Winch Repair & Rebuild

[maineSS]

After you get your bushings suitably modified and pressed in place, you need to measure their installed ID and compare it with your shaft OD. The bushing will collapse inward to the same degree of press fit, so a 2 thou press fit will result in a 2 thou smaller bushing ID. A manufacturer would simply ream everything out to a standard dia at this point, since they have close control over shaft and bushing diameters, but you won't likely want to spring for a $300 ream that will be used 3 times. Also, you're likely to discover unique variations in shaft vs bushing dia since you're dealing with different vendors. What I did was to take out 2-3 thou of the original 4-6 thou undersize of my bushings before I pressed them into place. Remember to compare your bushing ID measurement with your shaft OD to get the correct measurement for YOUR particular material removal needs- they will vary!

Braden told me they used a 1 thou per inch of shaft dia for clearance in their bushing fitup, so the 1.75" drum shaft should have 1.75 thousandths clearance in the bushing. I found this too tight- the shaft bound up in the case when rotated, even without the worm gear in place. I ended up with a 2 thou average clearance and things worked fine. I used the special tool shown in pics 23-4- it was threaded in the rear for a 1/2" shaft, which got chucked up in a 1/2" drill. After running the tool with the sanding strip thru the bushings several times, I'd do a trial fitup. When it got to the point where the shaft would bind occasionally in certain areas, the machinist went looking for high spots (shiny areas) with a scraper (pic #28). When you arrive at this point, you don't want to make the low spots any lower. The same proceedure was used on the leg bushing. Finally, after innumerable fitups, the drum shaft ran without sticking. Next will be Bearings & Retainers.

[maineSS]

A special modification was made to the case bushing. The OEM shaft had rusted in this area, due to water infiltration after the oil film ran out. I decided to try providing a grease "seal" in this area by cutting a 1/8" wide X 1/16" deep slot in the bushing, and fitting a 1/8" grease zerk to the case. The zerk was located 1/4" in from the end of the bushing.The oil slot goes almost to the end of the bushing, so the grease slot had to be soldered up where it intersected the oil slot (pic #26). The solder sanded down nicely with the brass (pic #27). We found out the hard way that the zerk thread was 1/4-20, NOT 1/8 NPT, so the case hole had to be bushed and redrilled. Check your zerk thread BEFORE drilling if you do this mod. If you use a plain bushing, you could machine a slot closer to the bushing end for an O-ring seal, which might be better. Careful work with a Dremel, or vertically cutting down the side of the bushing with a long shank burr held in the Mill would give an oil slot. Pic # 27 shows the present arrangement, I'd probably go the O-ring route if I do it over

[maineSS]

A file proved to be the quickest way to bring the bushing OD down to a 2 thou oversize (pic #24). Measure each bushing and housing combo- they're not all the same, and you may find the bushing varies from end to end, as they're cast. After getting the outside to spec, we sanded the inside out by 2 thou by holding the bushing as the lathe turned at very low speed. The pipe plug in the end of the tool was turned in just enough to prevent the end from collapsing, but not enough to cause any taper. The tool was then used to start the bushing (pic #25 shows the leg housing). After all the bushings were installed in their respective housings, the first of many fit-ups began.

[maineSS]

The bushings will need machining both externally and internally to fit, and there are several ways of doing it, some a lot more accurate than others.
You will need to make accurate measurements of the internal and external diameters of bushings, shaft, and housings, preferably to .001". I used a micometer and snap guage, but you can get by with a good set of calipers.
Take 4 measurements 90 deg apart at each end and in the center of your bushing to check concentricity and taper. I found my bushings about 4 to 6 thou oversize on the outside, and 3-4 thou small on the inside. 4 thou on the outside is a real stiff press fit- I cut it down to 2 thou oversize. Keep in mind the interior dia will shrink about the same as the press fit.

