Woods backhoe cylinder leaking?

Mousefield · Jun 1, 2010

Hi, I have a 2008 Woods BH70-X backhoe with about 50-60 hours at the most, it is on my Kioti CK35 with 224 hours.

What I did notice a few days ago while cutting some firewood that the backhoe dropped a lot. I had a Douglas Fir log, about 58 inches long and 16 inches in diameter about 3 ft from the ground. Went to sharpen the chainsaw and fill it with gas/oil, when I came back about 10-15 minutes later the backhoe had dropped at least 1 ft. Thought this was as awful lot given the small log was maybe 300 - 400 pounds at the most. Called the dealer and he had me extend the backhoe all the way up and out. Within 24 hours the bucket was on the ground. He is getting hold of Woods as we think the o ring in the main hydraulic cylinder may be leaking. It also does not seem to have the same lift it did before. I have just been told that Woods thinks that the leak-down rate is within tolerance. I do feel it does not have the same lifting capacity.
Anyone else have comments on if this is within tolerance?

AKKAMAAN · Jun 2, 2010

Mousefield said:
Hi, I have a 2008 Woods BH70-X backhoe with about 50-60 hours at the most, it is on my Kioti CK35 with 224 hours.

What I did notice a few days ago while cutting some firewood that the backhoe dropped a lot. I had a Douglas Fir log, about 58 inches long and 16 inches in diameter about 3 ft from the ground. Went to sharpen the chainsaw and fill it with gas/oil, when I came back about 10-15 minutes later the backhoe had dropped at least 1 ft. Thought this was as awful lot given the small log was maybe 300 - 400 pounds at the most. Called the dealer and he had me extend the backhoe all the way up and out. Within 24 hours the bucket was on the ground. He is getting hold of Woods as we think the o ring in the main hydraulic cylinder may be leaking. It also does not seem to have the same lift it did before. I have just been told that Woods thinks that the leak-down rate is within tolerance. I do feel it does not have the same lifting capacity.
Anyone else have comments on if this is within 杯olerance?

Hydraulic cylinder is retracting while lifting the boom, most likely there must be a piston seal leak.

(If cylinder had been extending while lifting, there also must be a leak between the work port lines and return line, either through the spool in the control valve, or through a work port relief valve, if there is such on the circuit....)

My bet is the piston seal...If you have noticed a recent change in performance, keep pushing Woods with a claim on the piston seal.....

It is hard to see the size of the cylinder, so it would be interesting to know the dimensions...like bore, rod and stroke....

make this test....lift and let boom hank in the air fully stretched out, horisontally.....make a line with a sharpie pen on the rod, measure distance as exact as possible...(with in a 32nd of an inch) to the rod end of cylinder....let it sit for 10 minutes (600 secs) and measure again... you can also rig a video camera...and shoot a 10 min video, showing the drift on the cylinder rod........then tell us the result.... we will from that calculate the cc per minute leakage....and go from there.....If you also could T a pressure gauge on the line to the rod side to check the pressure.....

Mousefield · Jun 2, 2010

I will have time on the weekend to really look at this. When you say piston rings do you mean O rings?

Ductape · Jun 2, 2010

I've never timed mine to see how long it would take for it to reach the ground, but it does settle over time. I suspect mine would also be on the ground overnight. I consider it normal...... it certainly doesn't effect anything while the hoe is in use. I lock mine up when my tractor is not being used.

AKKAMAAN · Jun 2, 2010

Mousefield said:
I will have time on the weekend to really look at this. When you say piston rings do you mean O rings?

Sorry I did not say "piston rings", I said "piston seal leak"...
Weather it is a O-ring style seal or something else is unknown just now...

If manufacturer defends him self by saying the leakage is with in the "tolerance", he should be able to tell the tolerances....like a max volume per minute at a certain pressure....

Owners manual
RV setting 2030psi

BTW...I found the owners manual...and it is a very nice documentation...all parts in explosion pictures....still cant tell what type of piston seal they are using....the groove in the piston seems wide and not so deep...do not look like O-ring...
Picture from manual...

AKKAMAAN · Jun 2, 2010

AKKAMAAN said:
make this test....lift and let boom hank in the air fully stretched out, horisontally.....make a line with a sharpie pen on the rod, measure distance as exact as possible...(with in a 32nd of an inch) to the rod end of cylinder....let it sit for 10 minutes (600 secs) and measure again... you can also rig a video camera...and shoot a 10 min video, showing the drift on the cylinder rod........then tell us the result.... we will from that calculate the cc per minute leakage....and go from there.....If you also could T a pressure gauge on the line to the rod side to check the pressure.....

each inch of drift on the lift cylinder rod equals about 60.3 cc, cubic centimeter, or 3.68 cui.....
If there is one inch of piston drift per minute, is IMO, quite a lot, not good.....60cc/min or 3.68cui/min...more reasonable would be around 5-10 cc/min....

here is a link to a similar test on a front loader tilt cylinder

wdchyd · Jun 2, 2010

AKKAMAAN said:
Sorry I did not say "piston rings", I said "piston seal leak"...
Weather it is a O-ring style seal or something else is unknown just now...

