I'm a mechanic and I love ur channel. Its nice to see someone who knows what they are talkin about. I'm a huge fan. thanks for takin time to make videos

I love seeing people who are passionate and nerdy about their profession. So many tradespeople don't take pride in their occupation but they should. Mike Rowe has done a tremendous service to the trades. Great channel!

The short answer: a jake brake pops the exhaust valve open at the top of the compression stroke to release the compression that would otherwise push the piston back down like a spring.

This answers all my questions. I was getting the check engine light when the jakes were engaged on my C15. I'm subscribing now! Thanks a million!!

One of the best channels I've got, right next to dieseltech Ron. Keep these great videos with the knowledge that you provide with them!! Again thank you sir!!

I heard a good way to describe a compression brake when I was in school a few years ago. “The compression brake turns your power producing Diesel engine to a power absorbing air compressor.”

Great video, your explanation is much easier to understand, than any other video I've seen. Thanks

Not into Diesel engine repair but always wondered how a Jake brake works. Lots of good info thanks for sharing.

Thanks as always, fixed my Jacks , got wiring diagram from Kenworth and after suspecting switch found high wire is broken couldn't find where too cold outside re routed New wire from ECM to switch and all good. I always had complaint high med low are not holding that strongly even low med vibrates, CAT techs adjusted twice and said all good or use service kit. after putting new wire now found what real cat brake. can do when 100% .it was closed wire from year's decreasing current client from12.6 to broken wire.Current flows ECM to switch and then back.

Thank you much appreciated . from Australia

Very informative. Thanks for sharing your wisdom with all.

Awesome video!! Thank you so much. Very informative!

Just want to say im an auto tech have been for 20 years.work on sum light weight diesles. Nothing as big as you but really enjoy watching your videos very informative! Can tell you have a passion for your feild of work. Anyway thanks keep up the good work

Thanks for all knowledge, I have a 1999 peterbilt 377 with a cruise control that works only for idle meaning it won't work on the road.

hi friend!!!thanks for all the great videos and i have good news, i got the bus engine running!!!! the huey pump was no good but also the pcm had a burnt circuit, with your help and all the research i got the thing running am a auto mechanic and now i have a great respect for diesel mechanic any way my friend keep up the great work and have a very merry chrismas. sinc marcial adorno from puerto rico

I'm working on a Detroit engine for the first time and to my findings this is exactly how it works. Also on trouble shooting I opened the top cover en test the solenoid with a test light acting like a resister while engine on idle and the Jake sounds was responding I suspect the fault is in the ecm

Damn bro! Just watched ur video on jake troubleshooting. Sure as shit u confirmed what i had been thinking. My jakes on the medium / high stage would only hit on the low side. So what i mean by that is position #1 works like a charm, positions 2-3, not at all. I gotta tell ya brother u my friend are a wealth of knowledge. I know as a newer O-op i sure as shit appreciate it. Thank you much. Keep up the good work hoss!

Thank you so much. Very well presented.

Thank you very much for such valuable information. God bless you.

Adept ape thanks for the videos ,they are super helpful ,just had a question so I have a c15 single turbo engine and the exhaust brake quit working while driving and engine light came on ,when I checked the engine the engine oil was at the add mark on dipstick just wondering if low oil would cause the Jake's not to work??

Thank you for another great video.

Awesome as usual 👍

First off your channel and videos are awesome. My issue is on a 5EK41063 the jakes do not work on any setting when engine gets to operating temperature. Not even when manually pushing the center button solenoid. Issue stated after engine was overhauled and has since had overhead ran a few different times with no luck. Solenoids, wire harness, switches all have been replaced.

Wow! Thanks Josh! I have "check engine light" when jakes are active and stage one cuts out after a few seconds. Now i know where to look and hopefully my "fix it list" for you will be a bit smaller...lol

Great video Josh. Just curious, but what would be the effect of a loose or tight lash setting? For instance, an early 6NZ with a lash setting of .033", plus or minus .003". If the lash were set at .028", or .037"? What mechanical effect would these settings have on the engine, and engine braking performance? And, would any engine damage result? Thanks in advance.

Your the man! excellent video!

What will cause a week Jake brake on 06Cat C15? I can feel the difference between stages but still jakes are week and cant hold even a 25k load down hill. I recently did a overhead and nothing changed.

