Pitman Arm to PS Box Spline Engagement

[W_A_Watson_II]

I'm replacing my PS box on the M as this summer late while off-roading with the M I experienced some times of no steering, both while driving and while setting still. The steering would suddenly start again after I stopped and/or moved.

I've had some problems for the past couple of years where the steering was much harder than it should be from time to time. Nothing consistent, but always at the wrong time. It seemed to act like I didn't have enough power in the PS, but some times I swear I could not turn as short as I think I should have been able to. I don't remember if the PS Pump would squall in those cases, but it seems like it might have.

This time while driving late this summer I just suddenly could no longer turn, left or right, it was like the steering wheel was locked. No I don't have a locking steering column, I'm using a stock M column.

While setting still once in a while the exact same, except no wheel movement. In both cases there was no typical PS Pump squall like I was trying to force the truck to turn turn further than it was supposed to.

As with no PS Pump squall, and the fact that the truck was moving in 4WD, my conclusion was that it was not related to the front axles tracts joints.

So now I've installed the new Box, and am also installing a NOS Pitman Arm as the one I had on since I broke the original one in May was a well used, but functional unit.

With the original Arm and PS Box I could only get about 2/3 of the splines to engage, and just barley had enough threads to install the lock washer and nut. Now with everything new, and the threads as clean as I can, I can only get about 1/5 spline engagement, and no room for the lock washer.

The splines are correctly aligned and inside the arm, you get some evidence of shaving metal out of the valleys of the splines. You see nothing on the PS Box.

The picture is after I used a file and cleaned the Pitman Arm splines of any burs from the previous install attempts, and warmed it up some and this is still as for as it will go on. I'm using a 1/2" breaker bar with a cheater pipe to tighten it as for as I dare (I'm stronger than my impact wrench even with out the cheater bar).

What is/have everyone else who has done the PS conversion seen for spline engagement and did you have room for the lock washer?

[maineSS]

Before I did the Toyota PS conversion, I got one of the Saginaw reverse-rotation boxes off a Dodge W-100 4wd. As I recall, the PW arm splines appeared to match the taper and number of splines on the steering box, and there was room for the washer- my arm was from the B1 series.

Things might have changed by the early 50's when the M37 entered service- it sounds like the taper may be slightly different, or the taper starts at a smaller dia with the M37 arm. I definitely would not accept a 1/5 engagement on a critical part like the pitman arm.

[Kevin Tighe]

Pitman Arm Spline Engagement

I know just what you are talking about. Several years ago I purchased a NOS manual steering sector shaft for my M37. I got it from a parts vendor that we all know and love. It appeared to be a good quality part. I NEVER could get the pitman arm to fit that sector they way it should. I studied the problem till the cows came home, and never did figured it out. The arm would would not go on the shaft far enough to get the lock washer and the nut on properly. It would go on similar to your photo, without the lock washer. HOWEVER, this summer I chucked that NOS sector and the old manual steering box and replaced it with a reverse rotation Saginaw from a Chevy van. The same pitman arm (the one that did not fit the NOS sector) fit the Saginaw perfectly. So, I have to deduce that the splines on the sector shaft were somehow bad. I miced, burnished and filed that stupid thing, and I'll be darned if I could tell you why it would not fit the way it should have. I feel your pain!