Leaking Final Drive

[sdavies2000]

I purchased a 2009 hitachi zaxis 200lc 3 excavator fairly recently to build some trails on my property. I was crawling around under the machine yesterday and noticed a small leak in behind the sprocket and on the chain. Decided I better check the oil level in the drives and found out there was ZERO oil in the drive (took drain plug out after I couldn't find the level). At this point there is no noise coming from it and I'm lucky I haven't done much traveling but I have no idea how long it's been empty and how long previous owner used it like that. Question is, how difficult is it to change the floating face seal and can it be done without pulling the drive? I keep reading that you shouldn't just keep topping it off as dirt will get in and wreck the drive which makes sense. I don't plan on owning this machine for long but this can't be ignored.

 

[92U 3406]

Not a bad job. Requires a crane and a very thorough cleaning. Also will need a special tool to remove the nut.

 

[sdavies2000]

ahhh, i was worried i would need special tools. the nut is probably torqued to some unimaginable spec i assume as well. So even if i can get the drive off and opened up, I wont be able to remove the nut and definitely wont be able to torque it to the required torque afterwards. i was really hoping it wouldn't require a trip to the shop.

 

[Nige]

You're assuming that the leak is a result of the face seal being worn. Prepare yourself for the other possibility that it could be worn bearings causing the face seal to lose compression and leak.

 

[John C.]

How many hours are on the machine?

 

[sdavies2000]

yes I was making that assumption . I was not familiar with the relationship between the bearings and the seal.... would there be noise if the bearings were bad?

there's roughly 11,000 hours on the machine.

 

[Nige]

I was not familiar with the relationship between the bearings and the seal.... would there be noise if the bearings were bad?

Not necessarily. Do the plugs on the final drives have magnets embedded in them.? If so, are they showing a lot of "fur".? Post photos........

 

[sdavies2000]

no they don't have magnets which i thought was strange. the other final drive is at the proper level but the oil is gray. not milky, but grey...i havent drained it yet but i will on my day off.

 

[John C.]

Those hours indicate a total teardown, inspection of components and rebuild. You are going to need thrust washers, bearings and the seals. The gray oil indicates wear in the other final and it will need the same thing done.

 

[Nige]

I concur with John. The final with no oil in it needs to be removed, disassembled, and evaluated. You can't do this installed on the machine.
The other one with the grey oil could be made to go a bit longer with a flush and an oil change. What you learn on the side that is leaking while repairing it will prepare you for the other side.

 

[92U 3406]

You should be able to get that final pretty close to 100% apart on the machine, only the spindle would remain attached to the track frame.

In all honesty, with the amount of work involved and the huge possibility of contamination doing it in the field it wouldn't take much more effort to just pull the drive motor and unbolt the final drive as a unit.

 

[sdavies2000]

Well this is bad news...

what is a new or reman drive worth? i'm guessing my local shop will want nothing shy of 5k to rebuild it. Is there any benefit to topping it up and running until it completely fails?

I have the mechanical ability to tear it down and rebuild myself but i wouldn't know what to look for and i have no way of removing the special nut or torquing it. Don't know what you don't know.

would a service manual have the level of detail or info required to do this?

 

[John C.]

Start making phone calls and asking questions of the dealer or shops of your choice. Just keep in mind that most will tell you one thing on the phone and another whole line once the component is torn down. Best way to get and idea is to get a quote for exchange and a new one if available.

I had a client ask me about doing finals on that size of iron. Dealer quoted $6,000 in labor to do both finals. Turned around when the finals were apart and quoted $33,000 to put them back together. Made me angry enough to pull all the parts out of their shop and bring them to mine. Got them back together with seals, bearings and thrust washers for less that $7,000.

 

[92U 3406]

The socket for the nut I believe is a "dealer fabricated tool." They may be able to provide you with the specs or drawings for it as well as a torque spec on the nut. I doubt it gets much more than a couple hundred ft-lbs. If I'm remembering it right, I would use a 3/4 drive torque wrench on the 450 finals.

Disassembly is pretty easy, all the planetary pinion shafts should be retained with split pins. The biggest pain would be replacing the tapered main bearing outer races and even then if you can freeze them they should drop right in.

 

[Tones]

These planetaries aren't exclusive to Hitachi, other Japanese machines use them. Also there are businesses who specialise in the repair and or parts supply. I suggest you start searching for them as they usually offer a better service and lower costs the OEM dealers plus they may also share the info you require should you do the job yourself.

 

[Nige]

would a service manual have the level of detail or info required to do this?

A half-way decent one ought to. For a Cat machine of similar size it would be guaranteed to, I can't comment on how extensive Hitachi manuals are for a machine that size. For the larger machines they are pretty good.

 

[John Shipp]

Is there any benefit to topping it up and running until it completely fails?

No, not if you want to rebuild original using most of it's goodies. If problem caught early, limited tooth damage and wear from contaminated oil to components. If left past that point, it starts to grind itself into grey paste. Final drives I've seen like this are impressively mashed to bits inside, new would be the only replacement.

The special tool for the bearing nut is made of a section of tube, with "teeth" welded around one end to fit whatever slots are in the nut, the other end has a plate welded across with a spare socket welded on. I'll see if I can find one and take picture. Obsolete gas cylinders get kept in the junk pile for making these specials

Holding the final drive from turning is the only other thing to consider.

 

[Vetech63]

You could just fill it with oil and run it over the auction block. This forum is full of that equipment.

 

[sdavies2000]

Would the same vintage and size Deere use the same drives? I was under the impression they were the same machine with a different power plant. Those manuals would probably be decent too?

I've been searching for specialized companies but I'm not coming up with much, I don't know if we have the same availability to parts and services here in Canada. Most things I find are all through 3rd parties.

I guess the other question is, if i don't rebuild it myself, would it be cheaper to buy a rebuilt one as opposed to having mine rebuilt.

A picture would be great

I wonder if the grey paste you speak of is the grey crap in the "good" drive.

 

[John C.]

The gray stuff is the grindings from all the moving parts inside the unit. There is a member on this board that does handle final drives. I've also made contact with Tones in Australia who clued me to a source there with contacts to companies in Asia. I'll try to find our thread.