dump trailer hydraulic leak

Try a little baby powder. Do NOT use on reciprocating shafts (or you could wind up with a worse leak due to the powder abrading the shaft seals). Sprinkle around connectors, plugs, etc. Should be pretty obvious where the leak is, if it is that big.

If you can pressure wash the whole thing from every angle you can. Then give it a generous dusting of chalk powder or talcum powder once its dry. The leak will show its location rather easily then.

Most often its a pump shaft seal or tank seal. Its also fairly common to get a hair line crack in a fitting or the tank itself.

Likely it is a leak like the others suggested but I'll mention an two other occasional problem.

It may be possible that air (or fluid) in the system expands and contracts as ambient temperature varies. Operation temperature could also affect it. I have topped systems off when cold and they don't have enough take up volume due to expansion when at operating temperature. In this case the excess fluid comes out the vent, overflow, or fill tube.

The large single acting cyinder and take up tank that is usually on a dump system would be an expansion/contraction concern.

Another unlikely but possible problem would be a one way valve or hold valve that slowly leaks off. If the system had a one way valve that was positioned up high in the system, over time it might leak off and cause too much fluid go to the take up tank causing it to overfill.

They make a power sterring fluid and transmissm fliud that have trace maker in it get it auto part stores

Hello lewby,

Firstly, are you sure the tank is not rubbing on anything as it is used, like wheels, and or the vibrating engine, muffler etc.

I suggest you give it a very good clean and pay particular attention to possible leak points. Bear in mind anywhere the rubber pipe changes to a steel one and where the steel or rubber goes under or through a 'bulkhead' or frame member.

Before you next use it, rap some kind of tissue or absorbent paper round the pipe joints and where it goes into the Tank. To keep it on use some tape.

This and the sticky tape should be applied after it has dried.

The leak will be obvious when it next happens because of the colour of the oil.. You may find the blue absorbent Engineering 'wipe' type thick soft blue paper may be easier to see.

I have used the trick twice and it does work. But the surface must be clean of water and any oils before the paper is applied. Of course you can take oil the paper and tape off when you find the leak.

Good luck,

Take care.

The most common leak we had on the county's fleet of dumps was the pump shaft seals. A short stack of chevron shaped rings that were on the rotating shaft connected to the PTO. But these were easy to see, because of the location.

What was less common, but harder to find was hydraulic hose failures. Because the lift cylinder is working at it''s hardest when the dump is full, it mat not show up when the body is empty. Try the cleansing routine, send it out for one load, and then recheck. A small pin hole leak will seep fluid for a long time before the reservoir is too low to work.

Good luck, and be careful the oil can shoot right through your skin if allowed to. That can enter your blood system if that happens.