EXCESSIVE PLAY IN B-61 STEERING

[HarryS]

There is about 6"-8" play in the steering wheel on my 1960 B-61 with SG-26 steering box. All the front end components check out. I have a Garrison hydraulic assist power steering set up seems to be working as it should. There is an adjustment on the side of the steering box which is as tight as it will go. The other problem with the box is a it leaks at the drag link stud. What is the next step for a fix?

[mechohaulic]

steering box "tight as it will go ";; with front end jacked up off ground - are you trying adjustment ???complete turn to left then to right ??  the garrison hyd assist is a new one for me or just another example of senior brain loss. , reservoir with filter in canister ??? air assist I have seen/installed. with out a doubt you have checked the steering u-joints in  shaft , spring NOT broke in pitman arm; have seen that happen. is out put shaft "moving up/ down as wheel is turned =worn bronze bushing leading to out put shaft seal leakage,

[HarryS]

     Thanks for the reply. I see two things to check. I did not have the wheels off the ground and did not go full left to right and return. The other thing to check is for movement at the steering box output shaft.

     The steering box and steering shaft as far as I know are one unit with no u-joints. The Garrison valve replaces the drag link with the lines running from the pump and to the hyd cylinder which attaches to the spring u bolts at one end and the tie rod on the other. The reservoir does have the filter in the canister. I had leaks in the valve and the cylinder and both of those have been fixed. I will check the two things mentioned and report back.

[mechohaulic]

NO u-joints in cab to box column  ?? can't confirm based on brain  cells. has to / should be a swivel in there some place. purpose of front off ground with wheel movement helps adjusting procedure. that small  1/2- 5/8th adjusting bolt WILL NOT move wheels on ground .. also improper adjustment you may find yourself with steering that bind one two spots. check the pitman arm spring with wheels ON the ground. easier for one in cab turning  steering wheel while assistant  watches ball joint movement under (leather - I know i'm old ) cover.

[terry]

The B models that came without factory p/s had no u joints in steering column, factory p/s had one u joint right at steering box.   Terry

[Vladislav]

A bit of addition to what Mech said.

Full check left to right is also aimed to figure out is your steering box in ITS central position when the wheels are straight forward. The reason to check is the most steering gears are designed having minimal or no play only near the center of the operational range. So if the gear is off its central position while the wheels look straight you would have excessive play in a good steering box. Usually a box have a mark on its housing with another mark at the pitman arm shaft end but you can always do preliminary check just counting steering wheel turns. 

The 2nd point is that devuice - the valve assembly - you have installed in place of the drag link. The valves are necessary for the hyd system to figure out when to assist and how hard to. The principal is when you start turning the steering wheel the Pitman arm forces the drag link to move. Truck's wheels resist the movement being on the ground. There's a spring in the drag link (acually 2 of them for L and R) and when you put force on the steering wheel you start compressing one. If the wheels are steady the force is sufficient so the compressed spring opens a valve (talking with simple words) and pressurized fluid goes to the power cylinder helping you. As long as the wheels are moved and no more force to the steering wheel the valve closes stopping the assistance. If you act the same but the truck drives on a highway the wheels don't give much resistance. So no force enough to compress the spring and open the valve so the hyd system doesn't help out and actually you steer mechanically. 

All that above is a theory. But the theory is the valve MUST have some play. To allow space for the spring to compress to a certain grade before activating the assistance. So in very theory such power steering desings (with the most other styles) have additional play to what just a mechanical box would have with no hydraulic (or pneumatic) add on.

What I mean? Or what to do? Looks like a check of that valve unit in the drag link should also be provided. Along with other points mentioned above.

 

[HarryS]

Vlad, Your description of the hydraulic steering assist operation is spot on. I had the valve checked and it is working as it should. What happens when driving is you feel like you are chasing the front end. When you turn the steering even slightly in one direction the truck follows and when you turn it the opposite direction there is a delay due to the play.

   I raised the front end and moved the steering lock to lock and then tried adjustment of the box and didn't get any additional adjustment. I checked for centering of the steering wheel by counting the revolutions, didn't see any marks. I disconnected the drag link/steering valve to see if there was any looseness in the pitman arm, nothing there. At this point I don't see anything else but the box.

     To remove the box it looks like the steering wheel would come off then the tube which is clamped at the steering box and as far as I can tell there is no disconnect for the steering shaft as Terry mentions. It looks like it should come out from the bottom once unbolted from the frame and removal of the pitman arm. I don't know if I'm adventurous enough to get into the box.

[mechohaulic]

5 hours ago, Vladislav said:

A bit of addition to what Mech said.

Full check left to right is also aimed to figure out is your steering box in ITS central position when the wheels are straight forward. The reason to check is the most steering gears are designed having minimal or no play only near the center of the operational range. So if the gear is off its central position while the wheels look straight you would have excessive play in a good steering box. Usually a box have a mark on its housing with another mark at the pitman arm shaft end but you can always do preliminary check just counting steering wheel turns. 

