32LC Bucket Failed

[ezslim]

Hi Gang,

Need some help diagnosing a problem with my 2005 TN75DA 4RM tractor with joystick mount bucket controls and a 32 LC loader. While digging out some drainage swails, I was "scooping" with the bucket and got a hard "bang." From then on, the bucket just free-floated (hung down rather sadly, swinging with every bounce). With the motor at full rpm, and the bucket commanded to scoop (cutting edge up), I only get some turbulence in the valve and no up-action. The "dump" action seems to still work under pressure. When I command "scoop" it just leans forward a little, but has no real power to lift the bucket. The main fork cylinders still lift the whole assembly, so I was able to get the tractor back to my shop. I checked the easy stuff first and disconnected each feed line to check for problems. I found a small piece of thin black O-ring in the bucket-side quick-connect of the blue (bucket base) circuit. Then things got expensive...

Based on a phone call to the parts counter, I bought a new, $945 valve assembly and spent the afternoon reattaching fittings and controls. When I fired it up, I got the same problem. I thought there may be air in the lines (though I can't imagine a 3,000 psi system couldn't purge itself, especially since the main fork lift still worked), so I cracked a fitting on the left bucket cylinder and fired it up. I got the same failure and was surprised the "leak" I created wasn't higher pressure.

The problem acts like a tripped relief valve, but I don't see anything between the new valve and the cylinder. Anyone know if one failed cylinder would cripple both? Is there a pressure relief someplace in-line? Is there a proper procedure to bleed air in the system? At this point, I am facing purchase/rebuild of the cylinders unless one of the experts out there has a recommendation. I appreciate any help you can offer. The nearest New Holland dealer is two hours away and very pricey.

Thanks,
Slim

 

[Jbrink64]

Sounds like a piston got pulled off one of the bucket cyl rods. That was probably the pop you heard.

One piston fails, neither works. They fail because there is no relief between the cyl and valve.

Remove the pins connecting the rod to the bucket linkage. The failed side will allow free movement, sometimes the rod can just be pulled out.

 

[Jerry/MT]

Hi Gang,

Need some help diagnosing a problem with my 2005 TN75DA 4RM tractor with joystick mount bucket controls and a 32 LC loader. While digging out some drainage swails, I was "scooping" with the bucket and got a hard "bang." From then on, the bucket just free-floated (hung down rather sadly, swinging with every bounce). With the motor at full rpm, and the bucket commanded to scoop (cutting edge up), I only get some turbulence in the valve and no up-action. The "dump" action seems to still work under pressure. When I command "scoop" it just leans forward a little, but has no real power to lift the bucket. The main fork cylinders still lift the whole assembly, so I was able to get the tractor back to my shop. I checked the easy stuff first and disconnected each feed line to check for problems. I found a small piece of thin black O-ring in the bucket-side quick-connect of the blue (bucket base) circuit. Then things got expensive...

Based on a phone call to the parts counter, I bought a new, $945 valve assembly and spent the afternoon reattaching fittings and controls. When I fired it up, I got the same problem. I thought there may be air in the lines (though I can't imagine a 3,000 psi system couldn't purge itself, especially since the main fork lift still worked), so I cracked a fitting on the left bucket cylinder and fired it up. I got the same failure and was surprised the "leak" I created wasn't higher pressure.

The problem acts like a tripped relief valve, but I don't see anything between the new valve and the cylinder. Anyone know if one failed cylinder would cripple both? Is there a pressure relief someplace in-line? Is there a proper procedure to bleed air in the system? At this point, I am facing purchase/rebuild of the cylinders unless one of the experts out there has a recommendation. I appreciate any help you can offer. The nearest New Holland dealer is two hours away and very pricey.

Thanks,
Slim

You should have to bleed the system. Just cycling the hydraulics should purge any air out.
As I understand the problem, the bucket won't curl (raise the cutting edge up). Do you have a mid mount valve? If so ,are the loader connections seated properly? Are any of the hoses between the valve and cylinders damaged or blocked?
I wonder if you blew the seal(s) on the curl cylinder(s)? If you can put a "T" in the line where it connects to the curl cylinder and put a pressure gauge( 0-5000 psi gauge) in it, I would think if the seals were shot you just be bypassing flow around the piston when you tried to curl the bucket and wouldn't develop much pressure in that direction. The dump seals might still be useful because they seal in the other direction.So when you dump you'd have pressure. I'm just kind of thinking out loud, here.

 

[ezslim]

Thanks for the reply. The connections were sound (and I even replaced a couple of the male hose ends just for good measure). Hoses and hard-piping all look good with no obvious damage. When I pulled the hoses off the right side bucket cylinder, - in a vertical position, the lower fitting continued to dribble-leak for over half an hour - not connected to the tractor. Seems something is leaking internally and might account for the low/no pressure as well as the O-ring fragment I found in the line. I think I'll pull both cylinders off and find a good hydraulic shop and see if they can repack/rebuild them. $1100 a side for replacements is not affordable, especially after buying a valve I didn;t need. This is getting pricey...

 

[jimmysisson]

MUCH cheaper to rebuild, find a hydraulic shop.
Jim

 

[Jerry/MT]

Thanks for the reply. The connections were sound (and I even replaced a couple of the male hose ends just for good measure). Hoses and hard-piping all look good with no obvious damage. When I pulled the hoses off the right side bucket cylinder, - in a vertical position, the lower fitting continued to dribble-leak for over half an hour - not connected to the tractor. Seems something is leaking internally and might account for the low/no pressure as well as the O-ring fragment I found in the line. I think I'll pull both cylinders off and find a good hydraulic shop and see if they can repack/rebuild them. $1100 a side for replacements is not affordable, especially after buying a valve I didn;t need. This is getting pricey...

$1100 for a curl cylinder! They're pretty proud of that! If you have to do that , you can certainly find a replacement cheaper than that.

There's no reason to replace the cylinder unless it's damaged internally so repacking it is the way to go. Your hydraulic shop will be able to check it out. I worked on industrial equipment in a steel mill when I was working my way through engineering school and that equipment was rode hard and put up wet. In the three years I worked there, I never saw a hydraulic cylinder fail except for the piston seals. I think it's a common problem whe you over load it.

Any chance you could return the valve? At $945, that's an expensive lesson!

 

[Jbrink64]

Gut feeling says the nut pulled off the end of the rod.

 

[Jerry/MT]

Gut feeling says the nut pulled off the end of the rod.

You must have seen that happen before. I would think that's a pretty unusual failure.

 

[Jbrink64]

With the digging Ezslim was doing, and the description of the problem, coupled with the lack of circuit relief valves draws my conclusion.
It also happens when pushing snow and striking a curb.

 

[ezslim]

Thanks for all the info. Based on needing the tractor in service, I bit the bullet and ordered one replacement cylinder. If anyone knows a good (trustworthy) hydraulic shop in central VA or DC/Baltimore area, please let me know. Maybe I can refurb the bad one once I figure out which one failed - Looks like I'll need a spare if this is a common failure. If I can get it rebuilt, I'll let y'all know what the post-mortem reveals. Thanks again to all!