Troubleshooting Your Filter Press Air Hydraulic System

We have cataloged a few common issues & troubleshooting tips for air-over-oil filter press hydraulics. If you have any other questions, give us a call: 616.399.8850


1) My hydraulic pump won’t stop running after the filter press achieves clamp pressure.

Inspect the fittings, hydraulic components, and exhaust muffler for loss of oil.

If there’s no loss of oil…
>> The relief valve could be failing. Try to reset the relief pressure.

>> If relief valve can’t be set to hold pressure, it may need to be replaced.

If there is a loss of oil…
>> Identify the leak and repair at the fittings.

If oil is leaking from the exhaust muffler…
See #2

2) There is a large amount of oil leaking from my exhaust muffler.

Oil leaking from your exhaust muffler is the result of either damaged cylinder seals or a damaged cylinder.

A damaged cylinder allows oil to leak into the air portion of the cylinder and the oil travels out of the exhaust. The solution is to rebuild or replace the cylinder.

Damaged cylinder seals can be replaced. Air-over-oil hydraulic cylinders have special seals for this application; please contact us for OEM replacement seal kits.

3) How often should I change my oil?

M.W. Watermark recommends annual oil changes on an air-over-oil filter press. As compressed air is introduced into the oil with each cycle, the oil absorbs moisture from the air. This can cause premature failure in components if the oil is not changed regularly.

4) What type of oil should I use?

We recommend a high quality ISO-46 for air-over-oil hydraulic systems.

If you have any other questions (or if this sounds like your filter press), contact our Sales & Service Team and they will happily help you: 616.399.8850.

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