Thank you so much for sharing your knowledge, and explaining easy so we can try it on our own. I do have a lot of oil coming around the solenoid, how hard is to do the tune up kit? Do you have a video that shows how to do it? Is it easy enough for a low level mechanic? Thanks in advance, hope the best and success for you.

Eng. 1 fmi 5 spn 1072. Would this be cyl 3&4 center v.cover?

Good Job...Keep Teaching...

Hey josh love your channel I’m a truck and coach mechanic and work on a number of different model engines I got asked a question the other day if a too high of oil pressure could cause the jakes not to work and I was stumped I wonder if you would have any input to that thanks a million

Great stuff Josh! What about the other 2 solenoids on the jake brake assembly. One on each side of the center solenoid. The ones I tested all read 1.1 ohms. The center solenoid measured 10.2 ohms as you mentioned. Thanks bud!😊

I have Jake’s that are only working on low. No medium or high level. I do have Cat ET and my ecm is showing correct position when commanded by the switch. My question is can you simply take a DVOM and test for voltage at the wires going into the solenoids? It’d on a 5EK 3406E with I believe they are 310 model Jake’s.

A little tip to help. many Jake solenoids have a plunger in the center. If you push that down with a screwdriver, you can manually activate the Jakes this is a quick way to determine if you were issue is mechanical oil or electric.

Great Videos keep it up

I'm just a driver looking to buy my own, i come across your and was impressed on how you explained the workings of the motor , is it possible to do a ideo on what to look for in a used truck (CAT) as i am looking for a 550 cat hope this makes sense

There is a sensor/switch on a clutch pedal, if a bushing gets worn on pedal arm it will play and won't send a signal to the ECM. That switch also for cruise control. If my Jake or cruise don't work I pull the pedal up. It's 387 2007.

Our 96 Pete dump has a front Jake that will blow a fuse immediately if it is applied. So I keep it unplugged until we get around to pulling the valve cover.

very good video bro ... I have a question ... 2001 caterpilla C15 475 jake brake cylinder # 1 end # 2 it broke down and I replace it end broke again!

Great help thank you

Damn you have the gift to teach...

Wow, great teaching. I am not a mechanic but I understand What you have educated. And my jake brake is not working the oil shooting upward through the solenoid to the engine cover so much and I am having a problem. Some times I am going short in fuel in fuel filter. Is there a possibility to fix this jake brake or do I have to buy a new one? Thanks.

I have a 94' 425 3406B and it only has 1 switch "0ff, 1,2" and checking with a text light has power to the jakes be when applied runs/shakes roughly. was intermittent but now constant. I've replaced the switch at the back of the pump and no change. could the jakes need rebuilt or where should i start to look?

Great info although I'm having a N14 Celect jake issue! Can a bad idle control switch make the jake power go in and out??? Meaning level 3 is giving me level 2 power one minute and then kicking in to level 3 power after a while or sometimes never and will just stay at level 2 power while on level 3 and sometimes will give me level 1 power! Only code that read was cruise control but my cruise control works, the Idle control switch which is below the 2 cruise switches is the only one that doesn't work!

I just bought a 97 pete 379 and I'm still working on it i heard it back fire threw exhaust, any idea has cat 3406 not sure B or E. Can it run like that so I can save some more cash to fix or should I fix it asap runs good but it does have a check engine light on and I still waiting on a mechanic to come check it out.

my man I hope you can read this and answer my question please I have a cat c15 twin turbo ,,,,That when I used the engine brakes for the first time ( I never used it before)... I have very bad and toomuch air in coolant pushing coolant out that happened right after a new cylinder head installed please any suggestions Thank You

Hello!! I have a peterbilt 335 with the paccar x6 engine with engine brake, my question is my transmission sometimes fails and the scanner showed low voltage but we couldn't find the problem, whenever the transmission fails the jake brake doesn't work either. Have you had any experience like that?

Thank you sir

How often do jake housings need rebuild or tuned up. I had a number 3 exhaust rocker break and someone I know says the jakes need rebuilt.

my Jake works on low, but on medium or high the check engine light comes on, and the Jake make s little noise then nothing. about how much would that job cost, answer greatly appreciated. c12.

my dad has a mack CX613 and the jake is strong the first time you use it for the day then it is weak for the rest of the day under operation. no check engine light. if you had to take a guess what is wrong with it what would it be?

