Couple ?'s on hydro system L555 or similar models

[irwin]

First: does the gear pump have enough suction (without any priming) to recharge system?........
Second: has anyone ever had or heard about a woodruff key failing (or the shaft breaking at the keyway) between the transmissions or between engine and the tranmissions? http://en.wikipedia.org/wiki/Woodruff_key ........
I removed the pump and it turns (maybe too easily). It has a pump like noise when I turn it by hand, the shaft looks fine where it slides into the front transimssion pump shaft. I plan to take the gear pump apart monday at work and see if there any obvious internal issue........
What happened..I found a hole in my suction hose while hunting for the reason my hydro charge light was staying on..... After replacing that holey suction hose I still had no suction from the gear pump.
I tried to prime it, (before I removed the pump) by pouring hyraulic fluid into the hose (after disconnecting the hose from the sump and bending it upward). I cranked the engine over (with the fuel shut off) and the hose did not empty. :-( I'm thinking either the gear pump is bad or the key/keyway (somewhere down the line) is bad. Any other ideas?

 

[Tazza]

With the pump off, try turning the engine by hand, if the shaft spins there is no problem with the key/shaft. I guess all shafts can break for no real reason other than load.
The pump should self prime, but i found the best way was to use a lift ram, extending it while operating the controls. This draws oil up through the pump and into the cylinder. It can take a bit of effort to pull the ram stick by hand, but can be done.

 

[irwin]

With the pump off, try turning the engine by hand, if the shaft spins there is no problem with the key/shaft. I guess all shafts can break for no real reason other than load.
The pump should self prime, but i found the best way was to use a lift ram, extending it while operating the controls. This draws oil up through the pump and into the cylinder. It can take a bit of effort to pull the ram stick by hand, but can be done.

Good idea with drawing oil up with the rams, though it sounds like help will be needed when I try. When I have time I'll see if I can set up something to see if the shafts turn
Here's what I found inside the gear pump. The hard plastic(?) seal is damaged and has a piece missing. It's that thing on top, broken off piece is still in the groove (left side lower). It's an odd seal..wonder what it does? Basically the rest is in okay shape.

This is a shot of the wear plate, got some grooves huh?

 

[Tazza]

Good idea with drawing oil up with the rams, though it sounds like help will be needed when I try. When I have time I'll see if I can set up something to see if the shafts turn
Here's what I found inside the gear pump. The hard plastic(?) seal is damaged and has a piece missing. It's that thing on top, broken off piece is still in the groove (left side lower). It's an odd seal..wonder what it does? Basically the rest is in okay shape.

This is a shot of the wear plate, got some grooves huh?

At first glance the plastic seemed like a backup ring, but looking again it doesn't look like it. Its almost as if its there to hold the gear off the end plates? strange.... The wear doesn't look bad on the plate. The biggest area that causes problems is the part that the gears run in. When the bearings wear the gears push outwards and wear the housing. The more it wears the more oil can by-pass making the pump not work as well. Look for scoring in this area.

 

[Earthwerks Unlimited]

At first glance the plastic seemed like a backup ring, but looking again it doesn't look like it. Its almost as if its there to hold the gear off the end plates? strange.... The wear doesn't look bad on the plate. The biggest area that causes problems is the part that the gears run in. When the bearings wear the gears push outwards and wear the housing. The more it wears the more oil can by-pass making the pump not work as well. Look for scoring in this area.

