Caterpillar D-6c hydraulic tank leaking

[Steve.ahlgren85]

Nige, here’s a picture of the plate .looks like 39g14787.

 

[Nige]

Here's the Tank & Valve Gp corresponding to 163 Hydraulic controls with Serial Numbers from 39G12797 to 16642. I didn't look at it to see how it compares to the illustration you have.

 

[Steve.ahlgren85]

Here's the Tank & Valve Gp corresponding to 163 Hydraulic controls with Serial Numbers from 39G12797 to 16642. I didn't look at it to see how it compares to the illustration you have.

Thank's Nige, that’s a big help

 

[56wrench]

#16 is a gasket between the bearing assy and the tank. Maybe its seeping?

 

[Steve.ahlgren85]

#16 is a gasket between the bearing assy and the tank. Maybe its seeping?

I see that. Don’t think the gasket is the problem but I will replace it. I ran yesterday for about 3hours, lost 5 gallons of hydraulic oil. Dripping bad after oil warms up, not noticeable at startup. Thanks for the help 56wrench!

 

[56wrench]

No problem. Its a miserable enough job that i would change the gasket while you’re in there just to eliminate it. They don’t usually leak but on an old machine, you never know

 

[Steve.ahlgren85]

I see that. Don’t think the gasket is the problem but I will replace it. I ran yesterday for about 3hours, lost 5 gallons of hydraulic oil. Dripping bad after oil warms up, not noticeable at startup. Thanks for the help 56wrench!

Does anyone have a sure fire way of checking for leaks after installing the new seal, gaskets and bearing assembly before putting two halves together? The problem happens when oil is under pressure and hot.

 

[kshansen]

I see that. Don’t think the gasket is the problem but I will replace it. I ran yesterday for about 3hours, lost 5 gallons of hydraulic oil. Dripping bad after oil warms up, not noticeable at startup. Thanks for the help 56wrench!

5 gallons of oil in just three hours? That is one hell of a leak! Is anything gaining oil? Been way too long since I worked on a D-6 but is the a breather or some kind of pressure relief for the tank? Seems like I recall most Cat loaders had some type of Sintered Bronze Breather with a pressure relief to keep a little pressure in the tank, just enough to keep pump from cavitating.

 

[Steve.ahlgren85]

5 gallons of oil in just three hours? That is one hell of a leak! Is anything gaining oil? Been way too long since I worked on a D-6 but is the a breather or some kind of pressure relief for the tank? Seems like I recall most Cat loaders had some type of Sintered Bronze Breather with a pressure relief to keep a little pressure in the tank, just enough to keep pump from cavitating.

It is a bad leak.dripping very steadily after warms up! Don’t know if there’s a leak underneath above the belly pan . Don’t want to take that off unless I have to. I’ve got to fix tank first.

 

[Mcrafty1]

Does anyone have a sure fire way of checking for leaks after installing the new seal, gaskets and bearing assembly before putting two halves together? The problem happens when oil is under pressure and hot.

I've never done it but you could always make an adapter to plug the filler with an opportunity to pressurize the tank with air and then use the soapy water method to see if you could identify any leaks.

 

[Nige]

Don’t know if there’s a leak underneath above the belly pan . Don’t want to take that off unless I have to.

Are you sure that all of the gallons of oil you are losing are from the tank.?
Are you even sure that it's the tank that is actually leaking.?
Could you possibly have more than one leak.?
If so dropping the belly pan might just reveal the source of another leak if there happen to be multiple ones.

 

[Steve.ahlgren85]

Are you sure that all of the gallons of oil you are losing are from the tank.?
Are you even sure that it's the tank that is actually leaking.?
Could you possibly have more than one leak.?
If so dropping the belly pan might just reveal the source of another leak if there happen to be multiple ones.

I’ve thought about another leak maybe down below. I’m quite sure it’s leaking from the control rod for blade tilt, visably dripping fast after running for awhile.Another leak is possible though Nige.

 

[Steve.ahlgren85]

I've never done it but you could always make an adapter to plug the filler with an opportunity to pressurize the tank with air and then use the soapy water method to see if you could identify any leaks.

I guess that’s possible but looking for a simpler solution. Thanks for the advice though

 

[Welder Dave]

In the pic. of the inside of the tank with the rag stuffed in an opening, there looks to be crack of some sort above the rag. May not be a concern though. If the tank is in half, can you place it flat and plug the openings? If so you could warn up some oil and pour it over where the shaft is leaking. It wouldn't be under pressure but assuming the tank is venting properly could still indicate if there's a leak. Let it sit for a while.

 

[Steve.ahlgren85]

In the pic. of the inside of the tank with the rag stuffed in an opening, there looks to be crack of some sort above the rag. May not be a concern though. If the tank is in half, can you place it flat and plug the openings? If so you could warn up some oil and pour it over where the shaft is leaking. It wouldn't be under pressure but assuming the tank is venting properly could still indicate if there's a leak. Let it sit for a while.

No visable cracks in tank but will definitely check that when I take it off this week.diesel fuel was suggested, it would be thinner than oil , would be more prone to leaks. Wierd thing about it is that the other control rod had a groove worn on shaft but wasn’t leaking!

 

[kshansen]

Are you sure that all of the gallons of oil you are losing are from the tank.?
Are you even sure that it's the tank that is actually leaking.?
Could you possibly have more than one leak.?
If so dropping the belly pan might just reveal the source of another leak if there happen to be multiple ones.

Just for fun you could take a one gallon paint can poke a 1/4 inch hole in the bottom and fill it with warm oil and see how long it takes to empty. Then multiply that time by 5 and see how it compares to your leak.

Five gallons of oil is a lot and should be leaving puddles all over the place every time you stop. Someone should call the EPA!

 

[Old Magnet]

May not be just a seal problem, there are two sleeve bearings in there that may be worn beyond the range of the seal working.

 

[Steve.ahlgren85]

Just for fun you could take a one gallon paint can poke a 1/4 inch hole in the bottom and fill it with warm oil and see how long it takes to empty. Then multiply that time by 5 and see how it compares to your leak.

Five gallons of oil is a lot and should be leaving puddles all over the place every time you stop. Someone should call the EPA!

I’m not saying that you are wrong, there very well could be a hose connection or some other problem on under side of the dozer. I’m going to fix the known problem leak first which is bad after oil gets hot and is in a pressurized tank.

 

[Welder Dave]

With that big of a leak you're lucky you didn't take out a pump or other hyd. component. Definitely investigate further. I think it would make more sense for a blown hose to leak that amount of oil but see Old Magnet's post above.

 

[OzDozer]

I'd be looking carefully for corrosion pinholes or cracked welds. Welds on pipe flanges commonly crack with vibration.