Taylormade

Pitman Arm and Drag Link

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I posted this in the Dodge section, but I think it's a common problem in prewar cars and would like to get suggestions, experiences and soutions from other members.

 

looked over my pitman arm and the drag link of my 1932 dodge DL today and the news is not good.  The ball on the pitman arm is of the cast on type and is not replaceable.  As you can see, it has some flat spots and it sure isn't the good old perfect sphere it used to be.

 

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I have heard a new ball can be welded on by turning the old, worn ball down to a shaft on a lathe and then inserting a bored ball onto the shaft and welding it on.  Some have also suggested that the ball can be build up by adding metal to the worn areas and then turning the ball to the correct dimensions.  Anyone have any experience with this who could recommend someone who knows what they're doing in this area?  This is one operation that has to be right - failure is not an option, especially at 45 miles per hour.

 

The drag link doesn't look much better.  The keyways are worn pretty badly.  I have a rebuild kit with all new balls, springs and cups, but that doesn't help the worn keyways.

 

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I have heard that you can take an available Chevy draglink and cut off the ends of both draglinks and weld the ends of the Chevy link to the shaft of the original Dodge drag link.  The smaller diameter of the Chevy link fits into the Dodge drag link section and with a good weld should be okay.  Bummer day of disappointing discoveries, but I have all winter to deal with it if necessary.  If anyone has a line on these parts in better condition, let me know.

 

I suppose some will recommend Rare Parts, and I'm sure they could make them, but I'm figuring the cost would be astronomical based on some other quotes I've gotten from them.

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Just a thought.....have you looked for removed parts from the guys on the H.A.M.B? Those guys are the first ones to tear out the original stuff to put in a Mustang II front suspension.

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I was a welder and machinist most of my working life (still am on occasion).

If you want to salvage the ball build up the low spots and hand grind them to fit.

No way on earth would I chance welding a new ball to that shank or weld close to the point where the ball meets the shank.

Take it slow so as not to over heat the metal.

The ball socket halves are undoubtedly worn as well but a lot of times all that's necessary is one or two machine washers under the socket halves to restore some adjustment.

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You say "the ball on the pitman arm is of the cast on type". I would be pretty surprised if it was a casting, more likely a forging. Castings are typically brittle, not a characteristic you want for a part that will be taking lots of impact loads from tires striking rocks and pot holes in the road.

 

That doesn't change or alter your problem though.

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6 hours ago, Taylormade said:

I have heard a new ball can be welded on by turning the old, worn ball down to a shaft on a lathe and then inserting a bored ball onto the shaft and welding it on. 

 

That is exactly how I would do it. Keep the turned off section's diameter slightly smaller than the original shaft to create a shoulder and there will be very little to no reduction of strength. Steel balls are available from McMaster and boring them to fit the turned shaft should be no problem. I would recommend a light press fit on the shaft and the only welding I would do would be TIG welding at the ball top and shaft joint. I might also cross pin the ball as a back up to the weld. I would not hesitate to weld whatever link ends were available to your existing link to match the new ball diameter.

The biggest fly in the ointment will be setting up and holding the pitman arm for machining off the ball.  A milling machine might be a better choice than a lathe. If the ball is hardened, carbide tooling will be needed. The alignment of the shaft need not be perfect since the drag link will adjust itself to the new ball.

Looks like a doable and fun project to me..................................Bob

Edited by Bhigdog (see edit history)

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1 hour ago, Bhigdog said:

Looks like a doable and fun project to me..................................Bob

 Great, Bob, where do you live...I'll be right over. :D

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Eastern Pa. Any small machine shop should be able to do the job..................Bob

 

 

 

 

 

 

 

 

 

 

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Do let us know how the project is progressing. I think finding a shop that's actually interested will be key. BTW, machining new ball socket halves would be fairly easy also. A ball end mill the same radius as the new ball would make short work of it.......... .........Bob

Edited by Bhigdog (see edit history)

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This is the solution for Auburns that exhibit the same problem.

-Hardened steel balls are available at McMaster Carr.

- send balls to heat treater to remove temper.

- Machine ball and drill arm. and assemble.

- Back to heat treat

 

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Yup there it is. My only concern would be heat treating the ball after assembly. There is the danger of making the arm brittle. Twer it me I would either use an unhardened ball or leave the ball in an annealed state. Considering the probable low usage an unhardened ball will likely out last the owner...........Bob

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30 minutes ago, Bhigdog said:

Yup there it is. My only concern would be heat treating the ball after assembly. There is the danger of making the arm brittle. Twer it me I would either use an unhardened ball or leave the ball in an annealed state. Considering the probable low usage an unhardened ball will likely out last the owner...........Bob

 

Good point Bob, that step would save the money of re-hardening it.  A metallurgist did assure me that  hardening of this steel would not be deleterious. 

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I have the same problem at the moment with my 1930 Dodge DC drag link and steering arm. This morning I visited a machine shop.

 

After a long pause and a bit of discussion a method was probably arrived at. Buy a hardened steel ball (e.g. a ball bearing). Drill it to fit. Apparently carbide can cut hardened steel. The ball must be hardened right through.

