Checking hydraulic pressure on 743

[Websterspower]

Machine looses power, but engine does not loose RPM... Want to check hydraulic output... Should I make a loop with a gauge and hook it up to the aux in front? Would this check output for whole system? Output should be around 3000psi right? Suggestions would be appreciated. Thanks in advance, Shawn

 

[mrfixitpaul]

Not positive on the specs but probably around 2500PSI and 11gpm. If you loop the auxiliaries you won't get much pressure as it will just flow through to the return, you just need to put a guage in one of the couplers and engage the auxiliaries for that coupler....that will give you the auxiliary pressure and if that is ok then the pump is making pressure but not necessarily enough flow. The best way to completely test the hydraulic pump is to plumb a flowmeter w/ pressure guage inline at the pump outlet, that will tell how much flow you have, then deadhead a hydraulic function and see if the flow stays close and what the pressure goes to....that will be either the most the pump can build or the setting for the relief valve on that function.

 

[Tazza]

Not positive on the specs but probably around 2500PSI and 11gpm. If you loop the auxiliaries you won't get much pressure as it will just flow through to the return, you just need to put a guage in one of the couplers and engage the auxiliaries for that coupler....that will give you the auxiliary pressure and if that is ok then the pump is making pressure but not necessarily enough flow. The best way to completely test the hydraulic pump is to plumb a flowmeter w/ pressure guage inline at the pump outlet, that will tell how much flow you have, then deadhead a hydraulic function and see if the flow stays close and what the pressure goes to....that will be either the most the pump can build or the setting for the relief valve on that function.

mrfixitpaul is spot on, it will be about 2,500 psi. A loop will tell you nothing, you need it on one coupler as stated already.
Your readings may change between hot and cold too, as the oil thins out the pressure may change slightly.
Do note, that when you operate another function you will lose pressure to the aux or any other cylinder in the system. Its not something as simple as that was it? like trying to curl the bucket while using the aux to grab something with say a 4 in 1 bucket. It will work with the most power when you operate one function at a time, multiple functions at a time will work, but not with full power.

 

[Websterspower]

mrfixitpaul is spot on, it will be about 2,500 psi. A loop will tell you nothing, you need it on one coupler as stated already.
Your readings may change between hot and cold too, as the oil thins out the pressure may change slightly.
Do note, that when you operate another function you will lose pressure to the aux or any other cylinder in the system. Its not something as simple as that was it? like trying to curl the bucket while using the aux to grab something with say a 4 in 1 bucket. It will work with the most power when you operate one function at a time, multiple functions at a time will work, but not with full power.

First off, thanks guys.... I haven't gone to look at the machine yet. From what I am told " I just doesn't have the b@!!s that it used to" when moving into a pile and loading the bucket it is said to loose its' juice. Don't know the machine personally so was looking for a way to establish a baseline on hydro pressure and flow. Could a worn/slipping belt be the culprit? Possibly.... Sounds like you guys are leading me in the right direction. Thanks for all the info.. Shawn

 

[Fishfiles]

First off, thanks guys.... I haven't gone to look at the machine yet. From what I am told " I just doesn't have the b@!!s that it used to" when moving into a pile and loading the bucket it is said to loose its' juice. Don't know the machine personally so was looking for a way to establish a baseline on hydro pressure and flow. Could a worn/slipping belt be the culprit? Possibly.... Sounds like you guys are leading me in the right direction. Thanks for all the info.. Shawn

The way you put it " when moving into a pile and loading the bucket " , makes me wonder which is giving you the problem , moving into the pile doesn't use the same pump as the boom, aux and bucket , if the bucket don't have the power to curl or raise under a load then the pressure can be tested at the aux ports , if the machine has no tracking power to push into the pile then that is a different thing , if both travel into the pile and bucket power are weak then first look to a fuel problem

 

[Tazza]

The way you put it " when moving into a pile and loading the bucket " , makes me wonder which is giving you the problem , moving into the pile doesn't use the same pump as the boom, aux and bucket , if the bucket don't have the power to curl or raise under a load then the pressure can be tested at the aux ports , if the machine has no tracking power to push into the pile then that is a different thing , if both travel into the pile and bucket power are weak then first look to a fuel problem

This machine does not run a drive belt.
Plowing in to a pile of dirt, it should bog down a fair bit.
It could be a weak vane pump.

 

[Websterspower]

This machine does not run a drive belt.
Plowing in to a pile of dirt, it should bog down a fair bit.
It could be a weak vane pump.

Thanks again.... This machine is on next weeks to-do list. When I get to look at it I'll post my findings. Happy to have found this site for sure, Thanks