First: does the gear pump have enough suction (without any priming) to recharge system?
>>>>>.Yes, but if the pump is drained or new fill it with fluid first or you may detroy the side seals (which is what those plastic parts look like). You can buy resealing kits for about $35-45.
Second: has anyone ever had or heard about a woodruff key failing (or the shaft breaking at the keyway) between the transmissions or between engine and the tranmissions? http://en.wikipedia.org/wiki/Woodruff_key .......
<<<<< Yes it happens. In fact www.LoaderPartsService.com sells reconditioned pumps and sells those shafts.
I removed the pump and it turns (maybe too easily).
>>>>>>>>It's wiped out.
It has a pump like noise when I turn it by hand,
>>>>>>>That's the gears inside meshing.
What happened..I found a hole in my suction hose while hunting for the reason my hydro charge light was staying on..... After replacing that holey suction hose I still had no suction from the gear pump.
>>>>>That's because the pump was wiped out from lack of fluid
I tried to prime it, (before I removed the pump) by pouring hyraulic fluid into the hose (after disconnecting the hose from the sump and bending it upward).
>>>>>>>>Toooo late.
I cranked the engine over (with the fuel shut off) and the hose did not empty. :-( I'm thinking either the gear pump is bad or the key/keyway (somewhere down the line) is bad. Any other ideas?
>>>>>>There's no pressure being built up so it follows no suction either.

 

[irwin]

First: does the gear pump have enough suction (without any priming) to recharge system?
>>>>>.Yes, but if the pump is drained or new fill it with fluid first or you may detroy the side seals (which is what those plastic parts look like). You can buy resealing kits for about $35-45.
Second: has anyone ever had or heard about a woodruff key failing (or the shaft breaking at the keyway) between the transmissions or between engine and the tranmissions? http://en.wikipedia.org/wiki/Woodruff_key .......
<<<<< Yes it happens. In fact www.LoaderPartsService.com sells reconditioned pumps and sells those shafts.
I removed the pump and it turns (maybe too easily).
>>>>>>>>It's wiped out.
It has a pump like noise when I turn it by hand,
>>>>>>>That's the gears inside meshing.
What happened..I found a hole in my suction hose while hunting for the reason my hydro charge light was staying on..... After replacing that holey suction hose I still had no suction from the gear pump.
>>>>>That's because the pump was wiped out from lack of fluid
I tried to prime it, (before I removed the pump) by pouring hyraulic fluid into the hose (after disconnecting the hose from the sump and bending it upward).
>>>>>>>>Toooo late.
I cranked the engine over (with the fuel shut off) and the hose did not empty. :-( I'm thinking either the gear pump is bad or the key/keyway (somewhere down the line) is bad. Any other ideas?
>>>>>>There's no pressure being built up so it follows no suction either.

Thanks for replying Tazza and Earthwerks Unlimited.
What had me most concerned was this.....
I tried to prime it, (before I removed the pump) by pouring hyraulic fluid into the hose (after disconnecting the hose from the sump and bending it upward).
(here Earthwerks said)>>>>>>>>"Toooo late."

I cranked the engine over (with the fuel shut off) and the hose did not empty. :-( I'm thinking either the gear pump is bad or the key/keyway (somewhere down the line) is bad. Any other ideas? )
Shouldn't, even a weak pump move fluid that's poured into it with gravity feed?
Trust me I want this issue to be a pump failure..all other options are high labor hour jobs. The pump is a 15-20 minute swap over. I'll know for sure in a couple days if I have deeper problems... ie: the transmission pump coupler or a shaft broke. I've bought a new gear pump from Messicks, (time is tight and I don't want to mess around) Friday or Saturday I'll put the shaft from the old pump in the output shaft hole on the outer trans pump and if it turns with a good solid feel.. the new pump will get a spin.
If it doesn't spin, or does spin but slips, I'll know the transmissions have to come out..(praying hands here)....
See below parts illustration .. #6 is the coupler for the two trans shafts. the engine to trans connection appears to be another slotted shaft to slotted hole connection. Not as likely to fail but possible.. I run a auto repair shop but these machines are a little different than the family sedan.

