Foaming hydraulic oil excess

[josharb87]

Jensen 530 vari-track, checked the hydraulic oil level (when very cold) and topped up yesterday morning (couldn't see it in the glass which seems "normal" when cold) but it seeps oil from the stop-bar plunger (looking at this on monday), so topped up anyway to mid-way between min and max. turned machine on and after a few minutes on a fast idle it chucked out a bit of oil from the breather and after showed to be more than full in the viewing glass.

used the machine for about 2 hours yesterday.

Today, on warm up (been out all night again in -15c it done the same, but this time chucking out foaming oil, quite a bit, then settled down and worked fine

Why does it do this? is the level in the viewing glass for warm oil? 

 

@Mike Hill, @PeteB?

 

 

[Mike Hill]

Two things mate.

 

1) you hdo is english stuff not designed to be viscous at low temps. Drain and change.

 

2) overfilling will cause it to foam up too. The filler lid on mine is a breather and as the oil is forced through it when overfilled it foams.

 

I take it you have acceptable function on the rollers and you just filled the oil level to the bottom of the sight glass?

[Gary Prentice]

Pretty sure that the viewing glass is for cold oil.  Have you checked the filter, as our forst chucked a load of oil out this week due to a combination of a severely dirty filter and drawing air in at the pump - due to worn seals around the pulley shaft.

[josharb87]

Cheers for the quick replies!

 

It is still on the uk hyd oil, never any problem with roller or track function, or last winter, a little slow when cold but normally let the machine warm up before going full revs/chipping. 

 

Fillers the breather on this one too, just never noticed the excess oil foaming, even in the filler neck before.

 

I filled up to midway in the sight glass, but it seems to chuck oil out if theres any oil visible in the sight glass. 

 

What was "abnormal" was not that it chucked out oil after potentially over filling, thats fine, but that it done it again today in the morning without topping up, even after chipping for 2 hours yesterday, id thought the oil level had sorted itself out yesterday morning!

 

I'll change oil and see if i can find a filter on Monday. tracks in for changing the oil?

[dig-dug-dan]

I had a similar issue on one of my crushers, hydraulic oil coming out the breather.

Turned out to be a faulty pressure relief valve in the end. 

[Mike Hill]

Are you chipping with the flow valve wide open or have you slowed down the rollers?

 

The filter is in the grey housing on the back of the cutting disc housing on mine,the relief valve is on I think the left had side close to the filter housing.Its Brass coloured and has a knurled knob on the top of it.

 

You can disconnect the return line to the pump and idle the machine untill no more oil comes out,I cant remember if there is a drain on the oil tank?

 

 

[PeteB]

Foaming or frothy oil could be 'cavitation', air is being mixed with the oil as to it is circulated. Usually from a faulty pump (as Gary says) or a loose hose fitting. Is the oil a milky colour on rest? Does it clear after a long rest? It isn't turning to a mayonnaise with water and oil mixed together?

[openspaceman]

5 hours ago, Gary Prentice said:

our forst chucked a load of oil out this week due to a combination of a severely dirty filter and drawing air in at the pump - due to worn seals around the pulley shaft.

Did you replace the outrigger bearing with the pump? Belt tension correct?

 

Oil seals are effective in one direction not the other so in cold weather it pays to warm up the machine gently to prevent a depression at the inlet port which pulls air past the seal. Once air is in the system it cannot settle out and hence overflows the breather. Because of the way the side pieces of a gear pumps are pressure compensated often the damage is done as they get forced sideways onto the gears.

 

Cavitation is a separate phenomena, also worse as oil thickens, where the depression behind the gears causes a vacuum bubble which then collapses,this can erode the metal. The first grapple loaders I saw had pressurised tanks to try and prevent cavitation, perhaps that was because they came from Sweden.

 

Both result in loss of power.