Kubota front drive shaft oil seals

I have an L3940 Kubota front oil seals seem to be an item that several have had leaking, I did not have the time or the ability to change them myself due to age and an accident. Well I did haul it to the dealer they changed them last summer and now one is leaking quit a bit, i watched several videos and a couple had roughness or rust where the seal rides, I am thinking maybe they did not clean it up or something got stuck up in there? This tractor does not get abused at all, I use it but do not abuse it. And only have one side that leaks so Monday when i call to see when i can get it in to tell them to fix the one leaking and leave the one that is not leaking alone. My question to you guys is my thinking shouldn't these last for quite a while? or is it a design problem? To add a note i replace the utd fluid shortly after i had a leak to 80 90w. And like others have said a design problem for sure. In an application like this they should have used Timken roller bearings

Seal life is very difficult to determine on equipment in the field because operating conditions are unknown, and they vary considerably. It’s hard to define a “typical” application. Furthermore, the applications are usually not ideal (defined as clean lab type environments, fully lubricated, low speed, ambient temps, no pressure, no misalignment or runout, no exposure to chemicals or solids, everything is sized correctly, etc), and the reality is that these factors change seal life considerably.  

How Long Does a Camshaft Seal Last?

The air/fuel mixture that your car has is vital and the only way that the car will be able to complete the combustion process properly. A number of different components have to work together in order for the air and fuel mixture of the car to work. The camshaft helps to open and close the valves when trying to ramp up for combustion. The camshaft seal fits between the camshaft and the timing covers. In order for the camshaft to have the airtight chamber it needs during the combustion process, the seal will have to perform its job. The camshaft seal is used constantly, which will usually lead to it wearing out over time.

The camshaft seal is made to last for around 80,000 miles but in some cases, it will wear out prematurely due to damage to the camshaft. The heat that the engine produces can lead to the seal becoming damaged over time. These seals are made from a mix of rubber and metal and the rubber coating can help to protect the metal underneath from damage. When this seal does wear out, you will have to act immediately to avoid further the damage that this repair issue can do.

In some cases, you may have to replace this seal when the timing belt has to be replaced or if there is an issue with the camshaft. Due to where the camshaft seal is located, it will difficult to inspect it on a regular basis. There will be a number of warning signs when our camshaft seal is in need of repair and here are some of them:

Oil is leaking from behind the timing cover

The combustion process is not right

Lower than normal engine oil levels

Harder to start the car

Getting the camshaft seal replaced is a job that is best left to a professional. Due to the complexity that comes along with getting to and fixing this seal, it is much better to let professionals with previous experience handle the work.

The life-span of engine oil seal

Post by Marc » Mon Apr 26, 2010 1:53 pm

hemicat wrote:....Usually where the seal lip rides on the crank. You will find a groove worn on the end of the crank. When this happens you have several options. First option if you are lucky they offer a wear sleeve. This will fit over the end of the crank and give you a quick fresh surface and you can continue on. If not then you are faced with either having your crank turned or looking for a replacement...

The front seal on an ACVW rides on the flywheel, not the crank. A "speedi-sleeve" fix might work, if one were available - but I've never heard of one for the VW flywheel.
Sagaboy's flywheel shows some pretty serious pitting, personally I'd replace it if I was hoping to be totally leak-free. If that's not in the cards, I'd polish it with emery cloth and use an orange hi-silicon seal. Preferably a double-lip, but if only a single-lip could be found I'd put it in at a different depth than the old one (i.e., if the old one was only flush with the case surface put the new one in until it bottoms in the bore - or vise-versa) and cross my fingers.
The oil on the clutch disk got there by bypassing the O-ring seal inside the flywheel snout. That must be replaced, a new flywheel seal alone won't fix that problem.

The front seal on an ACVW rides on the flywheel, not the crank. A "speedi-sleeve" fix might work, if one were available - but I've never heard of one for the VW flywheel.Sagaboy's flywheel shows some pretty serious pitting, personally I'd replace it if I was hoping to be totally leak-free. If that's not in the cards, I'd polish it with emery cloth and use an orange hi-silicon seal. Preferably a double-lip, but if only a single-lip could be found I'd put it in at a different depth than the old one (i.e., if the old one was only flush with the case surface put the new one in until it bottoms in the bore - or vise-versa) and cross my fingers.The oil on the clutch disk got there by bypassing the O-ring seal inside the flywheel snout. That must be replaced, a new flywheel seal alone won't fix that problem.

Gaskets Don't Last Forever

By the time a vehicle is 10 to 15 years old, chances are some of the engine’s original equipment gaskets may be starting to leak. These include valve cover and oil pan gaskets, front cover gaskets, intake and exhaust manifold gaskets and front and rear crankshaft seals. The combination of time, temperature and many miles driven cause many of these gaskets to fail.

Oil leaks are a common problem with high-mileage engines regardless of the year, make or model of vehicle. High-end imports develop leaks just as often as more common domestic nameplates. No vehicle manufacturer is immune from the effects of gasket-aging. Most late model oil pan and valve cover gaskets are made of molded rubber (neoprene or other high-temperature synthetic rubbers) and are much longer-lived than the old cork/rubber gaskets of years gone by. Some molded rubber gaskets also have metal or plastic carriers for reinforcement and to control compression thickness. Molded rubber has good elasticity and resists taking a compression set. It also swells slightly when exposed to oil, allowing it to fill any gaps that might allow a leak. But durable as they are, they don’t last forever. Eventually, the rubber deteriorates, loses elasticity and cracks or leaks.

The first sign of trouble may be oil spots on a garage floor or driveway, or a gradual loss of oil between oil changes. A really bad oil leak may cause a loss of oil pressure if the dipstick isn’t checked regularly so make-up oil can be added to offset the loss. Oil leaks also can drip on hot exhaust pipes and create a burnt smell that may be noticeable while driving or after parking the car.

Many leaky pan and cover gaskets can be replaced fairly easily, but others can be more difficult to install depending on their location and accessibility. With leaky crankshaft end seals, a leaky rear main seal typically requires major surgery to replace, though front seals are usually easier to change. Crankshaft repair sleeves are available if the area where the seal rubs against the crank is worn or grooved.

Coolant leaks can be a problem with some high-mileage intake manifold gaskets. These include 1990 to 2005 Buick, Chevrolet, Oldsmobile and Pontiac 3.1L, 3.4L, 3.8L, 4.2L and 4.3L V6 engines, and 1996 to 2002 Chevy 5.0L and 5.7L V8 engines. Corrosion around the coolant ports in the cylinder head and/or deterioration of the gasket itself allows coolant to leak into the valley area of the block, which then dribbles down into the crankcase. The loss of coolant (which often can’t be seen) eventually causes the engine to overheat, and if the problem isn’t fixed, oil dilution and sludging can cause engine damage and possible engine failure.

Selling your customer a bottle of cooling system sealer may provide a temporary fix for such a leak. But the only permanent fix is to replace the leaky intake manifold gaskets, which on many of these engines is a time-consuming and expensive job — but much cheaper than replacing an engine.

Other applications where intake manifold gasket coolant leaks sometimes occur include Ford 3.8L, 3.9L, 4.0L and 4.2L V6 engines, and 4.6L and 5.0L V8s, also 1990 to 2002 Chrysler 3.3L and 3.8L V6s.
A customer who is replacing intake manifold gaskets will also need coolant to refill the cooling system (50/50 mix or concentrate that is compatible with the OEM coolant). GM also recommends using thread sealer on the 3.1L intake manifold bolts.