hydraulic problems 70's vintage John Deere 300b loader

   / hydraulic problems 70's vintage John Deere 300b loader #1  

dneufell

New member
Joined
Oct 31, 2008
Messages
19
Location
New Hampshire
Tractor
2002 T7 Terramite
Hello all !!!
Last month I bought a 70's vintage John Deere 300b tractor with a loader and a cab. After 1/2 hour of using it, the hydraulics start to shutter. If I let it rest for 10 min it will start to work again. I have changed the hydraulic oil and both filters. I also (watched a youtube vid) pulled out the long screen in the filter housing and cleaned it....very little goop. Book says it takes 8.5 gal of fluid plus 2.5 gal for loader. I put all 11 gal in the filler hole in the middle of the rear pumpkin behind the seat. What about that little round tank under the hood behind the radiator? Weird....if I shut the machine off and go to check the dipstick (below my right foot) oil will pour out of it ! I have to start the machine to check it (sucks the oil level down)
So before and after the oil change it acts about the same...shutters after 1/2 hour or so.....I also have a question about the accumulator.......
Thank you very much.....Dean
 
   / hydraulic problems 70's vintage John Deere 300b loader #2  
dneufell
Hydraulic pressure problem might be detected if you get a pressure gauge hooked up and watch the pressures over that 1/2 hour..

What did the hyd. oil look like what drained? Any milky look to it?

Is the tranny fluid the same as the hydraulic system on the 300B ?
 
   / hydraulic problems 70's vintage John Deere 300b loader
  • Thread Starter
#3  
   / hydraulic problems 70's vintage John Deere 300b loader #4  
1518538540176.jpg

Transmission pump
 
   / hydraulic problems 70's vintage John Deere 300b loader #6  
1518538611648.jpg

Pressure control valve. I'm betting you have a issue here. Buy like stated before put a gauge on it
 
   / hydraulic problems 70's vintage John Deere 300b loader #8  
This tractor should have the radial piston pump. I'd suggest getting a tech manual for this machine.
 
   / hydraulic problems 70's vintage John Deere 300b loader #9  
1518539082275.jpggauge readings are taken from here
 
   / hydraulic problems 70's vintage John Deere 300b loader
  • Thread Starter
#10  
ok.....looks like I have to buy a gauge and some fittings.
all those pumps look difficult to replace :(
I will look thru the tractor threads to find a place to buy the gauge and what size fittings
thank you very much
 
 
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