I have an older Case 680E and am having trouble with the air brakes. It will not build pressure and exhausts from the bottom of the treadle valves. (they worked ok in the fall) I disassembled one valve and cleaned all areas including seals and sealing faces, but this has not helped. Air continues to exhaust out the bottom of the valve. I hooked up a separate air supply at the tank to ensure sufficient air volume/pressure was obtained and had the same result. Could anything else be causing air to exhaust from the bottom of the treadle valves other than seals within the valve?
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Case 680 E Air Brake Trouble
- Thread starter scott954
- Start date
Does it only exhaust after releasing the parking brakes? If so you have leaking piston seals in one of the air cans. Remove the parking brake hose from one air can at a time and plug it off to isolate which one needs repair/replaced. THERE IS A VERY LARGE SPRING in these cans, do not try to service one without properly securing that spring!
If the air is exhausting with out activating the parking brake release, the problem is elsewhere, possibly the clutch cutout system?
If the air is exhausting with out activating the parking brake release, the problem is elsewhere, possibly the clutch cutout system?
Tinkerer
Senior Member
Scott; Everything in your 680 E air brake system (including a treadle valve overhaul kit) is available at NAPA or any heavy truck repair shop parts counter. If one or both of the air brake chambers are leaking don't even consider repairing them. NAPA can sell you a new one cheaper than you can repair your leaky one. Plus it is a lot safer.Unhook the air discharge line at the air compressor and connect a shop air compressor onto it. You can look for leaks with the tractor engine shut off by doing that.
Shimmy1
Senior Member
My vote is the treadle valve(s) needs to be replaced. It sounds just like ours did if they were froze up. If they leak without releasing the park brake, they are not holding air internally. Th clutch cutout is just an air operated hydraulic valve that disengages the shuttle.
Tinkerer, Thanks. I will take the valve to NAPA and see if they have an overhaul kit. The shop air suggestion is a good one, that's how I found my problem.
Shimmy, Thanks for your input. I agree it sounds like it is frozen (perhaps some corrosion).
Shimmy, Thanks for your input. I agree it sounds like it is frozen (perhaps some corrosion).
Tinkerer
Senior Member
This is most likely what you have for treadle valves. The image is from a 680CK service manual. This link will give you an idea as to the cost of a new one. http://www.anythingtruck.com/product/061-286171X.html Those valves are a really hard to get at. To make it a whole lot easier I used a 4 inch grinder and cut the floor plate from the bottom all the way to the top next to the accelerator. I welded a 1"x2"x1/8" steel strap on the underside of the left side and left 1" of it exposed so I could bolt the left side of the floor plate onto the strap. I drilled the strap and welded 1/4' bolts to anchor the left side of the floor plate.
Attachments
Tinkerer - This looks to be the valve. I think it is a Model E-2 or E-3 single circuit valve. I assume that the E-2 and E-3 have the same mounting bolt pattern. Thanks for the reference to anythingtruck.com. Their prices are competitive. And you are absolutely correct, the valves are a pain to get to. Thanks for your help on this one.
Tinkerer
Senior Member
If you need a brake chamber don't buy it at NAPA. They would charge you $134.00 plus tax. Here is a link to one a little cheaper. http://www.nickstruckparts.com/sb2424s.html . This is why I advise to get new ones and not attempt to repair old ones. It should be a perfect fit and you will get new caging bolts with them.
Hey Tinkerer, Is there a pictorial of the Valve from the manual that explains the ports like this one. I cant figure out if this is direct replacement since mine doesn't have factory treadle valves
Tinkerer
Senior Member
I don't understand your question. The page from my service manual is all I can provide for visual reference. The only thing that may be a problem for you would be how the pedal attaches to a new replacement. But, you can get replacements with a new pedal on them.
Tinkerer
Senior Member
Ok, now I know what you mean. Yes the ports on the new valves should be the same as the ones you now have. If there is any doubt in your mind clamp the new valve in a vice and apply compressed air into the appropriate port. Then operate the valve to determine what each port is for.
Well, it appears that I have crossed a line or these new valves function in a way I still dont understand. I am only able to reach about 20 psi and there isn't any air leaks I can hear or feel. I think I must not understand the supply/reservoir,deliver
vs 
.
Some how I placed a line or placed a plug in wrong place.
I even had it patterned along the lines of the old valves I removed. They leaked so bad tho I couldn't test anything on the bench when I used shop air. Wish they would have some sort of marking on the original valves. According to the Case picture I am seeing the side of the valve closest to the battery box correct? So left side would be on door side and right would be closet to throttle pedal?
vs .Some how I placed a line or placed a plug in wrong place.
I even had it patterned along the lines of the old valves I removed. They leaked so bad tho I couldn't test anything on the bench when I used shop air. Wish they would have some sort of marking on the original valves. According to the Case picture I am seeing the side of the valve closest to the battery box correct? So left side would be on door side and right would be closet to throttle pedal?
Lantraxco, could you elaborate please, you and Tinkerer are a wealth of knowledge and for the price a dealer wanted if they could find the correct valves was outrageous. Would you or Tinkerer know which valves would be correct for my 680CK?