YM1700 hydraulic problem

bigdawggreaser · Sep 19, 2005

I have a YM1700. The Hydraulic lines hung down and hooked on a stump and pulled loose at the quick connect. Now none of the hydraulics work. the bucket will not lift and the 3ph will not lift or lower. I don't seem to be getting any pressure from the pump. any suggestions where to look?

ym2610 · Sep 19, 2005

you didn't say so I'm guessing you didn't loose any fluid, but could air have got in some way, just wondering.

mark777 · Sep 19, 2005

Does the pump whine or make any noise? I'm thinking a pressure line is badly kinked somewhere.

Mark

DavesTractor · Sep 19, 2005

When the lines disconnected at the QD, the QD shut off the flow from the pump and the flow had no where to go. The pressure relief is downstream from the loader. The pump should have blown to bits, but to protect from such a violent expolsion, most pumps have a "fuse" of sorts, either a key in a keyway, or sometimes a groove machined in the shaft (newer "F" series) The pump likely either sheared the shaft or the key in the keyway if so equipped. It is very possible that the pump is damaged, but if the key sheared immediately it may have protected the pump. I'm not sure of the design on that pump, but others will know.

Sorry for the bad news, but welcome to TBN where someone always seems to know the answer and be able to provide a solution

1danny · Sep 19, 2005

There is a 3m x 13m shear key on the pump shaft.

Danny

bigdawggreaser · Sep 20, 2005

Thanks Daves tractor! You were absolutely correct. After checking the screen, we decided to pull the pump to see if there was a problem there (when in doubt disassemble is my moto). The key was sheared smooth. Thanks everyone.

Eddie · Sep 20, 2005

That's good information to know since I have a ym1700 with quick disconnects on the FEL. I learned something as I have so many times on this forum.

Mickey_Fx · Sep 21, 2005

Anyone ever give thought to adding a bypass line with a pressure relief valve? Have the valve set so it would open up in the event a QD poped off causing excessive load on the pump. The likely hardest thing is to find the valve with the correct pressure.

DavesTractor · Sep 21, 2005

Mickey,

Good idea, but it does require some hardware and some additional plumbing. Sometimes it isn't so easy to find a good "tank" location to dump the bypass either.

Most people hardly ever remove their loader, so an easy and practical solution is to remove the QD's and just connect the hoses. If a hose gets ripped off, it will squirt oil, but it won't damage the pump. If you do remove the loader every couple of years, just unscrew the hoses.

Soundguy · Sep 21, 2005

I've seen ( on heavy equipment ) a relief plumbed right after the pump, with a short hose just pointing out/up... if a qd broke.. relif would dump/spray oil in a fountain and not deadhead the pump.. easy to see.

Seen this on big pull pan setups with 2 pans behind a big tractor...

wastefull and not ideal.. but then.. some of the pumps on those big machines are a couple thousand dollars to rebuild
and 6k to 7k$ to repalce...

Soundguy

Eddie · Sep 21, 2005

( Mickey,

Good idea, but it does require some hardware and some additional plumbing. Sometimes it isn't so easy to find a good "tank" location to dump the bypass either.
)

My FEL used 3 lines. I had to plumb one back to my large return line. Could you not dump the bypass back in to the return line which goes from the sump in the rear end of the tractor to the pump? /forums/images/graemlins/confused.gif /forums/images/graemlins/confused.gif /forums/images/graemlins/confused.gif

DavesTractor · Sep 22, 2005

Soundguy, your idea would sure work. I hadn't thought about that simple of a solution.

Eddie, probably tying into the suction line would work, as it is connected to the tank.

How many guys remove the loader often enough to really need QD's? I suspect guys that mow a lot with MMM's might remove them more often, but we seldom see a customer remove a loader.

Soundguy · Sep 22, 2005

( your idea would sure work. I hadn't thought about that simple of a solution )

A tad wastefull.. but works.

( How many guys remove the loader often enough to really need QD's )

My same thoughts. however.. on another tractor forum.. ( chinese ).. aparently, the dealer method of plumbing the pump involves the use of QD's right at the pump.. for some awefull reason... There is a story now and then about something popping a qd at the pump and then the pump deadheading.. IMHO.. a relief is needed before a qd, any time one is present...

