Air getting in hydraulic system

jhilyer

Member
I have a "modern" tractor, a JD 5303 2WD with front end loader, and I have a problem I can only describe as air in the hydraulic system.

Here's what's happening: At cold start up, everything is fine for say 5-10 minutes. Then I'll start noticing "hitches" in the steering, and also when lifting the front end loader. This will get progressively worse over the span of 2 hours (like when I'm cutting hay).

Let it sit for an hour or so, and it will be fine again.

The only thing I've done lately is top it off with Tractor Supply tranny/hydro fluid, yes I read the back and it said it was good for JD. But maybe this is the problem? I can't say if I had the problem before or after adding this fluid. You only really notice it after running a while.

I do not see anything spraying out like from a leak. I added the fluid only because we ran a leaky log splitter this winter (using tractor hydraulics), and lost some fluid that way.

Any ideas?

Thanks,

- jhilyer
 
Check your suction filter or screen . It may be plugged and the pump is sucking air from a hose fitting.....
 
You could also be having cavitation in the pump do to the oil thinning when hot. It acts a lot like air in the system.

You should do some pressure tests.
 
Pull and clean the pump suction screen,very simple. change the hydraulic filter. My (2008) JD 4320 did the same and this cured the problem.
 
Good suggestions here, but I would also have a look at the rubber hoses used to connect the steel pump inlet line on the RH side of the tractor. There is one hose at the back by the filter and the other is at the pump itself. Yes it is possible for air to be drawn in and not let oil run out.
 

My experience with mixing TSC fluid with another brad was not good, it foamed. Others who have used it by itself had no problems. Since then I have tried not to mix brands of hydraulic oil.

KEH
 
How much TSC oil did you add, and what is the capacity of the system?

Cheap oil is not worth it. Go get a good oil from AGCO, MF, JD, Kubota Case IH or New Holland. Doesn"t matter who, whatever"s cheapest. (provided were talking about straight, regular Trans-Hydraulic Fluid). The TSC stuff is maybe $3/gallon cheaper. That"s $12 vs $15-$16/gal. Your 5303 likely holds about 10 gallons. $120 vs $150-160. I can buy AGCO 821XL for 69.95/5 gal HERE, in Canada. That"s 13.99/gal. Certainly shouldn"t be anymore there.
 
It may be simple like cleaning screen and changing filter.

Unfortunately it may not be simple. I had a JD3350 with same symptoms. Turned out to be a problem with the charge pump in the transmission. Tractor was worth $20,000 and quote from trusted mechanic was about $20,000 to $25,000 to fix the problem. I considered doing the job myself, but thought I might get in too deep. Traded the tractor at a big loss on a new JD
 
Tim

I remember that you helped me on the way to diagnosing this
problem.

Parts were going to cost about $12,000 (JD knows how to charge
here) and some parts were difficult to get.

Labor was also very expensive then (middle of the mining boom
and most good mechanics had headed off to cash in at the
mines). Labor costs have eased off now but are still close to
$100 per hour. The big labor cost was getting the cab off and
getting at transmission.

Traded the 3350 on a new 6330. It is the utility tractor on 4,500
acre grain farms. Main farm work is done by 8000 series (not
mine) JDs in no till system.
 

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