Steering box issue

[mowerman]

My steering box needs to be rebuilt, but frankly, like turning radius on this thing is absolutely horrible. I was wondering if anybody knew how far up and age would still call for the same box? I’m just starting to kick some things around whether I would just rather replace the box than  fix this one. Possibly wrecking yard and anyone suggest any area doesn’t matter

[Joey Mack]

Bob, did you try to find the part number with the V.I.N.?  it may point you towards a parts kit, or a new production unit..  Just curious..  jojo

[mowerman]

No I don’t even know where to look I was going to move it in the garage to start working on the fuel lines and then I got to thinking well. Wait a minute don’t forget the steering box leaks ha ha besides, it rained a bunch of times here, and I really can’t move it yet Because of the muddy yard 

[Joey Mack]

Trust me... It has rained here all weekend and yes to muddy yard..  I had to pull a Granite Tri-X out yesterday when my customer picked it up...  All I could hear in my head was,,,  MY Wife..  Your tearing up the yard!!!!  anyway,  There should be numbers cast into the body of the steering box. Can you clean them up and post picture's? I'm not trying to make it sound easy, but as you know, there are guys on here that are 'Super Smart'...  

[mowerman]

Yes, I am not necessarily a cheapskate. Just trying to figure out the best route. There is a lot of free play in the steering wheel I think it’s mainly side shaft Pitman arm area. And yes, it’s too sloppy right around the area right now but thanks for the fast … response .. Bob

[mowerman]

OK they turned my neighbors leaky pipe off. Water department came down. I will be able to look at it Saturday. Try to give you some numbers Joey.

[mowerman]

I should have numbers in a little while I had to run out of here and meet the old lady yesterday when I tryed to get them yard is completely dry and jackass neighbor is pissed at all of us. He has no water. No yeah neither do I…. 

[Vladislav]

Bob, is that steering box a PS or just mechanical? 

Those are two almost different stories.

[mowerman]

It’s power steering, which is really surprising for a 1966 Roads trucks we never heard of it till around 1976

[Vladislav]

I haven't put my hands on revising a Mack steering box so far. But pretty sure many guys on here have. Seems worth posting a couple of overall view pics of it and someone may point out further ways to go.

[mowerman]

thanks for that,,,,not in any rush ,,,right now im just kind of poking around,,,so far i havent found correct numbers my area has been wet for months,,,finally dried up a few days ago ....all i could get off it so far was sheppard box with manufacturing area it has 60 years of dirt on it..thanks for your interest...bob

[Geoff Weeks]

If it is a Shepard from the 60's it will be a low pressure system,  Likely a "39" box. A picture would be a big help. These old boxes will have a LOT of play with the engine off, but should have less with the engine running. It has to do with valveing built into the box.

 Now the bad news No parts available for the older boxes.

 I'll see if I can post a picture of a 39 Shepard.

[Geoff Weeks]

Here are some pic's. It looks similar to the 392 box that was the next generation Shepard box. The early ones run low pressure, I don't remember the max it may be as low as 1200 psi. Often driven with belt drive vane pumps.

[Geoff Weeks]

If you look close, you can see the number cast in just above the pitman shaft (upside down in the photo) the exact model should be stamped on the box behind the Pitman arm, There are a bunch of bolt holes and hopefully some number/letters stamped there, Or at least they were on my 392 boxes. Kind of academic as parts are NLA. Some 392 parts MAY fit, like pitman shaft bushing, but I can't say for sure. Seal kits are different to my knowledge on the higher pressure boxes 392 etc.

[mowerman]

All right man thanks for that I will go look at it a little later. I was hoping to replace the damn thing with a used box Mack, parts, are extinct around here, and years ago I ordered a used air starter from Arkansas and it got here and it was junk  buddy of mine had one rebuilt 250 miles from here. They only charge them 300 bucks but it’s a Ford F 600 I might wind up contacting them just to see what they have to say. Oooooooooooo forgot to mention steering wheel play is around 7 inches running or not Bob 

[Geoff Weeks]

What brand air starter? Startmaster didn't have as good a rep as Ingersoll Rand.  I used ASC out of Tx for my air start parts. That being said, both my starters come out of Roadway trucks (so likely got a lot of use) and I never need to touch the motors. Tank check valves, yes and one relay valve over the decades I had them. I had the lube injector tied to the fuel return on the engine, so everytime the motor was activated they got a shot of diesel in the air.  I liked I-R relay valves better than Sealco, had less problem with them.

