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615 scraper bowl wont lift

Joined
Oct 13, 2020
Messages
6
Location
Michigan
I have 2 46z serial number machines that once loaded wont lift their bowls. We have replaced cables to the bowl control levers, new hydrualic pumps, and rebuilt the valve spools. Cables are within adjustment and we are getting full throw on the valves. At a loss so any ideas would be great. Thanks in advance!
 

Vetech63

Senior Member
Joined
Aug 10, 2016
Messages
6,362
Location
Oklahoma
Have you checked the bowl lift cylinders? Those packings are usually the culprit, either one cylinder or both.
 
Joined
Oct 13, 2020
Messages
6
Location
Michigan
We did replace one lift cylinder too, and the other is weeping. Actually both machines have a cylinder weeping, so Ill dive into it this morning. Appreciate it.
 

Bls repair

Senior Member
Joined
Jan 21, 2017
Messages
1,612
Location
S E Pa
Occupation
Equipment operator,mechanic
Had it happen to me on a 627 . A piece of o ring was stuck it pressure relief..
 

Nige

Senior Member
Joined
Jun 22, 2011
Messages
28,973
Location
G..G..G..Granville.........!! Fetch your cloth.
Try raising the scraper bowl for an extended period of time when the machine fluids are cold - say a couple of minutes.
Carefully touch the bowl cylinder barrels. Is one of them warm around the location where the piston ought to be, or maybe both.?
If that's the case you've found your culprit - leaking cylinder piston seals.
 

.RC.

Senior Member
Joined
Nov 27, 2012
Messages
729
Location
Qld, Australia
Carefully touch the bowl cylinder barrels. Is one of them warm around the location where the piston ought to be, or maybe both.?
If that's the case you've found your culprit - leaking cylinder piston seals.

How would the leaking oil heat the cylinder where the piston is?
 

old-iron-habit

Senior Member
Joined
Nov 22, 2012
Messages
4,233
Location
Moose Lake, MN
Occupation
Retired Cons't. Supt./Hospitals
Got it nipped, the new pump on one of them wasnt working. Took care of one and pressure relief on the other. Thanks guys.


Thanks for letting us know what the culprit was. It cleans the post up nicely and may help someone in the future. Well done.
 

old-iron-habit

Senior Member
Joined
Nov 22, 2012
Messages
4,233
Location
Moose Lake, MN
Occupation
Retired Cons't. Supt./Hospitals
How would the leaking oil heat the cylinder where the piston is?

The high pressure oil leaking past the piston very quickly heats that spot. To find which cylinder is leaking past the piston om a dual cylinder system we have restrained the lift cylinders at midpoint and the leaker is soon found. Often saves pulling the wrong side down.
 

fastline

Senior Member
Joined
Aug 8, 2011
Messages
1,104
Location
OK
How would the leaking oil heat the cylinder where the piston is?

Pressure 1 on one side of cylinder is high. P2 is at tank pressure. When the oils leaks by, it is losing all that energy. It will heat the pistons and cylinder. I can 100% confirm this in a few documented cases. One of which is a ag implement. Has to work way harder than it should to lift. After 15min of work, one cylinder certainly stands out in temperature. That is all I need for confirmation!
 

Nige

Senior Member
Joined
Jun 22, 2011
Messages
28,973
Location
G..G..G..Granville.........!! Fetch your cloth.
How would the leaking oil heat the cylinder where the piston is?
Because if the piston seals are leaking oil will be forced at high pressure through a very small space between the seals and the cylinder barrel. That will create heat - loads of it. Thermal imaging cameras are wonderful for picking up leaking cylinder piston seals.
 
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