MileMarker H12 Pictorial Rebuild

[Bull Bar Cowboy]

Some threads lately have tended to dismiss the MM as having plastic bearings and mechanicals that are not up to the job ………………. So whilst I have it all in pieces, here is a pictorial rebuild and you can decide for your selves…………

First off I always use this grease in the gearbox…………… the winch is 5 years old and I packed it with this from new ………. Its only been stripped twice in the 5 years…….

Here is the end of the drum and a close up of the roller bearing that the main shaft runs in. That is not rust you see…………… its some sh!t from the drum centre as I have just sprayed the bearing with a seriously strong degreaser to clean it out……….

Once cleaned, the bearing and gear shafts are liberally greased…………

Next the roller bearings in the 3 low range gears are cleaned ……….. the old grease turns a to grey brown liquid as the degreaser gets to work on it………

The 3 gears are repacked and mounted ……………….

Then the thrust washers are added and each gear is retained with its circlip.

This is followed by the high gear bias springs………….

The high gear is a plate, 7mm thick and extremely f’kin hard………… its made of the same stuff as the drum end plate and refuses to be centre punched or drilled……. Even with a colbalt drill bit. The plate must be mounted with the chamfer toward the main shaft………. This is so it will engage quickly and cleanly……

The plate is mounted and secured with 3 more circlips.

It has been reported that you should not really winch in high gear (a statement with which I wholeheartedly agree). Note that in high gear the thickness of the gear is only about 6mm, however, I guess the main shaft gear will shear before the plate ring gear. The high gear pull in lbs can be calculated as (motor torque (inlb) / drum radius (in))

In my application this is 3471/ 1.25 = 2776lbs or 1.2T, however, with a line speed of 45+ft/min in low I never use high gear…………

Next its time to give the whole gear assembly a good protective coat of grease. The more grease we get in the gearbox means there is less room for water…………

Now its time to assemble the gearbox casing……………this is the low gear locking pin. When you are dangling on the end of the rope this pin is holding the full weight ………. From this point on we will refer to it as the ‘Jesus’ pin. To engage low gear in dropping into any one of 4 holes in the periphery of the ring gear, thus the drum can only do 90 degrees before low is engaged. The pin engages by about a ¼ inch………

Grease the pin, fit the spring and insert from the inner of the casing. Then attached the low/free lever with its roll pin. It should be noted that the hole contains a small O ring to seal the pin shaft.

Then we move onto the high gear thrust bearing. This pushes against the spring loaded high gear plate to engage it with the main shaft. Again this is greased, spring fitted and inserted from the inner end of the case. The high / free lever is attached with its roll pin.

Both levers need to be operated a few times to made sure that there is no hydraulic action from the grease as the clearances are reasonably tight.

This is the ring gear thrust washer ……….. it is made from PTFE………….grease both sides and fit into the recess in the casing.

Here is the ring gear. This is the thrust side that goes face down onto the PTFE thrust washer. Again liberally grease and carefully slide it into the casing. Be careful not to get too much grease into the ‘Jesus’ pin locking holes, otherwise the grease will hydraulic and prevent it from locking……..spin the ring gear by hand to make sure that it will lock at each 90 degrees.

Then we fit the PTFE (NOT plastic) drum guide split bearing………….

Then the drum O ring seal goes carefully into the housing.

Now the tricky bit…………. Set the high / free to free and set the low / free to low………….carefully slide the housing onto the drum with a sloe turning motion. After a little fiddling and turning all 3 gears will line up with the ring gear and the housing will slide home

Stand the winch on end and fit prepare the mainshaft.

Ensure that the mainshaft thrust washer is fitted.

Grease the whole shaft and slide it into the drum centre to engage with the gear set.

This is the motor end drum split bearing………again PTFE.

Grease the end housing and fit the bearing with the thrust side toward the drum. Then fit the drum O ring seal into the housing……………

The end casing is fitted by a slight turning motion in order not to damage the O ring seal.

Fit the SS tie bars ……………..these are custom and the housing lugs have been helicoiled to 3/8 UNC……

Next the motor is cleaned for fitting………

Note that this also has an O ring seal……………

Liberally grease the motor face and bolt it to the housing using 7/16 UNC bolts………

Now we have a completed winch that will fight on for another year or two………

This is the reason for the rebuild………..

