JD 300B hydraulics

LionFishSlayer · Oct 2, 2020

Hello and thanks for allowing me to join. Im hoping someone here can help me out. I have a sudden loss of hydraulics on my 300b backhoe. Strangely just as I was finished using it (carrying logs) and was about to shut it off for the day it started making a noise that I thought was the belt squealing. I shut it down came back next day only to find none of the hydraulics work. The fluid was low so I topped that off .. no change, changed filters, still nothing. Now the pump is making a chattering sqeaky type noise but I dont know if it is from air or something mechanical. Forward and reverse are working just no loader or hoe. Anyone have any experience or knowledge of what could cause this pretty much instantly? Thanks.

Tx Jim · Oct 3, 2020

Welcome to TBN
How much oil did you add to get to full mark on dipstick? I suggest to change hyd filters & check/clean sump screen(key 30) if not changed very recently. You should also check filter relief valve(keys 18-20). Check to be sure frt hyd pump shaft turns when engine crankshaft turns because drive coupler has been known to strip on pump shaft.

LionFishSlayer · Oct 3, 2020

Thanks Tx Jim, I added about 3 gallons to get back to full. I already changed filters and will check the screen and relief valve next.

Tx Jim · Oct 4, 2020

You're welcome
Another possibility is debris lodged in seat of frt hyd pump stroke control valve. If foreign debris in SC valve is problem sometimes can be solved by if present on this tractor by turning destroking screw in then out when engine is running.