Big D 23 Posted February 12, 2022 Share Posted February 12, 2022 😬big D 23 Quote Link to comment Share on other sites More sharing options...
Big D 23 Posted February 12, 2022 Author Share Posted February 12, 2022 Hey I’m having trouble out of my 2003 Mack E7 jake break. It takes a second or so to kick in then when it does kick on in higher rpms it’s very weak and barely sounds like it’s working till it gets to around 14-15 then it’s sounds good and kicks on stonger Quote Link to comment Share on other sites More sharing options...
Big D 23 Posted February 12, 2022 Author Share Posted February 12, 2022 Does anyone has any ideas on what could help? I have racked my brain and tested everything I know to test. Lash settings power to solenoids oil pressure. Quote Link to comment Share on other sites More sharing options...
BOBWhite Posted February 12, 2022 Share Posted February 12, 2022 The lash on those jakes is crucial. But I'm not Sure what they were using in 2003. I thought it was the power leash but they could have still been using dynatard. Someone around here will know! Quote Link to comment Share on other sites More sharing options...
JoeH Posted February 12, 2022 Share Posted February 12, 2022 The E7's had oil pressure issues to the Jakes, there was an external oil line kit to resolve this. But by 2003 you don't have an E7 you have either an ETECH or an ASET AI/AC. Quote Link to comment Share on other sites More sharing options...
blackdog2 Posted February 12, 2022 Share Posted February 12, 2022 I have a 350-HP 2001 RD when new had the same the dealer were putting " oversized " bearing to increase oil pressure ......then corporate say's we have a fix a new oil pump so mine was the fix before the external line's in other area's work well after ?  Quote Ed Link to comment Share on other sites More sharing options...
Joey Mack Posted February 12, 2022 Share Posted February 12, 2022 If he has Jacob's 690 head, the lash was changed to .021".. From .017" after a top oil feed update was done and the reset screws in the bridges were replaced with the 'Armoly' screws, and the check valve under the jake head was removed and replaced with the little screw in check valve. If these are not done then lash is .017" .. even after all of these updates, the engine brake still sucked, just not as bad. next: If you have "powerleash" you will see the celenoids are clamped directly into the rocker shaft's. they are sealed by 2 orings and the bail's that hold them in is 'it' usually a bad oring will cause the engine brake to operate all the time, however, it wouldnt hurt to check them, the bottom oring will stay in the hole, so you will have to pick it out. with this engine brake set up, the lash adjustment is different than for the 690 heads. Please post which engine brake you have. I assume Jacob's because of youre issue.. jojo P.S. correct bridge clearence adjustment and valve adjustment is really important. you may have pinless intake bridges, so no adjustment needed there.. 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted February 13, 2022 Share Posted February 13, 2022 Here is the part number for the top oil feed system.. the drilling procedure is VERY IMPORTANT. if you 'miss', the Jake head is junk.. Jojo 2 Quote Link to comment Share on other sites More sharing options...
Onyx610 Posted February 13, 2022 Share Posted February 13, 2022 (edited) There is a drilling fixture for this since it’s so important like Joey said.  https://www.bigmacktrucks.com/applications/core/interface/file/attachment.php?id=127406&key=e2c59db5a11bfd0e1983c492d8551f62 Edited February 13, 2022 by Onyx610 1 Quote Link to comment Share on other sites More sharing options...
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