Cat 980g loader problems

[Demo man]

I have 980 g. 2kr01589. Got the machine this summer and have not had real good luck so far we put 32 hours on it and the motor locked up so we got that back together and now I can not get the loader to function right. Take 3-10 seconds before it will start to lift the bucket or curls. Loader arms will lower right away to the ground but then takes the same amount of time to pick the front end of the ground. At a idle when you bottom ou the hydraulics it will stall the motor. I have check the hose clams a couple times on the suction lines. And I can sit and press the brake pedal for a minute and no pressure lights came on the dash. The only other thing that I can think of is that after it sitting for 10 minutes the oil level goes up in the hydraulic tank and when you come back th next day it will be full all the way to the top of the filler cap. Normal or not? Any ideas where to go from here thanks

 

[kshansen]

One thing right off the bat. If you are pushing the brake pedal with engine off but key on and just holding it down you should not get any low pressure light to come on. Now if you press and release the brake pedal say 5-6 times then you would get the low pressure light and warning horn to come on.

Might be worth while to check "pilot pressure" on the system. Also calibrate the hydraulic controls. Believe on this vintage to do the calibration you need to use a "clicker box".

 

[kshansen]

Pilot Pressure tests:

View attachment 980G Pilot Pressue.pdf

 

[rmllarue91]

Aeration of oil will cause level to change and will make fictions slow I'd test pilot and main pressures might be worn implement pump

 

[kshansen]

Well I forgot to ask an important question or two. Has this machine ever worked since you got it or is this slow hydraulic problem something new. If new what was done just before the problem occurred?

 

[Demo man]

I will check pressure and let you know what I come up with. As far as brake I was a idle to see if it would lose pressure and the brake light would come on which it did not. The hydraulic work fine before the motor locked up that was at the end of July and I did the over haul when I had time so just got it together now

 

[Mark250]

I have 980 g. 2kr01589. . Take 3-10 seconds before it will start to lift the bucket or curls. Loader arms will lower right away to the ground but then takes the same amount of time to pick the front end of the ground.

if the pump has been left sitting for a while it is possible that the vanes have stuck in there slots. do you mean when you lift the load frame into the air it immediately drops by itself to the ground. if so I sounds like contamination has got into the control valve
Mark

 

[Cmark]

It does sound like a pilot pressure issue. As Mark says, maybe some dirt has got in there.

Where the pilot line joins the pilot valve on the front frame there should be a screen inside the fitting. Check it for blockage.

 

[John C.]

Brake accumulators would be a concern if the light comes on. The other concern is if the machine has ride control.

 

[Jonas302]

Make sure the hydraulic tank is getting pressurized Might have to strip the hydraulic pump and have a look

 

[kshansen]

Okay, thought of another question, he's always asking more questions!

How does the tilt control work? Does the bucket roll back promptly when you move the control or does it hesitate to move just like the boom arms?

Just thinking if the tilt and roll back work normal it may indicate the problem is more in the control valve than in the pilot pump area.

This is one of the problems with trying to diagnose something from a remote location, things one would try or notice right off are sometimes not thought about till next morning's coffee kicks in!

 

[Demo man]

The loader and bucket will stay in position when you let off the controls. Came up with 1200 psi while running and 900 shut off

 

[Demo man]

Both bucket and boom arms are acting the same way

 

[Demo man]

Got a different gage put on and the pressures read 550 psi running and 380 when I shut it off

 

[rmllarue91]

Hey demo was that pilot pressure or brake?

 

[Mobiltech]

The pilot control solenoids are very touchy on these machines. I have seen them all do what your saying if they get contaminated. There are test ports on the end of each main spool in the control valve. Check the pressure there too.

 

[JakeHarrington]

Sorry to bring up an old thread. But is the pilot testing procedure pdf the same for a 980h serial number jms03132

 

[Nige]

I sent you the applicable pilot testing procedure.

 

[Ricardo Ibarra]

I sent you the applicable pilot testing procedure.

Hi Nige. Can you send me that procedure too?

 

[Nige]

Post a Serial Number first please, just to be sure the info is correct for your machine.
Second, take a look at the attachment posted by kshansen in post #3 right at the start of the thread. Is that what you are looking for..?