md70 hydraulic problems

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roblarss

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I just bought a project 99 md70. I cant seem to get the hydraulics that run the loader to work. The drive motors work fine (they spin but no tracks yet to see how good). The aux hydraulics pressure up and when on PTO the pump spins. I noticed from the pictures the aux/pto and main hydraulics are from same pump but maybe different impeller. I dont get any flow when I disconnect the line right where it exits the fluid tank. What else should I look at before I go and pull the pump out of the tank? Also what do the small hydraulic lines do on the undercarriage that tie in downstream of the drive motors before the chaincase? One was broken off but nothing was coming out of it. Thanks
 
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roblarss

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Pulled the pump today and found the problem. The discharge side of the pump on the lower flow screw was blown off. A piece of the housing is still attached to the threaded fitting. Looks like I need a new pump or a dead pump with a housing section. Pump must have been deadheaded before i bought it.
 

Tazza

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Pulled the pump today and found the problem. The discharge side of the pump on the lower flow screw was blown off. A piece of the housing is still attached to the threaded fitting. Looks like I need a new pump or a dead pump with a housing section. Pump must have been deadheaded before i bought it.
Ouch...
Try loader parts source for a pump, or at least get a price and work from there.
Hopefully that's all that is wrong with it.
 
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roblarss

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Ouch...
Try loader parts source for a pump, or at least get a price and work from there.
Hopefully that's all that is wrong with it.
I found a pump locally here in alberta but its $2900 and couple weeks wait. Im hoping to locate a broken pump with the end casing still good. The localish dealer checked as they were going to give me one if they had one but no luck. I have my new tracks coming next week. Anyone tried to run the aux hydraulics for the loader? Should only need a flow splitter to return some flow to avoid having the loader move way to fast. This would get me by until I can find a deal on a pump. Anyone got a broken pump they want to sell???
 

Tazza

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I found a pump locally here in alberta but its $2900 and couple weeks wait. Im hoping to locate a broken pump with the end casing still good. The localish dealer checked as they were going to give me one if they had one but no luck. I have my new tracks coming next week. Anyone tried to run the aux hydraulics for the loader? Should only need a flow splitter to return some flow to avoid having the loader move way to fast. This would get me by until I can find a deal on a pump. Anyone got a broken pump they want to sell???
$2,900 just for a hydraulic pump or is that a drive pump?
If it is just a housing, can it be welded? as you thought something was dead headed causing it to fail, i assume it's not as easy as getting it welded up though.....
 
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roblarss

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$2,900 just for a hydraulic pump or is that a drive pump?
If it is just a housing, can it be welded? as you thought something was dead headed causing it to fail, i assume it's not as easy as getting it welded up though.....
That was for just the hydraulic pump at the dealer. I got a local welder to weld it up. Looks good. He figured it wouldnt be a problem. Going to install it today hopefully then double check the lines and see if it works.
 
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roblarss

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That was for just the hydraulic pump at the dealer. I got a local welder to weld it up. Looks good. He figured it wouldnt be a problem. Going to install it today hopefully then double check the lines and see if it works.
Got the repaired pump installed. Found one problem with the lines so far. The return to the filter/cooler was tied into the grapple control. Lucky nothing else exploded. Now I have to try to traceout all the lines so I can get them all in the correct locations...Managed to get the loader to go up so the pump seems to work. Still trying to figure out what the smaller hydraulic lines next to the drive motors are. Anyone have a service manual. Dealer was going to email me one but I never saw it.
 

Tazza

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Got the repaired pump installed. Found one problem with the lines so far. The return to the filter/cooler was tied into the grapple control. Lucky nothing else exploded. Now I have to try to traceout all the lines so I can get them all in the correct locations...Managed to get the loader to go up so the pump seems to work. Still trying to figure out what the smaller hydraulic lines next to the drive motors are. Anyone have a service manual. Dealer was going to email me one but I never saw it.
Good to hear you are one step closer.
Yeah, plunbing direct from the pump to the aux hydraulics isn't the best way for the previous owner to plumb it. Hopefully there is still a relief in the line though, so it may not be the main cause of the damage.
 
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