Steering Box Questions

jagnweiner

Senior Member
Finally got my new-to-me '47 Mercury yesterday. I'm really loving it, but starting to work on the few issues I need to iron out. One of the top priorities is a worn steering box causing a huge amount of play in the steering. I've adjusted the screw which helped a bit, but leads me to a few questions:

1) when I started working on it, I noticed that the lock nut for the adjustment screw is gone. Washer was still sitting on it but nut is gone. Does anyone know what size and thread that nut is?
2) There is a wire coming out of the front of the box and running into a wiring harness. (See photo). What on earth is that for? I have no idea.
3) It's leaking. what are the most likely culprits?
4) I may try to rebuild it or I may send it out. I see "Mike" from NC advertises here and I've seen threads where a couple of people have said they are sending theirs to him for a rebuild, but haven't seen any reports of the finished products. Anyone have any feedback on Mike or anybody else that rebuilds boxes?
 

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Haven't been there yet but personally, I'd vote for sending it out for rebuild. Only thing is you need to dismantle the steering wheel and column to do that but there's treads in the forums that help with that. There's one particular tread about what lubricant to use if you just concerned about leakage.

Nice Merc there. Have a '47 Ford coupe and love it .... a nice driver.

Just had that lock nut off the box tonight - can check it if you need. One thing I don't understand is that the steering box adjusting screw in my car is directly under the exhaust manifold and there's no way to get at it.
 
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Just had that lock nut off the box tonight - can check it if you need. One thing I don't understand is that the steering box adjusting screw in my car is directly under the exhaust manifold and there's no way to get at it.

Yeah, it's not convenient. I've been able to get a screwdriver on about half the slot of the screw.

It would be helpful is you could check, unless someone else chimes in.
 
I am not sure of the steering mechanism for your car but you also need to check the linkage and king pins. It all adds up.
 
Haven't been there yet but personally, I'd vote for sending it out for rebuild. Only thing is you need to dismantle the steering wheel and column to do that but there's treads in the forums that help with that. There's one particular tread about what lubricant to use if you just concerned about leakage.

Nice Merc there. Have a '47 Ford coupe and love it .... a nice driver.

Just had that lock nut off the box tonight - can check it if you need. One thing I don't understand is that the steering box adjusting screw in my car is directly under the exhaust manifold and there's no way to get at it.

Where would I find the post that talks about the lubricant, mine has just been rebuilt and has a small leak.
 
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I don't think that adjuster nut is 9/16-18. That would be a big one. The original adjuster nut is P/N 78-3539-A. It's not a plain type nut. It's made to work in unison with the star washer to properly secure the sector shaft position. The threaded screw that the nut secures fits into a slot in the top of the sector shaft and there may be a problem with it. It's no wonder you have a lot of play since there is nothing to hold the position of the sector shaft without that nut and star washer being there. The OEM nut is a cap nut. It completely covers the threaded screw and locks it down.

That tube that the wire runs through can crack and cause leaks. The sector shaft seal is the most common offender of leakage.
 
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I don't think that adjuster nut is 9/16-18. That would be a big one. The original adjuster nut is P/N 78-3539-A. It's not a plain type nut. It's made to work in unison with the star washer to properly secure the sector shaft position. The threaded screw that the nut secures fits into a slot in the top of the sector shaft and there may be a problem with it. It's no wonder you have a lot of play since there is nothing to position the sector shaft without that nut and star washer being there.

Hmm, well either way I ordered a replacement nut and screw today.

Edit: Yeah, you're right. 9/16 would be huge. Perhaps that was referring to the outer diameter.
 
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