I need some help w/680G air brakes. The air brakes will not release. If I idle the machine for about a minute at 1200+ then push the park brake button on the dash it will stay in but not release the brakes. I replaced the compressor to tank hose; park brake valve to brake quick release valve hose; disassembled & cleaned the governor; disassembled & cleaned the park brake valve; disconnected and blew air thru' the quick release valve to brake chamber hoses; fixed a leak in the clutch cut out to double check valve hose; new belt on compressor; drained the tank(about 1/4 cup black nasty); removed & cleaned the check valve at the tank. When I step on the treadle pedal I get the "normal" sounds but if I step on it 4-5 times the park brake valve big red button pops back out. No release. HELP????
When you push in the red knob is air pressure actually getting to the brake actuator chambers? can you move the slack adjusters by hand? Maybe the brake camshafts are seized? Did someone adjust the brakes all the way tight? Just a few ideas.
More information is needed. When you push in the parking brake valve does your air pressure gauge come back up and show normal air pressure ? If it does I would disconnect an air line from one of the brake chambers and and determine if the applied air is getting to the chambers. let us know what you find out. Also, if you have that much engine oil in your air tank you may want consider overhauling the air compressor.That oil has to be fouling up everything in the system including the bladders in the brake chambers.
Frozen slack adjusters, stuck brake shoes, put away wet, could be a lot of different things. Start by checking to see that parts aren't frozen up. What type of air chambers are on the machine? can you capture the locking spring?
I will unhook the air hose at the chamber & see if air is getting there. With the button in everything at the wheel is tight. I will see if I can can find the camshafts and give them a go too. They worked last summer when i got it & its been here since so I don't see it being too tight an adjustment. THANKS much. I'll keep it posted.
Air gauge? Funny stuff. It is WELL used & I'm constantly finding unhooked or disconnected pieces and parts. What would you suggest for overhauling the compressor? Seals? Rings?THANKS.
680G brakes SO, here is the results of this afternoon's work. I removed the lines from the park brake quick release valve to the brake chambers and blew compressed air into the lines. The right one is an Aeroquip and the left is a Maxibrake. The chamber rods moved which shows they aren't locked up. Then I fired it up, idled it at about 14-1500 and had someone step on the treadle pedals. Again, the rods moved so that seems good. Then I had my helper push the park brake button in and the rods reversed direction. I never did see the brake shoes move. They seem to still be in tight contact with the drums. Are they supposed to come clear of the drums? Are the slack adjusters what attach the chamber rods to the brake cams? Do the wheels and drums have to come off to get to the cams? I don't know anything about "capturing the locking spring." Explanation? It takes a couple minutes before the park brake valve big red button will stay in and when I step on the treadle pedals a couple times it pops right back out. ?? I only have a parts books so apologize for the "stupid" questions but I have officially eclipsed my knowledge. Thanks everyone. You are saving me!!!
Did you check out everything that carogator suggested ? The brake release circuit should be fully charged with air within 30 seconds after pushing in the valve. That valve should not pop back out. The only reason that will happen is because you are losing a lot of air (probably one or both bladders) and / or a leaking air line. Your air pressure gauge should be showing 120 PSI in slightly less than a minute at 1/4 throttle. In regards to the compressor overhaul , consider as if it were a small two cylinder engine. If it were mine it would give it a complete overhaul. That would include pistons if it needs them, piston rings,bearings, seals and gaskets. If the air gauge is questionable, replace it. I would suggest an Autometer brand they have one that will fit perfectly.
680g brakes I did try to move the brake shoes with the park brake in "release" position by sticking a small bar between the shoes & drum. No gap or movement. I can't move the slack adjusters by hand. It looks like there is a bolt on the slack adjuster that has a worm drive gear that is meshed with a worm driven gear that the brake camshaft splines fit into. If I adjust that all the way will I get slack in the slack adjuster and brake shoes? A way to maybe see if the camshafts are frozen? How else could I check to see if the camshafts are frozen? Maybe remove the brake chambers and have someone more qualified than me take 'em apart & check them out? The air gauge is electric & the needle just lays on the bottom. Not sure its even getting any signal. I see in the parts book that there are 2 air pressure switches at the park brake valve. One for the air pressure warning buzzer and one that is just listed as "air pressure switch". The second one has a 40 ohm resistor in line before it connects to its wire that then is wired in with the plug for the headlight switch that then disappears in the harness. Neither of these 2 are connected thanks to someone before me. Thanks again for all the help Tinkerer, carogator, bolt thrower.