My machinist had a special tool leftover from another job that proved very useful for bushing prep inside/outside, and even as a press tool! It's a 4" dia aluminum round bar turned down about 1/8" under the bushing dia, with the small end split 4 ways and tapped with i/2" NPT(pic #22). A 1/2" pipe plug forces the split apart to help grip the inside of the bushing. We used 2" sanding strip to make up the 1/8" dia difference, and to open up the bushing interior (pic#23). The rear was drilled and tapped for a 3/8" bolt, so it could be chucked up in a 1/2" drill and used on the case bushing after it was pressed in. A 2" dia bar would work as well to fabricate the tool, the 4" stock just happened to be handy when the previous job was done.

[maineSS]

I gave this idea some help with heavy gear oil by opening up the slot end of the bushing (pic #20), as the stock slot opening is VERY small. You definitely want to check that the open slot end faces the inside of the gearcase BEFORE you press the bushing in, ESPECIALLY on the cap, as you have to destroy the bushing in order to remove it (pic #21). I ended up having to carefully slot the cap bushing with an air grinder after trying several other methods. The case bushing and the leg bushing can be pressed out with a suitable adapter, which needs to be slightly under 2" OD. The Leg bushing will have to be drilled with a grease hole that has to center under the grease channel (pic #21)- this channel is not centered in the leg casting, so you also have to pay attention bushing orientation when you install it. The channel carries grease all around the bushing, so the hole need not be under the zerk.

[maineSS]

Here we go with bushing removal, fitting, and modification. Take whatever time is necessary to get this right, because it will make a big difference in gear/shaft life. The silver urethane paint job on the gearcase interior is not absolutely necessary, but it makes cleanouts much easier by showing up chips and dirt. Pic #17 shows the two bushing types used, the gearcase bushings are slotted, the leg bushing is not. My winch had plain bushings in the gearcase, which meant somebody had replaced them. The slot is aligned with cutouts in the cap and case at the top of the shaft (pic #18 & 19). The cutouts collect gear oil that falls off the bull gear and feed it to the slot to distribute across the shaft.

[maineSS]

Soldiering on thru my MU-2 mess, I found the winch drum shaft to be worn in the bushing areas and pitted in the case bushing area by water infiltration. I had a local machine shop make a new shaft out of 4140, as there don't seem to be any non-rusted OEM shafts available. You want a good grade of 1.75" shaft stock used for this, "ground, polished, and straightened". The placement of the keyways is absolutely critical- which is why the shop spent $150 in material and who knows what in labor making it 3 times- I paid $147 for the original Quote. The keys are a non-standard size in depth- make sure the shop understands that, bring in your old shaft and keys so there's NO misunderstandings. The dog keys can't be real sloppy either- I ended up having my keyway made "tight", then I surface ground the keys to fit snug- but loose enough to remove with pliers. Pic #14 shows the new shaft alongside the original. Pic #15 & 16 shows the spacing of the bushings, gear, and dog- again note the "zero tolerance" fit of the spacer that separates the dog keys from the winch housing. When you press on your new gear, you need to have a good idea when to stop. The dog is countersunk to almost the depth of the spacer in order to disengage from the drum, and the dog keys riding against the spacer prevent side thrust against the gear & sideplate, so it's wise to check the original spacer for wear. If the original is too thin, try substituting the other spacer from the drum end of the dog. The next topic will be bushings- the most labor-intensive part of the entire project.

[MasterYota]

These were my thoughts exactly. Any particular worries about this operation, or is it pretty straight forward?

[Charles Talbert]

Great post! I was hoping to find something like this. I've a question for you though, and you can probably answer it. I believe the winch to be the stock MU2 (its on my 53 M37).

When facing the winch on the truck there is a lever on the top left corner. It appears to have two detents cast into the housing that the spring loaded knob slips into. My lever is stuck in place - won't move or budge at all. It looks like its been "tapped" on before judging from the divit in the handle.
Is this a common problem, and if so, what is the fix? Complete teardown involved in the repair or is it something external and simple? I've got the winch off the truck right now, but haven't opened it up yet...

Thanks for the help Maine!

What you have going on is a common problem, steel shaft in an aluminum housing bore. Corrosion common to aluminum when mated with a dissimilar metal. You will need to remove the clutch end housing, remove the shift fork set screw, remove the plug on the bottom side of the housing that is pressed into the shaft bore, apply penetrating oil liberally, and persuade the shaft out by whatever means you have available.

