ckuske Posted May 26 Author Share Posted May 26 Make sure that vacuum line going to the valve on the brake pedal isn't open. That's a dump valve and needs to be sealed for the system to work. The line is connected to the servo, and looks to be good all the way through the firewall to the dump valve in the cab. But as a test, would capping the nipple for that hose at the servo work? Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 26 Share Posted May 26 The line is connected to the servo, and looks to be good all the way through the firewall to the dump valve in the cab. But as a test, would capping the nipple for that hose at the servo work? Yes, for a test you can cap it at the servo. Just be aware that then the only way to turn it off is via the switches on the horn pad. Or turn the key off. Link to comment Share on other sites More sharing options...
ckuske Posted May 26 Author Share Posted May 26 Yes, for a test you can cap it at the servo. Just be aware that then the only way to turn it off is via the switches on the horn pad. Or turn the key off. I capped the line that goes to the Vacuum Dump Valve at the servo and... Speed Control now works!!! . On, Off, Set Accel and Coast all work - I didn't try Resume yet (it won't work without the dump valve working, anyway). To determine if its the line or the dump valve itself, how would you guys go about testing it? I was thinking to just pinch the line near the valve, and see if the line holds vacuum from the servo to where it is being pinched off. Should I just buy a new valve as well since I'll be trying to put a new brake pedal adapter in too? This one has been driving me crazy, I'm happy to have the end in sight. Thank you again to Gary for the parts! Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 26 Share Posted May 26 I capped the line that goes to the Vacuum Dump Valve at the servo and... Speed Control now works!!! . On, Off, Set Accel and Coast all work - I didn't try Resume yet (it won't work without the dump valve working, anyway). To determine if its the line or the dump valve itself, how would you guys go about testing it? I was thinking to just pinch the line near the valve, and see if the line holds vacuum from the servo to where it is being pinched off. Should I just buy a new valve as well since I'll be trying to put a new brake pedal adapter in too? This one has been driving me crazy, I'm happy to have the end in sight. Thank you again to Gary for the parts! Yippee!!! Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 26 Share Posted May 26 Yippee!!! Link to comment Share on other sites More sharing options...
ckuske Posted May 26 Author Share Posted May 26 Found a dump valve, but I cannot find the bracket that goes on the brake pedal, officially known as ADAPTOR (SPEED CONTROL VACUUM VALVE ACTUATOR) and the one you need is PN E2TZ 9C962-B and has ID #'s of E0TA 9C962-AC or AD; E1TA 9C962-AA; or E2TA 9C962-DA. I know I have the one that came off of Big Blue but cannot find it. In the pic on the left you can see the right one in the middle, the black one. And in the pic on the right you can see how it mounts. I'll look more tomorrow and then if I find it I can send it along with the dump valve - if you need it. Or you may be able to find the "adapter" online. It is a very common part - that is good at hiding. Hi Gary, Thanks for the part numbers. I did check the line - it didn't hold vacuum but of course after thinking about it and pulling the valve, the valve is supposed to hold vacuum when the button is pressed IN (which it seems to do). For some reason in my mind with the brake pedal I had the button being pressed in to release the vacuum, and not the other way around. I think the valve I have is ok (it holds vacuum when the button is depressed). Since I don't have the brake pedal adapter, the line is always "open" right now. I am going to run a new line from the servo to the valve in the cab - the line was in good shape on the inside but I didn't like the way it looked/felt in the engine bay. It seems to be 5/16" as well. Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 26 Share Posted May 26 Hi Gary, Thanks for the part numbers. I did check the line - it didn't hold vacuum but of course after thinking about it and pulling the valve, the valve is supposed to hold vacuum when the button is pressed IN (which it seems to do). For some reason in my mind with the brake pedal I had the button being pressed in to release the vacuum, and not the other way around. I think the valve I have is ok (it holds vacuum when the button is depressed). Since I don't have the brake pedal adapter, the line is always "open" right now. I am going to run a new line from the servo to the valve in the cab - the line was in good shape on the inside but I didn't like the way it looked/felt in the engine bay. It seems to be 5/16" as well. I think running a new line is a good idea. As for the way the valve works, I was surprised how it worked as well until I thought about it. So your valve is probably good, you just need the bracket. I'll look again tomorrow, but if I can't find one and you don't find one online then you might consider gluing a piece of aluminum angle to the pedal. I welded one on Big Blue's pedal since the hydroboost pedal is different and the old bracket wouldn't work. So I know that approach works well. Link to comment Share on other sites More sharing options...
ckuske Posted May 27 Author Share Posted May 27 I think running a new line is a good idea. As for the way the valve works, I was surprised how it worked as well until I thought about it. So your valve is probably good, you just need the bracket. I'll look again tomorrow, but if I can't find one and you don't find one online then you might consider gluing a piece of aluminum angle to the pedal. I welded one on Big Blue's pedal since the hydroboost pedal is different and the old bracket wouldn't work. So I know that approach works well. I've started looking on Google. Not any hits yet, but I'll keep trying! Maybe it'll be another part I end up getting 3D printed for myself and others? Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 27 Share Posted May 27 I've started looking on Google. Not any hits yet, but I'll keep trying! Maybe it'll be another part I end up getting 3D printed for myself and others? That would be a good application of 3D printing. But you need one to measure. Still, a piece of aluminum angle epoxied to the brake pedal would be easy. I can post a pic of what I did if it would help. Link to comment Share on other sites More sharing options...
ckuske Posted May 27 Author Share Posted May 27 That would be a good application of 3D printing. But you need one to measure. Still, a piece of aluminum angle epoxied to the brake pedal would be easy. I can post a pic of what I did if it would help. Yes, agreed on the measuring. I'd have to do some trial and error to get it right without a reference part, to be sure. If you wouldn't mind posting a picture of what you came up with, I would appreciate it. Link to comment Share on other sites More sharing options...
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