It sounds to me like your chambers are working, maybe the camshafts or brake shoe anchor pins are seized up. If you remove the clevis pins from the chamber pushrods @ the slack adjusters, then turn the worm adjuster with a wrench, the slack adjuster will pivot away from the chamber. You can then grab onto the slack adjuster and try to turn the brake camshaft with it. I might even hit them with a soft hammer to try to break them free.You should be able to see the shoes moving into and out of contact with the drums. If the camshaft turns but the shoes dont move, the anchor pins are prob. seized. The camshaft bearings should have grease nipples so you can lube them up. It does sound like you have some other air system problems also. A good troubleshooting procedure is to connect an external air supply to the air system on your tractor and operate the brake valves. This way you can hear the air leaks because the engine noise wont drown out the hiss. I wouldn't be too worried about a little oil getting past the compressor, its normal for them to pass some, and if the air tanks aren't drained regularly, the oil will accumulate. Just my 2 cents.
By all means do as bolt thrower said about hooking up an air compressor to charge the system. I have done it several times so I could hear even the smallest leak. Unhook the air line right at the tractor air compressor and then attach the auxiliary air to the line you have taken off. It may be easier to abandon the electric air gauge and mount a mechanical one with a 1/4" DOT air line from the air tank. After you remove the clevis pins from both air chambers have someone charge the air chambers with air while you are underneath watching them. You can then determine if they are moving and also if they are holding air with no leaking.
Yeah, I found the compressor to tank hose and park brake valve to quick release valve hose leaks with 'external' air pressure. Then I attacked it with a spray bottle of soapy water and can't find any more leaks. Not to say there isn't a leaky seal in one of the release, treadle, pressure valves or diaphragms that I have yet to discover. Seems like if the park brake valve button pops out it must be loosing air somewhere, huh? There are zerks on the slack arms but I can't see any on the brake shoe anchor pins. So, bolt thrower, should the gear shaft bolt on the slack adjuster turn freely after I disconnect the chamber rods like you guys suggested. Your 2 cents are worth $$$$ to me. Thanks!
I think you need a working air pressure gauge in the system. You really need to know if you are pumping up and holding enough air to charge the system to about 120 PSI. If you are not then you have one or more leaks anywhere in the system. If you do have 120 PSI and your pressure drops and does not recover after applying the brakes then your loss of air is somewhere in the applied brake circuit That is why the parking brake button will pop out after trying to release the parking brakes. If you cannot get 120 PSI and are reasonably certain you have no leaks I would suggest that you unhook the air compressor discharge line, then hook a mechanical air pressure gauge onto the compressor itself. Do it with a simple pipe fitting and do not reconnect the air line. You want only the gauge hooked up. Start the engine and see if the compressor is actually pumping up about 120 PSI. Hopefully it is . If it isn't then there is a problem in compressor itself.
So, how do I get the pins out of the slack adjusters? The rods seem to be under tension & don't want to just slide out. I can see the left one & was able to get the cotter pin out but the main clevis pin is TIGHT. I tapped it with a small hammer & got it to move about 1/4 inch but am afraid it I do happen to get it out that I will never get it back in. I spent 15 minutes just getting the cotter pin out of the right one and no way can I swing a hammer in there. Can't grab it w/channel locks and spin it even. I can barely see it. The good news is that when I disconnected the lines from the park brake quick release valve & pressurized the line to the chambers everything moves. I actually was able to see the shoes come out of contact with the drums. Space about equal to a business card thickness. Left side seems OK. The bad news is when I do the right I hear air hissing outta the chamber. Air comes out the forward facing hole that you stick a tool into to manually release the brakes. Sound like a bad diaphragm?? I'm off to town to try & get some fittings and a gauge so when I pressurize w/o it running I can watch for pressure drops. Thanks again!!!!!!!!!!!
Yes you have a diaphragm leaking. DO NOT attempt to repair it yourself unless you have the proper tools and experience. The spring in it is very strong and will cause severe bodily injury if it isn't contained with the proper tools. Take it to a repair shop that repairs them. To get the pins out of the chamber rods turn the slack adjuster until the pins are loose. I don't think there is any need to remove the one that isn't leaking. You say it releases the brake and holds air.
I'm not sure what you mean by 'turn the slack adjusters'. Right now they seems to be under quite a bit of tension. How do I get that backed off? Thanks again!
In the lower RH corner of the drawing is the slack adjuster. Part #40,41 and 42 is the adjusting bolt assembly. The adjusting bolt is locked in place with a spring loaded collar. Push the collar in and hold it in with a wrench to release the lock on the adjusting bolt. Then you can turn the adjusting bolt either way.
So I got the collar to release by "nudging" it with a bar & got the pin out & chamber off. Now to find a shop to fix it. I think you are right that the next step will be to work on the compressor. When I flipped the chamber over on the ground oil dribbled out. Probably not good. Thanks again for all the help so far.
case 680g brakes..round 3 The ongoing battle that I thought was going to be fixed with help from a bunch of you guys. First a real simple air brake question. The rod is extended from the brake chamber with the spring and retracts with air pressure, correct? I had diaphragms put in one chamber by the Case dealer but still have brakes on one side(the non-rebuilt side). I put compressed air to the chamber but the rod doesn't move. Seems like it was not rebuilt correctly. With just the non-rebuilt side(left) hooked up and the right side hosed plugged the park brake button stays in. Any thoughts?
help needed again 680 brakes So, I took the brake chamber to the Case dealer from diaphragms & now it wont work at all. I put it back on(after returning to the dealer to have the bands put on in the correct orientation) and have no brakes. Had my gal get in and stomp on the brakes and only the non-rebuilt(L) works. I took the chamber back off & put air to it but the rod doesn't move. It seems that the spring pushes the rod out and air pressure moves it back 'in.' Is that correct? Either way, with air the rod doesn't move either direction. Any suggestions? Thanks
I moved this post to keep the same topic in the same thread. thanks.