 

[Earthwerks Unlimited]

Thanks for replying Tazza and Earthwerks Unlimited.
What had me most concerned was this.....
I tried to prime it, (before I removed the pump) by pouring hyraulic fluid into the hose (after disconnecting the hose from the sump and bending it upward).
(here Earthwerks said)>>>>>>>>"Toooo late."
I cranked the engine over (with the fuel shut off) and the hose did not empty. :-( I'm thinking either the gear pump is bad or the key/keyway (somewhere down the line) is bad. Any other ideas? )
Shouldn't, even a weak pump move fluid that's poured into it with gravity feed?
Trust me I want this issue to be a pump failure..all other options are high labor hour jobs. The pump is a 15-20 minute swap over. I'll know for sure in a couple days if I have deeper problems... ie: the transmission pump coupler or a shaft broke. I've bought a new gear pump from Messicks, (time is tight and I don't want to mess around) Friday or Saturday I'll put the shaft from the old pump in the output shaft hole on the outer trans pump and if it turns with a good solid feel.. the new pump will get a spin.
If it doesn't spin, or does spin but slips, I'll know the transmissions have to come out..(praying hands here)....
See below parts illustration .. #6 is the coupler for the two trans shafts. the engine to trans connection appears to be another slotted shaft to slotted hole connection. Not as likely to fail but possible.. I run a auto repair shop but these machines are a little different than the family sedan.

The side plates in the pump are what keeps pressure in the pump--pressure from the fluid presses against the gears as they rotate. If the pressure or sealing ability is lost as in this case due to catastrophic wear to the plastic plates due to sucking air (normally they're aluminum or thin steel) and what will happen is any fluid in the gear cavities will just be regurgitated--just like putting your head back and gargling. Until you swallow no pressure (to your stomach) is developed--but it makes a lot of noise.
My concern is part number 12---that is "internally splined" ("slotted" is not the proper terminology---just edumacating ya when you call for parts ). Vibration from the engine combined or opposed to the vibration in pump system will destroy the splines---my former L555 with a Perkins did just that. I think it was an $85 part to replace it. Luckily the pump female splines weren't damaged. And my backhoe's spline did the same thing. It's an easy fix--it cost $175 for a hydraulics shop to remove the old spline and insert a new one. Also the rubber grommets at the flywheel (near no. 12) also wear out and increase vibration as there will be metal-against-metal tansferring the energy.

 

[irwin]

The side plates in the pump are what keeps pressure in the pump--pressure from the fluid presses against the gears as they rotate. If the pressure or sealing ability is lost as in this case due to catastrophic wear to the plastic plates due to sucking air (normally they're aluminum or thin steel) and what will happen is any fluid in the gear cavities will just be regurgitated--just like putting your head back and gargling. Until you swallow no pressure (to your stomach) is developed--but it makes a lot of noise.
My concern is part number 12---that is "internally splined" ("slotted" is not the proper terminology---just edumacating ya when you call for parts ). Vibration from the engine combined or opposed to the vibration in pump system will destroy the splines---my former L555 with a Perkins did just that. I think it was an $85 part to replace it. Luckily the pump female splines weren't damaged. And my backhoe's spline did the same thing. It's an easy fix--it cost $175 for a hydraulics shop to remove the old spline and insert a new one. Also the rubber grommets at the flywheel (near no. 12) also wear out and increase vibration as there will be metal-against-metal tansferring the energy.

Next phase:
I disassembled the old pump took the old shaft and put it in the outer trans splined hole. It's solid no slip.
Installed the new pump and filled the system up to the full line on dipstick. Shut the throttle off and cranked the engione over 6 times for 15-20 seconds each.. The hydro charvge light did not go out. I let it rest for 1/2 hour and did it again..still hydro charge light on..not even a flicker..(I'm concerned about damaging the new pump seals) While it was cranking I had my hand on the pump..it feels like it's spinning.
(note: I replaced both hydro filters while the system was down, so it has more air pockets)
Does it take long to build up pressure?
I'm about ready to do as Tazza suggested here ..
"The pump should self prime, but i found the best way was to use a lift ram, extending it while operating the controls. This draws oil up through the pump and into the cylinder. It can take a bit of effort to pull the ram stick by hand, but can be done."

Will it draw fluid through the pump with the pump static (not turning)?
If I try this with the key on and the foot control pressed in the correct (lift) position will this be enough to suck any air from the lines, control valve, + gearpump?
And Earthwerks said ."
There's no pressure being built up so it follows no suction either."
How do I insure pressure can build? Or should I be looking for another problem?
I'm not afraid of taking something apart..but I am concerned about spending a lot of time if it's not beneficial.
I'm hoping for some good news soon.

