sllimec47 Posted May 2, 2019 Share Posted May 2, 2019 Hey all. I have a 95 CL with a 454 E7. The Jake brake activates (both stages) but doesn't seem to hold back the truck much. It's also very quiet. I had it rebuilt but it didn't make any difference. I used to drive a 94 RD with a 350 E7 and even hauling heavy I rarely had to use the brakes. Any suggestions would be greatly appreciated. Quote Link to comment https://www.bigmacktrucks.com/topic/57020-e7-jake-brake/ Share on other sites More sharing options...
OldRedMack Posted May 2, 2019 Share Posted May 2, 2019 You can try to adjust the valves. Is it an actual Jacob's "Jake brake" or mack version "Jake break" of the time. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/57020-e7-jake-brake/#findComment-421794 Share on other sites More sharing options...
sllimec47 Posted May 3, 2019 Author Share Posted May 3, 2019 It's a Jacobs. I assume the valves were adjusted when the brake was rebuilt. Are you talking about the regular valves or the brake lash adjustment? Quote Link to comment https://www.bigmacktrucks.com/topic/57020-e7-jake-brake/#findComment-421854 Share on other sites More sharing options...
OldRedMack Posted May 3, 2019 Share Posted May 3, 2019 Intake, exhaust and brake lash. We had a 94 that had a weak Jake, adjusted all the valves and brake lash and it got a lot better. Still not great, but definitely better. Quote Link to comment https://www.bigmacktrucks.com/topic/57020-e7-jake-brake/#findComment-421866 Share on other sites More sharing options...
JoeH Posted May 9, 2019 Share Posted May 9, 2019 My 95 e7 350 if I don't use the engine brake while the engine is cool it won't work when it's at temp. Below 170 degrees both heads work. Above that they only work if I used them a lot before getting to 180. If I didn't use them at all, only one head works at all, and it cuts out and stops working at about 1500rpms. Solve that e7 engine brake problem. Dash switch says Jacobs, so I assume it's a Jacobs brake. Quote Link to comment https://www.bigmacktrucks.com/topic/57020-e7-jake-brake/#findComment-422256 Share on other sites More sharing options...
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