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What in the world is the size of the nut on the pitman arm? I bought a kit for the steering box on my '63 and went to use the nut that came with the kit. My 1-1/4 socket wouldn't fit it, so I dug out the old original nut. SAME SIZE!! Both nuts measure about 1.280 across flats. Sears doesn't list a 1-5/16 socket and a 32mm is too small. WHAT GIVES??!!?
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Re: PITMAN ARM NUT
Pete; you are right, my 65 is 1.280 and a 1 5/16" socket is sloppy on it but 1 1/4" won't go but I'm sure it would loosen it. My 62 is 1 1/4" David -
Re: PITMAN ARM NUT
Pete-----
I've never been able to figure this one out, myself. A 1-1/4" socket is too small to fit on the nut and a 1-5/16" is a poor fit. Considering the torque applied to this nut, using the 1-5/16" risks slipping the socket and/or damage to the nut.
I don't think that this nut could be metric since this thing dates back to 1963 and metric fastners weren't being used on US built cars anywhere near that far back. Also, there are NO special sockets or tools available for this nut. I always figured that this "odd-ball" size was GM's way of ensuring that a special tool was used on this nut for some otherwise inapparent reason. However, no such tool has ever been available----I checked this out exhaustively.
I'm still quite sure that GM had a very specific purpose for creating this "odd-ball" across-the-flats nut dimension. I just don't know what it is. The only thing that I could figure is that they did this to force one to use an adjustable ("crescent") wrench to remove and re-install it. However, that doesn't make any sense, at all, especially since there would be no way to apply a specified torque using this type tool. I sure would like to know why it was done, though. I've been wondering for YEARS.In Appreciation of John HinckleyComment
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Re: PITMAN ARM NUT
In that case..go metric.Comment
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Re: PITMAN ARM NUT
One of the first jobs I had when I went to work for Ford Motor Co. was building up steering gear boxes. That means selecting the appropriate gear from a stock basket, laying it on a build-up table and then releasing an air clamp to hold the gear to a fixture. The pitman arm was then placed over the sector shaft and a "large nut and washer" was hand started to the shaft. A foot pedal was then pushed which started an air motor with an "oversize socket" on it spinning and sliding onto and over the large nut on the sector. The nut was secured to torque and then the gear was hung to the frame. As I remember, the socket was oversize to the nut. I remember the socket was a six pointer and did not slip or round corners. It also had a lead on the edges of the flats in addition to the oversize to allow the two parts to engage while the socket was rotating.
Maybe GM did the same thing.
Somewhere in my archives, I have the process sheets (you guys call it AIM) on how to build the chassis on a '66 LTD. If I can find it, I will look up the socket and nut size.
Whatever the reason, a six point socket should be fine to secure to torque without damage.Comment
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Re: PITMAN ARM NUT
1-5/16" socket fits my '67 just fine, also fits my '69 Camaro; just measured both (original) nuts, and they're exactly 1.30", which is .0125" smaller than a 1-5/16" socket. Sounds like you got a "bogus" pitman nut in the kit - the GM pitman nut is NOT an oddball size.Comment
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Re: PITMAN ARM NUT
Thanks everyone! I just wanted to make sure that I wasn't loosing my mind on this one. PeteComment
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Re: PITMAN ARM NUT
i just did this job and i had to use a pipe wrench. it is a pefect tool for the job because you won't repeatedly remove and replace this nut; if you jazz up the flats a little, so what [unless this is a super show car]. after all, how many times do you have to remove the pitman arm from the same steering box. maybe once every four years, maybe. so, i vote for a pipe wrench.
finally, i don't see where the torque setting is that crucial. this is a jam fitting, as i recall. in other words, the pitman arm will jam against the splined shaft. so as long as it is good and tight, it ought to be just fine.
good luck.Comment
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Re: PITMAN ARM NUT
I just did this job adding power steering to my 67. Sears sells a 1 5/16 socket, you just need to buy the size up adapter to fit on your 1/2 inch drive rachet. Worked well for me.
RonComment
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