Hi I just bought a Peterbilt with a 3406e cat I have never drove a semi with a Cat before what is the highest rpm should I run at ? Thank you

I’ve got a 2001 c-15 in a Pete 378 and this thing either has a normal functioning engine brake alike every other truck I’ve driven or.. for out of no reason that I can pinpoint as of yet, it will only engage after a solid 20psi+ brake application when it’s having one of these no work normal fits.. Notably on one drive when fully loaded going downhill slow for a long time the engine brake system disengaged and never worked the remainder of that drive until the next time the truck was used.. I’ve installed a new oe on off switch and replaced the throttle pedal sensor .. any hints or clues?

Just to add to Josh's excellent video, I would like to mention one additional malfunctioning scenario along with its repair. Occasionally, a computer controlled 340 Jake and other Jake models will remain on after the engine has decelerated to idle speed or remains on when accelerating. The problem lies with a broken control valve spring (there are two) per Jake. Just remove the valve cover(s) and the control valve cover(s) to replace the spring(s). Good luck locating just a new spring, though, as I have had to purchase the entire Jake Brake rebuild kit just to secure a new spring - so all the Jakes receive new parts minus the solenoids. If one desires to only replace the defective spring, the #1 and #2 dash Jake switches can be employed to narrow your troubleshooting efforts to locate the offending Jake.

Thank you

Hey, I need a little help. I have a rollback with a cat c7 motor & Allison transmission combination. it quit while I was driving on Friday, turns over has fuel and won't start. all my lights come on my dash when I turn the key besides my check engine light. I assumed the ecm isn't getting power but I don't know, I got a check engine light before it cut off while running at 68 mile per hour hit a bump then motor turned off.

I had a question so I have a 3406e with the old style Jake’s we’re good from ecm to solenoid and switch to ecm is getting voltage but James won’t turn on. Apparently truck obtained a new ecm and previously the Jake’s worked I’m in desperate need of help this truck has me stumped also it has no check engine lights 🙏🙏

Maybe you’ll see this maybe you won’t. But my issue is intermediate. I get full jakes when the oil is colder and the pressure is higher but when the oil is up to temp there’s an audible loss of power and you can physically feel it. I thought it was the solenoids going bad but now im not sure. I’m planning on replacing them all here in 5 days so hopefully that fixes my problem. Before I go that route do you think my problem lies elsewhere?

You're the man

Cat trucks sold in Australia. Do you know if freightliner builds these and if they have the c15 or are the engines from elsewhere

I assume that the Jake brake equipped engine is non-interference type where the open exhaust valve will not strike the piston crown when the exhaust valve opens at piston TDC compression stroke for Jake brake operation.

98 Kenworth W900L, 60 Series Detroit & only have Jake on 2 not 1 or 3. I'm going to pull the rocker cover & hope it's a wire, it's the old school push on wires so here's to hoping! Wasn't going to attempt this but this video changed my mind lol

since jakes are manually adjustable. can they be tweet far as filler gauge goes , to get better performance?

Would you please explain the DETROIT 12.7 JAKE BRAKE function process. Thank you

Hey josh i love your channel, thanks for posting these videos. Do you have the name to the multimeter tool you used to diagnose the issue? Your amazon link to it is no longer is active.

Well I need your help am having problems with my jakes there not slowing me down at just had the tune up kit put in set the valves again and still not doing much motor is a 6nz C15 thank you plz help

Trying to see if I can get some help with a jake issue. 2006 Peterbilt 379 with 475 acert cat. Engine was rebuilt about 2 months ago by cat. Engine brakes don’t work properly. Seems as if they are on low to medium even though the the switch is on high. I can move the switch from medium to high and it seems as if there’s hardly any difference at all. The mechanic at my shop checked the overhead and said it was out very little. These things are driving me crazy because they aren’t working properly. Also, in the mornings below freezing the truck skips and sputters when I start driving it for about 2 miles with lots of smoke out of the exhaust and raw fuel smell. Fuel filters have been replaced, but they are not cat filters. Also it doesn’t have the power that it should have. No engine codes at all. The mechanic at my shop doesn’t want to take it back to Cat because without an engine code he says they won’t touch it. I’m pretty mechanically inclined and been driving these for years. I know this engine isn’t operating properly. I want to try to fix it myself if i can. Can you help me with any advice at all? Thanks!

