Clutch looses pedal pressure and wont work after driving vechicle for about 100 kilometers but comes good when vechicle cools down

I suspect that the full engagement of the clutch pressure plate is not being achieved
if a pressure plate is held at reduced application pressure , it will continuously slip marginally and this build up to a point where the clutch plate will not absorb any more heat and so it fades and slips completely ( same affect as brake fade from worn pads and too heavy brake application -like long down hill runs )
the area I would check is the clutch master cylinder as it appears that the compensating port is blocked , and holding pressure in the clutch line which with increasing heat from the clutch builds up more pressure and compounds the pressure plate problem
this is identical to a heavy truck clutch problem where full testing produced no problems , yet at 100 miles and on a range the clutch failed completely but when cooled down again tested as good
on replacing the clutch pressure plate and clutch plate it was revealed by a clutch specialist shop that the pressure springs were actually weaker that specifications and were in fact allowing the clutch top slip and so go into the fade situation

Just a guess from an old shadetree mechanic: pedal pressure is wrong-too weak, or the clutch pressure plate bolted to the flywheel is bad. They will wear on the fingers and the plate's springs can wear. There should be a Case repair facility at a dealership, anywhere close? A mechanic familiar with your case 580, they often don't mind talking a bit over the phone about a mechanical problem. I meant by pedal pressure-I don't know if the rig is hydraulic clutch or mechanical linkage or cable operated, but check if the clutch pedal can be adjusted. On a hydraulic clutch with a clutch master cylinder and an associated slave cylinder, there is no adjustment. You just have to keep the reservoir full of dot-3, or dot-4 brake fluid. So that's my guess, something wrong with the pedal, or worse, something wrong with the pressure plate. You definitely need a second opinion. Good luck.

Check the clutch fluid level. If it's low, add some (takes brake fluid). There is a bleed valve down on the clutch slave cylinder on the bellhousing. Open the bleed valve and have someone push the clutch pedal slowly to floor, and hold. Close the bleed valve, and repeat until fluid comes out in a steady stream when the pedal is depressed. Your pedal should have pressure now, and the clutch should be working.
If no fluid is forced out the clutch master cylinder, into the line, and to the slave cylinder when clutch is pressed, then you may have a bad clutch master cylinder. If fluid does come out the bleed valve, but still no pressure on the pedal, it may be a bad slave cylinder.
Post back for more. Would like to know what you find out, and what the problem was, OB. Good luck.

my sunfire is automatic, and the gear shifter is VERY LOOSE, doesnt catch in any of the drive options. just slides up & down, with no pressure

when engine over heating to keep from doing engine damage determine how long you drive vechicle if you stopped in time.replace thermostat, radiator pressure cap and replace radiator if it has holes in it and leaking replace top and bottom radiator hoses.check your engine oil on oil dip stick if dip stick look like milk shake you could blowed head gasket if you did drive too long when truck over heated.check your radiator cooling clutch fan should when engine cold turn clutch fan by hand should drag when engine get hotter then clutch fan should be more harder to turn by hand.if clutch fan feel loose and spin easily free wheel clutch fan need replacing it will cause engine to overheat.

If the clutch is good and works right, then probably the big spring on the clutch pedal under dash may have come loose or broke. You need to look at the pedal operation while you push and release. It's a bit of a job to work on the pedals. Not sure, but you may have to remove the pedal assembly to fix it. good luck.

CHECK BRAKE LIGHTS FUSE.IF FUSE OKAY.BRAKE LIGHT SWITCH IS BAD.VECHICLE NOT SHIFTING OUT OF PARK PROBLEM COULD BE BLOWED FUSE OR CLUTCH PEDAL SWITCH FOR MANUAL TRANSMISSION OR TRANSMISSION RANGE SENSOR FAULTY AND PROBLEM IN BRAKE LIGHT SWITCH IF FAULTY IT WILL KEEP THE BRAKE TRANSMISSION SHIFT INTERLOCK SOLENOID FROM WORKING KEEPING YOU FROM GETTING VECHICLE OUT OF PARK.IF BRAKE SWITCH IS GOOD.PROBLEM IN THE BRAKE TRANSMISSION SHIFT INTERLOCK SOLENOID.

U have either a defective hydraulic clutch Master or Slave cylinder, this should be replaced as a pair

The smell of a burned clutch is one that permeates the car for quite sometime after the incident. It may take as long as two weeks for the smell to alleviate.

Meanwhile if the car is shifting normally and not slipping I would say the clutch is ok.

yes it could be also check the fluid level!