g741.org

Braden LU4 Rebuild Saga

For the four years I have had my M37, my winch has been frozen in the wind in and power out position, and would not freewheel the cable. Not a problem for me, I never intended to use it. I did fill both sides with the proper viscous oil, but it dripped out and spotted my driveway, so I drained it. Then recently I got stuck, and had to winch 25 feet out of some mud.

So, just in case I may someday have to use it again, I decided to have it rebuilt by Charles T, who has fixed a lot of things on my truck the past few years. I was about to take it up to him, when my wife told me that we needed a new dryer, and since they come as a set, got a new washer too. So…

That made it necessary for me to attempt the rebuild, and Charles T gave me advice and cautions, and suggestions for my own effort. While I have no doubt his rebuild wold have been better than Braden’s original, my goal was to make my LU4 functional for some future emergency, and not leak on my driveway.

There are some videos on this, with lots of pics, but I did not follow them exactly, using instead the Army TM’s guide. There is a lot that is not in there, by the way. And the exploded diagram on VPW’s parts list does not show one of the spacer rings, which go on each side of the “dog”.

First, I used my hoist to remove my winch, finding it easiest to remove the upper grill than the driver side bumper extension, which I had done in the past. I first powered off the cable. I still can’t really lift the naked winch, though. First problem was getting the clutch half off. The clutch “dog” was frozen on the main shaft, and the clutch shaft had a loose set screw to the fork.

I separated the clutch housing by using two hydraulic jacks, which pulled the bushing in the clutch housing out with it. Then the drum would not come off, because the keys were frozen, one broke off in it’s recess, and only by using Dry Ice to slightly shrink the other was I able to pull it out with a vice grips. (By the way, the original Vice Grips were made for decades in a tiny town in Nebraska, Dewitt, where they had a street sale once a year. )

Next, the drum was likewise frozen on the main shaft, because of rust on the shaft inside the drum. Again, used jacks to pull it off, only after using Crocus Cloth to polish the shaft. I bought via Ebay long strips of 320 to 600 grit, and used WD40, and used my diamond stones to remove the nicks on the edges of the key slots. Got the drum off, which pulled off the bronze gear on the other end; fortunately, both the bronze gear and and worm were perfect and unworn.

Next used my power washer and lots of scrubbing to clean the aluminum halves, with mag wheel etching to really get them gleaming as new, after also using stripper on the paint. When I blasted the inside of the drum, lots of oily mud came out. So scrubbed that with long brushes and assorted soaps and degreasers, even got out river sand, as if my truck at some point winched itself out from under water. I then put some Ospho rust converter in the drum, and let that dry. I polished the main shaft, and primed and painted the center section, to lessen rust in the drum section in the future. Spray painted it with several cans of 24087 after an etching primer.

I had a machine shop pull my brake gear off, and remove a few seals for me, and when a Cobalt drill and my Dremel didn’t touch the broken imbedded key, he tapped on it, and it came out in pieces.

Drove the hour to Ft Jackson, and used their shop press to install more seals. The seals for the worm l did in my own vice, with appropriate sockets. Bearings and races seemed fine, so used the gaskets as instructed to set the worm clearances, although this is done without the seals in, so pushed the new ones out, ruining them, and reinstalled another set after setting the correct gasket set. New keys for the the bronze gear, took time to press it back on the main shaft to precisely the thousandth of an inch required from the shaft end.

Found the new clutch fork was beefier than the one in my winch. One problem is that the new shift bottom seal is thicker than the old army ones, so in order to put the snap ring back on, the clutch shaft has to be some mm lower in the housing, and found my new fork’s set screw was several mm higher in the fork, so I also ground off a few mm from the pads ends of the fork arms so the whole shebang would line up the main shaft, the fork, the dog and the bushing. I reused my old fork, it was marked LU4, and the center set screw hole was an important mm lower.

Got a new clutch shaft and set screw, (NF not NC) and then used assorted grit hones, to fit the main shaft to the new clutch housing bushing. I bought Flex ones in 400-600 grits, with these many abrasive “balls” on a flex shaft, using my drill to open up the bushing just enough. From Amazon, via Zoro company.

Assembled the winch, mounted it, and it worked great, except a big leak from the clutch housing drum seal!!!! So, took the winch off again, a 15 min drill, and it was apart in a few minutes, took the drum down to Ft Jackson’s Auto Craft shop again, because the drum flanges were spread out about 3/8 inch, and thus would not let me pull the halves together enough to ensure the drum’s oil seal in the clutch housing was actually ON its drum sealing surface. Carefully pressed the drum flanges true and 3/8 inch closer, then put it all back together, but this time checked for leaks Before I mounted it. All good, so only took about half hour to mount it, and used a hydraulic jack to slightly spread the bumpers apart so I could bolt up the side mounts without cross threading one of them.

The next problem was the shifter snap ring lacked one mm of being able to snap into its recess, and the shaft could pull up and pop off the circlip due to the the thicker lower oil seal. I then used a hammer and punch on the rim of the seal just next to the shaft, and got the mm I needed to have the circlip snap into its recess.

Tested the winch both wind and unwind, the shifter smoothly moves the dog in and out. No leaks.

I hace a waterproof canvas cover which covers the whole winch, side to side, so that will lessen water intrusion. Now to rewind my cable, and hope I never have to use it again. But if I do…

And thanks to Charles T for his suggestions and cautions both via email to me, and his prior posts on this forum.

Next to put in new transfer case output seals.

