1925 Master Pitman Arm

[dibarlaw]

Since we have had this spring like weather I thought I would sort out the sloppy steering on the 1925-Master. My friend Pete who trailered it home for me thought that the steering rod adjustment just needed attention. Wrong! The pitman arm ball stud was very loose and had worn out the arm forging. Now oversized /out of round and tapered hole. It appears that when the former owner worked on the car in the 1960s the ball stud was already loose. The outside end was peened over and a lot of center punch marks to hold in place. Has any one else dealt with this issue on their car?  According to the master Parts book # 254998, forging #255066 was only used on the 1925 master and 1926 master first type.

 I also find some looseness in the King Pins Part # 188975. They appear to be the same from 1924 6 cylinder,1925 master up to 1931 80 and 90 series. I know that these are available from Bob's

 My thoughts on repair would be to grind out he misshapen rear end to remove the stud. Bore out the arm to true the hole. Make a bushing then try to find a compatible hardened ball stud to refit. In the 1925 Book of parts these Ball studs are a replaceable item (at least in the Standard book). The 1931 Master book only shows the complete arm as being available. $3.00! That would still represent several days wages to many who still had a job in 1931.

[ROD W]

Larry,  I have seen plenty of worn oval balls, but never a loose stud.  the one,s I have seen look like they have been pressed in at the factory.

[dibarlaw]

Thanks for the reply Rod.

I was able to remove the ball stud. I was able to chuck up on the ball with a center on the opposite end. With the arm resting on the lathe carriage I was able to slowly turn off the peened over edge.  The photos show how it was worn. The largest diameter on the pin is .631 the smallest diameter on the end toward the shoulder is .566. A 90 degree measurement is .610, .044 out of round.

The arm bore tapers from .669 to .639. In other words pretty sloppy.

 Back to the lathe...

Larry

[bradsan]

Larry

 

There is always Rare Parts.

http://rareparts.com/

They can put a new ball stud on for you. I'm not sure if they will sell you one to put on yourself. They rebuilt the tie rods and pitman arm for my Auburn. Looks like quality work but the only way you know for sure that it isn't quality is when it falls apart. Which, understandably,  is why they likely won't sell you the part to do yourself.

It will definitely be more than $3, Probably a couple of today's days wages so maybe things haven't changed that much!

 

Brad

[bradsan]

Larry

 

Looks like we posted simultaneously.

I was misunderstanding the issue. I thought the ball was 'ovalled'.

What you have is downright scary!.

I also forgot your machining talents. Sleeving the hole likely not an option given the wall thickness the sleeve would have to be...right? Probably better to ream the hole the next size up and make a stud with a custom shaft. As mentioned, Rare Parts could make a ball with a custom shaft size but they won't let you play with it for all of the good corporate liability reasonss.

Can you machine something like that ? I think the ball should be hardened and I think Rare Parts does that.

 

Brad

[dibarlaw]

Brad:

 The ball itself is hardly "ovalled" only about .025. When I weld the bushed/finished stud back in I will just index the ball to the least worn area The ball is case hardened. The stud shaft surface turns well. I just have to figure how I will set up the arm to properly line bore it.

[Hubert_25-25]

Larry,   You are very lucky it just wobbled and did not work its way out.   

 

Hugh

[Bob Engle]

I would suspect that the original ball stud was a heat shrink fit.  After you make a sleeve, I would install it with a heat on the arm and ice on the ball shaft.  Your alignment of the bore does not require perfection, the spherical surface will make up for a degree or two of misalignment.

Bob Engle

[pepcak]

This is how my 1928 Master part looks like. Seems the "peening" is very well made, looks factory(?)

[dibarlaw]

pepcak:

 This is what the finished product looks like.  I removed the ball stud, made a split collar to mount in the 3 jaw chuck. I was able to remove about .030 to straighten and true up the diameter. I fit a bushing that I made a press fit over the turned surface. I then set up the arm on the drill press so I could drill out the out of round/tapered hole to a true diameter. I then turned the bushing on the pin to an interference fit for the hole in the arm. I pressed the pin to the arm then had it welded.

[pepcak]

Sweet :-) I have asked at Rareparts what it would cost to replace single ball joint like this and they quoted USD 185 (plus shipping to & from), using my Pitman arm as a core part.

 

On different topic - are you still interested in water return pipe I offered?

 

Josef