This was caused by the end plate to drum weld parting due to bunching on the side of the drum. The early MM’s are well known for this failure due to very poor factory welding in that area……………later models are fine……….

The end……….

Ian

[Milemarker Type S]

Yet another top write up Ian- the new drum and tie rods look damn fine. Did you fabricate the new tie rods?

[SiWhite]

Wow - I'm going out to put more grease in mine after reading this.....

[m&mv80]

excellent write up,

going to be doing mine soon so good timing

that little engagement pin taking all the load is a bit worrying though

cheers

martin

[BogMonster]

Good write up

They say you should not winch in high but I have done it quite a few times with no apparent problems. Prefer to use low though - that's what it is there for!

[jbs]

Thank you very much for putting up this write up as i couldn't find anything on the the net about rebuilding this particular winch, I recently broke the end casing with the gears in and had to replace the casing after i ended towing me and someone else out of a steep country lane and the S.W.R. bunched up on one side that caused the tie bars break through the casing -he's also paid for the repair which is a bonus -i got my bit's through first four in dunkeswell in Devon they've taken the mile marker franchise on from Alfred Murray 4x4 and they're also very helpful-i emailed them on Friday when it happened and got several replies over the weekend, Nice people to do business with

[zim]

i got my bit's through first four in dunkeswell in Devon they've taken the mile marker franchise on from Alfred Murray 4x4 and they're also very helpful-i emailed them on Friday when it happened and got several replies over the weekend, Nice people to do business with

oooo.... what are their prices like compared to before ?

a nice upgrade for the milemarkers is air operated high / free / low lever selectors i've put a thread up about it before.

G

[jbs]

G, No idea if his prices are any better than the previous franchisee but here's the web link http://www.firstfour.co.uk have a look on there and give him a ring if ness his name is peter lamb really helpful bloke

John

[Turbocharger]

I strongly suspect mine would benefit from similar attention. so this is well timed (and very informative, thanks Ian- can't you bodge something, just once, so we know you're human?)

Is there a service kit of parts available for the MM?

[SiWhite]

Not sure about a service kit - really the only things that need doing are the O Rings and the bearing surfaces.

[wib]

hi i have the same winch as u . u said u get 45 ft a min i would like my winch 2 go that fast what have u done to make it go that fast many thanks ian

[jimmy mad]

just quick one I know its a bit off track but I have a type R winch that has a label hanging around the selector saying fill with oil ???? what oil what does it mean? I can't see any oil points or does it need greasing ???

[red90 driver]

My label that is attached to the winch states to lubricate the shafts for the high/low/freespool levers with oil.

So from that I would guess that a few drops of 3 in 1 oil on the plunger shafts would be sufficient.

[Milemarker Type S]

hi i have the same winch as u . u said u get 45 ft a min i would like my winch 2 go that fast what have u done to make it go that fast many thanks ian

Your wish is BBC's command...here

In relation to service kits I am mot sure that there is one- all the o rings and ptfe bearings can be bought seperately as required- speak to Peter at First Four- very helpful chap.

Si

[Turbocharger]

Ian - any chance of re-loading your pictures for this guide?

After 7 years of continuous abuse and no maintenance whatsoever, my high-gear lever has seized so I've taken the box apart and found that I need to free off the selection lever, the box needs a little greasing, and the larger PTFE bush has split into two pieces (assuming this isn't how it should be, though the break is quite clean). Quite a hardy little machine for the environment it lives in.

[fotograf@jakobcarlsen.dk]

The pictures are not visible in either Safari or Firefox. Can you repost them?

[Team Idris]

I'm not sure he can do that, but it isn't a bad rebuild by any stretch of the imagination. If you remove the gearbox cover the single set of gears are part of the drum. There is no comparison to the goldfish with its brake and three sets of gears. The only slight downer is that there are two plastic bearing sizes.

[porky]

That look a great detailed article but the pics aren't displaying. Is there any chance it could be reposted please?

With no Milemarker dealers left after they pulled out of Europe there isn't much information to be had!