Winch Repair & Rebuild

[maineSS]

Charles- excellent point about yesterday's lubricants- like yesterday's gasoline, they're just not made anymore, you'll need a Time Machine to find them. Even if you did find them, there's much better available if you know how to look.

I suspect a lot of winch users are looking for an oil that doesn't cost too much, won't eat bronze gears like many auto store GL 5 oils will, and will cover a wide temp range. Their winch leaks a lot because of worn seals/worm shaft, and they need frequent refills. The closest possibilty I've been able to find is an 85-140 Super Tech semi-synthetic marketed by Wal Mart. It's made by Lubrizol. The engineer there said he didn't see any corrosion or lubrication problems other than the life of the viscosity modifier- which is why he couldn't fully endorse it for this use. If you're going thru frequent oil changes, viscosity modifier breakdown shouldn't be a problem, but everyone's winch use is unique, so this is very much a case of the the user being aware and watching his winch. If I come across something better that's widely available, I'll post it.

[Charles Talbert]

Great analysis concering oils, possible adverse effects, etc.

Checking out all the details is vital not only in the winch, but other components as well. Failure to do so has caused many problems for operators that were blamed on bad component parts, seals, poor quality workmanship, etc. The RIGHT lube is the life of mechanical components. Doing you homework in regards to up to date products as you have done in this case will update users of many better products that are out there today instead of trying to source products of many years ago that will not afford near the protection. Updating your components to avoid oil leaks is immperative also to a long running trouble free component. You have done a great job on research and putting proper updates into place.

Folks with the mindset that a 60 year old product is the best choice because the book says so, well they will be the loser. Technology has come a long way with mechanicals and lubricants in 60 years. Take advantage of it and build a better running, longer lasting, and leak free component. It cost a little more initially of course, but you will have a dependable component that runs great anytime you need it, and you can and will be proud of the unit you built.

[maineSS]

There are two types of mineral-based worm gear oils, and two types of synthetic available. Your biggest problem is finding small quantities at a reasonable price- most of these oils cost around $200 for a 5 gallon pail, and 5 gallons is the smallest size normally available thru lube distributors.

The traditional oils are "Compounded Gear Oil", which are mineral base oils mixed with 4-6% acidless tallow for better wetting ability. These oils were originally used in steam cylinders (Mobil has a 600 wt "Steam Cylinder Oil") because of their ability to displace water. Since they're mainly ISO 460 and above, they're mostly limited to temps above 50-60 deg, which crosses them off most oudoor user's list.

The other class is the EP "Extreme Pressure" oils. Most of these have sulphur/phosphorus as the EP agent, some have borate or "non-active" sulphur chemistries that don't attack brass/bronze. The early pressure to develop "non-active" additives came from Porche, who discovered that the synchros in their transmissions were being eaten up. Sulphur/phosphorus additives activate with heat to form a protective oxide coating on ferrous metals. Unfortunately, they rapidly corrode brass/bronze unless they are deactivated. You can recognize this if the sides of the brass/bronze gear are black, and the teeth are worn razor-thin and bent over- it doesn't take very long under load. Since worm gears run about 40 deg hotter than other gears, you need to ask the lubricant vendor if a "non-active" oil is still safe for worm gearing, because heat is what activates sulfur/phosphorus. Talk to a lube engineer- not a salesman! Most of today's automotive GL-5 rear end oils have high levels of sulfur/phosphorus, and should be checked out thoroughly before use in your winch. The main disadvantage of mineral base oils is the necessity of having at least two different viscosities (ISO 220/460) on hand to follow seasonal temp variations in most of the U.S.. Using an 85-140 wt multigrade is tempting, but shear breaks down the viscosity modifier rapidly, and worm gears are all about shear. When the modifier is gone, you're left with just an 85 wt oil. Fortunately, there's a better option- single wt synthetics.

