Going to look at a D8H. Rear main seal is leaking. How bad of a job is that? Can you get to it with the engine in the machine or does the engine have to come out? Just trying to get an idea before I drive out to look at this thing. Also what are standard areas to check when looking at a dozer like this? I guess what are standard weak points of a D8H? I’m well versed mechanically just haven’t spent a lot of time around dozers. Thanks
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CAT D8H Rear Main Seal
- Thread starter NNYDairy
- Start date
OzDozer
Senior Member
Need a tractor serial number to assist properly. The D8H was built from 1963 to 1975, and over 40,000 were manufactured. The amount of engineering changes in the D8H over that time period, would fill a couple of books.
There are direct drive (manual transmission) D8H's and powershift transmission D8H's. Also, any associated engine problems or any repair history will help.
There are direct drive (manual transmission) D8H's and powershift transmission D8H's. Also, any associated engine problems or any repair history will help.
No it isn't and the engine has to come out to change the rear main seal.
The main problem is its over 55 years old .
Bad Bob
What do you mean no it isn’t? That’s just what I was told.
A 36A is a direct drive machine .
Bad Bob
It’s not usual for the rear crank seal to leak.Is the owner sure?
I think it would be prudent to take a look at it yourself as there is uncertainty as to wether it’s powershift or direct drive?If that basic fact is in question,then so is the leaking rear crank seal I reakon.
I think it would be prudent to take a look at it yourself as there is uncertainty as to wether it’s powershift or direct drive?If that basic fact is in question,then so is the leaking rear crank seal I reakon.
If it’s a 1970 powershift tractor then it would possibly be a 46A or 68A.
Be wary that major components made not be original .
If memory serves that is a rope seal? I ran a 46A with an engine rear seal leak for a long time, not so good for the transmission etc. but with my little valve on the pressure port of the transmission pump, and a nice little rubber hose, I'd just check the engine dip stick occasionally, and if low pump some oil back to the engine. It was a cheap out fit I worked for.
Welder Dave
Senior Member
The county my property is in had 2 original D8H's from around that era. They bought brand new, maybe 1968? Direct drive with CCU's and matching scrapers. Pony start. They used one to dig clay on my property to upgrade the road. Had almost new undercarriage. What was impressive was the torque that engine had. They were using their new D6N to help push the scraper and when the D8 operator released the clutch at the same time he stabbed the throttle it just rolled coal and never missed a beat. Finning only offered $10,000 trade in so they kept the 2 D8's and scrapers. I heard they sold them at auction a few years ago. They would have been worth putting a little $$$ into. They also had a 627 scraper from about 1970 they used for the road.