Hydraulic press

[Yngvar FParticipant @yngvarf]

I’ve had a this 10 ton hydraulic press for maybe ten years. The return action has been getting worse and worse. From being able to push it by hand I now have to use a car jack to get the piston to retract.

I have changed the fluid and bled the system.

The spring inside the piston seems strong. (Tried getting it to open whithout fluid)

Any ideas on what could be wrong?

[Yngvar FParticipant @yngvarf]

Piston not retracting

[not done it yetParticipant @notdoneityet]

Seems like the pumping head needs some attention? Or will the piston not retract even if the supply line is released?

Initially remove hydraulic pipe at the pumping head. If the piston retracts it is the head at fault, if not it could be the hydraulic pipe or the ram. Disconnect hydraulic pipe at the ram to determine if it is pipe or piston/ram.

Proceed from there.

[HOWARDTParticipant @howardt]

May be the check valve on the return line. Pressure on the outlet side locks the return check valve to stop the piston moving back. On hand pumps a manual lever releases the lock pressure.

[Brian WoodParticipant @brianwood45127]

Bent piston?

[Yngvar FParticipant @yngvarf]

Had to leave the workshop cause the neighbours rotting house had fallen om our fibre connection.

Will try again next weekend.

[SamsarandaParticipant @samsaranda]

Could be the seal on the piston?

Dave W

[FLguyParticipant @flguy]

Your press looks to be exactly like the Dake 10 ton press I have with the same problem….. so far no luck in correcting it but I haven't jumped into it much. I think the check valve comment may be it. Need to try that right now.

[FMESParticipant @fmes]

Check the flexible hose, ten years is the normal recommended service life for flexi hoses and it could well be failing internally, causing a possible restriction.

Regards

Lofty

[Yngvar FParticipant @yngvarf]

Posted by Samsaranda on 28/01/2018 18:36:07:

Could be the seal on the piston?

Dave W

I think we have a winner.

Removed the hose at the pump. Nothing

At the piston. Nothing

Removed check valve. Nothing

Even removed the gauge.. still nothing

Took the piston off the press and over to the bench. Put it down a little to hard, piston retracts and showers me and everything else in oil.

[not done it yetParticipant @notdoneityet]

Ha ha! Once diagnosed to the cylinder/piston area, you should have jacked the oil out before dismantling.

When one has been sprayed with hydraulic oil, from head to toe, by a leaking hose on a trailer ram (at full lift), one remembers to take precautions with pressurised systems – even if at low pressure.

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