Challenger MT275B Hydraulic oil air lock

[Bullfloat]

Changed hydraulic oil and pump would not pick it up. Disconnected front loader lines disconnected backhoe lines to eliminate the possibility of those lines possibly sucking air. Still nothing, it took cracking two small bolts on the pump to get the pump to clear the air and start moving oil.
Anyone have a similar experience and is there a better way to accomplish this or prevent it?

Thank you

 

[BeezFun]

Given that you didn't do anything to the pump and it was working fine before you changed the oil, I'd say that makes it unlikely there's anything wrong with the pump. My guess is a suction leak was created when you did the oil change. Could be the old filter gasket was left on so now there's two gaskets on the filter and they're not sealing. Or the filter's not tight. Or maybe you moved a suction line to get at a filter and the hose was old, so it cracked. Or it had a small suction leak before you changed the oil but it only showed up once the pump had to prime itself. The only place there can be a suction leak is between the reservoir and the pump. All the lines you disconnected on the loader are pressurized, even the return lines. So those lines may leak but they won't suck air. If you're sure the filter is on correctly, I'd clean off all the hoses and fittings between the reservoir and the pump and then check the next day to see if you see any signs of leaks. I'd watch for foam in the oil, if it's still sucking air you should see some.

 

[MapleLeafFarmer]

sorry I can't help but you made me laugh.

When I hear Challenger tractor the first image that pops into my mind is... got me excited

then I google your model and found my first impression was WAY OUT there... Wish I could help

 

[Tx Jim]

I glad you got hyd pump primed. IMHO disconnecting FEL & BH supply lines isn't necessary to get frt pump primed & pumping oil. Loosening line supply line as you did on the hyd pump is the simplest method.

 

[ArlyA]

sorry I can't help but you made me laugh.

When I hear Challenger tractor the first image that pops into my mind is... got me excited
View attachment 732981

then I google your model and found my first impression was WAY OUT there... Wish I could help

Caterpillar made ones are the only Challenger tractors I am familiar with.

 

[oldnslo]

To get a pump to prime make sure inlet has no leaks and open pressure line at the pump and jog the engine over a few times till oil comes out the pressure line. This allows the trapped air to be expelled and once the pump gets a gulp of oil it will continue to run.

 

[Bullfloat]

Given that you didn't do anything to the pump and it was working fine before you changed the oil, I'd say that makes it unlikely there's anything wrong with the pump. My guess is a suction leak was created when you did the oil change. Could be the old filter gasket was left on so now there's two gaskets on the filter and they're not sealing. Or the filter's not tight. Or maybe you moved a suction line to get at a filter and the hose was old, so it cracked. Or it had a small suction leak before you changed the oil but it only showed up once the pump had to prime itself. The only place there can be a suction leak is between the reservoir and the pump. All the lines you disconnected on the loader are pressurized, even the return lines. So those lines may leak but they won't suck air. If you're sure the filter is on correctly, I'd clean off all the hoses and fittings between the reservoir and the pump and then check the next day to see if you see any signs of leaks. I'd watch for foam in the oil, if it's still sucking air you should see some.

 

[Bullfloat]

Thanks for the input, I think you nailed it. There’s two o rings and a rubber hose about 4” long to compensate for movement between engine and reservoir it’s directly below the engine oil filter and over the years and oil changes I suspect it’s brittle. It’s up and running and I’ve ordered replacement parts.

Thanks for the input, much appreciated.

 

[Bullfloat]

sorry I can't help but you made me laugh.

When I hear Challenger tractor the first image that pops into my mind is... got me excited
View attachment 732981

then I google your model and found my first impression was WAY OUT there... Wish I could help

Sorry to disappoint, but might be a distant relative. Lol

 

[MapleLeafFarmer]

View attachment 733005

Sorry to disappoint, but might be a distant relative. Lol

that's a good looking 40hp tractor! I like the industrial lines and the duty look versus some of the swoops/plastic etc... used these days by some that seem fragile