 You might be able to fit a 392 box, but I have no info on that. Might contact Straight Line steering out of Calif and see if they have any ideas, been in the business for ever, and may have run across what you have.

[mrsmackpaul]

Steering wheel play could have nothing to with the steering box, a lot of pivot points could be worn adding to the play

Does the hubs stop on the stoppers when on full lock, if so a different steering box isn't gunna help much 

 

Paul

[Geoff Weeks]

17 minutes ago, mrsmackpaul said:

Steering wheel play could have nothing to with the steering box, a lot of pivot points could be worn adding to the play

Does the hubs stop on the stoppers when on full lock, if so a different steering box isn't gunna help much 

 

Paul

Very true I assumed (always bad) that because he said "steering wheel play" that he checked, and it was play between the input and output shaft of the box.  I've seen my share of oblong holes attaching the box to the frame, whole box is moving. Lots to check if not the  box.

 And as I said, the old 39 box had lots of play when no oil was circulating, it is even in the CVSA book that you have to check play with the engine running, although most DOT cops don't know it. Later boxes use a different valveing system, and on those the play is about the same running or not.

Edited July 1, 2023 by Geoff Weeks
Typo's

[Geoff Weeks]

Permissible play for P/S measured at the wheel with engine running varies from 4 1/2" for a 16" wheel up to 5 3/4" for a 22" wheel. These are not ideal reading but OOS criteria.

 Any way you cut it 7" is a problem.

[mrsmackpaul]

I would also assume that if the motor has to be running when checking the play then the oil pressure in the steering system is also important 

 

As in it must be above 1200 psi or something similar 

Would I be even close in that assumption ?

I guess all I'm saying is there's lots to check before making the plan of attack to fix it 

 

 

Paul

 

 

[mowerman]

Yes, I went out there and started it couple of minutes ago. It’s got more like over a foot of FreePlay. Also, I have an Ingersoll rand bought it brand new Southern California and I have a sealco valve. I put it all in around 30 years ago still holds air  forever. And yes, that’s what a Mac parts man told me years ago you’re supposed to hook up return line to don’t use it that much and it’s still not running on the road. I just pull out the main airline every once in a while and shoot transmission fluid. Into the starter and yes, as I mentioned in my steering radius is absolutely horrible. At another reason I was hoping to replace the box with something. Thanks for your input fellas. I’ll take a look at it in a little while and see if I can find any numbers…. Bob

[Geoff Weeks]

14 minutes ago, mrsmackpaul said:

I would also assume that if the motor has to be running when checking the play then the oil pressure in the steering system is also important 

 

As in it must be above 1200 psi or something similar 

Would I be even close in that assumption ?

I guess all I'm saying is there's lots to check before making the plan of attack to fix it 

 

 

Paul

 

 

Paul, I'd have to search through some manuals, but the early Sheppard boxes run a much lower pressure than modern boxes do. They were designed for the old vane type pumps, and will "pop" if hooked to a modern pump with a 2000 psi or something relief. 

 My mind is like a steel sieve, I remember that the pressure is low, but not what it should be. The two digit boxes (29,39) were low and the three digit boxes were high pressure (292, 392 M100 etc).

 I don't know what has been checked, or even if it is a factory install, I am just responding to the info provided.  Lots to look into, can't assume it is as it left the line all those years ago. I think I remember him saying there was play in the pitman shaft.

[Geoff Weeks]

Manual was no help. The section on the Sheppard 39 just says to adjust the  steering relief to 400 PSI below relief on the pump. The section on the pump says 'Relief set by the factory for the truck and axle fitted, no adjustment possible"

 Manual did confirm that the 39 was a "low pressure" box, but without going more into it.

 My guess you'd be ok with a setting of around 1000Psi.

Edited July 1, 2023 by Geoff Weeks

[Geoff Weeks]

Found this: http://www.hydrosteer.com.au/wp-content/uploads/2014/12/Sheppard-Manual-92-Series.pdf

Low pressure is under 1300, High pressure 2000, so I wasn't too far off.

[mowerman]

Thanks for all your input pump also howls when turning steering wheel and yes free play at pitman shaft as well as leaking oil