Pitman arm to pitman shaft orientation problem.

jameydan · Post by **jameydan** » Sun Apr 22, 2012 11:50 am

I ran into a little trouble with aligning my pitman arm on the steering gear. I bought a rebuilt steering gear form John at MWM. I took my pitman arm and mounted it as best as possible according to the directions in TM 9-8014, paragraph 230, (c) installation. (I figure this is where I did not get things correct.)

With the gear out of the vehicle, I found I had 6 revolutions total of the steering wheel from stop to stop. I mounted the pitman arm as directed in the above mentioned paragraph, and re-installed the gear into the jeep as written. However after bolting the gear in, and before I connected the drag link, I discovered the pitman arm is striking the engine block at the oil pump after only turning the wheel 2 revolutions from the centered position (it maintains 3 full revolutions in the other direction as the pitman arm rotates back towards the driver).

So, I suspect the pitman arm is not mounted on the shaft correctly. I would like to remove the pitman shaft with the gear still in the jeep and re-position it. I want to try to pull this off as the steering gear is a pup to remove thru the floor pans.

My question is how far forward should the pit man shaft be in relation to the oil pump when the steering is at it's fullest travel in that direction?

I hope I can correct this problem with the gear in the jeep, but at I do have the steering wheel off and can pull the whole assemble if need be.

Thanks and any other advice in this area is appreciated!

Jamey Williams
Conrad, MT

donthedickens · Post by **donthedickens** » Sun Apr 22, 2012 6:49 pm

Jamey,
I got close to 3/4" between the arm and the oil pump with the wheels hard right. If you need more details I'll get under tomorrow. Raining now.

PS What kind of jeep and what engine?

jameydan · Post by **jameydan** » Sun Apr 22, 2012 9:46 pm

DtD,

Thanks for the info, now I hope I can get it off and moved easy enough. I will let you know if I need more info. I think where I went wrong with indexing the pitman arm, was where the manual calls for it to be perpendicular to the long side of the gear box. I guess I placed it wrong on the shaft and not quite perpendicular.

I have a 53 M38A1 with the std F-Head.

Thanks again.

JW

artificer · Post by **artificer** » Mon Apr 23, 2012 12:52 pm

Do not put the pitman arm on tightly until the steering box is in the vehicle & you have done the following:

Remove/loosen the pitman arm from the steering box splines enough to re-centre your steering box without the pitman arm moving.

Line up your front wheels to near straight ahead position with all tie rods & drag link in place [with the pitman arm attached] as they would be on the road.

Re-fit the pitman arm to the steering box splines now & tighten the nut on the spring washer.

You should be right to go & set your toe-in, up.

Often the sector shaft & the pitman arm have marked alignment grooves which one sets up to alleviate the method I described above, but either way achieves the same result.

jameydan · Post by **jameydan** » Mon Apr 23, 2012 1:05 pm

John,

Thanks for the advice and your method seems quite logical. I will give that method a try tonight or tomorrow. The pitman arm and the steering gear both had alignment marks chiseled into them, but the parts were from different units, so they were of no help.

Best regards,

Jamey Williams

Post by **wesk** » Mon Apr 23, 2012 3:04 pm

The primary reason for insuring you set the pitman arm 90 degrees to the long side of the steering box is to insure you clear the engine through it's entire range.

What John suggests above usually works fine unless your are doing a complete resto and all steering linkage has been removed and or replaced. The steering bellcrank on the other end of the drag ling is properly positioned relative to the pitman arm already being properly positioned. If you have removed the bell crank and not indexed it prior to removal then you have a 50/50 chance John's method will work for you. If the rest of the steering parts have not been off the jeep then John's method will certainly work.

Since you have the book out I would suggest you learn the book way now and use the other ways later.

jimm · Post by **jimm** » Mon Apr 23, 2012 10:49 pm

Wes,
I'd like a better understanding of why you say John's method has a 50/50 chance for a total rebuild. Is it because that even if the wheels are straight ahead, the left and right tie rods may be adjusted such that the bell crank is not in the correct neutral position? Is there any way to improve the odds?

The book Jamey references doesn't really help, because it assumes the alignment marks for the pitman arm to sector gear are correct, and that the rest of the system hasn't been disassembled at the same time.

