CAT 345 Hydraulics

[steed6557]

AGS01473 has had MCV rebuilt, two new joysticks. When AEC is on, hydraulic function drops off, now hydraulic function is very slow. 60 man hours from two CAT dealers and I'm being told by one that it is the logik valve and the other the pump. My diagnosis is the pump and yesterday the hydraulic function fell right off, the machine stalls now when you try to walk it.

 

[wsw]

If the engine is stalling it is because the engine output is not matching pump demand, I'd be looking at pump controls before I changed a pump. does it try to move when you try and walk it or does it just snuff the engine without even moving a sprocket

 

[Per Eriksson]

What standby pressures do you have for the 2 pump outputs?

 

[steed6557]

Thanks for the input, I will be on the machine all day tomorrow. Haven't had time to get to it until it quit yesterday thats why we called in local CAT guys. Will post my findings tomorrow night for further advice or confirmation. Thanks

 

[steed6557]

Yes it does try to move, and the rest of the hydraulics are very slow or non existent until you ask for two functions and then some hydraulics kick in.

 

[wsw]

You say when you ask for 2 functions the hydraulics kick in, What about rpm ? you can e-mail me at wswhelan@hotmail.com as the e-mail address I have associated with this account is no longer active and I do not know how to change it

 

[willie59]

the e-mail address I have associated with this account is no longer active and I do not know how to change it

Go to the top of the page and click the "Settings" button. It will take you to a new page, on the left side of page are various links. There's a link there to "Edit Email and Password".

 

[steed6557]

Update, sorry for the length of time between posts. Went to do some work on the machine and the problems have gotten worse. The machine will not move, at full rpm and you move the travel levers the machine tries to move forward then bogs downwithout moving an inch. Had a similar problem on a 330 and found the swivel at fault, resealed and worked ok but not on this problem still there. At full rpm, move joystick nothing happens, move two joysticks and you get hydraulic function but slow and lacking any power. Measured implement pilot pressure at MCV and only get 325psi at max rpm.

 

[Per Eriksson]

Do you mean you only have 325psi pilot pressure at the pilot relief?

Why was the mcv valve rebuilt, was there any problems that led to that decision?
Somewhere in the back of my head I'm thinking that perhaps the ncf signal lines could be crossed left to right, you could check that they are fitted correctly.

 

[30 B]

If your pilot pressure is to low if will not release the travel brakes and will make all the other functions slow or not work at all. We had a machine with a weak spring in the pilot relief that sounds like similar symptoms. I adjusted the pilot pressure and the problems went away. Most pilot or stand by pressures are 400 plus pounds

 

[WhyWhyZed]

Yes it does try to move, and the rest of the hydraulics are very slow or non existent until you ask for two functions and then some hydraulics kick in.

I wonder if the NFC lines to the pumps got reversed.