If manufacturer defends him self by saying the leakage is with in the "tolerance", he should be able to tell the tolerances....like a max volume per minute at a certain pressure....

Owners manual
RV setting 2030psi

BTW...I found the owners manual...and it is a very nice documentation...all parts in explosion pictures....still cant tell what type of piston seal they are using....the groove in the piston seems wide and not so deep...do not look like O-ring...
Picture from manual...

Hercules Part# PS2700-40......5000psi rated...http://www.herculesus.com/home.php?cat=1069

AKKAMAAN · Jun 2, 2010

wdchyd said:
Hercules Part# PS2700-40......5000psi rated...http://www.herculesus.com/home.php?cat=1069

ouch....Your link require IE8 only, and I am using Google Chrome and IE7...
Will be tough for Hercules to make Online biz for a while....:laughing:

AKKAMAAN · Jun 2, 2010

wdchyd said:
Hercules Part# PS2700-40......5000psi rated...http://www.herculesus.com/home.php?cat=1069

wdchyd:
Is this the original seal, or just your call for replacement seal???

wdchyd · Jun 2, 2010

without measuring the groove I'd say it's the same...very common...

best to yank it and measure groove...(picture could be off dimensionally)....there is others listed that are pretty close...

Wayne County Hose · Jun 3, 2010

wdchyd said:
Hercules Part# PS2700-40......5000psi rated...http://www.herculesus.com/home.php?cat=1069

The Hercules PS2700 series is an excellent piston seal. They, like any other piston seal, can be installed with a nick, burr, or twist which may take a little time to be a problem. Hercules is an OEM for most cylinder manufacturers. Many times when you purchase a seal kit from a dealer, it will come in a Hercules bag. John Deere is famous for this.

Here is what I would do. Extend the cylinder all the way. Make sure there is no weight or pressure on the cylinder. Slowly, remove the hose on the rod side of the cylinder, again, make certain there is no npressure in the line. Start the tractor, move the lever to extend the cylinder. Check the flow of oil out of the fitting on the rod side. If there is flow, hook everything back up. Go to the dealer and tell him exactly what you did. If there is flow, it verifies a faulty piston seal. No flow says your piston seal is probably ok. Granted this is a backyard way to do it, but unless you have pressure and flow gauges and a toolbox full of adapters and high pressure valves, it's the next best thing. Just be careful and if you aren't absolutely sure of yourself and what you are doing, either get help or don't do it.

Good luck,
Andy

Mousefield · Jun 3, 2010

Hi to all that responded. Some of this is a bit over my head. I will have time on the weekend to really study your responses and try and do what you have suggested. Just in the middle of a building project today and tomorrow. I should have some more info for you no later than Sunday.

This is what I had sent to the dealer.
As suggested I warmed the tractor up to its normal operating temperature and then worked the left lever that controls the swing cylinders and main? hydraulic cylinder.
I extended the backhoe all the way out and up. Opened the thumb all the way and curled the bucket so it was pointing towards the tractor. Thumb and bucket parallel to the boom.
Measured from the ground to a point at the top of the bucket.
May 18th
10:10AM 83 1/8 inch
12:05PM 72 ½
3:55PM 56 1/2
7:00PM 45
9:30PM 38 ½
May 19th
6:00AM 19 ½ also bottom of bucket 5 ½ inches from the ground.

Pics are of the small log that dropped the bucket down about 1 - 1 1/2 feet in 22 minutes.

Regards,
George

shaley · Jun 3, 2010

Wayne County Hose said:
The Hercules PS2700 series is an excellent piston seal. They, like any other piston seal, can be installed with a nick, burr, or twist which may take a little time to be a problem. Hercules is an OEM for most cylinder manufacturers. Many times when you purchase a seal kit from a dealer, it will come in a Hercules bag. John Deere is famous for this.

Here is what I would do. Extend the cylinder all the way. Make sure there is no weight or pressure on the cylinder. Slowly, remove the hose on the rod side of the cylinder, again, make certain there is no npressure in the line. Start the tractor, move the lever to extend the cylinder. Check the flow of oil out of the fitting on the rod side. If there is flow, hook everything back up. Go to the dealer and tell him exactly what you did. If there is flow, it verifies a faulty piston seal. No flow says your piston seal is probably ok. Granted this is a backyard way to do it, but unless you have pressure and flow gauges and a toolbox full of adapters and high pressure valves, it's the next best thing. Just be careful and if you aren't absolutely sure of yourself and what you are doing, either get help or don't do it.

