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CAT D5K final drive case pressure

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hotwire22

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Searched for this before posting but did not find.
Removed drain plug from final drive on CAT D5K and after final thread removed the oil shot across the shop under pressure. The other side drained out normally. I cannot find a case drain filter anywhere and the CAT parts system does not show on. The case drainlines simply lead back up to the tank (although there are some junctions with other lines near the pump).
I am suspecting I have a blown seal that is letting hydraulic pressure into the planetary? Or could the case drain line be plugged somehow?
 
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hotwire22

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I did not relieve the pressure. Do you mean actuate the blade after turning the machine off?
 
John C.

John C.

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Case drains go back to the hydraulic tank. Next time remove the cap before pulling the plug.

The real issue though is you are right about a leaking seal allowing hydraulic oil into the final drive housing. There should be slight pressure if checking the oil when the machine is warm. It should not be able to "shoot across the shop under pressure".
 
N

newguy2k3

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Likely the brake piston seal is leaking. The brakes are sandwiched between the motor and final drive housing. The brakes are lubricated by the final drive oil but are released by hydraulic oil. The seal starts leaking and fills your final with hydraulic oil. You catch it before the duocone seal fails if you're lucky.
 
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newguy2k3

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Nige said:
If you have a significant leak from a brake pack you ought to be adding oil from time to time provided the rest of the hydraulic system is oil-tight.
Click to expand...

Doesn't take much leakage to create pressure in the final. A leak significant enough that shows up on the hydraulic oil level probably have blown the duo-cone seal.
 
Dave Neubert

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is the final over full or is there just pressure 953s are known for brake pistons leaking if it is over full I would agree that your brake is leaking. You can do a test but it is not real easy to do you have to remove brake line hook it up to a porta power pump with a gauge and watch for a pressure drop
 
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Simon C

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Dave Neubert said:
is the final over full or is there just pressure 953s are known for brake pistons leaking if it is over full I would agree that your brake is leaking. You can do a test but it is not real easy to do you have to remove brake line hook it up to a porta power pump with a gauge and watch for a pressure drop
Click to expand...
If you have Dye in the Hydraulic Oil it will be visible in the final drive oil when dumped. Daves idea about the Enerpac is good also as long as you have a very accurate gauge on the porta power. Some have blown the seals with a porta power with a poor gauge or no gauge.
 
Nige

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Cat Part Numbers 9U-5031 or 9U-5032. Blue or Red oil dye.
Best thing since sliced bread for tracing where oil is going if it isn't staying where it should be.

It was only a couple of months ago that we convinced an oil supplier to add the dye to their bulk deliveries. The difference it makes when reading sight glasses is also worth having.
 
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Nige said:
Cat Part Numbers 9U-5031 or 9U-5032. Blue or Red oil dye.
Best thing since sliced bread for tracing where oil is going if it isn't staying where it should be.

It was only a couple of months ago that we convinced an oil supplier to add the dye to their bulk deliveries. The difference it makes when reading sight glasses is also worth having.
Click to expand...
I have a bottle of the blue stuff from Petro Canada and you dont need much in a system. Best to pour in and run the hydraulics instanly to prevent too much of it ending up on sight glass. Diluted is good. Also works good to put in the top of Fuel Filter and start motor to see where fuel is leaking into the oil around injectors and internal fuel lines espescially with a black light. Cat Sells a product for this , not sure if same part number. Too many machines have been destroyed because the operator could not see the sight glass oil level.
 
JD955SC

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Nige said:
Cat Part Numbers 9U-5031 or 9U-5032. Blue or Red oil dye.
Best thing since sliced bread for tracing where oil is going if it isn't staying where it should be.

It was only a couple of months ago that we convinced an oil supplier to add the dye to their bulk deliveries. The difference it makes when reading sight glasses is also worth having.
Click to expand...


I put red dye in hydraulic oil and blue in trans oil. Many machines now come from the factory with red in the hydraulic oil. I keep a gallon jug each of 30 wt TDTO and 10W HYDO with a heavy dye mix to add to machines for diagnosing. Need to get me some of the UV dye for dark oil.
 
Nige

Nige

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That's weird. All the biug stuff comes with red in the trnsmission, so that's what we've always stuck with.
Having only two colours it means that hydraulic systems, which are normally delivered empty on big kit, get the blue dye.
I heard tell of a yellow oil dye which makes sense seeing as red, blue, & yellow are the three primary colours, but I've never come across it.
 
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