The engine purrs like a kitten and the hydraulics were very strong before this failure. I'm trying to wrap my head around how the hydraulic pressure and the gear pump work. My reason says..if the pump pushes enough fluid there will be pressure..is this right?

 

[Earthwerks Unlimited]

Next phase:
I disassembled the old pump took the old shaft and put it in the outer trans splined hole. It's solid no slip.
Installed the new pump and filled the system up to the full line on dipstick. Shut the throttle off and cranked the engione over 6 times for 15-20 seconds each.. The hydro charvge light did not go out. I let it rest for 1/2 hour and did it again..still hydro charge light on..not even a flicker..(I'm concerned about damaging the new pump seals) While it was cranking I had my hand on the pump..it feels like it's spinning.
(note: I replaced both hydro filters while the system was down, so it has more air pockets)
Does it take long to build up pressure?
I'm about ready to do as Tazza suggested here ..
"The pump should self prime, but i found the best way was to use a lift ram, extending it while operating the controls. This draws oil up through the pump and into the cylinder. It can take a bit of effort to pull the ram stick by hand, but can be done."

Will it draw fluid through the pump with the pump static (not turning)?
If I try this with the key on and the foot control pressed in the correct (lift) position will this be enough to suck any air from the lines, control valve, + gearpump?
And Earthwerks said ."
There's no pressure being built up so it follows no suction either."
How do I insure pressure can build? Or should I be looking for another problem?
I'm not afraid of taking something apart..but I am concerned about spending a lot of time if it's not beneficial.
I'm hoping for some good news soon.
The engine purrs like a kitten and the hydraulics were very strong before this failure. I'm trying to wrap my head around how the hydraulic pressure and the gear pump work. My reason says..if the pump pushes enough fluid there will be pressure..is this right?

I've run plenty of punps out of fluid---even wiped a few out.
The charge pump is strictly for the hydro drive system, not the loader/bucket.
Simply turning the engine over is usually not enough to have any of the three pumps suck new fluid and build pressure especially if you had air in the lines. The pumps have to spin fast. All the air eventually has to or will be purged on its own---USUALLY. That said, if you know you have a good or decent (gear) pump and suction line(s) and fluid level, just start it up and see what happens. The fluid will circulate through the valves regardless if control levers are activated--it's called an open-center system. Once you get it running (all I do is) operate the machine like usual--typically, under the type of failure you have had, the air will work itself out---there shouldn't be that much air in the cylinders. Air in the drive motors and pumps will work its way out just by going back and forth or simply just driving it.

 

[irwin]

I've run plenty of punps out of fluid---even wiped a few out.
The charge pump is strictly for the hydro drive system, not the loader/bucket.
Simply turning the engine over is usually not enough to have any of the three pumps suck new fluid and build pressure especially if you had air in the lines. The pumps have to spin fast. All the air eventually has to or will be purged on its own---USUALLY. That said, if you know you have a good or decent (gear) pump and suction line(s) and fluid level, just start it up and see what happens. The fluid will circulate through the valves regardless if control levers are activated--it's called an open-center system. Once you get it running (all I do is) operate the machine like usual--typically, under the type of failure you have had, the air will work itself out---there shouldn't be that much air in the cylinders. Air in the drive motors and pumps will work its way out just by going back and forth or simply just driving it.

Okay next phase:
I started it up and ran it for a few seconds (about 5 seconds) nothing. I opened the output side fitting of the pump enough that fluid dribbled out and cranked it .. nothing.
Frustrated I finally did what I should of done when I did this.
[ irwin said "I disassembled the old pump took the old shaft and put it in the outer trans splined hole. It's solid no slip."
I couldn't see the shaft well while cranking it over so earlier today I used a large channel lock plier to try and turn the old pump shaft..that's when I thought it was fine...]
This time I removed the pump completely and manged to get my somewhat fat out of shape old body in a position where I could watch the shaft while I cranked the starter...Oops' no rotation I feel like an idiot..I spent a couple hours screwing around after I had it off the first time trying to figure how to get it to prime itself
So a big thank you to Tazza for the suggestion to crank it with the old shaft in.
And thanks to Earthwerks for the suggestion on the next place to look (#12 wasn't it?

