SSB Farm Tractor Parts, Manuals & Antique TractorsAftermarket Farm & Old Antique Tractor PartsTractor Service, Repair & Owners Operators Manual ShopTractor ImplementsTractor SeatsTractor Front End LoadersPedal Toy Tractors Farm Tractors For Sale ClassifiedsAntique Tractors For Sale ClassifiedsTractors Forum - Help & AdviceTractor, Gardening, Mowers & Outdoor Equipment BooksTractor ProductsContact Us
How much is your farm tractor worth? Find resale prices for tractors built from 1939 through today, with complete specifications and serial numbers. Save 15% on our Official Tractor Blue Book sale!

Search This Message Board:

7810 and 7420 hyd hiss

tc both these tractors have had this problem (hyd hiss at pump but the noise can be canceled by playing with levers /joystick ) 74 got to the place it would overheat oil when running orbit motor. dealer tore down replaced thousands of dollars in parts on rear scv stack /brake oring etc [bill $6000] found out that the center mounting 3pt controller block had a sub change in prod. run causing weakness and internal crack(bypassing causing pump to run fullout)dealer thought i was going to foot bill for all the trial and error parts that had been installed! no my cost after fight $1000 plus yr warranty on main pump. 7810 (no 3pt) still hisses thoughts?
Hoss It sounds like after a lot of money, prats, and guessing they got your 7420 to work. as for the 7810 it could be many things but if you can play with the scv levers and get it to stop i'm guessing the stroke plunger in the hyd pump is sticking. I have seen this and you can work the scv levers back and forth and it will neutralize. Just a guess without seeing it.
tc Im guessing this stroke valve controls the output/demand in system when noise momentarily cancels with joystick, steering,brake (any additional demand). one mech mentioned charge pump? another dime valves in stack ,another oring in brake valve. I know that these systems are complicated and may need a trained pro but I hope someone out there may have had similar problems and might save multiple long trips to the dealer
Hoss Probably not the charge pump. Dime valves are possible. The oring in the brake valve usually will let it build up to max pressure gradually you can see this on a pressure gauge in system pressure. The stroke piston usually will neutralise when you work the scv levers back and forth and stay in neutral until the next time it is called on to pump. This is just a few of the simptoms of the problem you have. I know these are a little vague but I hope it helps.
tc "stroke plunger in hyd pump sticking" would this suggest a dismantle and clean, spring/piston replacement thankyou hoss
Hoss Dismantle and inspect the plunger if it is gaulded this could be your problem. I'm not sure about a 7810 but the last one I had do this there was no individual parts for it just a replacement pump. I hope I haven't sent you chasing rabbits that aren't there. These are just some ideas from the problems I have had. Good luck.

Post a Followup

Enter Code Shown Above As it Appears:

Upload Picture (Optional - Choose File):



Sign Up For Our Monthly Special Sales!