[maineSS]

If you have to install a new Bull gear, you should measure the distance from the shaft end to the gear hub- mine was 1 19/32". The LU-4 gear was a couple thou thicker at the hub than my MU-2 gear. What you have to watch is the distance between the gear hub and the dog key spacer- pic #11 shows there's almost NO slop between the key, spacer, and gear housing. The gear is fitted to turn freely with NO endplay against the cap by means of spacer gaskets. Pic #12 shows one cut from .028" gasket paper on the left, and VPW's .013" gasket on the right- you have to trim the outside. Pic # 13 shows a hole punch turned from 1/2" rod with a 3/8" hole in the center. Press down and rotate- perfect bolt holes every time. Cut the inside hole to the OUTSIDE of your tracing line if you're using a cap gasket as a form- better slightly too large than a little too small! I ended up with a 3-gasket pack of (2) .028" and (1) .013" to get the proper clearance. I also had to file off some high spots on the hub- you'll know if the gear sticks in certain places during a full rotation. Use an ink marker to coat the hub face, any high spot will come up shiny after you rotate the gear. You will be assembling and disassembling the gearcase MANY times during fitup, so learn to get good at it.

[maineSS]

More Winch Tech... rebuilding one of these is a good preview of coming attractions in Power Wagon rebuilding. The key is NOT opening more than ONE can of Whup A$$ at a time. One day I was feeling powerful peckish, and I opened 3 cans simutaneously- a million demons flew out and started putting the boots to me! I'll never try that again.

If you decide to replace the worm gear bearings, you'll need a good-sized puller or a press- pic #9 shows the MINIMUM size puller you'll need, and it wasn't easy- the bearings are on quite tight! Pic #10 shows how it's done with a press- lots faster. The split bearing puller plate was convenient, but you could use press bars against the bearing if you're careful. When you re-intall the bearings, you'll have to make a spacer about the same OD as the worm gear spacer to avoid damaging the bearing- you can't press against the outside cage. I had a new worm gear, shaft, and spacers, so I used one of the old spacers for this job. Be sure to install the cutout side of the spacers against the shaft key, and the bearing with the small end facing out.

[MasterYota]

Sorry guys, must've had my designation wrong - according to the pics I've found on Google, its an LU4

[maineSS]

Master Yota- The MU2 clutch lever is on the right side of the winch, and has a spring-loaded knob that slides over a horizontal plate to engage a slot for either the "In" or "Out" position. The head of the bolt that holds the knob is used to drop into these slots. Have a pic of your winch?

[712edf]

Great post! I was hoping to find something like this. I've a question for you though, and you can probably answer it. I believe the winch to be the stock MU2 (its on my 53 M37).

When facing the winch on the truck there is a lever on the top left corner. It appears to have two detents cast into the housing that the spring loaded knob slips into. My lever is stuck in place - won't move or budge at all. It looks like its been "tapped" on before judging from the divit in the handle.
Is this a common problem, and if so, what is the fix? Complete teardown involved in the repair or is it something external and simple? I've got the winch off the truck right now, but haven't opened it up yet...

Thanks for the help Maine!

My LU-2 has a similar lever, frozen also. I believe it is there to release the spool from the drum allowing the cable to be unspooled quickly instead of having to "winch out" using the PTO. I was able to get mine unstuck, but not before the flimsey lever broke. The frozen part was a sliding collar on the drum accessable from the underside. Hope this helps.
Bucky

[MasterYota]

Great post! I was hoping to find something like this. I've a question for you though, and you can probably answer it. I believe the winch to be the stock MU2 (its on my 53 M37).

When facing the winch on the truck there is a lever on the top left corner. It appears to have two detents cast into the housing that the spring loaded knob slips into. My lever is stuck in place - won't move or budge at all. It looks like its been "tapped" on before judging from the divit in the handle.
Is this a common problem, and if so, what is the fix? Complete teardown involved in the repair or is it something external and simple? I've got the winch off the truck right now, but haven't opened it up yet...

Thanks for the help Maine!