1070 hydraulic suction leak

Anonymous-0

Well-known Member
'77 1070 appears to have a suction leak. I have a loader plumbed to the to remotes. Seems a little weak. Hoses pulse and make noise like air in the oil. Inching pedal is grabby at anything above idle. Brakes are grabby. Power shift seems to shift fine. Power steering is fine. I had the pto housing off about 10 hrs ago to replace the pto brake. Rolled pin had fallen out (hole in the shaft worn out). Tractor was fine until just the past hour or so. Thought maybe I had cut the O-ring on the suction pipe but it is fine. Only thing I can think of is the suction pipe is leaking. Any place else to look? Not looking forward to pulling the pto housing again. I find it hard to believe that the pipe would be loose in 10 hours. Oil level is fine. Any ideas?
 
If it is not the O-ring on the suction line behind the pump, or the filter, I think you will have to pull the PTO housing again. Anything in the suction screen last time? Before you pull things appart, hook a 4 foot hose to one of the couplers and run full flow back into the fill hole. Try it both cold and warmed up. If you are pumping air it is easy to tell by the flow from the hose. I had an Eagle Hitch 830 that did that to me once. It took at least 6 times off before I found the trouble. (The suction line did not line up with the pump, and I had to modify the mounting holes to fix the problem. That can not happen to a 70 series.)
 
Thanks for the reply DKase. The suction screen was clean but pretty beat up. If I have it back apart I may try and do something with the screen. It didn't have any holes in it but it had been patched up. Bottom of the case was pretty clean too. Is the filter you refer to the suction screen, or is there another filter I don't know about? I replaced both filters on the side of the transmission when I had it apart. I'll try running oil back in the fill hole to confirm it is air in the oil. Do you know if the port the suction pipe bolts to is submerged in oil? Looking at the parts breakdown it looks low enough that it may be covered, probably eliminating that as a source of air. It will probably be this afternoon before I can confirm air in the oil.
 
So I have no air in the oil using a hose dumping back into the fill hole, but the hole won't take the full output of the remote, if that would make a difference. No pulsing or noise either. Still have the noise and pulsing in the loader hoses. Switched remotes and have the same thing with the loader hoses and same no air result dumping back into the fill hole. Hooked the three point blade up and that set acts the same as the loader. Remotes are running through open center spool valves for both the loader and the blade. There is no noise with the remotes in neutral. Pressure checked one remote and had 1800 psi @1000 rpm which seems a little low? So do I have a problem or is this normal and I just noticed this pulsing? If so, what about the inching pedal grabbing and the brakes? Cold weather? I'm at a loss.
 
Filters are the 2 under the right platform that you changed. Red element goes in the front one, and the white element goes in the back one. MAKE SURE YOU TAKE THE RELIEF VALVE OUT OF THE OLD FILTER AND INSTALL IT IN THE NEW FILTER! The suction line that bolts to the front of the PTO housing would be below the oil for sure if the tractor is headed up hill. Make sure the o-ring on the suction line behind the pump is not leaking.
 

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