Post by **wesk** » Mon Apr 23, 2012 11:17 pm

Is it because that even if the wheels are straight ahead, the left and right tie rods may be adjusted such that the bell crank is not in the correct neutral position?

You haven't told me the state of the rest of your steering system. If it's as I assumed and totally removed for resto then the best way to improve the odds is to do it by the book and properly set the pitman arm which is suppose to be done first to give you the correct starting point for the drag link and bellcrank.

You are doing work on the resto right now that you only want to do once so the best insurance is do it by the book.

The book Jamey references doesn't really help, because it assumes the alignment marks for the pitman arm to sector gear are correct, and that the rest of the system hasn't been disassembled at the same time.

This is not true if you are using the correct manual. TM 9-8012 and TM 9-8014 say to reassemble a sector and pitman arm that were origianally a matched pair use the match marks. It then says if you have a new part then ignore the match marks and set the pitman arm 90 degrees to the long side of the steering gear box with the steering worm/sector in the center of it's travel.

It doesn't get much plainer then that. I have done a hundred or so of these and that's the way to make sure that the arm doesn't travel so far in one direction that it hits the engine. It is also the required starting point to reference the bellcrank's proper angular arrangement on it's installation.

jameydan · Post by **jameydan** » Tue Apr 24, 2012 12:00 am

"This is not true if you are using the correct manual. TM 9-8012 and TM 9-8014 say to reassemble a sector and pitman arm that were origianally a matched pair use the match marks. It then says if you have a new part then ignore the match marks and set the pitman arm 90 degrees to the long side of the steering gear box with the steering worm/sector in the center of it's travel.

It doesn't get much plainer then that. I have done a hundred or so of these and that's the way to make sure that the arm doesn't travel so far in one direction that it hits the engine. It is also the required starting point to reference the bellcrank's proper angular arrangement on it's installation."

Wes, I think where I had trouble was installing a curved pitman arm "perpendicular" to the long side of the gear box. I was not quite sure which portion of the pitman arm to imagine as the perpendicular point. I goofed on that by picking what I thought was correct at the time. I suspect that I should have indexed the pitman arm so that the ball of the pitman arm was as far as possible away from the long side of the steering gear box.
Now, I need to pull the whole gear out and reattempt to get perpendicular right, or try and fix the situation in the jeep - and so that it is safe with steering/handling.

I did not disconnect any other steering components other than removing the drag link from the pitman arm and pulling out the steering gear.

I hope to get at it tomorrow and I have some thinking to do when I look over things tomorrow.

I do appreciate the opinions everyone is sharing.

JW

artificer · Post by **artificer** » Tue Apr 24, 2012 7:27 am

Line up your front wheels to near straight ahead position....then later....& set your toe-in

is exactly what John said.

jimm · Post by **jimm** » Tue Apr 24, 2012 8:57 pm

wesk wrote:
Is it because that even if the wheels are straight ahead, the left and right tie rods may be adjusted such that the bell crank is not in the correct neutral position?
You haven't told me the state of the rest of your steering system. If it's as I assumed and totally removed for resto then the best way to improve the odds is to do it by the book and properly set the pitman arm which is suppose to be done first to give you the correct starting point for the drag link and bellcrank.

By "for a total rebuild", I meant the rest of the steering system as well as the steering gear itself, so your assumption is correct.

wesk wrote:
The book Jamey references doesn't really help, because it assumes the alignment marks for the pitman arm to sector gear are correct, and that the rest of the system hasn't been disassembled at the same time.
This is not true if you are using the correct manual. TM 9-8012 and TM 9-8014 say to reassemble a sector and pitman arm that were origianally a matched pair use the match marks. It then says if you have a new part then ignore the match marks and set the pitman arm 90 degrees to the long side of the steering gear box with the steering worm/sector in the center of it's travel.

My mistake - somehow I missed the note about missing marks, even though it is right there below the main paragraph. And for reference, TM 9-8012, Jan. 1956 for the M38 (not A1) makes no reference to alignment marks but says, "push the pitman arm onto the pitman arm shaft with the ball directly below the shaft", which eliminates any confusion due to a curved arm. (I'm not saying, or implying, that this is applies to an A1.)

I'm sure I can figure it out when I get to that point. Gotta be a piece of cake compared to rebuilding the axles