There are two flavors, polyalphaolefins (PAO's) and polyalkene glycols (PAG's). PAO's are the way to go- PAG's aren't compatible with other oils, and attack seals and paint. Since synthetics have low pour points, you can use an ISO 460 at below zero- some pour at -50! You do have to check for sulphur/phosphorus, as some synthetics have these as EP additives. I'm leaning toward a worm gear oil made by Lubriplate- (PN LO981)- you can get it in 1 Qt bottles thru distributors! It has a corrosion test rating of 1a- the best available for brass/bonze, and a pour point of -50 deg. Other vendors such as Amsoil or Royal Purple likely have similar products, but you may be looking at that 5 gal minimum.

In order to use synthetics, your worm shaft and seals have to be in good condition, or the synthetic will be gone. You will also have to either seal the case bushing with an "O" ring or grease groove, and keep an eye on the level. Do this, and your gears will last a long, long time. Site #3 relates the experience of a can manufacturer who was replacing a worm gear set 4 times a year at a cost of $12,000 per event. After replacing the compounded gear oil with a synthetic, gear temps dropped 20 deg, and no failures occured for 18 months, even though the gear sets ran at higher speed and load!

[maineSS]

Moving on with winch lubrication- you'll note that Braden's viscosity spec changes with ambient temperature. It's a balance between the oil being thin enough to flow between the gear teeth, but thick enough to resist shear and the wiping action of the worm. The lower the temp, the lighter the viscosity- as a rule of thumb, the lowest working temperature of a lubricant is 10 deg above its pour point. The higher the temp, the higher the viscosity needs to be. Too high a viscosity at low temp means grinding gears, as does too low a viscosity at high temps. When a worm gear is working, it runs hotter than other gear types- about 90 deg over ambient vs 50 deg. This is why the usual viscosities for indoor worm gear sets run around ISO 460-680, much thicker than other gear types.

How well does the traditional 90 wt SAE work in a worm gear? If you look at the viscosity cross-reference tables mentioned earlier, you'll see that an 85 wt oil covers ISO 100-130, a 90 wt covers ISO 130-320, and a 140 wt covers ISO 320-680. Looking at Braden's actual chart, I'd say 90 wt would be safe from -5 to 70 deg. Back in the 40's, gear oils were limited in technology and availability, and 90 wt was the best most people were likely to find. The introduction of lead styphnate as an EP agent in the 50's helped, as it didn't attack brass/bronze. When Dodge specified 90 wt, it was likely thought most people wouldn't use the winch continuously like an industrial application, so excess wear wouldn't be a common problem. In the 70's, lead styphnate was replaced by sulphur/phosphorous compounds, which quickly destroy brass/bronze under certain conditions. This is when Braden started testing for oil compatability and recommending specific oil brands. Today, those brands are: MOBIL Mobilgear XP; SHELL Omala; CHEVRON Gear Compounds EP; and TEXACO Meropa in the appropriate viscosity for each temp range (Tier). Synthetic versions of the listed brands are fine, other brands should equivalent in specification to the listed ones.

If you have a new set of gears, they have to be broken in on mineral oil BEFORE switching to synthetic. Braden recommends 10 pulls at 60% of the load rating of the winch. Make sure the bushings and gears are lubed before starting the pull by running the winch disengaged for a few minutes. If the gearcase starts getting hot, stop and let it cool before resuming breakin.
I happen to have Meropa available at work, so that's what I'm using for breakin. Others will have to enter the wide world of industrial lubricants- on our next lube essay....

[maineSS]

It looked like the case side was responsible for the taper at the leg, and the amount of taper varied depending on whether one case end bolt or two were tightend up. At the time, tapering the shim seemed the quickest way out (before we found that surface grinding thin stainless didn't work too well).

[Desoto61]

Excellent writeup, I had disassembled mine just before I went out of town, so I'll definitally be referencing this as I start my rebuild. Luckily mine was lightly used so I should be OK with just a refresh and re-assembly.

A tapered shim was made of stainless to fit the gap, pic #41 shows it in place. Making the shim took a bit of setup work which I'll detail next.

Could you have machined or ground the end of the drum support to get rid of the taper and then just used a flat piece of shim stock cut to fit to fill the gap?

