Woods backhoe problems

[80cj]

i have a woods bh70-x backhoe on my mf1532. i have had it a year and the backhoe has noticably lost power since it was new. the dealer says that nothing is wrong, so i called another local woods bh owner and he has been having the same issues. has anyone else noticed the same problems?

thanks
shawn

 

[Brad_Blazer]

Lost power = low pressure. I would install a gauge on the hydraulic line feeding the backhoe and check the relief pressure when operating each valve section by running it against the ground or the end of travel.

 

[80cj]

the dealer has put gauges on it and says all pressures are correct. i am going to the dealer this afternoon and call woods from there to see what we can figure out.

i was just really surprised when i talked to another woods bh owner and he was having the same problem. he also has a woods FEL on the same tractor that is NOT getting weaker. so now i am curious if anyone else is having the same problem and it is a design issue.

thanks
shawn

 

[Mousefield]

Used mine yesterday and works just like when I got it new about 21 months ago. :thumbsup:

 

[wedge40]

the dealer has put gauges on it and says all pressures are correct. i am going to the dealer this afternoon and call woods from there to see what we can figure out.

i was just really surprised when i talked to another woods bh owner and he was having the same problem. he also has a woods FEL on the same tractor that is NOT getting weaker. so now i am curious if anyone else is having the same problem and it is a design issue.

thanks
shawn

Did you witness this? You can get the stuff to do this yourself for about $25.00. I'm sure people here can lead you through the process.

Wedge

 

[kennyd]

Is it powered from a PTO driven pump or from the tractor's hydraulics? We need that info to help you better.

 

[IXLR8]

I had the same thing happen to my Kioti BH, not sure if you might have the same problem. When I first got it, I could drag the tractor around with the BH, now I can barely move any dirt. Static pressure to BH was fine, I didn't have the hardware to measure pressure while using the BH. Actually, I was using borrowed gauges and didn't want to modify tools that weren't mine. Turns out, even thought the dipper cylinder only had 30 hrs on it.. it had a blown seal. This seems to be more common on the Kioti cylinders than folks would like. Cylinder rebuild kit from Kioti- $265.00, new seals from Martin Fluid Power- $22.00, at my door 3 days later. Will know in 2 weeks when I put BH back on tractor if that fixes the issue.

See pics here;

http://www.tractorbynet.com/forums/kioti-owning-operating/166305-thanks-folks-i-found-problem.html

 

[80cj]

the backhoe uses the tractor's hydraulics. i took yesterday afternoon off work and spent it with the dealer to try to figure it out. by luck, the AGCO rep was there and offered some suggestions.

they said they had tested all the pressures (at the bh cylinders), but he asked them to do it again. we also found out that when they measured the back pressure, they didnt use a 'T', just a dead-headed leg. that was disheartening. after hearing that, i just want my tractor back and i will do it myself.

at the bh cylinder we measured 1800 psi @ idle and 2000 psi @ 2500 rpm

on the FEL 2200 psi @ idle and 2300 psi @ 2500 rpm

right now it is plumbed so it goes from the pump to the back hoe, to the FEL.

the AGCO tech said this needs to be changed because the back hoe doesn't have power beyond and also to preotect his tractor. (he doesn't care about the bh, it's not a massey) according to the previous dealer that worked on it, he said that originally had it hooked up that way, but changed it to help with the power problem.

we called the Woods tech and they said we could turn up the relief valve setting, so we did. now it is about 2000 psi @ idle. but when we went out and used it, it didnt seem to make much difference.

they never did measure the back pressure. i asked them to try to get the wood's rep to come out and look at it. so the dealer said he will call him today.

it has been there a month, i need to get it back, im just really frustrated. i bought a brand new tractor because i have a 1,000 projects and this was supposed to help with them, not BE ONE! grrrr.

thanks
shawn

 

[80cj]

Mousefield,
that is what mine USED to do. now it can barely pic up its own weight! with the boom fully extended, it can barely pick up a bucket full of dirt.

thanks
shawn

 

[J_J]

You folks are definitely having pressure problems. What is the max pressure on the hyd pump? If you put the gage in right after the pump, it will then show any pressure, no matter what valve you activate. If the BH has the correct pressure, then everything should work as advertised. If the reliefs are not going off, then there is hyd fluid leakage somewhere. What is the relief setting on the BH.

You said the fluid went to the BH first, and it read 1800 psi, and then you said that the FEL which is downstream read a higher pressure of 2300 psi. Where on the BH did he take the pressure reading. In doing all the pressure readings, the gage should be installed before any component, after the pump. Everything downstream should have the same reading unless the relief for that component is set different. If there are 2 or 3 relief, then they should be all set the same, about 50 to 100 psi below pump max pressure.