Soundguy

Eddie · Sep 22, 2005

Maybe some of you knowledgeable guys will figure out what relief valve we need. I can install it but the other is over my head.

thanks
Eddie

gbirky · Sep 22, 2005

Dave,

"How many guys remove the loader often enough to really need QD's? I suspect guys that mow a lot with MMM's might remove them more often, but we seldom see a customer remove a loader."

Funny you should say that - I just posted a reply in another thread about the frequency of loader removal. I only put the loader on when I am going to use it. Then remove it immediately. I do mow with a belly mower, and the loader just makes it difficult to maneuver. The extra weight on the front tires mashes the grass and makes it difficult to get a nice clean cut.

Mickey_Fx · Sep 22, 2005

( Mickey,

Good idea, but it does require some hardware and some additional plumbing. Sometimes it isn't so easy to find a good "tank" location to dump the bypass either. )

Here's food for thought.

Plumb in the pressure regulated by-pass so it reestablishes the original flow path, i.e. by-pass the FEL plumbing. Another way is to plumb in the pressure regulated by-pass to the down stream side is tapped in to the same flow path as the lowe pressure return line on the FEL.

On my rig the FEL line are up up tight and outa sight so little if any chance to get caught on anything. Both hi-pressure lines are secured to the mount on the FEL via the flange both hoses pass through. I've got my QD plumbed in at this point. No loose ends.

EFC · Sep 22, 2005

I posted about this same problem in the Chinese forum. We had pumps coming in all the time (and still do) because customers would unplug the disconnects while the tractor was running. We put a pressure bypass at the pump just like soundguy mentioned with a hose that would spray oil if the lines came apart. The problem is that the pumps working pressure was way lower that the shock pressure during loader work. In other words if your front tire dropped in a hole with dirt in the bucket the pressure relief would spray fluid everywhere. To stop that we had to crank up the pressure bypass so high that the pump would blow up anyway.

Next we routed the bypass line around the loader valve. Still had blown pumps coming in. The disconnects would come undone and the owners would just keep driving around, or worse yet would unplug them to take their loaders off and forget to hook them back together. The pumps on these smaller tractors cant run at 90% load for very long. Heat builds up and the pumps die. They are not built like pumps on large machinery and cant handle any abuse.

The final thing we did was to eliminate the disconnects in the main flow and hard mount the valve to the tractor. then put disconnects on the working ports of the loader valve. When you take the loader off the valve stays. It is more expensive to do it that way, $100.00 or so (2 sets of extra disconnects, more hose ends and fittings and bracket building and mounting) and I offer it to everyone that buys a tractor. To date I have not had one person willing to pay the extra $100.00

I have only seen 2 tractors that had disconnects come apart by accident. The rest are operators thinking about fishing instead of tractoring. Funny thing though I have never sold a $400 replacement pump twice to the same person.

Buck

Mickey_Fx · Sep 22, 2005

( Next we routed the bypass line around the loader valve. Still had blown pumps coming in. The disconnects would come undone and the owners would just keep driving around, or worse yet would unplug them to take their loaders off and forget to hook them back together.

Buck
)

Can you clarify this? Which disconnects are you talking about? You didn't have QD on the by-pass lines did you?

On the Koyker loader that is typ on gary market Yanmars, the controls are mounted to the section that comes off with the loader itself. To do as you suggest would take some additional mods.

EFC · Sep 22, 2005

No I didn’t have QD on the bypass line the pressure bypass was plumbed ahead and behind the QD's going to the loader valve.

To activate a pressure bypass you have to exceed the bypass pressure setting which means the pump has to go to almost full load. If you set the bypass pressure to low you don’t have enough pressure for the loader if you set it to high you blow the pump. Pressure is power, flow is speed. We found setting the bypass at 80% pump capacity was to low and caused noticeable loss of loader power. Even at 90% some loader power was lost but going beyond that didn’t make sense. At 90% you have 10 min max. You would think people would hear the engine change tone because it is under load….. Nope.

 On the Koyker loader that is typ on gary market Yanmars, the controls are mounted to the section that comes off with the loader itself. To do as you suggest would take some additional mods. 

That was the extra cost I was referring to.

Buck