The 2nd point is that devuice - the valve assembly - you have installed in place of the drag link. The valves are necessary for the hyd system to figure out when to assist and how hard to. The principal is when you start turning the steering wheel the Pitman arm forces the drag link to move. Truck's wheels resist the movement being on the ground. There's a spring in the drag link (acually 2 of them for L and R) and when you put force on the steering wheel you start compressing one. If the wheels are steady the force is sufficient so the compressed spring opens a valve (talking with simple words) and pressurized fluid goes to the power cylinder helping you. As long as the wheels are moved and no more force to the steering wheel the valve closes stopping the assistance. If you act the same but the truck drives on a highway the wheels don't give much resistance. So no force enough to compress the spring and open the valve so the hyd system doesn't help out and actually you steer mechanically. 

All that above is a theory. But the theory is the valve MUST have some play. To allow space for the spring to compress to a certain grade before activating the assistance. So in very theory such power steering desings (with the most other styles) have additional play to what just a mechanical box would have with no hydraulic (or pneumatic) add on.

What I mean? Or what to do? Looks like a check of that valve unit in the drag link should also be provided. Along with other points mentioned above.

 

for the most part the hyd set up is same as air-o=matic  which  operated on same principle.  air cyl clamped to tie rod always wore out  giving unsteady turning  .. memory is not 100 % ; to remove the steering box on some B's  pop steering wheel center cap remove  15/16th ?? nut  attaching inner steering shaft to steering wheel ? inner shaft will come out with steering box ??  if the spring in the control valve is broke don't thing hand pressure will show it. not sure .

[mechohaulic]

5 hours ago, Vladislav said:

A bit of addition to what Mech said.

Full check left to right is also aimed to figure out is your steering box in ITS central position when the wheels are straight forward. The reason to check is the most steering gears are designed having minimal or no play only near the center of the operational range. So if the gear is off its central position while the wheels look straight you would have excessive play in a good steering box. Usually a box have a mark on its housing with another mark at the pitman arm shaft end but you can always do preliminary check just counting steering wheel turns. 

The 2nd point is that devuice - the valve assembly - you have installed in place of the drag link. The valves are necessary for the hyd system to figure out when to assist and how hard to. The principal is when you start turning the steering wheel the Pitman arm forces the drag link to move. Truck's wheels resist the movement being on the ground. There's a spring in the drag link (acually 2 of them for L and R) and when you put force on the steering wheel you start compressing one. If the wheels are steady the force is sufficient so the compressed spring opens a valve (talking with simple words) and pressurized fluid goes to the power cylinder helping you. As long as the wheels are moved and no more force to the steering wheel the valve closes stopping the assistance. If you act the same but the truck drives on a highway the wheels don't give much resistance. So no force enough to compress the spring and open the valve so the hyd system doesn't help out and actually you steer mechanically. 

All that above is a theory. But the theory is the valve MUST have some play. To allow space for the spring to compress to a certain grade before activating the assistance. So in very theory such power steering desings (with the most other styles) have additional play to what just a mechanical box would have with no hydraulic (or pneumatic) add on.

What I mean? Or what to do? Looks like a check of that valve unit in the drag link should also be provided. Along with other points mentioned above.

 

original post stated 6-8 inches of play;; that's seems excessive. I would assume the play is engine running system up to pressure. there was =don't remember which one had a system with way excessive play WHEN SYSTEM SHUT OFF. 

[HarryS]

The play which I agree is excessive is pretty much the same (about 8") with engine running or not. Even now with the drag link/steering valve disconnected.

[Vladislav]

Here's a bit of what to look at. The unit is SG-16 made by Mack in 1945. Earlier than yours but from your description I guess very similar. Steering shaft put into a long tube you see in the cab which is attached to the top of the housing under the hood. No U-joints. I indeed had to remove the steering wheel when dismantled the unit off the chassis and that was a trouble with splines stuck to the shaft. Having no luck with simple movements I tried attaching a puller but ended up with a chiesel hitting from below the steering wheel and cracking its lower skird. Found no other way. But looks like you may try removing all the column off the housing together with the steering wheel. My style had the column driven into the housing with threads. Bend off the lip of the lock washer and turn the column (the tube) counterclockwise.

The gear itself is a simple warm and sector. My model had the Pitman arm shaft spinning in two needle bearings not cooper bushings. Originally the gear showed excessive play either so I went through it and finding play of the shaft and seeing no wear on its journals I started a hunt on the bearings. Those were marked Torrington-something and after stiring a pot at my local parts supplier I in a month and a half purchased... one bearing. And after telling them "Yes, that's true, I asked for two" and two more months to wait (and paying double shipping cost) I grabbed the 2nd one. To my big frustration after reinstalling both bearings the play rest as it was with the old ones. So it looked like Mack minded that way from the factory (and I didn't liked it). 

