Has anyone changed Mitsubishi BD2G bevel gear shaft seals?

Ffirebug

New User
Hey, first time poster. Just a little info on me; I'm a jack of all trades and master of none. Automotive repair is more my forte, but I have worked on heavy equipment and hydraulics
along with many other types of equipment. I'm comfortable working on most anything. However, 2 areas I have never got deeply involved with are setting up manual transmissions
or differentials/gear meshing. Hence, the reason for my post.

So I'm working on a Mitsubishi BD2GII(not sure the year but I might be able to find out if you need it). I'll give you a run down of what I've encountered and done so far and I'll post
my questions at the end. I borrowed this from my dads friend and it appears to have had many different hands working on it. Initially, it would only steer right. And I was told both
clutch packs were recently replaced.

Levers, pedals, linkage and brake bands were way out of adjustment. On top of this the left clutch housing had 6+ inches of water/oil(mostly water) and the right side had 4ish
inches of oil. The drain plug holes for the clutch housings were plugged with junk so I opted to drill and tap the holes for a 1 inch pipe plug to avoid this down the road. I also
adjusted the levers, pedals, stops, linkage and brake bands. After all that it was usable although it would still only steer right due to the left clutch pack being seized up from all the
water.

I decided to use it this way to finish my job and repair it afterwards, but unfortunately the left frictions eventually sheered all the teeth before I finished.

A little more info that may be relevant to someone- I was losing hydraulic fluid and the bevel gear oil was quite low too. I didn't do any diagnostics to figure out what oil was leaking
where(which may have been a mistake).

Since there were so many issues and so may people that had worked on this I decided to fix everything so I have a dependable machine to use.

Currently:
-Clutches are removed, disassembled and waiting to have the parts cleaned. New frictions, steels and springs are on the bench.
-Discarding old brake bands and I have new brake bands on the bench along with new springs for the bands(old springs were stretched and distorted)
-Clutch release cylinders are removed, disassembled and cleaned. The left side(with water) had practically no bearing left and the piston was scored pretty bad. I assume this was
from excessive rust build up as the piston was removed from the bore since the bore is fine. A new piston along with seal kits are currently shipping and I should have them next
week. I have 2 new bearings on the bench. One of the dogs on the steering clutch shifter had been broke off and welded poorly so I order a new one that is waiting on the bench.

Now, finally, for the reason for my post. I drained the oil from the bevel gear and filled it with diesel fuel to check for leaks. As I suspected, the diesel from the bevel gear is leaking
pretty good to the left side that was rusted up. I want to replace the seals on both sides, but the manual and pictures are pretty poor in my opinion for walking someone with my
experience through the process of replacing. It appears to have one lip seal and one or two o-rings per side. I'm confident I could take it apart and put it back together, but not with
the right preload and possibly screwing up the gear mesh.

Before I start taking this apart I'd like to know how it comes apart. Will the bearings and seals come out the bevel gear cavity or clutch cavity?

When I put it back together how do I make sure it's right? My initial idea was to mark the the location of the lock in the current position on the nut and count the turns as I remove it
and install it in the exact location. I was also thinking about bluing the gears and taking a video of the pattern before removal since I probably won't have a textbook pattern on a
used gear set and verify it's the same after reassembly.

Thank you in advance for any help you can offer. I apologize if this is a duplicate post but I haven't been able to find any information on this here or anywhere else.
 
Don't know if the G differs from the F, the F I done to change the seals we took the clutches out,undone the flange retaining bolt and removed the flange,prised out the lip seals,tap in the new ones and put the flanges and clutches back in without disturbing the bevel gear setup at all,I have set up lots of bevel gears and pinions in my career and by the rule of thumb the pre-load is set first,then the backlash,I always done it by feel and ear and never had one whine but then I am a time served mechanic,move the bevel gear away from the pinion and set the pre-load,then move the bevel gear to the pinion by loosening one adjuster and tightening the other the same amount, when it feels there is about 8 or 10 thou clearance lock it up and it will be ok,marking the adjusting nuts is a good guide,the pre-load on the bevel gear is set in the factory before the pinion is fitted using a special jig,one won't have that in the field.
Good luck
AJ
 

I did think about just changing the lip seal because it looked like I could remove it from the clutch side and not mess with the bevel gear.

I'm just not sure what purpose the o-ring(s) serves and whats going to happen if they are bad. It appears that the lip seal seals the bevel gear oil from leaking through the bearing so I assume the o-ring is sealing oil from leaking between the shaft and collar, but I'm not really sure without tearing it apart and the manual isn't much help either.

My concern is if I pull the seal will just installing a new one work or will it still need to be pulled apart to clean off any rust on the sealing surface? My other concern is it appears to be wet/leaking between the shaft and collar too. I suppose I can brake clean it really good to dry everything up and add some more diesel. Then, if I only have a leak at the seal I could just change that.

I think I'm in the neighborhood of $2,300 in parts with everything to finish up and I just have a hard time doing all that and not replacing $20 worth of o-rings that may fail shortly if they aren't already bad right now.
 
The o'rings that are on bearing carriers are static,I have never seen one leak on any make machine,the o'rings are trapped in a groove,there is no movement to wear the rings, the choice is entirely yours.
AJ
 
Lip or running seal is your problem. Forget the o rings and stick a seal in it. You will have it going.
 
I'm waiting for the lip seal order to go through right now. The guy I'm ordering from said that after the lip seal is removed it "may" be possible to remove the collar. That doesn't sound very promising, but if I can get the collar off he said I can change the o-ring on the shaft too. So it sounds like the only seal that you need to tear into the bevel gear for is the large o-ring on the bearing carrier. Since you guys don't think that large o-ring needs to be replaced I'll just skip that one.

This is probably a dumb question, but I'm having a hard time wrapping my head around the purpose of the large o-ring on the bearing carrier. It appears that the outer diameter of the lip seal is pressed into the metal that makes up the dozer frame . It's hard to tell with the shaft and bearings installed and the rust, but is the outer diameter of the seal actually pressed into the carrier or race or something else and there is actually another seam between that and the dozer frame metal that the large o-ring is sealing?
 
The large o'ring on the outer diameter of the bearing carrier is to make a seal between the carrier and housing.
AJ
 

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