I have a C-15 6nz. I can turn jakes on low and it works turn on medium different sound and more making power. When I turn on high it’s the same as medium. Any suggestions?

Question for you. Jake are working but when rpm starts coming down I start getting random popping from the front Jake break almost like a miss with that Jake. At high rpm it sounds right just happens when the rpm’s start to come down

Okay I have a question then 2ws 3406 in a 2000 w9 jake works on all three settings but won't go into stage 3 but on three it works like stage 2?

How to program ECM to give more boost when jake brake is activated or can it be adjusted to come on harder

Thank you going over the topic of Jake brakes. Maybe you've governed it before. HD Diesel over-the-road engines use high boost pressure in the range of 42 psi. to make much of their horsepower How does the Jake brake system produce such high braking hp nearly as high as when hot exhaust gases are generating high boost pressure for maximum engine power? With no combustion going on there is much less exhaust pressure to spin the turbo.

I just recently purchased a 05 w900l when I got the truck the jake brakes work perfectly about 3 to 4 days ago they're stopped working they still come on but does not slow the engine down like it used to when I first purchased it what will cause that

I'm having an issue with an mbn that on settings 1 and 2 works fine but on 3 it's like it stays on setting 2 and doesn't get stronger like it should. Now I had a guy check them and he literally did nothing but take the valve covers off and checked the overhead and solenoids to see if they were working.. he said everything looked fine and normal.. put the covers back on, I go down the road and crazy enough they worked fantastic, for about a week and went back to the way it was .. I had decided to just deal with it.. but then I had diesel in my coolant or we thought, so they checked to see if I had injector cups leaking and to do that you gotta remove the Jake housings. Turned out to be oil and not diesel and it was the oil cooler... long story short they put it all back together and I drove it and wouldn't you know the Jake's worked fantastic again on all 3 settings, until a week later I lost 3rd again... with all that being said I'm thinking it must be a bad wire in the harness somewhere where they had inadvertently got it working for a while by maybe moving the harness and then it eventually wiggles itself loose and it loses signal again.. would that be logical or would it be something else? Any thoughts? Or what I could check

I have a problem with my engine brake that i cant figure out. When its at higher rpms it works fantastic. When it gets down to 13 or less on the tac its breaks up, works and doesnt work in intervals. Is there a problem with the rpm sensor in the ecm? Or does it need to be hooked up to a conputer and adjusted? Im at a loss. Ive monitered oil pressure and such thinking the sensor was messing with it but no luck as it seems to be fine.

I have a question, my Jake will work only on stage 1 and rarely and I stress rarely will work all 3. where do you think I should start?

jake brakes are awesome they sound so nice

12.7 detroit early in the morning jakes work good but after 30-45 secs it sees like it fades out and stage 3 sounds like stage 2. But there are a difference in stage 2 and 3 when this happens. In your opinion what would be the issue?

I have a 1994 357 Peterbilt with the 3176 caterpillar. the jake brake will work great for 1 hour in the morning and then would not even try to work for the rest of the day until the engine has cooled to Luke temp. Then you may have another hour of Jake operating

Great info on this topic. Next video topic may I suggest is CAT Brake Saver, Can it be installed on any C15 engine? How does it work? Thanks again for all you do for this industry. JSL

Great video. Have you ever seen a jake stop working after the oil gets good and hot? Older 3406B , the voltage is present and don’t see any oil leaks.

like the new intro👍

In an English class, the subject would be "Engine Brakes" followed by subsection (a) Compression Brakes, and that followed by subsection (b) Exhaust Brakes. Clessie Cummins Sr. invented the "Jake Brake", an invention which was first declined by Cummins Engine Co., but then picked up by the Jacobs Manufacturing Co. Adept Ape - I am really enjoying your videos, as you are quite knowledgeable. There may be an instructor position awaiting you in your old age at your regional CAT HQ.

Hey sorry to bother, i got a Cat 15 single turbo, i notice the jake brake #2 is leaking more oil than the other 2? Any ideaz!!!!'

