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I'm sourcing new grade 8 hardware to mount my rebuilt winch, and noticed that the ORD 9 SNL (1954 version) specifies 5/8-11 x 1" hex head cap screws (p/n 122724, group 2001.1) to attach the "L" shaped bumper brackets to the front faces of the clutch and gear housings of the winch. But the housings on my LU-4 winch will definitely not accept a 5/8-11 thread. More like a 9/16-12 thread. Is the parts catalog in error, or do I have an LU-4 winch intended for some other application, maybe an M-715?

I will check what I have on my bumper/winch in the am, and see what works for me.

NV

My winch is 9/16". The bumper is ⅝".

just me wrote:My winch is 9/16". The bumper is ⅝".

Fig 21-1 must be reversed then. It shows the bolts from the bracket into the winch housings as p/n 122724, which the itemized listing in group 2001.1 describes as "SCREW, cap, hex hd, S, cd or zn-pltd, 5/8-11NC-3 x 1". The bolts from the bracket to the bumper (p/n 123605) are described as 1/2-20NF.

Just a thought
Was common to drill out damaged holes to 9/16 and re-tap.
Could be the case?
Tom

Tom P wrote:Just a thought
Was common to drill out damaged holes to 9/16 and re-tap.
Could be the case?
Tom

I'd be very hesitant to drill a hole tapped for 1/2-13 in aluminum and try to go to 9/16-12. The minor diameter of a 9/16-12 thread is less than the major diameter of a 1/2-13 thread.

A more likely repair would be a thread insert such as a Heli-Coil or a Timesert. The eight side mounting bracket stud female threads (9/16-12) in the aluminum clutch housing and worm housing covers of the LU-4 winch I've been working on were badly worn, so I repaired them all (plus quite a few other female threads elsewhere on those housings) with Heli-Coil inserts. Not an easy (or inexpensive) task, given that the threads for the studs are recessed, and required a special Heli-Coil bottom tap to get enough threaded length in the housing to screw the insert in. But the thread insert will be stronger than the original thread of the same size in aluminum.

I was dead tired last night and reversed the bolts when I typed. looked this morning and they are 5/8 in the top to the winch and 1/2 in the bottom to the bumper. (The 9/16 were the side studs.)

just me wrote:I was dead tired last night and reversed the bolts when I typed. looked this morning and they are 5/8 in the top to the winch and 1/2 in the bottom to the bumper. (The 9/16 were the side studs.)

Thanks for checking on the bolt sizes.

Now I just have to figure out why the female threads in the aluminum housings will not accept a 5/8-11 bolt.

I just pulled one to make sure. They are ⅝-11 X 1.5". All 4 holes int the face of both of my winches (m37 an M715) are ⅝-11.

just me wrote:I just pulled one to make sure. They are ⅝-11 X 1.5". All 4 holes int the face of both of my winches (m37 an M715) are ⅝-11.

Thanks again, just me.

Looks like I'll be ordering the Heli-Coil 5/8-11 kit and one of their special 5/8-11 bottom taps on Monday.

I recently painted my LU4, and re-aligned the top plate, and found the holes in my aluminum tops were a bit stripped. So perhaps yours are just partially stripped threads too, and need some gentle persuasion to take a bolt
NV

NAM VET wrote:I recently painted my LU4, and re-aligned the top plate, and found the holes in my aluminum tops were a bit stripped. So perhaps yours are just partially stripped threads too, and need some gentle persuasion to take a bolt
NV

Thanks NAMVET. The top plate holes on both left and right housings of my winch were almost stripped, too. Probably assembled repeatedly without any anti-seize between the steel fastener and aluminum housing. I ended up putting Heli-Coils in all of them.

The 5/8-11 female threads in the front faces of the housings are just the opposite: they're too tight to accept a 5/8-11 bolt. A 9/16-12 bolt fits, but feels loose, looser than a 1B fit. I think I'll just drill the housings and Heli-Coil them for a 5/8-11 thread.