)
So the next question is..do I have to remove the engine or the transmissions to acess that section? Either way it looks pretty tight in there.

 

[irwin]

Okay next phase:
I started it up and ran it for a few seconds (about 5 seconds) nothing. I opened the output side fitting of the pump enough that fluid dribbled out and cranked it .. nothing.
Frustrated I finally did what I should of done when I did this.
[ irwin said "I disassembled the old pump took the old shaft and put it in the outer trans splined hole. It's solid no slip."
I couldn't see the shaft well while cranking it over so earlier today I used a large channel lock plier to try and turn the old pump shaft..that's when I thought it was fine...]
This time I removed the pump completely and manged to get my somewhat fat out of shape old body in a position where I could watch the shaft while I cranked the starter...Oops' no rotation I feel like an idiot..I spent a couple hours screwing around after I had it off the first time trying to figure how to get it to prime itself
So a big thank you to Tazza for the suggestion to crank it with the old shaft in.
And thanks to Earthwerks for the suggestion on the next place to look (#12 wasn't it? )
So the next question is..do I have to remove the engine or the transmissions to acess that section? Either way it looks pretty tight in there.

Update:
I'm been so busy this summer, so the skid steer just sat around waiting for me to just do it.
The wife and I took this week off as a staycation. No' not to relax, but to catch up with our many projects. Finally tuesday I pulled it apart. Took about 2 hours. Here's what I found.
Earthwerks got the problem right, the hub at the flywheel came apart. While I went through the tear down I found a few issues that might be partly the cause of the failure. 1st: that suction hose. 2nd: the rear transmission inlet hose fitting was loose. 3rd: (and it's a good one) the rear trans is mounted to the flywheel cover with just two bolts.... only one is there! There's no place for it to go if it backed out, it would have to drop to the floor, it can't get out of there.. well it's not there. Good thing I paid so little for this machine

There's the center piece of the hub, the rest is either still bolted to the flywheel or inside the bellhousing.

 

[Earthwerks Unlimited]

Update:
I'm been so busy this summer, so the skid steer just sat around waiting for me to just do it.
The wife and I took this week off as a staycation. No' not to relax, but to catch up with our many projects. Finally tuesday I pulled it apart. Took about 2 hours. Here's what I found.
Earthwerks got the problem right, the hub at the flywheel came apart. While I went through the tear down I found a few issues that might be partly the cause of the failure. 1st: that suction hose. 2nd: the rear transmission inlet hose fitting was loose. 3rd: (and it's a good one) the rear trans is mounted to the flywheel cover with just two bolts.... only one is there! There's no place for it to go if it backed out, it would have to drop to the floor, it can't get out of there.. well it's not there. Good thing I paid so little for this machine
There's the center piece of the hub, the rest is either still bolted to the flywheel or inside the bellhousing.

Cool deal about the diagnosis--buuuuut like I tell my customers when it's time to pay me: "...and I do accept tip$". To date my biggest tip has been $200, and that was a few weeks ago. Not bad on what was a $500 job--that I got done in less than 2 hours (It took longer to drive there and back than it did to do the work!)

 

[irwin]

Cool deal about the diagnosis--buuuuut like I tell my customers when it's time to pay me: "...and I do accept tip$". To date my biggest tip has been $200, and that was a few weeks ago. Not bad on what was a $500 job--that I got done in less than 2 hours (It took longer to drive there and back than it did to do the work!)

Update:
The part showed up thursday, so friday I reassembled the skid steer (installed a few bolts that were missing ) and took a ride around my lot, ran the boom all the way up and down, then curled and dumped the bucket to purge any air. Everything appears to be fine...except the steering adjustment.. I had it working perfect last time I adjusted it, but it took time to fine tune the controls. I was unable to take the time today due to a commitment..so tomorrow the steering.
It sure is squirrely with the steering adjustment out of whack.