I have an 06 W900L 86 inch studio sleeper, so about a 19-20k weight truck. In the rain when I'm bobtail I can have the Jake's on high and the wheels don't skid, is that a weak Jake brake or is it normal for a big truck like that? In the 2015 Freightliner day cab with a Detroit the Jake's would throw me through the windshield just about.

The jake configuration is 212 not 122/221 so to eliminate snapping the crank on a unloaded motor. Eg: reving motor in neutral with jakes on.

Thanks for the vid man was helpful . I thought that the Jake break restricted the amount the valve opened to create higher compression more resistance on the engine. I would of thought if it completely opened the valve it would have no compression so I thought it would allow the engine to spin easier . Any way can’t argue with a diesel mechanic about Jake breaks . Cheers

Any idea where I can this kind of knowledge for a Cummins you're extremely knowable but I own a n14

I have a 6nz that the Jake's only work when the engine is cold, once the oil warms up..no Jake's. I have put a tune up kit in the Jake's and did not help. I don't see any damage or oil loss and took apart and cleaned each housing and reasembled. Could the oil be bypassing inside the housing around the Pistons instead of pushing the Pistons? The truck has 30psi hot idle oil, and 60+ 1400rpm oil psi

I'm coming to a stop sign and my truck starts engine braking on it's own is that normal? Engine was warm about 200. It is an auto so not sure. Sounds like lvl1 engine brake. But I don't have it on. It's not braking hard but it's just downshifting with the engine brake on as I slow down or come to a stop.

I have a CAT C-15 ACERT. DOES USING THE J-BRAKES TO OFTEN DAMAGE, CLOAK OR SHORTER ITS LIFE SPAN? THANK YOU. THE DPF FILTER

Good information! I came across your video in a search for an answer to another problem. So I figured I may as well ask you. I have a C-15 with a marine cam. When the jake is active, my cooling system is being massively pressurized. With the radiator cap removed, it will blow a column of coolant a foot high. I'm thinking head gasket, but then, wouldn't that pressurize the cooling system all the time? If there is anything else that could cause this, I'd like to figure that out BEFORE I pull the head. Any thoughts??? Scott

Hi, Do you know Where will I find the fuse for Jake brake 96 357 Peterbilt 3406c

Having a problem with my Jacob engine which only has (Off - lo -Hi) for the most part it works fine, except when I'm slowing down on a highway off ramp. When the engine rpms slow to about 13-14 rpms the engine start shacking rocking the whole truck. I just had my engine oil changed and it still does this...….What could it be?

when I push down on the jake solienod should oil spew out on top of the housing? I believe out of the solienod not sure but it was spewing oil

Great video. I have a MBN C15 or bridge motor and the Jakes are extremely weak. reminiscent of the old B models. I recently had it "un" bridged and an overhead done and check the Jakes. my power is up but the Jakes are the same. no check engine lights just extremely weak Jakes. any ideas? Thanks for any help.

Hi, I am attempting to repair a c15 acert engine compression brake non-operational issue. All 3 brakes failed at the same time. All 3 brakes were tested via external 12 vdc power source, none would function with this method either. But, the solenoids can be heard clicking when power is applied. The check valve at the back end of the oil manifold has been verified operational. Wiring continuity has been confirmed between ecm and all brake solenoids as well. Both solenoid power signals have been proven via 1amp test light when brakes are supposed to operate. I am at odds on where to go from here. Is it possible that this engine simply needs overhead adjustments? Strange that all 3 failed at same time. Any suggestions would be greatly appreciated. (The IVA system is setting check engine light also. The wiring continuity has been verified between the IVA oil pressure sensor, as well as, the IVA oil warmup solenoid. Both components have been replaced with new, but no improvements were observed. How can the IVA circuit and system affect the compression brake functionality?)

While the jack brakes on with low ,medium And high, will the ECM cut the power source to Injector solinoids

I have a cat 3176, its got the jake brake on when i stry stating it with ether, wont start at all, checked all pins for power anf grounds are fine, does that sound like a ecm problem or short between jake switch to ecm

I know its been years since you posted this, but hopefully you can help me some, Ive got a 1998 Kw T800 with a C12 older style, and the jakes work intermittently, some times they'll work others they just wont do anything at all, So i know theres functionality for them, it'll only randomly work when its on the road, if i was to try an make them work just sitting in the yard they wont work, where do you recommend i start looking? no access to scan tools either. thanks in advance