
I do not have the time and patience to reverse engineer a rack and pinion system.
But I looked under my friends Volkswagen Pasat this morning its possible if you treat it like a power tie rod I guess.

Thanks Wes :)
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Re: m38a1 steering

Post by modified » Mon Jun 29, 2009 4:27 pm

Hey Dave, any updates on your steering conversion? have you any pics you can share with us ? :D

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Re: m38a1 steering

Post by Joe Gopan » Mon Jun 29, 2009 5:17 pm

The Ross Steering Gears as used in the Willys Jeeps have Variable Ratio Steering design. The M-38A1 Ratio in straight ahead position is 17:1 where the groove is closest together and in the extreme Right or Left position is 19:1 where groove is farther apart. You will note that the groove opens up somewhat at the extreme ends allowing more backlash which is felt in the steering wheel. You can check the operators Manual for the M-38A1 P.264 TM9-8014, and the Ordnance Maintenance Manual P. 221 TM9-8015-2 to confirm what I have mentioned. There is more to this but the reason for more back lash in extreme turning is in the design for the Ross Cam and Lever Steering Gear and the extra back lash in those positions is normal. In the Straight ahead position both pins are engaged in the worm, and as the wheel is turned off center, only one pin is engaged.
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Re: m38a1 steering

Post by softskin_driver » Mon Jun 29, 2009 11:15 pm

Hi guys I have done a lot of looking at early CJ's that have done this conversion that started out with the same Ross box and switched to the later saginaw units both power and manual. There are many more power conversions than manual. There is really no clean way of swaping out the Ross for the Saginaw without causing some damage to the frame and or tub.
I have seen the Advance Adapters kit and several other companies kits. Most are designed for power steering which requires some pulley changes and brackets added to the motor.
Many I have seen are in early Jeeps with iron duke V6 conversions and use GM parts.
I have yet to come across a kit for the manual box for an M38A1.
I have seen several M38A1's with both power and manual Saginaw boxes but they were home grown conversions and were not done with alot of care to going back to stock and they utilized faricated front bumpers and frame mounts and some altered front spring shackles that almost always needed some cutting and boxing of the frame.
I picked up a NOS manual saginaw box and the Advance adapter kit at a swapmeet. The adapter is for the power steering swap which I do not think will work easily with my plan in not doing unrepairable damage to my frame and or altering my engine compartment from the military parts.
One of the painful things that you need to do is cut the steering column and add a joint so that you can change angle of the shaft since moving the box out in front of the radiator makes for a geometry change in the shaft angle and length.
Borgeson seems to be what eveyone uses although I did see a couple of GM rag joints.
Because my M170 is a late model USMC and rust free and all original I have come full circle back to buying a government rebuilt Ross box and just living with the sloppy steering. I will replace all the rest of the steering componets with the best NOS GI parts I can find and hopfully it will be a little better out on the six lane interstate.
When I am off road I hardly notice the slop because of the slow speeds and the terrain.
One of the things about the Ross boxes everyone has for sale is that you need to give them a core for the price you see advertised.
I would like to keep my original box so I will start looking for a detached Ross box to use as a core.
:) :) :)
Dave Ball
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Re: m38a1 steering

Post by Joe Gopan » Tue Jun 30, 2009 2:44 am

NOTE:
The M-170 was always more tipsy to drive than the M-38A1, even when new.
Be careful when replacing steering gears to always use an original M-38A1/M-170 unit as the M-38 will fit but the ratio is too quick and just may flip an M-170.
There is a good reason why the M-170 was equipped with Sway Bars, they are not as stable to drive as the M-38A1 especially at highway speeds.
They can bite you if the ratio of the Steering Gear is quicker than the original.

M-38 Steering Gears installed in M-38A1, and especially the M-170 are dangerous.
Last edited by Joe Gopan on Tue Jun 30, 2009 2:18 pm, edited 1 time in total.
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HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
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Re: m38a1 steering

Post by modified » Tue Jun 30, 2009 9:28 am

have you looked into hermtheoverdriveguy... his reverse steer "Ford box" looks interesting, though the prob I see is where the fuel line and motor support would seemingly clash in line of an installed steer-shaft. also, I've heard word of older swaps of a hudson steer box with a higher ratio... I suspect these units were made by ROSS and pretty much bolt on with a little manipulation given the mounting holes. I too am wary of such an evasive mod that may render butchering the frame and ...I'm looking into finding a tapered bearing system for the bellcrank for starters. It would seem possible to template an existing bellcrank design and refab to accommodate such bearings for load sdjustment :?
Most of the wear and shock, given the dual rod set up and proper kingpins and wheelbearing spec, appears to concentrate lateral load and fatigue to the bellcrank sleeve and needle bearing.

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Re: m38a1 steering

Post by Cuz » Tue Jun 30, 2009 11:41 am

It's a shame but the old Willys was just never meant to be a 60 + MPH highway cruiser. :wink:

Any Ross gearbox swapped in with the stock components in the rest of the system will not offer any long term relief or success. The reverse ford setup is very nice.

If the jeep is used for what it was originally designed for the Ross is more than adequate with proper installation and upkeep of the parts.

Since most steering upgrades are intentioned for high speed highway use I fail to see why the rack and pinion set-ups are overlooked. Seems to me they can be adapted to the frame with much less effort and eliminate all the old stuff. :wink:
Cuz (AKA Wes K)
45 MB, 51 M38, 54 M37, 6? M101A1, 60 CJ5, 76 DJ5D & 47 T3-C

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Re: m38a1 steering

Post by modified » Tue Jun 30, 2009 12:11 pm

if I'm not mistaken, the rack and pinion approach would be better suited for Independent front suspension. just guessing from visualizing a set up, I think an R&P would limit front wheel articulation greatly? :?: if one were to mount a Pinto or similar unit, one would need to mount it forward of the axle cover. ok, now I'm getting "mod" brainwash. :?

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Re: m38a1 steering

Post by Cuz » Tue Jun 30, 2009 8:34 pm

The fact that it is designed to accomadate independent front suspension motion is all the more reason it will allow very free movement of the fixed front axle setup. I cannot see where it will limit the jeep front wheel steering. The simplicity would be very good requiring only two brackets welded to the front crossmember to position it correctly and adapting the steering column shaft.
Cuz (AKA Wes K)
45 MB, 51 M38, 54 M37, 6? M101A1, 60 CJ5, 76 DJ5D & 47 T3-C


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