[maineSS]

What do you put in it?

Perhaps the best way to start this is to note three useful worm gear/lube sites, along with revealing what was NOT recommended for worm gear use.
Site #1 is www.qtcgears.com/Q410/QTC/Q410P440.htm -an excellent overview of worm gear tech and lubrication. Site #2 is [url]http://www.noria.com/learning_center/category_article.asp?articleid=1080&relatedbookgro up and Site#3 is http://www.noria.com/learning_center...relatedbookgro .
Now the gear speed/lube chart in site#1 suggest that a grease could be used in a worm gear, and I have a fishing reel worm gear that is grease lubricated. All of the major oil company lubrication engineers I spoke with (Mobil, Shell, Texaco, Exxon) strongly discouraged the idea. The two main objections were inadequate heat dissipation and lubricant channeling. One of the enginners said grease would be okay for a museum exhibit where interior corrosion protection and minimal seal leakage would be major concerns. The manufacturer of John Deere Corn Head Grease (Northland Products) told me they'd never tested it for worm gear use, and if I chose to use it that way, I was on my own. After considering all this learned opinion, I delegated my three tubes of JD grease to winch drum/shaft corrosion protection, and moved on to oil-bath lubrication.

Here is Braden's present recommendation for ambient temp & oil viscosity.

Tier A: -20 to 20 deg- AGMA Grade 3EP, Mobilgear 600XP 100 or equivalent.

Tier B: 0-50 deg- AGMA Grade 5EP, Mobilgear 600XP 220 or equivalent.

Tier C: 40-105 deg- AGMA Grade 7EP, Mobilgear 600XP 460 or equivalent.

Tier D: 90-130+ deg- AGMA Grade 8EP, Mobilgear 600XP 680 or equivalent.

The two important numbers here are the AGMA (American Gear Manufacturers Association) and the ISO (International Standards Organization) viscosity rating (100, 220, etc). The "EP" means Extreme Pressure additives are present, and you have to be very careful about these around brass/bronze. There is another gear lube rating- the SAE system. Many people use an automotive rear end oil instead of the correct worm gear oil- not always a good idea! The following web sites have tables that relate the three viscosity systems- www.synlube.com/images/viscosity_table_2.jpg and www.bobistheoilguy.com/visc.html . I strongly suggest you print out one of these tables for reference- it will help your product comparisons considerably!

[maineSS]

winch shaft greasing

Our last photo essay will deal with winch shaft rustproofing. The drum has a large cavity which can collect moisture over time and allow the winch shaft to rust to the point where heroic measures with Porta-Power and Torch are required to get it off. The best way of preventing this is to fill the cavity with semifluid grease. There are two zerks on either end of the drum which allow filling of a small circumferential slot, but these don't access the drum interior.
If you're doing this singlehanded, you'll have to stand the assembled winch up on the gearcase end, and then block the drum so it's about 1/2 way off the shaft (pic #46). You'll need 3 tubes of grease and a grease gun with a flexible hose. Run the hose down to the end of the drum, and start pumping, moving around the shaft as you go (pic #47). A complete fill will take almost three tubes, and you'll have to remove blocking as the cavity fills up (pic #48). Finish by filling the two zerk cavities, and you're good for years. Do this AFTER checking the winch base/shaft alignment- if you have to shim, it's MUCH easier without the drum weight and bulk in your way (Don't ask me how I know this). I used John Deere Corn Head Grease in the drum- I had originally meant to use it in the gear case, but talking with the supplier and various lubricant engineers steered me away from that idea. Worm gear lubrication will wrap up this series, hopefully it will be a once-in-a-lifetime experience.

