Who has experienced a pitman arm breaking?

[barronj]

Scary, scary stuff. Or, by all accounts, it should have been scary.

I was going to drive around the block after installing a new stock style steering linkage kit from Toms (this), and as I'm rolling out of the garage, headed down the driveway, sudden steering loss. I get out, look underneath, and it's immediately apparent what has happened.

I'm incredibly gratefull that this happened at 1mph in my driveway, and not at 65mph on the highway tomorrow morning, or at any speed, really.

Wow.

 

[barronj]

So, I guess my next questions are:

Why might this have happened? Poor geometry?

What are the corrective steps to proper geometry?

I currently have a 2.5" suspension lift, power steering from a 74 or 75, and an adjustable track arm.

Drop pitman arm & drop track bar bracket? I'd like to order whatever I need tonight, if possible. Thanks, now... GO!

 

[Fireball05]

Wow, that is scary? How tight did you torque that nut?

Do you have a head on photo of your front steering setup?

 

[barronj]

That's just it, I didn't torque it much at all. Finger tight & then 1/4 turn with the wrench.

When I bought the power steering pump from a board member, it had the original bolt stuck in it (from the drag link?) and I had to cut it off with a torch. Maybe it got brittle from being exposed to the heat?? I'm shocked.

The 2x4 is propping the steering linkage up to where it broke free from the pitman arm.

 

[BluebroncoNC]

Yikes, I have not seen anything like that. And hope I never do again.

 

[sp71eb]

So it was your original pitman arm or a new one? Also how hot did you have to heat it?

 

[cscotted]

It looks as though they are two different taper angles? Causing stress point to failure....its just me looking at a picture obviously...that could be scaaaary..

 

[cscotted]

If drag link has factory TRE and its a stock arm. As long as they match they in theory shouldnt do that.. Heating it could have weakened it

 

[barronj]

So it was your original pitman arm or a new one? Also how hot did you have to heat it?

My 68 came with no power steering, and I bought a 74 or 75 model power steering set up off a board member. I had someone (my local transmission shop) use a cutting torch to remove the old bolt. I watched, the whole end glowed, but that was about 4K miles back (or 2.5 years)

 

[barronj]

If drag link has factory TRE and its a stock arm. As long as they match they in theory shouldnt do that.. Heating it could have weakened it

Factory TRE, but the PS set up was off a mid 70's bronco, and mine is a '68.

 

[cscotted]

I would replace ( obviously) lol, with a new rod end, and a new pittman arm, and not really look back at it, Heating it is never a good idea if you plan on reusing it, when tapered items are fastened down, that stress combined with hardened steel ( from heat and cooling) makes it weak..

I think you will be fine. My .02

 

[cscotted]

I dont know the year beaks for rod ends...not a bronco guru but have dealt with plenty of different 4x4 s .... Just look at the tapers, there shouldnt be a gap anywhere, they should basically fit snug from top to bottom.

 

[cscotted]

Year breaks....is what i meant...from 68 to 74 or whatever

 

[broncnaz]

Most likely the heating that was done to it caused the break. steel that is heated to glowing red usually becomes softer than it was orginally. If you quenched it in cold water while glowing red it will become harder and also more brittle. So in either case heating that hot causes problems.

More than likely the mismatch in taper that people are refering to happened as the pitman arm came apart. It doesnt really look to me like there is/was any real mismatch.

 

[broncodriver99]

I agree it is likely from the heating. A little heat to loosen something up is one thing but glowing red is not good, especially something as structural and important as a pitman arm.

Man that is scary. I think you owe the big man a thank you. That could have gotten ugly.

 

[TwoDalesDad]

I would ". Bang" that nut at the tranny shop for heating that till it was red hot. HE DID YOU WRONG! You can heat something for just a few seconds with a propane torch....to break the rust....anything more...And you could have killed a bunch of innocents..

 

[savage]

I notice the castle nut has a washer under it.Did the drag linkage come with the washer?I have a drag linkage from toms bronco and it didnot come with a washer and my old drag didnot have a washer.

 

[barronj]

I notice the castle nut has a washer under it.Did the drag linkage come with the washer?I have a drag linkage from toms bronco and it didnot come with a washer and my old drag didnot have a washer.

That was only to get the castle nut high enough that a cotter pin would actually perform as intended. It was there before the new linkage as well. I put it there out of necessity.

 

[DirtDonk]

That would indicate some sort of a mis-match in the parts though barronj.
It is sometimes due to the tapered hole being larger than the rod end stud, but yours does not look like the typical big mismatch say, between a '66-'75 EB draglink and a full-size pitman arm.
But it could be.

It's possible that you had either a mismatched component issue or there was enough distortion in the arm after the heating to cause the rod end to not fit properly.

Not always a mis-match in parts, of course, as some parts are just not made to the same tolerances a the originals.
Often enough it's something like a '76 draglink being fitted to a '75 and prior pitman arm. But that's obviously not the case.
If it was that full-size vs EB bit I mentioned earlier, I think the mismatch would have been larger. Large enough in fact to have caused the dust boot to get crushed as the tapered stud was pulled too far up into the too-large hole.

Besides, it does look like a stock EB arm. The shape and angle look correct.
So it's a mystery for sure. But as long as you're safe and the new parts are on and fit, you're good.
I would at least show the shop what happened though. In case they're ever tempted to do that again to someone else's arm.

And let us know, just for comparison, if you need the washer on the new setup.

Paul

 

[barronj]

I will, thanks for the replies.