JCB 3CX slow hydraulics.

[Mikerb]

My 3CX hydraulics became slower and weaker yesterday to the point that it would hardly lift the boom or the front bucket.

For a long time before this; air would build up in the hydraulic system and would hiss out of the filler cap. I would only notice it when I turned the engine off. Is this normal? The backhoe would also hesitate for a second every now and then, but in the end it would stop start stop start stop start then gave up.

Does this mean a pump change, or is there anything else worth trying? I've read about a filter that can clog up and make everything slow.

Cheers,

Mike

[Jeremy Rowland]

Mike I would be looking at the filter before the hydraulic pump but somebody on here will probably be able to better help you as they may have come across this before.

Jeremy

[Mikerb]

Hi Jeremy,

Thanks for your reply.

I've just drained down the tank and taken the filters out; they were full of crap, there was also about half inch of crap at the bottom of the tank too. I'm surprised it was working at all!! The oil was grey and a bit cloudy too. A cup full of water came out of the tank first so I'm guessing this didn't help.

Hopefully this was the problem.

I'll have to wait until tomorrow now, to get some more oil and and filters to try again.

Not sure if it's worth draining oil from the cylinders too, as this will be holding contaminated oil? Bit of a job!

[Jeremy Rowland]

Hi Jeremy,

Thanks for your reply.

I've just drained down the tank and taken the filters out; they were full of crap, there was also about half inch of crap at the bottom of the tank too. I'm surprised it was working at all!! The oil was grey and a bit cloudy too. A cup full of water came out of the tank first so I'm guessing this didn't help.

Hopefully this was the problem.

I'll have to wait until tomorrow now, to get some more oil and and filters to try again.

Not sure if it's worth draining oil from the cylinders too, as this will be holding contaminated oil? Bit of a job!

Mike you will inevitably get a bit of contaminated oil left in the system; the only thing I would have thought was to perhaps do another oil change after operating the machine for a short while? At least you have made a start in the right direction so let us know how it works out.

Jeremy

[Mikerb]

Yeah I'll be replacing the filters first, then a new pump if still a problem.

The thing that is worrying me is the air pressure in the hydraulic tank. What could be causing this?

[essexpete]

Yeah I'll be replacing the filters first, then a new pump if still a problem.

The thing that is worrying me is the air pressure in the hydraulic tank. What could be causing this?

I would guess that the breather must be blocked. Would it be worth undoing some of the main pipe and letting the fluid out to save a little more contamination of new oil?

[agrimax]

Check the suction hose between the pump and tank. It could be perished and allowing the pump to suck in air.The breather is in the filler cap on my 3cx,so presumaby the same in yours?

[Mikerb]

I took the hydraulic filter out today and this is what I found!

IMAG1821.jpg

Must have been blocked and blown a hole right out of her.

I'm starting to think that the filter material has caused a blockage somewhere.

Off now to get some oil, filters (hopefully) and some fittings to connect my pressure gauge to the pump outlet hose to check pressure. Any idea what reading should be getting? Or can a f****d pump still show enough pressure without load?

.

[Mikerb]

Got a new filter to replace the blown one, but couldn't get hold of the filters in the tank but can get them for a shocking £150ish, so I washed out the old ones and they're good as new (almost).

Filled her back up and all is working better and stronger than it ever has.

I got them to make up a tee fitting with a 2m hose with the pressure gauge on the end of it that reaches inside the cab. The pressure gauge is showing 2200psi maxed out. Not sure what it is supposed to be?

[Jeremy Rowland]

Mike glad you got it sorted the pressure you quoted sounds to be in the right ball park to me although somebody may now the exact figure.

Jeremy