[maineSS]

The machinist and I thought the .004" taper would be a simple matter of surface grinding- we were quite wrong. The heat generated curled the shim like a potato chip. It happened during the initial sizing from .072" thickness to .070". The shim stock was Super Glued to a steel block, clamped to get an even glue thickness, and allowed to dry overnight. We ended up prying the first attempt off, and starting over. The next attempt featured a 1/2" High Speed Steel end mill- brand new. The block with the shim was supported in Mill vice on blocks and milled down .002" in 1/2 thou passes (pic #44). Next, one end of the block was raised .004" with a wedge, then clamped down and the taper machined in 1/2 thou passes at a moderate feed. Pic #45 shows what stainless does to a new HSS cutter- use carbide if you can get it. When I clamped the new shim in place, the effort was worth it. Fortunately, clamping down all 4 mounting bolts produced no bind.

[maineSS]

Squaring up the Base

When I got my winch, I noticed it seemed to stick at a certain point, and would require noticeably increased effort to rotate past. When I looked at the old bushings, they seemed worn oblong. The reason can be seen in pic #40. When I straightened up both base angles on the press, I found that the front had a tapering gap at the Leg varying from .070" to .066". Pic #41 shows how far off the new bushing was when clamped up against the base. When I initially tightened up the outside bolt, the shaft was hard to turn, and tightening up the inside bolt locked it up to the point where I couldn't turn the wormshaft with a screwdriver inserted thru the shear pin hole.
I tried "custom bending" the base angle to accomodate the Leg offset, with zero success. A tapered shim was made of stainless to fit the gap, pic #41 shows it in place. Making the shim took a bit of setup work which I'll detail next. Stainless isn't easy to machine, but I wanted one that wouldn't rust out in a few years and leave one corner adrift under heavy loads.

[maineSS]

There is a definite order of assembly- do it right the first time, or you'll do it again and again.. One of the housing bolts has to go in BEFORE you insert the band (Pic #37). Sid Beck's band has a long adjustment stud end which is difficult to squeeze in, but you'll want to wait before trimming it until you know the length of the tension spring. If your spring is totally rusted out (like mine), you can get one from VPW, Beck, or your local hardware store. Pic # 38 shows VPW's huge replacement next to Beck's OEM. The OEM spring has 8 coils of .074" wire, ID is .280", OD is .433", and length is 1.1". If you go with the VPW spring, you'll need a washer on the end due to its large dia.
The brake drum has a key and a setscrew, and needs to be adjusted to ride inside the band. My hub ended out 1/8" past the end of the wormshaft to achieve this (Pic # 39).
Once you get your band spring length figured out, you can trim the adjustment stud to length. You want just enough tension on the band to keep the winch from freewheeling after you stop input power, but not enough to have it brake heavily during inward rotation. If the housing gets hot during inward rotation, try loosening it up slightly.
Before I get into the Winch Oil dissertation, I found I'd missed a couple points. I'll wrap them up next.

[maineSS]

On to the Safety Brake. This is meant to assist the worm in holding a load, NOT to hold the load entirely by itself. It also damps overrun when you stop winching. The gearset does most of the work in holding a load, which is why Braden specifically warns against using a synthetic gear oil before a gearset is properly broken in.
Pic #34 shows how the brake band is oriented for the normal "underwind" pull. It's important that both holes in the housing face down/sideways to avoid having water collect inside and eventually run past the upper wormshaft seal into gear housing. My brake was setup with one of the holes facing up, and this is likely why my winch oil was half water.
Pic #35 shows how the band will look from the inside as you assemble it. The anchor bolt end of the band faces downward, and the adjustment end faces sideways. If you want "overwind" pull, the anchor bolt and adjustment end would still face down and sideways, respectively, but the housing would rotate 90 deg clockwise to the left (looking at pic #35).
There are a number of replacement bands out there. The OEM replacement now runs about $85 from Sam Winer Motors (home of the Golden Gears). Sid Beck sells a good repro, but the ends are metric- 6MM X 1.0. A 1/4 x 28 nut will thread on a ways- then jam. Don't force the nut if it seems to stick- you may have a metric thread! VPW presently sells a cheapo band they recommend as a source of replacement friction material for your backing plate (pic # 36)- try not to mangle your band when you take it off. The top band is VPW's, the bottom is the OEM.