All the best…. HC, aka NAM VET

Sounds like that winch really didn’t want to come apart. I imagine sitting out on the front of the truck they collect a lot of road dirt (and up here, salt) during their service days. Combined with infrequent use, I can see how they are often neglected items on these trucks.
I’m glad to read your write up on what you encountered during your rebuild, as I have a winch sitting on the floor of my shop that I will someday be pulling apart and cleaning up. Seeing as I don’t have the split bumpers or the frame extensions yet, I don’t think this will be a project for anytime soon but it’s always nice to read up on what you’re in for.

That's an amazing post, Nam Vet-would love to see some pictures!
Gary

OK, I will post some pics with how this all worked out for me, gradually with some steps backwards. NV

This is how I did it with what appears to be ultimate success. The TM 9-8031-2/TO19-75-=A-100, Powertrain and Body and Frame, has exploded diagrams and a description of how to disassemble and set clearances, and reassemble. But it assumes the winch easily comes apart. Nothing on how to deal with frozen parts.

By far it was hardest to disassemble. I could pull the clutch half about a half inch apart from the drum flanges, enough to peek down inside but could only see dark and greasy parts. So, in case someone someday pulls it apart again, I painted the "dog" yellow and the fork bright red, Rustoleum over primer. Since my clutch arm would turn without moving the dog, I thought about trying to push the clutch rod out and then the clutch half would pull off. But as I later discovered, the fork set screw was only loose, and not fully backed out. It would not have worked to try that.

So with two hydraulic jacks and wedges of wood, pulled the clutch half off. Did not crack the aluminum case half. Removed seal plate on bottom of clutch shaft, removed small ring, then circlip, and shaft was only slightly bent, so it came out the top without problem, after removing the NF thread set screw in the fork. (replace with a longer one, they come in short and long). Then this: Note fractured key, and one of two spacer rings, with I cleaned up on a diamond stone. I also then polished the drum seal flange with finer and finer Crocus cloth strips. Note also scoring on drum main shaft, so I removed any ridges with fine diamond stones, and also polished any ridges off with the Crocus cloth, leaving only microscopic grooves, which might serve to hold oil anyway. Bought strips of Crocus abrasive via Ebay or Amazon..

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Next had to have a machine shop remove the fractured key, after I was able to freeze the other with dry ice and pulled it out. Got new ones from the Vendors. Crocus cloth does not remove thousands of an inch on the shafts, just polishes and removes tiny ridges. Rust on the main shaft made it difficult to pull the drum off, but kept polishing and and tapping and little by little it came off. I used fine Flex-Hones to polish the bushings in the drum, finishing up with superfine sandpaper on my fingers. I got 3/4 in ones to clean the shaft holes, but it was not necessary to use them. Cost about $17 or so each via Amazon, a company called Zoro.

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the bushing in the clutch end came out broken, and used the Army shop's press to put in a new one, (all these are available from our vendors), but be sure to not press it deeper than the edge of the housing; if you press it all the way in, you will never be able to use a puller to get it out. Used the Flex-Hones to reduce the diameter to snuggly fit the now polished main shaft. Next, "stacked tolerances" of the dog, fork, other spacer ring and main shaft made it time consuming to be sure all these lined up just perfectly symmetrically. The fork pads (that push/pull the Dog) required a little grinding to allow me to center the Dog, since the set screw hole in the fork was off by several mm, the old fork being better in this than my new one. Painted the dog yellow, the fork red. Reading about how to try to keep the spacer on the Dog and not have it fall off, I ended up sticking it to the dog with a dab of adhesive. Used Red Loctite on the set screw, but had to use a torch to heat it enough to remove several times, don't glue it in until you are sure it is the last time.

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tried to pic of how these line up , this pic a bit off center, but you get the idea.
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I polished the bushings with my Baldor buffing system, with a shaft and with my fingers and got all the bushings shiny and smooth. Lined up the drum and the dog and it went together with a little encouragement, but the first time the drum flanges were a bit out of true and a little wide, so carefully pressed it back to even, and then the drum fully seated in the clutch half to have the big seal ride on the drum seal, fixing my big leak the first assembly. By the way, it is likely near impossible to do all this with the cable on, mine was frozen in the power out and in position, so removing the cable on the truck was easy. Oh, used my bench vise to remove and install the worm seals, twice, as you set the "drag" with no seals on the worm shaft, with the correct gasket pack on each end. My small puller would not remove the brake wheel so the machine shop did that for me, and installed and set a new brake band per the TM.

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After I had the two worm bearing ends off, I made their mating surfaces flat on a big belt sander at the machine ship and removed some edge nicks with my diamond stones. Important to have the flat and not warped to get the gasket set correct. used the same press to put the bronze gear back on to the perfect thousands of an inch. Tedious. Note the square locking screw on the brake wheel

By the way, it just takes a bit of wiggling to get the dog set in the fork's pads, easy.


and finally, since the new clutch shaft seals are thicker than the old hide ones, it had to tap the inner lip edge of the seal a half mm to have length to get the bottom 3/4 inch circlip security in the grove, I also trapped and otherwise cleaned every thread on bolts, and in aluminum housings. Big taps are expensive. When remounting my winch, the frame reales are slightly tweaked, so to keep from cross threading the bolts, I spread the frame just a tiny bit with a hydraulic jack, saved me hours of prying to line things up. Lots for antisieze every where, and me too.

all I can say is my winch works, the clutch slides in and out fine, and no leaks. Hopefully I will never have to rely on it, and perhaps it would not stand for heavy repeated use, but that is ok with me.

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A few random pics:
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