JD 70 FEL Hydraulics Problem- Need Advice

[UBHappy]

Hello,
I am new to this forum. I found TractorByNet when I was troubleshooting a problem with a JD 70 FEL attached to a JD 755 compact tractor. I have owned this equipment since 1992 and have used it for landscaping, building stone walls, transplanting trees, field mowing, and snow removal on my home properties in Eastern Massachusetts and now in Southeast Pennsylvania. The tractor was stored in a shed for the 13 years in Massachusetts but is stored outdoors for the past 5 years in Pennsylvania.

The tractor and FEL has run almost flawlessly until the very recent blizzard that hit the mid-Atlantic on 2/7/2010. While I was using the FEL blade to scrape frozen snow from the driveway, the FEL boom became stuck in the down position. This happened once in the previous 12/19/2009 blizzard but I was able to clear the problem by cycling the SCV lever through several up/down cycles. This time the FEL boom would not budge and I had to ditch the tractor and finish the snow removal by hand.

I checked the hydraulics troubleshooting section of the JD 755 tech manual. I was able to eliminate many potential causes but I was not able to pinpoint the exact problem. I went online and found this forum on TBN. I found some very good advice by many of the forum members, particularly the advice of kennyd to always check the simple things first: hydraulic fluid level and re-set the FEL quick-disconnect (QD) hydraulic fittings. I removed all four FEL QDs and found that the seal valve on the R3 QD (male connector) was not properly seated (the nose seal was cocked when it closed). I disconnected the QD fitting from the hydraulic hose and cleaned the fitting in acetone. The QD seemed to seal properly after cleaning. I re-assembled the QD onto the hydraulic hose and then reconnected all of the FEL QDs. The FEL is now running very smooth and I am back in business for the next blizzard on 2/9/2010. Many thanks to kennyd and other forum members who provided very helpful advice for troubleshooting FEL hydraulics!

This is the first time that I found a problem in a QD in over 18 years. I leave the 70 FEL on the 755 all of the time and have never had the need to touch the FEL QDs. Any advice as to what caused the R3 QD seal valve to get stuck and what can be done to prevent this in the future?

 

[B8FISH]

My first thought would be condensation or snow build-up? Since it has only happened twice, and both times during snow/blizzard conditions, I would suspect some condensation in the hydraulic fluid that is freezing and then getting stuck in the fittings--or maybe just snow getting driven into the fittings while plowing and forcing the QD open.

 

[kennyd]

Welcome to TBN UB

Glad I could help, even without knowing it

My guess is it got kicked or hit by a chunk of ice or snow and the collar moved back just enough to unseat the QD, but not pop the male nipple out.

 

[RoyJackson]

Running into hard packed snow could dislodge the QD. It doesn't take much. And, the QD may have not been seated all the way.
Not often that they wear out, but it does happen...

 

[RRacing]

Just on a very odd note, You don't think its stuck in Float mode ???

 

[UBHappy]

Thanks for all of the feedback. At first I thought that the snow from the last two blizzards could not have affected the QDs since I tackled many larger snowstorms in my 13 years in Massachusetts with no problem. After reading your comments, I then realized that snow was packed around the QDs in these last two blizzards because the tractor was stored outdoors in Pennsylvania. It is less likely that the QDs were ever packed in snow in Massachusetts because the tractor was always stored in a protected shed.

In the last two mid-Atlantic blizzards, the QDs were definitely covered in snow drifts while stored outdoors. I did not clear the packed snow from the QDs before plowing either time. I think that in the first blizzard the R3 QD may have been partially dislodged because of the packed snow which may have turned to ice. As suggested by B8FISH, kennyd and Roy Jackson, a chunk of ice may have hit the snow incrusted QD during plowing. That might explain how the boom became temporarily stuck in the down position in the first blizzard in December. When I thought I corrected the problem by cycling the SCV lever, the R3 QD may have only partially re-seated itself. In the second blizzard in February, the R3 QD may again have been partially dislodged by packed snow and ice, but this time the male nipple valve became cocked and could not properly re-seat itself.

As I mentioned in my first post, the FEL problem was solved when I took apart the R3 QD and cleaned it. The FEL seems to running just fine now and there is no indication that it is stuck in float mode.

The lesson that I learned from all of this is not to take the QDs for granted. I will be more careful to clear snow away from the QDs before I start to plow. I will also pay more attention and inspect the QDs during regular tractor maintenance.

Thanks to everyone for your help.

 

[Kevin M]

Welcome and you have stumbled across one of the best sites on the web (I would consider it the best ).

 

[UBHappy]

Well, we got hit with the third blizzard of the season on Tuesday and Wednesday (2/9-2/10/2010) and set a record for the most snowfall ever in Southeast Pennsylvania! Unfortunately my JD 70 FEL became stuck again and could remove snow during this major storm. Fortunately I had a vintage (1967) Ariens snow thrower that I had not used in many years. After a bit of gas and TLC (new spark plug, oil change, quick lube of rotating parts), the Ariens bailed me out.

On Saturday, I tried to troubleshoot the R3 and R4 QDs which control the FEL boom up/down. I noticed that the snap ring that secures the R3 female QD to the tractor mounting plate had popped out of the groove and the QD was very loose in the mounting plate. I can see how this fitting could vibrate and cause the QD to pop open or at least become unseated. I took the R3 female QD off, cleaned it in acetone and inspected it. The male part of the internal poppet valve appears to have some wear (possibly due to the constant vibration of the QD), and the internal poppet valve was also cocked. I tried to reseat the internal poppet valve to a straight position. I then mounted the R3 QD fitting back on the tractor with the snap ring in place to hold the fitting tight to the tractor mounting plate. I plan to order a replacement female QD fitting from my JD dealer on Monday.

As I was reconnecting the R4 QD, I noticed that there was residual pressure in the R4 FEL hydraulic line. I opened the hydraulic hose connection at the R4 male QD to bleed down the line and collected the hydraulic fluid that drained from this line. I noticed that the drained hydraulic fluid from this line was an awful mixture of dark hydraulic fluid and a cream colored liquid. I am guessing that this cream colored liquid was an emulsion of hydraulic fluid and water. I am guessing that small amounts of water gets into the hydraulic cylinder over long periods of time (about 15 years) from outdoor operation and storage, and that this water then mixed with the hydraulic oil to form a cream colored emulsion.

After draining as much of the R4 hydraulic line as possible, I re-assembled the R4 QD and started up the tractor. I cycled the FEL boom about a dozen times to remove any trapped air and then began using the FEL to remove some of the snow piles that the street plows left behind. I ran the FEL for about an hour with absolutely no problem!

Based on this experience, I plan to do the following FEL hydraulic system maintenance:
1) Replace the R3 female QD
2) Drain the R1, R2 and R3 hydraulic lines to remove any built up oil/ water emulsion

Any advice as to other FEL hydraulic system maintenance that I should do? For example, is there a better procedure to completely flush out bad hydraulic fluid from the cylinders? Should I try to inspect the inside of the FEL steel hydraulic lines and cylinders for corrosion due to the oil/ water emulsion? Your experience and advice is welcomed!

 

[beenthere]

Only additional advice...park it under cover.

Protect your investment. (just my opinion )

Welcome to the forum.

 

[kennyd]

The only advice to drain the cylinders is to take the QD's and hoses off, then cycle them manually. The cylinders are easy to remove, then you can use air to purge the lines.

This fluid never really get's back to the sump-it stay's in there all the time so I am not surprised by your finding of nasty fluid in there.