 

Set up the steering arm on a face plate and burn the ball off to a shaft. Fit the drilled ball. We didn't conclude on how to make it stay on, but the silver solder idea might work. Building up the wear on the arm near the ball will take a bit of clever work.  We thought it was cast (or forged), machined in a jig to provide for the bend, then hardened and tempered.

 

The ends of the drag link, which are worn inside as well as the holes being misshapen, is also hard. After figuring out how they were forged, the conclusion was that it would be best or easiest to make another tube end, slightly larger in outside diameter coz they didn't have the kit to hammer out the grease nipple mounting, then fit it over the end of the drag link (minus original end) and weld it on.

 

Apparently Chev ends could be used. The Filling Station have a photo in their catalogue. The ends on my DC link are longer than on the DL shown above, with two springs rather than one at each end. The Filling Station catalogue photo shows a link that is similar to the DL, which is no good for me but may work out for the DL. The holes are offset differently at each end as they are in the DL drag link.

Edited by Spinneyhill (see edit history)

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9 hours ago, Spinneyhill said:

After a long pause and a bit of discussion a method was probably arrived at. Buy a hardened steel ball (e.g. a ball bearing). Drill it to fit. Apparently carbide can cut hardened steel. The ball must be hardened right through.

 

That's the hard way. Far easier to anneal the ball by heating to yellow heat and cooling it slowly in vermiculite, ashes, or a heat treating oven then re harden if you feel it's necessary. If $ is no object drill the hole with an EDM machine.

10 hours ago, Spinneyhill said:

silver solder idea might work

 

Assuming you mean silver braze: That would mean heating the assembly to red heat and possibly causing embrittlement or softening of the arm. Better to TIG weld at the top of the ball.

 

 

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On August 23, 2016 at 8:12 AM, Curti said:

This is the solution for Auburns that exhibit the same problem.

-Hardened steel balls are available at McMaster Carr.

- send balls to heat treater to remove temper.

- Machine ball and drill arm. and assemble.

- Back to heat treat

 

 

 

I assume you meant machine arm and drill ball, or am I missing something?  Did you have the work done nearby in Wisconsin?  Just curious if I could send it to them since they are familiar with the problem.  It looks exactly like the solution I'm looking for - in fact your Pitman arm looks a lot like mine.

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23 hours ago, Bhigdog said:

 You didn't miss anything. I personally do not do it.. I have a friend that has retired from the machine shop at the 3M company. He has forgot more than I know. 

If you supply the balls and pitman arms I can get it done.  

I will PM you with a price. That data is in the business computer and the CFO (wife) is at a hair appointment.

Edited by Curti (see edit history)

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Bhigdog has been misquoted in the above................Bob

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While there seem to be a number of solutions for the ball end, what about the rod ends?  Does anyone reproduce those spring-loaded ends so that a new drag link could be built?

 

For my current project, I wound up using modern tie rods that screw into weld-on threaded collars from a Jeep 4x4 off-road supplier.  The collars were welded to 1.5" o.d. x 1" i.d. steel tube.  It fits and works, but is probably heavy and strong enough for a Sherman tank (or its modern equivalent).  How does one get the correct appearance for a '30s vehicle?

 

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Gary, most of the vintage tie rods I have worked on have a threaded tie rod and tie ends that screw on, one right hand thread, one left hand thread, with a slot that is tightened down with the attached bolt and nut.  I think yours look great and would pass muster anywhere.

 

IMG_2946.jpg.

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Gary....did you ever check with Rare Parts for the tie rod and ends? They sometimes have stuff not listed in their catalog. Your new ones look great.

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Gary, there are one or two suppliers of 1932-on seats for drag link ends for MOPAR. I don't know about Studebaker. They are easy enough to machine using a ball end or bull nose end mill of the right diameter. Then they must be hardened of course. Those from 1931 onwards are a hollow button. In 1930 Dodge the seats are integral with the pin that fits inside the spring and it has two springs at each end; in 1931 they introduced the shorter, simpler, cheaper single spring end.

 

The Filling Station sell Chev drag links. The ends may be able to be adapted.

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It wasn't the seats I was after, it's the outer shell where the seats go inside, with a kehyhole slot as shown in the last two pictures of the first post here. According to that 1920 article that I posted above, a tube end was expanded to form the larger diameter section. That's not a common procedure without very special equipment.  I suppose they could be machined from round stock and welded to a tube. Somebody must have encountered this issue while restoring a car in the last 60-70 years. 

 

A while back, I did find a company that would swage down the ends of a tube, as is common on old tie rods. Example: take a 36" length of 1" o.d. tube and reduce a 2" length at each end to 3/4" o.d.  The metal gets thicker on the reduced diameter part. Then you drill and tap for tie rod ends. Not cheap, but possible. 

Edited by Gary_Ash (see edit history)

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Gary, are we talking tie rod or drag link?  The last two pictures in my first post are the ends of my drag link.  The photo in post  #20 is of my tie rod ends.  If we are talking drag link, the ends of a 30s Chevy drag link can be used.

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1 hour ago, Gary_Ash said:

 I suppose they could be machined from round stock and welded to a tube.

 

That is what my machine shop foreman suggested yesterday. I can't use the Chev ends because I have two springs each end, not one - unless I modify it.

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