jerky hydrolics on fel

[namesray]

my friend just aquired a used john deere 4410 tractor with fel. great shape, well taken care of, and only lightly used. problem he is having is the fel controls are very jerky. runs smooth at idle, but as soon as throttle is added they become jerky. he checked the fluid and it was down slightly in sight glass and filled to correct level, but this did not fix anything. still jerky. the tractor has not been used much and hardly at all recently. i thought he should flush the fluid and change the filters, do to possible condensation/water build up. also i thought maybe the problem might be sticky valves, but not sure. tried the search here at tbn, but i must not be very good at using it as i have problems with the search here. typed in "jerky hydrolics" and only 2 results came up and they were no help. what do you guys think. help/knowlege is very appreciated.

 

[7snakes]

Um, spelling counts on searches(hydraulic).

 

[J_J]

Air in the cyl is the usual problem.


Cycle all the cyl, sometimes it might take up to 5 or 6 cycles to purge all the air.

Excerpt:

CYLINDERS
TROUBLE CAUSE REMEDY
ERRATIC
ACTION
1. Valves sticking or binding
2. Cylinder sticking or binding
3. Sluggish operation during
warm-up period
4. Pilot control pressure too low
5. Internal leakage in cylinder
6. Air in system
1. Check for dirt or gummy deposit. Check for contamination of
oil. Check for air in system. Check for worn parts. Excessive
wear may be due to oil contamination.
2. Check for dirt, gummy deposits or air leaks as above. Check
for misalignment, worn parts or defective packing.
3. Viscosity of oil too high or pour point too high at starting
temperature. Change to oil with lower viscosity or better
viscosity index and lower pour point. An immersion heater
placed in the oil may help under severe cold conditions.
4. Control line may be too small, or metering choke valve not
working properly.
5. Repair or replace worn parts and loose packing. Check oil to
see that viscosity is not too low. Check for excessive
contamination or wear.
6. Bleed air and check for leaks. Check to see that oil intake is
well below surface of oil in reservoir. Check pump packing and
line connections on intake side by pouring hydraulic oil over
suspected leak. If noise stops, the leak has been located.
Tighten joints or change packing or gaskets where necessary.

 

[namesray]

Um, spelling counts on searches(hydraulic).

:laughing: you're right. my bad. like i said, i am not very good with computers and spelling for that matter.:laughing: thanks for the lesson. might help me with future searches.

 

[namesray]

Air in the cyl is the usual problem.


Cycle all the cyl, sometimes it might take up to 5 or 6 cycles to purge all the air.

Excerpt:

CYLINDERS
TROUBLE CAUSE REMEDY
ERRATIC
ACTION
1. Valves sticking or binding
2. Cylinder sticking or binding
3. Sluggish operation during
warm-up period
4. Pilot control pressure too low
5. Internal leakage in cylinder
6. Air in system
1. Check for dirt or gummy deposit. Check for contamination of
oil. Check for air in system. Check for worn parts. Excessive
wear may be due to oil contamination.
2. Check for dirt, gummy deposits or air leaks as above. Check
for misalignment, worn parts or defective packing.
3. Viscosity of oil too high or pour point too high at starting
temperature. Change to oil with lower viscosity or better
viscosity index and lower pour point. An immersion heater
placed in the oil may help under severe cold conditions.
4. Control line may be too small, or metering choke valve not
working properly.
5. Repair or replace worn parts and loose packing. Check oil to
see that viscosity is not too low. Check for excessive
contamination or wear.
6. Bleed air and check for leaks. Check to see that oil intake is
well below surface of oil in reservoir. Check pump packing and
line connections on intake side by pouring hydraulic oil over
suspected leak. If noise stops, the leak has been located.
Tighten joints or change packing or gaskets where necessary.

thanks j j. VERY helpful post. answers a lot of questions quicky and very thourough. nice check list to have.:thumbsup:

 

[roman]

JJ is the MAN!! Just reading his replies to others questions is helpful.

Thanks JJ,
Roman