The warm and sector teeth didn't have any notable wear either so my further look put on the bronze bushing the sector seats against and limits its end play. I made additional shim and if assembled with it the shaft had no radial play and all the gear lost 95% of its play too. I was pleased but not cheered since if the shaft had no tight vertical support in the bearings it would lean (dance) under steering force trying to brake the cover or so. And the thickness of the gasket was a mistery to me too since it influences the required bushing thickness. 

That time I ended up with the original bushing and no gasket (put sealer) and some notable steering wheel play of a couple of inches I would like to minimize for perfection. But I never drove multiple old trucks down the road so kept it about the way Mack made it. Much later a large factory repair manual happened to appear in my hands and Mack engeneers were offering to set the shaft end play by thickness of the gasket (!). That was written there with a comment of no shims of other than standard thickness were avalible.

The truck is still in the shed having no engine and cab on so no comments on driving experience from my side. Hope the pics will help you.  

P.S. As I remember the warm could be removed from the steering shaft in a case you find it bad and no need to remove the steering wheel for that. Also look up for the electrical horn wire as it goes through the steering shaft getting out of the gear at its bottom end.

[HarryS]

Thanks for the pictures. That's a big help to know what's inside. The last time I remember opening up a steering box years ago there were many  ball bearings that went everywhere. That was on a antique car. I have had the steering wheel off a few years ago so hopefully that won't be too bad but as I remember it is not drilled for a puller. Hopefully I can get the box out in the next few days then see what I run into.

[Vladislav]

Yes, there's a style of steering boxes with circulating balls. That's good design regarding the function. As I understood it came on the big truck scene a bit later, after those simple warm and sector boxes. The steering box is of screw, nut and sector style. You spin a screw by steering shaft which drives or undrives in/out of a nut. The nut is also a rack having teeth on one outer side. The teeth are mashed to a teethed sector which turns Pitman arm shaft. The balls are put in the threads between the screw and the nut. So the threads operate as a ball bearing. If the box is an integrated power steering the nut also takes function of a piston having seal rings over its body and moving in a cylindrical cavit bored in the housing.

That style usually has a set screw but you can adjust mesh between teeth of the nut and sector only. And if you ran all that adjustment to its limit and still have play in the box that means the balls or their racing surfaces are worn and a fix is replacement of the parts or complete steering box.

[HarryS]

Well I didn't get too far. I don't have the right puller for the pitman arm. The ones I have that fit are three arm automotive type which aren't strong enough and the others are too small. I ordered one that should work on ebay. It says used once and was half price of a new one. Should be here the end of next week. I did get the steering wheel off without too much trouble.

[Freightrain]

I used a slacker adjuster puller to get my pitman arm off when I installed the air steering.  I bought a few others that didn't have the beef to do it.  The right puller and a smack with a BFH and it fell off.

 

These steering box resemble one from Cub cadet.  Rebuilt one before,this just a bit larger!

My air steering is a bit flighty sometimes on curvy roads.  Like mentioned it is similar design.  Beats Armstrong steering!  I have a spare steering box for my truck come the day it might need help.

[Vladislav]

I had to heat up my Pitman arm. Didn't go off with big puller. I put pressure than heated up to some grade (not red hot) and added a couple of good hits. Sure the situation may differ on a particular truck. 

[Freightrain]

Ya, it's a tapered fit that hasn't been apart in 60+ yrs.  No doubt she's snug.....

[HarryS]

14 hours ago, Freightrain said:

Ya, it's a tapered fit that hasn't been apart in 60+ yrs.  No doubt she's snug.....

That was going to be my next question. Hard to tell if it is tapered or just spline. I can see where some dirt was painted over when the frame was painted so that tells me it's probably been on there since new. I did not have to remove the pitman arm when the hyd steering assist was added. The puller should be here by the end of the week. Based on your's and Vlad's experience it looks like a three step process. Puller BFH and heat.

[Freightrain]

Most steering box splines have a slight taper to make the pitman arm fit tight.  It can't have any slop in the spline and like a tie rod end a taper makes it tight.

[Vladislav]

Mine had slight taper on the splines. You can barely but see it on my pics.

Those hydro units I had taken off Mercedes G and cars (with circulating balls) also had taper. So seems like typical design determined by what Larry explained above.

[Freightrain]

If you ever try to flip a pitman arm around and install it upside down, it won't go on much, if at all.  The taper makes it impossible.

[HarryS]

     The pitman arm finally came off using the recommended bigger puller, bfh, then some heat. I also had a hard time getting the steering shaft tube separated then there was a spacer between the steering box and frame that had to have been on since the truck was built in 1960. It had to come off before the box would come down and over the axle. It took lots of heat and prying enough to get a hydraulic spreader in and finally separate the spacer.

     Rather than tackle the rebuild I will have it rebuilt and hopefully not have to worry about missing something. Weller Truck Parts was recommended and they are close enough to not have to ship. They say a week to ten days turn around. They seem to be all over the country. Anybody had experience with them?