8n 3 point lift won't work right

rick gootee · Jun 16, 2011

i have rebuilt the pump put new saftey valve and on the top end have put piston and rings and gaskets and still i can not control the lift it also will not stay up when out of gear what needs to be done or get a new pump ? thanks rick

JMOR · Jun 16, 2011

(quoted from post at 14:43:53 06/16/11) i have rebuilt the pump put new saftey valve and on the top end have put piston and rings and gaskets and still i can not control the lift it also will not stay up when out of gear what needs to be done or get a new pump ? thanks rick

hen you kick it out of gear or kill engine, the pump stops runnig. It is no longer available to 'make up' for leaks, which is the reason lift falls. In this diagram, I have labeled 9 potential leak points. The check & relief valves and the Exhaust Control valves are located in the pump casting, all the other potential leak points are outside the pump assembly. You have to run down each of the 9 and find the culprit.

Anonymous-0 · Jun 16, 2011

it will not hold or stay up when running when i hook my bush hog

souNdguy · Jun 16, 2011

look at jomors diagram and ID the laeks.

IMHO.. the 3 metal ring piston setup, once the cyl bore is worn is way substandard. the oring / naa piston is a better setup at that point.

soundguy

JMOR · Jun 16, 2011

(quoted from post at 16:41:08 06/16/11) it will not hold or stay up when running when i hook my bush hog

load on the lift just makes the pressure higher & whatever leaks exist even worse, to the point that even running the pump can't keep up with leak volume. Find & fix leaks, then if still won't lift heavy load, but will hold a load once lifted, then pump may need work, too.

Dell (WA) · Jun 16, 2011

Rick.......yep, you do know that unless yer PTO operated hydraulic pump is OFF, you can NOT couple yer brushhogg to yer PTO shaft. (lever behind yer left heel) And surprizingly enuff, when yer PTO is OFF, guess what??? No pumpie; No liftie. ........sheesh

Ennytime you have "hydraulic issues", remove yer 6"-roundy dipstick plate behind yer right heel and look fer squirts. You gott squirts? fixx'em. Simple, eh? ........Dell

rick gootee · Jun 17, 2011

i have been looking for any leaks on the lift and when i drop the lift it leaks from the exhaust valve only on the way down and i don't know where to look for the check valve as the #2 place to look for leaks . have unit all the way out and it does leak on the way out of the piston ram on the top cover so going to put in new o ring piston . didn't see any other leaks

JMOR · Jun 17, 2011

(quoted from post at 13:23:38 06/17/11) i have been looking for any leaks on the lift and when i drop the lift it leaks from the exhaust valve only on the way down and i don't know where to look for the check valve as the #2 place to look for leaks . have unit all the way out and it does leak on the way out of the piston ram on the top cover so going to put in new o ring piston . didn't see any other leaks

"and i don't know where to look for the check valve as the #2 place to look for leaks"......there is no easy way to observe for a check valve leak. Almost nothing is impossible with enough time, money, effort, but here you would need to block off the pump outlet port, close the exhaust control valve, remove the inlet/outlet valve clamp & plugs so that you could observe for flow back past the check valve & into area above outlet valve while pressurizing the corner test port. May never have been done??
"Leak" out of exhaust control valve while lowering is the normal path for dumping ram cylinder during lowering.

8n 3 point lift won't work right

rick gootee

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JMOR

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Anonymous-0

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souNdguy

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JMOR

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Dell (WA)

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rick gootee

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JMOR

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