I just purchased a Case 680E, which has air brakes. I fixed the leaks in the air lines that I could find and replaced the e-brake valve. The brakes do no grab as good as the should. They will stop the machine if it is in nuetral, but not in gear. I think they need adjusted, but I don't know how. Any suggestions? Also, the brake system holds pressure until I hit the brakes a couple of times, then it looses enough to activate the parking brake valve. What would be causing this to happen?
I have a 680CK. Your 680E is the next generation. Many of the parts for both of them are very similar. If you are losing air when you apply either or both brakes you have either a line leaking or an actuator leaking. Can you hear air leaking when you apply the parking brakes ? The brake linings may be worn to such an extent that tightening the brakes won't help . Check if there is any differential oil leaking onto them. I copied the adjustment procedure from my service manual. Come back if you need more info.
Huh, those things actually have S-cam brakes?
I forgot to mention the all important air compressor and the belt that turns it. Check the belt tension and be sure it isn't glazed and slipping.
Back to the air compressor, is the govenor set right, may be cutting off too soon and not getting up to full pressure.