2tractors

Well-known Member
I'm told the planetary brakes on the older 65 should have oil inside, I see a bolt head about halfway up or 9 oclock position on right. It would seem that a drain should be on the bottom. How do you service these brakes?
 
The brakes are NOT with the planetaries. They are in the end of the axle housing next to the differential. You have to remove the entire axle housing and then take off a cover plate that is held on by 2 Allen head screws.
 
Bobs right on the money. But there should be a small like 3/8 plug to drain there somewhere if you want to service the planetaries.
 
Yeah I want to drain and replace the oil but am not seeing anything on the planetary except some slots.
 
Here's a picture of mine.
a167245.jpg
 
If you take the axle housing off all the oil from the transmission runs out.

Or so I'm told. It's not like it happened to me when I wasn't expecting it, or anything like that.

:D
 
Planetary housing is on the outside,(next to tire), drain bolt near bottom of housing. Brakes are housed on the inner side of the axle housing just outside of the flange connect to the differential, or rear housing. That housing contains an oil seal. Thee should not be oil on or in the brake housing. Brakes are a disc type, but operate much like a clutch plate.
 
I'm not sure what year MF changed the planetary housing and decided to install drain plugs, but no, the early ones didn't have a drain. FWIW, the parts catalog makes mention of some design changes at rear axle serial #CR-11027, and a 509029M91 drive cover with "heavy duty bearings" (which includes the drain plug), but gives no further details.

The only way to change the oil on an early unit would be to either stand the tractor on its nose to make the fill hole the drain hole, or to remove tire, (wheel weights) and wheel, then split the planetary housing just enough to get it to drain. If there is no milky oil, rusty water, obvious mud, and are no significant metallic particles in the old oil, clean the surfaces with brake cleaner, allow to dry, then bolt back together. Do not add silicone or any other gasket sealer, as it may change the axle bearing preload by a 'few thou' and may cause bigger problems later. If the old oil looks 'oh-oh..', better take the planetary completely apart and clean/check it throughly before drilling and tapping a drain hole in the cover housing and reassembling with new seals, bearings and gaskets that you don't have to repeat the disassembly process later when parts well on the way to failure eventually do. Make sure the vent on the top of the housing is clean, and has its proper cover. Mine was plugged with oily dust/dirt.

Be aware that servicing the planetaries is a chore requiring pretty good mechanical skills, a good service book, machinist quality measuring tools including bore gauges, micrometers to 3", a dial indicator with magnetic base, and several hours to set up the bearing preload correctly. I did it not exactly right (in a hurry, "close enuf", IOW: wrong) once, and had it apart again 4 months later cleaning metal shavings out of the planetary along with cleaning out the 'spare change' in my checking account.

I should put this in my sig line:
"They're called Factory Specifications for a reason: because a lot of guys a lot smarter than I and well paid by the company that built it, already figured out most of the ways it won't work as intended. Anyone doubting that wisdom usually pays dearly to figure out they were right."
 

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