Good luck,
Andy

Good idea. What Andy is saying is to pressurize the extend side of the piston using the tractor while measuring the oil amount comming around the piston seal and out of the rod side (retract side). This will be the leak-by rate. But, like he said, be careful.

AKKAMAAN · Jun 3, 2010

Mousefield said:
Hi to all that responded. Some of this is a bit over my head. I will have time on the weekend to really study your responses and try and do what you have suggested. Just in the middle of a building project today and tomorrow. I should have some more info for you no later than Sunday.

This is what I had sent to the dealer.
As suggested I warmed the tractor up to its normal operating temperature and then worked the left lever that controls the swing cylinders and main? hydraulic cylinder.
I extended the backhoe all the way out and up. Opened the thumb all the way and curled the bucket so it was pointing towards the tractor. Thumb and bucket parallel to the boom.
Measured from the ground to a point at the top of the bucket.
May 18th
10:10AM 83 1/8 inch
12:05PM 72 ｽ
3:55PM 56 1/2
7:00PM 45
9:30PM 38 ｽ
May 19th
6:00AM 19 ｽ also bottom of bucket 5 ｽ inches from the ground.

Pics are of the small log that dropped the bucket down about 1 - 1 1/2 feet in 22 minutes.

Regards,
George

I think the leakage is within tolerances too!!

It is a small cylinder 2.5" bore with a 1.25" rod....and the leakage volume is the difference between the capped volume and the rod volume...as I posted before....3.68 cui per inch of CYLINDER DRIFT...

Questions:
Under what pressure was the test??
What length of cylinder drift did your test represent??

I assume about 3/4 stroke, which would be about 12" (full stroke is 15.5")....
12 by 3.68=44cui or about 723cc....sound like it is a lot, but over 20 hrs or 1200 min, it is only 0.036 cui per min or 0.60 cc per min
your test with the log would accordingly be about 1" cylinder drift in 22 minutes, which is about 0.17 cui per min or 2.74 cc per min.....

These leakage volumes is combined leakage through spool valve, piston seal, work port valves etc....

so IMO,it is NOT VERY BIG NUMBERS if pressure have been some where nearby max system pressure!!!

The total leakage is added from all sources too...spool valve, piston seal, work port valves etc....

I do not think this leakage would have any noticeable effect on performance!!

wdchyd · Jun 3, 2010

AKKAMAAN said:
I think the leakage is within tolerances too!!

It is a small cylinder 2.5" bore with a 1.25" rod....and the leakage volume is the difference between the capped volume and the rod volume...as I posted before....3.68 cui per inch of CYLINDER DRIFT...

Questions:
Under what pressure was the test??
What length of cylinder drift did your test represent??

I assume about 3/4 stroke, which would be about 12" (full stroke is 15.5")....
12 by 3.68=44cui or about 723cc....sound like it is a lot, but over 20 hrs or 1200 min, it is only 0.036 cui per min or 0.60 cc per min
your test with the log would accordingly be about 1" cylinder drift in 22 minutes, which is about 0.17 cui per min or 2.74 cc per min.....

These leakage volumes is combined leakage through spool valve, piston seal, work port valves etc....

so IMO,it is NOT VERY BIG NUMBERS if pressure have been some where nearby max system pressure!!!

The total leakage is added from all sources too...spool valve, piston seal, work port valves etc....

I do not think this leakage would have any noticeable effect on performance!!

I agree, sometimes the surgery can do more harm sometimes than living with the symptoms.....BTW I may have been wrong about the Part# (not that it really matters) after closer look that seal could be a PSM-330 or PSM-330-WB....obviously the groove dim dictates which one to use...

Re: seal leakage....just monitor and document leak down rate....

wdchyd

AKKAMAAN · Jun 3, 2010

AKKAMAAN said:
I think the leakage is within tolerances too!!

It is a small cylinder 2.5" bore with a 1.25" rod....and the leakage volume is the difference between the capped volume and the rod volume...as I posted before....3.68 cui per inch of CYLINDER DRIFT...

Questions:
Under what pressure was the test??
What length of cylinder drift did your test represent??

I assume about 3/4 stroke, which would be about 12" (full stroke is 15.5")....
12 by 3.68=44cui or about 723cc....sound like it is a lot, but over 20 hrs or 1200 min, it is only 0.036 cui per min or 0.60 cc per min
your test with the log would accordingly be about 1" cylinder drift in 22 minutes, which is about 0.17 cui per min or 2.74 cc per min.....

These leakage volumes is combined leakage through spool valve, piston seal, work port valves etc....

so IMO,it is NOT VERY BIG NUMBERS if pressure have been some where nearby max system pressure!!!

The total leakage is added from all sources too...spool valve, piston seal, work port valves etc....

I do not think this leakage would have any noticeable effect on performance!!

This Wolverine valve from Prince have a rated spool leakage of 3cc/min....so you with your spool valve, piston seal and work port RV, combined your numbers are actually pretty good...