 

[kennyd]

80cj, You wrote:

they said they had tested all the pressures (at the bh cylinders), but he asked them to do it again. we also found out that when they measured the back pressure, they didnt use a 'T', just a dead-headed leg. that was disheartening. after hearing that, i just want my tractor back and i will do it myself.

Not quite sure what you mean by "back-pressure", but deadheading a line directly into a pressure gauge to test the PRV (pressure relief valve) pressure is an acceptable practice and will do not harm in short bursts. Even if you use a Tee, you still need to stroke the cylinder to the stop to deadhead the pump to get a reading.

they never did measure the back pressure. i asked them to try to get the wood's rep to come out and look at it. so the dealer said he will call him today.

Agian, not sure what you mean by "back pressure"

It sounds to me like there is a PRV somewhere that you are missing? I don't understand 2200 at the FEL and 1800 at the backhoe.

 

[80cj]

by back-pressure, i mean the return side. if you have 2000psi on one side of the cylinder, but have restrictions in the return side so that you have 500psi on the other side of the cylinder you will not have good performance.

deadheading is ok to test the relief valve, but it does not tell you anything about the pump performance under load. you need a T for that. they dead headed the line and read the pressure. then moved the lever the other way to read what the return pressure was. it was 0 becuase they would have pulled a vacuum since it was dead headed.

thanks
shawn

 

[wedge40]

I'm no expert and I'll be curious if I'm right. I would say the BH spool has a bad PRV. Also from what I've always been told, you wont get accurate measurements by using a T, you should dead end into the gauge.

Wedge

 

[80cj]

i dont believe it is the relief valve. you have to measure the pressure on the return (to tank) side with a 'T'. if you dead-head it, there won't be any flow and the pressure will just drop to 0. (it may pull a vacuum)

thanks
shawn

 

[80cj]

interesting update on my tractor, recall that it has been at the dealership for 5 weeks now, and this is the 3rd trip and 2nd dealer that i have taken it to to correct the problem in the last year.

after taking another day off work to go 'help' the dealer work on my tractor, i notice that the assembly instructions from woods have changed. it turns out that they changed them to use some sort of manifold block about a month or so after i bought my backhoe, but somehow nobody caught it. woods still has the old version on their website, but internally is working to the new version. ofcourse everyone is sick of me and continue to tell me to 'just let them do their job', but if everyone would have, i believe i wouldnt still be dealing with this. to woods credit, they are covering this under warranty.

my current theory is that it is a compound problem. the tractor pump is rated for ~8 gpm and the bh is spec'd for 4-6 gpm. the 1st day i had it i probably ran it for 10 or so hours straight. i could smell the hydraulic fluid, but they told me that was normal b/c a hose had broken during transport and it was just residual fluid. so since it is a constant displacement pump that relies on the relief valve to regulate pressure but the rv was sized for 4-6 gpm, it would build up excessive heat. and then i beileve the heat (or some other effect) damaged some seals on the bh.

that is just my theory, but i guess we will just have to wait and see.

thanks
shawn

 

[J_J]

Just don't run the tractor at high rpm, less GPM's. You will probably have better control on all the BH functions.

 

[80cj]

i had been running it at about 1500 rpm. when i ran it faster, it got hot faster (i could smell it) and it was very jerky to use. but they said that was part of the problem and that i was to be running it at 2500 rpm. i really believe that there is internal damage, maybe in the valve body.

thanks
shawn

 

[Mousefield]

Sorry to hear you (your dealers) have not been able to solve the problem. Must be getting pretty frustrating by now. Just to let you know I normally operate my Woods BH-7X backhoe at around 1,700 - 1,800 RPM.

 

[80cj]

i can't express how frustrated i am. but i'm running out of people to b!#ch at!

thanks
shawn

 

[80cj]

tell me if this seems wrong.

we T'd in gauges at both ends of a cylinder. when the cylinder bottomed out, it had 2000 psi on the press side (that makes sense), but on the other side, when the valve was open there was 125 psi, and if you closed it fast it would lock 700 or 800 psi on the cylinder. so you have 2000 on one side and 800 psi on the other. the woods guy assured me that was normal, but the more i think about it, the more i think that it cant be. i think that explains why i cant pick anything up with the thumb. as soon as i let the valve return, it loses all of its grip strength.

anyone else think this is wrong?

thanks
shawn