n2deep Posted July 9, 2009 Share Posted July 9, 2009 The jake brake on my 70 R seems like it works now when it wants to. It won't jake at all until the engine rpms get down around 1500 to 2000. Any one have any ideas. Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/10003-jake-problems/ Share on other sites More sharing options...
fjh Posted July 10, 2009 Share Posted July 10, 2009 The jake brake on my 70 R seems like it works now when it wants to. It won't jake at all until the engine rpms get down around 1500 to 2000. Any one have any ideas. ThanksJake or dynatard? Quote Link to comment https://www.bigmacktrucks.com/topic/10003-jake-problems/#findComment-37946 Share on other sites More sharing options...
n2deep Posted July 10, 2009 Author Share Posted July 10, 2009 675 Jacobs brake Quote Link to comment https://www.bigmacktrucks.com/topic/10003-jake-problems/#findComment-37947 Share on other sites More sharing options...
fjh Posted July 10, 2009 Share Posted July 10, 2009 My first guess is your throtle lever is not set deep enough into the switch that runs it! its on the thotle lever on the fuel pump. Quote Link to comment https://www.bigmacktrucks.com/topic/10003-jake-problems/#findComment-37948 Share on other sites More sharing options...
n2deep Posted July 10, 2009 Author Share Posted July 10, 2009 its set as far as it will go and even bent the arm a little for some more, checked all the switches. Quote Link to comment https://www.bigmacktrucks.com/topic/10003-jake-problems/#findComment-37949 Share on other sites More sharing options...
ThaddeusW Posted July 11, 2009 Share Posted July 11, 2009 its set as far as it will go and even bent the arm a little for some more, checked all the switches.Should be a switch on the clutch pedal too. So you have the on-off switch, hi-lo (or hi-med-low), throttle and clutch switch. Then on the engine you have the fuel cutoff solenoid. The wiring is simple so tracing the problem shouldn't be a problem. Quote -Thad What America needs is less bull and more Bulldog! Link to comment https://www.bigmacktrucks.com/topic/10003-jake-problems/#findComment-37961 Share on other sites More sharing options...
fjh Posted July 11, 2009 Share Posted July 11, 2009 Should be a switch on the clutch pedal too. So you have the on-off switch, hi-lo (or hi-med-low), throttle and clutch switch. Then on the engine you have the fuel cutoff solenoid. The wiring is simple so tracing the problem shouldn't be a problem. I beleive the engine switch is faulty from what you discribe , if the switch feels rough to push in change it! Quote Link to comment https://www.bigmacktrucks.com/topic/10003-jake-problems/#findComment-37974 Share on other sites More sharing options...
n2deep Posted July 12, 2009 Author Share Posted July 12, 2009 Checked all the switches again and they function properly. Anything mechanical that could cause this, the truck runs good with plenty of power so it has to be in the jake heads. ""don't it""???? Quote Link to comment https://www.bigmacktrucks.com/topic/10003-jake-problems/#findComment-38017 Share on other sites More sharing options...
fjh Posted July 13, 2009 Share Posted July 13, 2009 Checked all the switches again and they function properly. Anything mechanical that could cause this, the truck runs good with plenty of power so it has to be in the jake heads. ""don't it""????To test the heads run 12v from a power souce ie: start relay hot side directly to the head with the engine running it should fire the jakes!If it dont then the solnoids can be haywire!If it takes a few tempts to gt em to work you may need to rebuild the heads . Quote Link to comment https://www.bigmacktrucks.com/topic/10003-jake-problems/#findComment-38022 Share on other sites More sharing options...
n2deep Posted July 14, 2009 Author Share Posted July 14, 2009 Checked the heads and they worked great. Changed the throttle return spring and the jake works like it should, guess it was weak. You were right Fjh. thanks for the help Quote Link to comment https://www.bigmacktrucks.com/topic/10003-jake-problems/#findComment-38088 Share on other sites More sharing options...
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