Woods backhoe cylinder leaking?

[Mousefield]

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]

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]

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

 

[Ductape]

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]

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]

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]

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]

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]

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]

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...