I've got a 2017 Pete w/ the Paccar PX-9 engine. The engine brake hasn't been working for about 6 months now. Finally took the time to start diagnosing it and see what's up. So yesterday, before I lit out from one customer to another; I hooked my mulitmeter to the power wires for the solenoids. I cut some strands off a 14awg wire and stuffed them into the bullet connector and then put the bullet connector back on the stud. The thinking there was to see what voltage I'd get under the load of the solenoid and not open circuit voltage (for people just learning........open circuit voltage might lie to you. You could get 12-14v of open circuit voltage, but when you put a load on it the voltage could drop to something or maybe nothing...........this being due to corrosion or broken wires..........fyi). So the voltage was 13.9 voltage (running vehicle voltage) on both circuits with the jake set at 3 (max). Pulled valve cover this afternoon hoping to find a broken wire........nope, all good. Did a continuity test from stud outside of valve cover to blade connector at solenoids-all good. Ohm check on solenoids-10.1 ohms on both solenoids at blade connector to block and from stud outside of engine, through wire to solenoid and ground on block. Ran 12v+ from battery to solenoids and got healthy clicking from both solenoids. Checked for broken springs or missing C clip on the covers-all good. Called Peterbilt and ordered a 'tune up kit' for the jake brake.............initially told kit was a week out. Then got a call back that Cummins was out of stock, on back order, and God only knows when it will be in!!LOL The truck and engine have about 6,000hrs on engine and 163,000 miles on it. Engine brake is a Jacobs 490A. I honestly can't hear the jake even trying to kick in...........lazy jake not even making an effort!! Ok.........so that being said..........anybody know of any common problems with the Jake brakes?? No sense in tearing the brake out and just poking through it without the kit. Any O rings that commonly go bad on these things?? Just throwing it out there...........Thank you!!
I think I would check oil feed to the jake manifold. I'd also check the feed jumper between the housings.
Just out of curiousity...........how would the feed tubes get clogged up?? Anything in particular I should be looking for?? They wouldn't be silly enough to hide a screen in there, would they?? NEW UPDATED FEATURE..........SECRET SCREEN IN THE FEED TUBE!!LOL I'll pull a solenoid this weekend, check the O rings, and run it and see how much oil comes squirting out. Thank you for the reply and the idea.
Anything is possible, you said you could clearly hear the solenoids clicking, so process of elimination says check oil. I'm running on 25 year old experiences, but I seem to recall, instead of having a plugged galley, there was a restriction plug. Basically a plug with a .030" hole in the center . You can easily see a restriction fitting getting plugged.
Yup.........you are absolutely correct!!! Didn't know about the restriction plug, but that makes sense. Found plenty of crap in restriction orfices for hydraulics. Stumbled upon plenty of screens 'hidden' for the fuel system. Could be a piece of gasket or a small clump of RTV that was over zealously applied by the precious owner. Thank you sharing that. My family owned a pile driving business when I grew up. The knowledge that my grandfather and uncles had regarding heavy equipment was amazing. I really wished I was able to just download all that learned info that they had and put it in my brain. Every thing we've all learned, sadly; vanishes over time and due to our deaths.
But the internet is eternal, (for now) once someone shares, it's there for all to see.
It is eternal.............almost. I grew up, as my nieces and nephews so eloquently put it; back in the 1900's!!LOL Before cable, before cell phones, before the internet. Chiltons manuals were the bibles. If you screwed up, it was entirely acceptable to receive a smack upside the head to drive that point home. You wanted to get somewhere, you pulled out the map book and plotted your own course. No GPS with turn by turn directions.
Ok.............so update on the Jake brake dilema. I have spent some evening doing searches for Cummins 3800917 (I've got the number BURNED into my memory) which is the tune up kit for said 490A jacobs brake systems engine brake. Also searched for the Jacobs number (that escapes me at present). No luck to be on either end. This weekend had an INternational 4700 Ambulance warning about the brakes. This used the WABCO hydraulic/ electric pump system............which was replaced back in August of 2021. So while talking to International this morning at 7am, I inquired about the 'kit'. No joy...........non to be found in their system. Called KW of Boston and NH...........none to be found. Freightliner, Mack, etc. Non to be found. Called Cummins NE.......again. No availability. No estimate. If I ordered a kit, then it may show up Christmas next year. 25% restocking fee. Kit is $550 including shipping from Cummins. Fired off an email to Jake brake at the customer support email (honestly wasn't expecting any kind of help or timely reply). Those guys emailed me back pretty quick. Told me to try Cummins North East............told them I had. That I have a kit on order through Peterbilt from 2 weeks ago, listed everyone I've tried, and Ebay, etc. The business manager for the NE said the kits are going out every week and it shouldn't be a problem..........I begged to differ, forwarded 1st email listing attempts. Now sometime around 10 or 11 am, I received a call back from Cummins NE. 'We a made a few calls for you!!! We're getting a kit sent out today!! You'll have it tomorrow!!" I think someone from Jacobs called them...........got the ball rolling. I queried why the kits weren't available to Cummins NE................they said the kits are put together as needed, when needed, and shipped out..........they don't stock them. Jacobs says otherwise..............whole lot BS going right now!!! Ohhhh.............CUMMINS purchased Jacobs Brake Systems back in April of this year fyi!! They also bought Meritor ABS systems..........the big fish are eating the littler fish!!! Anyway...............just an update.