I just read through this quickly but will offer a few suggestions. When you apply your foot treadle air goes into your brake chamber pushing against the diaphragm thus compressing the spring which in turn pushes out the rod and applies the brakes. When applying the park brake it exhausts the air in the chambers (spring brake) thus pushing the rod out and applies the brakes. Now if you have your park brake on and you push in on your foot treadle it can "compound" your brakes as 2 forces are working against each other. If your park brake valve keeps popping back out then you don't have enough air pressure built up to keep it released. Think of it this way..if you lose your air pressure the park brake will activate at or around 20 lbs psi. I'm not sure of your set up so I'm refering to a truck setup with spring brakes. Is your compressor running all the time? If working properly it will shut off after the maximum pressure is reached. With your brakes off pull out on your slack adjuster and see how far the rod will come out from the brake chamber. Your brakes might have to be adjusted or they might be adjusted to tight. You should have between 1/2 and 3/4 inch slack On edit...when checking your brakes make sure your wheels are chauked...safety first
All the info Grader4me provided is absolutely correct. If you are using the tractor air pressure, hook a 200 lb psi air pressure gauge on the end of the air line where it attaches to the brake chamber. See if you are getting 100 to 125 psi of air at the end of that line when you charge the brake chamber(use either the foot pedal or the parking brake). If you are not, then you have a problem in the tractors supply to that chamber.If you do have the required amount of pressure and the rod doesn't move, either the brake chamber was assembled wrong or something is binding inside it. Take it back to whoever it was that did the overhaul and tell them to correct the situation. Be sure to tell them to verify that it works properly before you go back and get it.
The in dash air gauge is no worky & Tinkerer suggested a manual gauge so that's what I'm working on. But, when I put air to the right side chamber that I just had Case put diaphragms in with my shop compressor the rod does NOT move either direction. On the machine with the slack adjuster disconnected, on the bench, it doesn't matter. Before I took it to Case it did move while still on the machine but I could hear air escaping. Tinkerer suggested new diaphragms as the fix so that's why I'm thinking that the rebuild is the problem??
The rod isn't already all the way out is it? If it is then all the air in the world isn't going to move it further..If its backed off all the way then it won't move either way until its adjusted up. Not sure if it would work with the slack adjuster disconnected as there wouldn't be any pressure to work against. I could be wayyy off here to... Did you try it on your machine with the brakes adjusted to where they are supposed to be? Make sure you have max air pressure and if it doesn't work take it back then. Or..while you have it all off just take it back and get it checked out....
I'm suspecting that it was reassembled incorrectly as the rod traveled in & out before I took it to Case. The rod seems to be all the way out. When I put external air to it on the bench it wont move either direction. Back to Case 1 more time. I assembled an air gauge onto a 1/4 T so I will put it on the line and see what it shows. With the right side hoses plugged the left side works fine and the park brake button stays in so I must be getting some air. Hopefully it is enough for both sides and the bad chamber is the culprit. Thanks for the help.
Sorry that I wasn't able to answer before. Computer has been down for virus. You need to be sure that your air lines are hooked correctly. If you didn't have your spring captured, you would end up with just the problem you have described. Usually, there is a bolt attached to the outside of your chamber in a holding tube. it has a unique shape on the head that fits into a slot inside the chamber, when inserted thru the hole located under a rubber plug in the center of the rear cover. You insert the bolt, turn to lock into place, install nut and washer, and tighten until you collapse the spring and retract the bolt into the chamber. This allows you to reinstall the chamber on the tractor and is also the way to release the brakes when necessary to move the tractor without air. It disables the brake. As explained, air releases brakes, and lack of air applies emergency brake. Managed air applies controlled brakes. Always remember that self adjusting brakes must have locking assy removed before backing off slack adjuster. Manual brakes are backed off as already explained by deprssing collar and esing wrench loosen brakes.Self adjusters usually need a 5/16 wrench and manual need a 9/16.
My pleasure..thats what this forum is all about....
Case 680E Air Brake Trouble All - I have an older Case 680E and am having trouble with the air brakes. It will not build pressure and leaks from the bottom of the treadle valve. I disassembled the valve and cleaned all areas including seals and sealing faces, but this has not helped. I can't find any replacement parts for this machine, but they do have them for one model year newer. Any input on whether or not they will work?