Hesitation in Hydraulics Off Topic Q - Update
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=193810
Printed Date: 25 Aug 2025 at 11:43am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: Hesitation in Hydraulics Off Topic Q - Update
Posted By: Dave(inMA)
Subject: Hesitation in Hydraulics Off Topic Q - Update
Date Posted: 28 Feb 2023 at 6:32pm
|
I have a JD 3520 with a hydrostatic transmission. The FEL has an intermittent hesitation when rising. I can hear/feel/see it. The hydraulic fluid is up to the full level. I'm wondering what might be causing this. Could it be water in the hydraulics caused by condensation? Or is this maybe a hydraulic pump issue?
Any suggestions would be greatly appreciated! Thanks much.
Update - hesitation cured - see March 9 post.
-------------
WC, CA, D14, WD45
|
Replies:
Posted By: steve(ill)
Date Posted: 02 Mar 2023 at 9:45am
water will normally mix with the hydraulic oils so it will turn a dirty light brown color.. Keeping the water in suspension is suppose to cause less problems, than letting it collect at the bottom of the tank by the suction tube... This normally is not a big problem unless it gets cold and the water turns to ice crystals... but if you get TOO much water then the oil turns more to sludge and can plug up ports / valves........... Look at the oil, or drain off a cup and see what it looks like.. If it looks like OIL, then there is no water contamination.. If it looks like chocolate milk mixed with cottage cheese, then you should change it.
-------------
Like them all, but love the "B"s.
|
Posted By: steve(ill)
Date Posted: 02 Mar 2023 at 9:49am
if you can "feel" the vibration and "hear" the pump momentarily squeel, it is normally cavitation.. That can be caused by too thick of oil ( too cold or sludge/water).. or a suction hose from tank to the pump is kinked, or collapsed ( even peeling apart internal) , os something plugging the suction screen .... normally at bottom of the tank.
-------------
Like them all, but love the "B"s.
|
Posted By: Joe(TX)
Date Posted: 02 Mar 2023 at 10:32am
Could be air in the lines. My 190 will do that sometimes when first started. My power beyond valve will bleed down some.
-------------
1970 190XT, 1973 200, 1962 D-19 Diesel, 1979 7010, 1957 WD45, 1950 WD, 1961 D17, Speed Patrol, D14, All crop 66 big bin, 180 diesel, 1970 170 diesel, FP80 forklift. Gleaner A
|
Posted By: Steve in NJ
Date Posted: 02 Mar 2023 at 1:35pm
|
Dave, Sounds to me like it's air in the system to me as well. I"m wit' Joe on that one.....See if there's a bleed in the return line going back to the tranny. In order to get the system bled properly, the system needs to be hot. Use a long wrench on the bleed! Keep your skin away from and pressurized hydraulic system.
Steve@B&B
-------------
39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife
|
Posted By: Dave(inMA)
Date Posted: 03 Mar 2023 at 9:43am
|
Thanks, guys. I really appreciate the diagnoses and suggestions. I'll let you know what I find.
Dave
-------------
WC, CA, D14, WD45
|
Posted By: HudCo
Date Posted: 03 Mar 2023 at 9:57am
|
the suction screen in the bottom is clogged
|
Posted By: AC7060IL
Date Posted: 04 Mar 2023 at 9:35am
|
https://m.youtube.com/watch?v=mNJQvTFTu8M" rel="nofollow - https://m.youtube.com/watch?v=mNJQvTFTu8M
|
Posted By: Dave(inMA)
Date Posted: 04 Mar 2023 at 5:48pm
"Suction screen" sounds like it's internal to the tractor. I know that this is a JD we're talking about, but does anyone have information about accessing the screen? Thanks!
-------------
WC, CA, D14, WD45
|
Posted By: Stan R
Date Posted: 04 Mar 2023 at 5:58pm
|
I'd start with any "external" hydraulic filters (if any) before going into the guts of the tractor. Owners manual would be helpful to verify.
|
Posted By: Dave(inMA)
Date Posted: 04 Mar 2023 at 6:22pm
|
Good point. The manual only mentions two filters, both external. No mention of a suction screen. There's a filter that sits in a case that's part of the hydrostatic tranny and an in-line filter in the return line. I will drain the fluid, replace the main filter, and clean the in-line filter....all per the book.
Just in case, I'll ask about the suction screen when I pick up parts at the local JD emporium.
-------------
WC, CA, D14, WD45
|
Posted By: steve(ill)
Date Posted: 04 Mar 2023 at 8:22pm
|
check out this movie at 16:20 mark .......... not sure if this is the hydraulics or trans filter..
https://www.youtube.com/watch?v=brw9WfifSw8" rel="nofollow - https://www.youtube.com/watch?v=brw9WfifSw8
-------------
Like them all, but love the "B"s.
|
Posted By: HudCo
Date Posted: 04 Mar 2023 at 9:02pm
|
most of the john deere tractors we work on here the suction can be mremoved by removing a external suction hose or a large plug or cover on the left or right side of the rearend housing i dont know about your model without getting in the jd book but i do see alot of clogged suction screens thats almost where i start looking if things sound weird or act jerkey and mostly the oil is all milky and needs changed anyways also the things you find down in or by the suction screen will give you a good idea on the shape of things inside their
|
Posted By: HudCo
Date Posted: 04 Mar 2023 at 9:19pm
|
i just looked it up thats just a little guy the filter housing number is lva12678 the element number is lva13065 looks like its on the front othe trans and has the suction line coming out the top housing is held on by to bolts anit looks like to orings may be required
|
Posted By: Dave(inMA)
Date Posted: 05 Mar 2023 at 1:04am
Hudco and Steve, thanks a lot for researching this! LVA13065 is the big sucker in the tranny that gets pulled out when the fellow starts draining the tranny. I have that filter - it's the one I mentioned in my last post.
-------------
WC, CA, D14, WD45
|
Posted By: Dave(inMA)
Date Posted: 09 Mar 2023 at 6:10pm
|
I'm back with an update. This afternoon I drained the eHydro oil, replaced the filter, cleaned the supply return filter and refilled the tranny. The oil varied in appearance - the first gallon or so looked like nice healthy hydraulic fluid. But some of the fluid looked almost black, and some seemed to have a watery appearance. With new fluid on board, the FEL hesitation is gone. This tractor has about 780 hours on it - the tranny fluid was changed about 100 hours ago in 2018 (yup, it's a low-use machine). Hopefully it'll be good for a few years!
Thanks much to all of you who responded to this thread. It's great to get advice that works from the Orange community - even when the machine is green!!
Dave
-------------
WC, CA, D14, WD45
|
|