I recently pulled apart my '59 Ural M-72 motorcycle transmission to fix a pretty bad leak (was missing an o-ring). There is quite a bit of sludge build-up on the bottom, and I was wondering what is the best way to go about cleaning and re-lubing the transmission before I reassemble? I have several varieties of degreaser, but I am worried about the rubber seals and bearings that are already in there. I would like to find the easiest way to quickly clean it, without having to dismantle it completely (ie remove the currently working and unobtainable seals, and removing the bearings).

Would it be safe to use a degreaser and then just lube everything up with gear oil before I reassemble? Would it be safer to not worry about cleaning it for now (rest of internals are fairly clean)?

Inquiring newbie minds want to know! Thanks for any suggestions.

- Michael

High pressure water, and a toothbrush, and some turpentine or vinegar or something else acidic.

Try to blast as much grease away as possible, then go back with the toothbrush and your chemical of choice. Scrub it cleen. Remember. A clean trans is a happy trans.

This topic is perfectly acceptable in the garage Michael. In fact, you're likely to get more response there anyway.

Moving...

Thanks Gint!

alpha434: I thought using anything acidic on aluminum was taboo , is there any risk of damaging the rubber seals or bearings if I use my generic degreasers, simple green, or gasoline - or is vinegar/turpentine/lemon juice really the good option?

Also an addendum question: my reverse gear has a lot of wear on one side of the teeth, is there a good supplier in the US for a component of this type? (ie provide #teeth, ID, OD, width and they match me a gear?)

Is this the justification for buying the pressure washer that ive always wanted?

id say carb cleaner.....

QUOTE (Aaron Cox @ Apr 2 2006, 08:11 PM)

id say carb cleaner.....

actually, i'd say "brake" cleaner ...

get a case of brake cleaner and use it generously. make sure you are in a well ventilated place when you do so.
it'll take all the sludge right off it. it's also safe to use on rubber, but *not* plastic ...

for assembly, lube parts and o-rings and such with whatever transmission oil you're going to use later on ...

i have done many bike transmission in my dirt-bike racing days ...
Andy

QUOTE (Michael Oberg @ Apr 2 2006, 09:01 PM)

Thanks Gint! alpha434: I thought using anything acidic on aluminum was taboo , is there any risk of damaging the rubber seals or bearings if I use my generic degreasers, simple green, or gasoline - or is vinegar/turpentine/lemon juice really the good option? Also an addendum question: my reverse gear has a lot of wear on one side of the teeth, is there a good supplier in the US for a component of this type? (ie provide #teeth, ID, OD, width and they match me a gear?) Is this the justification for buying the pressure washer that ive always wanted?

Acid on aluminum isn't bad unless you let it set or electrically charge it. Those are both bad. But any minor damage that acid does can be *fixed* with steam. The acid reacts with the surface to create aluminum oxide. The oxide seals itself and makes a harder layer with steam. See "annodizing."

The key is to not destroy the seals. And a small amount of acid will not. Use the vinegar. That will be more than enough.

Clean everything really good and bolt it back up. No problem.