L5450: hydraulic warning light

[geneP]

I bought this tractor last winter and it would light the hydraulic warning light when revved up. The manual calls it an "alarm for when the hydraulic filter is clogged". I'm in Mississippi, so I don't think cold oil was/is the culprit here. I changed the filter for a new Kubota hydraulic filter and the light went out. I've put about 60 engine hours on the tractor since. The previous owner assured me the oil was good because it had a leak on the loader and they were always adding oil.

All has been well until this morning I was bush hogging and the light began to slightly glow. I have noticed a switch up near the pump, I guess that is the switch for this light? If so, it must monitor for a vacuum on the suction side of the pump?

When I first got the tractor I mentioned this light to my dealer and he said they are always coming on and Kubota service rep suggests disconnecting the light since the alarms are erroneous.

I don't want to do anything to harm the hydraulic pump. Have any of you had any experience with these lights? If so, what is the fix?

 

[rbargeron]

Hi Gene - my hydraulic pump's vacuum light comes on on colder winter mornings. It goes out a minute or two later as the oil gets a bit warmer. Do you know if the hyd filter has been changed recently? If you have a new filter ready you can swap it quickly without loosing much into the catch pan. Does your machine still have a belly cover? Is the filter accessible? Take care, Dick B

 

[geneP]

Yes, I replaced it with a Kubota filter right after I got it. I cleaned the magnetic trap at the time. It does still have the belly pan on it. The pan slowed down the replacement process and I lost about 5 gallons of oil and replaced it. The dipstick shows the reservoir to be full. The light isn't on full bright, just a flickering glow. Do you think I should replace the filter again?

Thanks for your response.

 

[varmint]

Un-informed observation, which may be shot down or reinforced by someone with more knowledge: maybe the sensor switch is bad, or a wiring terminal is loose? If you pull the wire when it's glowing, you can tell if it's a grounding circuit by measuring voltage from the lead.

 

[geneP]

Hi Gene - my hydraulic pump's vacuum light comes on on colder winter mornings. It goes out a minute or two later as the oil gets a bit warmer. Do you know if the hyd filter has been changed recently? If you have a new filter ready you can swap it quickly without loosing much into the catch pan. Does your machine still have a belly cover? Is the filter accessible? Take care, Dick B

Since yours acts normally, I decided to follow your recipe of new Wal Mart Heavy duty tractor transmission and hydraulic oil with a new filter. I'll never know the condition of the oil until I start with new. In order to get good access to everything for thorough checks, I removed the belly pan. I drained the oil then wiped my finger in the drain hole looking for sludge buildup but didn't find any. Cleaned al the magnets, refilled with new oil and new filter. A trip around the field didn't produce the warning light. Hoping for the best.

 

[rbargeron]

Years ago my L4150 would make a random snapping noise going down the road, making the loader hoses jump with the snapping. KTC had a tech bulletin that transmission gears could make air pockets and send them through the hydraulic system, causing the noise. The solution was a higher recommended oil level. The kit from KTC was complete with a short dipstick !.

If the light comes on again, I'd try adding more oil so the filter has more static head on it. The housings run only about half full - there's plenty of room for a couple extra gallons. Glad you took off the belly plate - they help keep the brush out - but they make it a lot easier to get stuck in mud & snow (ok, more likely just mud in Mississippi )

 

[geneP]

Thanks, Dick. I'll add extra fluid if it happens again.

There are trade-offs on using a belly pan. When I first got the tractor I was in cutover acreage and was glad I had the pan. There is so much exposed linkages, hoses, etc, under the tractor I'm sure I would have damaged something in all the brush and limbs. Hopefully all that is cleaned up now so I will try leaving it off.