cat 973 hydraulics stopped working

[Harleyone]

Hello all we have a cat 973 loader that the bucket just stopped working. The last time we used it was about a month ago and everything worked fine. Went out there 2 days ago started it up went to lift the bucket and nothing. The machine will move but no functions on the bucket will work no lift, no curl, and no 4 in 1 operation. Its full of fluid but nothing works which is odd because this machine has never let us down. But I guess there a first time for everything lol I am kinda at a lose where to go from here any idrs would be appreciated

 

[Fri973]

Could be the Main relief valve
Has something stuck in it holding it open

 

[Bls repair]

Never worked on one of these. Pump to engine connections ok,sound like pump is working?

 

[Dave Neubert]

963 uses pilot pressure to operate the control valve check pilot pressure.I would think the 973 is pilot also

 

[Nige]

It would be nice to know which of the dozen or so 973 variants this one actually is. If the OP would post a Serial Number it mght help.

 

[Harleyone]

ok the serial number is 086G01173 i hope that helps and as for pilot pressure im not sure what that is or how to check it i really need to find a service manual fo it if any one has one

 

[rmllarue91]

Striped pilot pump splines just a guess.

 

[Nige]

I really need to find a service manual fo it if any one has one

The Cat Publication reference for the Service Manual is SENR2454. Like this one on eBay -
https://www.ebay.com/itm/CAT-Caterp...ACK-LOADER-26-32Z-66G-86-90L-91-/372320415088

A brand-new paper manual goes for four times the price that one is selling for. The only question to ask anyone offering a used paper Service Manual for sale. Is it complete..?

Pilot Pressure should be 350 ± 10 psi. Attached is the hydraulic schematic. The Pilot Pump Test Point is "D" (highlighted) on Page 2.
Also attached the Parts Manual for the lines. Pilot Pump is arrowed. Test point is #14, right on the back of the pump itself.

 

[Harleyone]

can i ask another stupid question if the hyd. fluid was way low could that be the problem because it was and i filled it up but still no movement

 

[Harleyone]

i do not have a pressure gauge to test pressure at the pilot pump but it does shoot out fluid with the test port out and spinning the engine over

 

[Nige]

If it’s pumping oil out of the test port then it’s not the pilot pump coupling that’s failed. Is that with the engine running at idle speed or just spinning it over on the starter..?

I understand that you don’t have any gauges yourself but could you borrow something from somewhere.? Trying to diagnose a hydraulic problem without gauges is like trying to find the proverbial needle in a haystack.

 

[Harleyone]

I just spun the engine over and fluid shoot out pretty good