[maineSS]

Endplay continued..

Too much wormshaft endplay leads to oil seal leaks along with heating and worm/bull gear wear. Too little play will not allow enough room for thermal expansion of the worm, leading to bearing and retainer damage.
Braden's way involves:
(1) Dropping the winch driveshaft and retightening the retainer capscrews to 30 lb/ft torque.
(2) Setting up a mag-base dial indicator on the face of the rear bearing retainer with the probe squarely against the end of the wormshaft.
(3) Engage the winch drum, rotate firmly in one direction till it stops, then hold constant tension. Zero the indicator. Firmly rotate the drum in the other direction and hold contant tension. Note the reading on the indicator and compare it to spec (.007-.014").
(4) If too tight/loose, remove retainer cap(s) and add/remove shims and recheck endplay. You may have to drain the gear oil to obtain a balanced shim pack.
(5) Tighten capscrews to 30 lb/ft, refill winch with oil, and readjust the safety brake.
As I mentioned before, this gave me an .010" endplay, which was much too loose for my liking. I then used the M37 TM method, which involves just the wormshaft in the housing- (take the bull gear out). The Braden engineer I spoke to said he always sets them up at the tight end of their spec, but my shim selection wouldn't give me .007". I intend to use synthetic wormgear oil once break-in is complete, so experience will show if I'm too tight. Next will be setting up the safety brake- our last show & tell picture essay. After the safety brake I'll finish up with "What Do You Put In It?"- my distillation of hours of wormgear lubrication research.

[maineSS]

The easy way to remove the bearing race is to weld a number of beads onto it (Pic #32). The race almost fell out after cooldown- definitely the way to go here. The replacement race is NOT bottomed out in the retainer- just press it level with the topside. Replacement bearing number is 23100, race number is 23256.
I was interested to see whether it would be necessary to index the retainers to the gearcase to obtain a straight wormshaft axis relative to the Bull gear shaft, but they were machined accurately enough so that the wormshaft would be centrally located on both ends regardless of retainer orientation. You may wish to check this on your unit, as the machining is pre-CNC, and mistakes occasionally did happen.
Setting the bearing preload for wormshaft endplay is absolutely critical according to Braden, and their specs call for .007-.015 endplay. The retainers have two different thicknesses (.010/.020) of paper shim between the case and the retainer to accomplish this. You make up a shim pack on each retainer, asssemble the worm shaft and retainers into the case, draw the retainer bolts up to 30 lb/ft torque, and measure the back and forth play of the wormshaft with a mag base dial indicator.
I found that .010 endplay was unbelievably sloppy- you could push the worm shaft side to side and round in a spiral! I removed 1 .010 gasket, and ended up with about .001 endplay- too tight by Braden standards, but more acceptable to me. The M-37 TM 9-1808B manual recommends that "the wormshaft turn freely by hand with no perceptible endplay"- which is what I got after using 3 .020 gaskets on one retainer, and 3 .020 and 1 .010 gasket on the other. I also ended up using a mix of LU4 and MU2 gaskets, because I didn't order enough from VPW. You want at least 6 gaskets of each thickness for this exercise. The LU4 gasket holes had to be slotted to match the MU2 bolt pattern (Pic#33).

[maineSS]

There are a couple of trouble spots in reconditioning the worm shaft bearings. The first is removing the bearing races from the retainers, and the second is setting the proper bearing preload.
Pic #29 shows the retainer in a vice prior to removing the bearing seal. The seal is easily removed and replaced with a suitable dia rod and a few hammer taps. The bearing race is quite difficult to remove by forcible methods, as access to the backside is very limited (pic #30). I initially tried freezing the race with a special cold spray, but it still required a lot of hammering with a mini-sledge on my mini cats-paw. You need to have the retainer held in a 6" or larger vice with the cats-paw alongside the lower half of the vice (pic #31). Hit the top of the cats-paw with a drift, and move around the race at 180 deg intervals. If you have access to welding equipment, the next post will show you a MUCH easier way....