So just adding some info on the truck and engine. So BEFORE the whole jake brake crapped out I would get a CHECK ENGINE LIGHT for multiple cylinder misfires. Checked fuel pressure and valve lash............all good. It was a mystery!! Engine brake completely craps out..............No more codes and CEL!! So this makes sense...............NOW!! If only parts of the engine brake were working, then the engine would propbably think that different cylinders were misfiring. Probably varying amounts of compression on each cylinder. Just figured I'd throw that out there as an fyi..........
Have you ever verified your oil feed?
No, not yet. Waiting for the Cummins Unicorn Farts to show up w/ the Tune up kit. Didn't want to take it apart, find broken stuff, and have no parts. Figure I have enough aggravation in my life without doing it 3 times. I'll let you know though!! Reminds me..........need to call Peterbilt.
How sad is it that I'm excited like a kid at Christmas that the tune up kit showed up?? Called Cummins yesterday..........they said their computer system was screwed up and couldn't get me a tracking number. They said they'd call me back this morning with the tracking number. No call. Called them at 1pm looking for tracking. They said it had been delivered this morning at 9am. And LO AND BEHOLD...........IT HAD!! EARLY OVERNIGHT DELIVERY!!LOL Rebuild is going to have to wait until this weekend though...........
Well............started the day at 7am. Jumped on the computer, looked up some parts, did some research........out to the truck by around 8:30. Jockeyed some vehicles around to put the truck into the shade. Started pulling the valve cover off.......which includes removing the air intake tube and all the other crap in the way. Around 10am wife ordered me to go take a shower and change so I could take her and her sister to the airport. Got home, changed into work clothes then had to go pickup my daughter at her friends house. Went and picked her up, had to swing by the grocery store to pick up groceries, with the daughter........who didn't want to go in because some of the people who she goes to school with might see her. Home, groceries put away, child placated.......then my wife had hired a friend of the family to come over and cut wood.............when it was 100F and no shade on the wood pile. Had to take the backhoe off and put the splitter on for him. Then his saw died and needed to get one of my saws.........blah!! Got the jakes pulled out, pulled the solenoids, tested them on a battery and blew through them with my mouth. They don't seem to open much. Both solenoids open the same amount though. Screens on them are clean. Sprayed brake clean through both with valves open. Replaced check balls and springs from kit. Pulled everything else apart and checked them out. Spent 45 minutes trying to figure out why they decided it was good idea to put the hole for the engine turning tool above the starter, behind the ecm, with the wiring harness and some air lines running on that side and under the cab. Pulled the steering shaft to make some room then finally said screw it and pulled the plug out of the bottom of the transmission and used a screw driver to pry the fly wheel around to TDC. Put the brake assemblies back on and dropped one bolt down into the head. 45 minutes of using the magnets and o ring picks and I got the bolt out. Got the assemblies on, set 1,3,5 to .09 clearance, turned the engine 180 and set 2,4,and 6. Before I pulled the jake brakes I checked the valve lash as set. No chance at getting the .09 gauge in. I managed to get the 0.06 gauge in, but barely. Pulled the solenoids after setting clearance and fired the truck up. Plenty of oil flowing into the jake brake. That was at 7pm. Had to order pizza and then go pick it up before the pizza place closed at 8pm. The truck still awaits me to put the valve cover back on and reassemble. Tomorrow morning............doctors appointment, dentist at 12:15, then prothodontist at 2:15.........Tuesday......another dentist appointment at some time. I asked my wife this morning if she had scheduled all of this for when she was away.........LOL..............its been scheduled for over 6 months. So.....................that's how I'm making out with the jake brake. Just need to get truck back together and test drive. Someday.............good to have dreams...........LOL