MOloghauler Posted November 18, 2018 Share Posted November 18, 2018 I have an older model E7, mechanical motor with a 2 stage Jake. The jakes work on the low side, but the high isn’t working at all. I took the valve cover off and the power wire was broken, replaced the wire, and still nothing. Are there more wires under there I need to check? I couldn’t get the valve cover all the way off, just slid out of the way enough to get to the power wire. Is there a solinoid that could possibly be bad? Any help is greatly appreciated! Quote Link to comment https://www.bigmacktrucks.com/topic/54845-jake-brake-troubles/ Share on other sites More sharing options...
fjh Posted November 18, 2018 Share Posted November 18, 2018 (edited) 56 minutes ago, MOloghauler said: I have an older model E7, mechanical motor with a 2 stage Jake. The jakes work on the low side, but the high isn’t working at all. I took the valve cover off and the power wire was broken, replaced the wire, and still nothing. Are there more wires under there I need to check? I couldn’t get the valve cover all the way off, just slid out of the way enough to get to the power wire. Is there a solinoid that could possibly be bad? Any help is greatly appreciated! Year Please! Give us info or we can't help ! E7 Means very little! you need to pull the valve cover and look for rocker shaft pugs on some!need to know what year! Edited November 18, 2018 by fjh Quote Link to comment https://www.bigmacktrucks.com/topic/54845-jake-brake-troubles/#findComment-409598 Share on other sites More sharing options...
MOloghauler Posted November 18, 2018 Author Share Posted November 18, 2018 37 minutes ago, fjh said: Year Please! Give us info or we can't help ! E7 Means very little! you need to pull the valve cover and look for rocker shaft pugs on some!need to know what year! It’s in a 93 RD688 Quote Link to comment https://www.bigmacktrucks.com/topic/54845-jake-brake-troubles/#findComment-409602 Share on other sites More sharing options...
Challenger Posted November 18, 2018 Share Posted November 18, 2018 (edited) low side-1 head High-both heads Truck off, run power to the terminal sticking out of valve cover. They should make a "click" noise when the power makes contact. Click-good solenoid. No click-broken wire to solenoid or bad solenoid. You could also let truck idle and hold power to the same terminals (1at a time) and the engine brake should turn on (you'll hear brake) If you heard both solenoids click, but still have only 1 head working when you ran power while running, it could be- Loss of oil pressure in engine brake housing examples- split orings on solenoid most likely the bottom oring, missing plugs at the end of rocker shaft (plugs look like little freeze plugs), valve/ engine brake adjustment (in my experience this is more of a red engine problem MP8), Jake Brake needing updated Edited November 18, 2018 by Challenger Quote Link to comment https://www.bigmacktrucks.com/topic/54845-jake-brake-troubles/#findComment-409606 Share on other sites More sharing options...
MOloghauler Posted November 18, 2018 Author Share Posted November 18, 2018 Challenger, I’ll definitely check those things. I turned the switch on high with ending running and unplugged both terminals and had an arc from each wire when in plugging, and while I had the valve cover off I checked and am getting power to the solenoid. Quote Link to comment https://www.bigmacktrucks.com/topic/54845-jake-brake-troubles/#findComment-409608 Share on other sites More sharing options...
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