Freight liner Engine Brake

PapaD · 04-13-2015, 11:27 AM

Hi guys;
I have read before that the engine brake on these things are not the best. But someone told me that using a computer they can be set to be more aggressive?
what i have right now does not seem to control the speed when in cruise going down a med hill let alone anything larger. And going from low, med, high I really feel no difference. Anyone ever done this? New to driving these but have about 10,000 miles and have been playing but maybe not doing something right also.

I have a 2009 columbia w/ 450HP MB 45' Haulmark

thanks PapaD
2013 4501TS Haulmark

Bob86ZZ4 · 04-13-2015, 06:04 PM

You're doing everything right. And you've noticed something that nobody told you about. I had the same experience. Nobody told me about it either. I don't remember what forum I finally found this info out on. Apparently it is a programming thing. They set it up so the engine brake doesn't apply when the cruise control is powered on. Not just when it's set and holding a speed. But just having the power switch "on" for the cruise system. I don't know why they set it up that way but that's how mine is set and it sounds like yours is the same. I've had a lot of practice (about 50k miles) so it's not a problem for me. I usually shut off the engine brake when I'm cruising along. Have the cruise set. Everything is fine. Then when I start to go down a hill i shut off the cruise power switch. Then as the speed starts to increase I switch on the engine brake (mine is a true Jacobs brand so I can call mine a "Jake" brake, but I think Mercedes isn't actually made by Jacobs so to be most accurate you could call it an engine brake). Mine is only two stage. I start with the first stage, then if it's a steep hill and I'm not getting enough slowing I switch to the second stage. Then as the grade starts to smooth out I just switch back on the power to the cruise and push the "set" switch when it's going the speed I want to lock in. I then switch back the Jake to "off." Ready to do it all again. It sounds complicated I guess but I'm used to doing it this way and it works pretty good for me. I was told you can have somebody program it so that the Jake works even if the cruise is set. I haven't bothered trying to figure that out since my system works good for me.

I think Don (Bushpilot) has a similar truck to yours? Maybe he'll post something for us?

bushpilot · 04-13-2015, 11:07 PM

similar results w/ our coach (meritor smart shift 12 speed)....our (single stage) exhaust brake will not activate if the cruise is SET....

the exhaust brake will work if the cruise is ON (but not set).

i wish i had a multi stage exhaust brake...but the single stage we have seems fairly effective.

PapaD · 04-14-2015, 11:27 PM

thanks for the feed back and after reading the response I see i could have more clearly defined the issue while what i wrote was correct what i failed to add was the even when the the cruise was not engaged the engine brake does not seem to have much effect in either low/med/high. however i need to try and shut the cruise power off as Bob86ZZ4 mentioned above this may work. However the manual i have talks about the engine brake working with the cruise so i'm a little confused. Will need to talk with freightliner service center to see if they can program the brake to work a little better. thanks again for the info

A.J. · 04-15-2015, 11:35 AM

R u sure u have a 3 stage brake?
I know on mine and others I have seen most r only 2 stage.
Middle position on the switch is off, down is low and up is high.
Yes, as stated the cruise needs to be in the off position or the exhaust brake will not work.

bushpilot · 04-15-2015, 12:07 PM

how easy is it to upgrade from a single stage to a duel ?

our MBE4000 uses a different system (special 5th valve)....and the turbo ring (which i know i have).
there doesnt appear to me that there is a control (at least on our coach) for one or the other or...im guessing its all or nothing.

http://www.todaystrucking.com/road-test-mbe-4000-engine

PapaD · 04-15-2015, 06:03 PM

A.J I have a separate switch for on/off and i'm pretty sure the light says med whine the middle but now you have me second guessing myself. It is at the manufacturer this week getting a little work done and will sure check it out next week when I pick it up.

thanks again for the feed back

PapaD

Bob86ZZ4 · 04-15-2015, 09:50 PM

My Jake switch is not back lit. I don't think any of my switches are back lit? The Jake switch on mine is a three position rocker. Bottom pushed in is off. Middle position is light, and top pushed in is strongest.

Bob86ZZ4 · 04-15-2015, 09:55 PM

My son has a Freightliner FL120, 2003, with a Cummins N-14. He's an owner/operator hauling inter-modal containers. I just asked him about how his cruise/Jake play together. He said his Jake (forgot to ask but pretty sure it's a 2 stage Jake) works the same when the cruise power is turned on or off. He said if he's got cruise engaged and starts going down a hill the Jake will activate when the truck gains about 5 mph over the set speed.

rhead78 · 07-13-2015, 09:21 PM

I just purchased a 1996 FL 112 with the Cummings 330 hp engine. I have two flat switches on the dash one on the right has 4 cyls/2 cyls on it and the one to the left has a pic of a truck cab with what looks like a "shower head" with water coming out of it. Is this the power to the engine break? This switch is also illuminated.

bushpilot · 07-13-2015, 10:16 PM

the 4 / 2 cyl switch is gotta be the jake/engine brake, 4 cyl will provide the maximum "engine" braking possible (on your truck).

the other switch is probably an AIR dump (probably for the suspension air bags, but could be something else too).

bushpilot · 07-13-2015, 10:24 PM

btw / as an update on our coach - as much as i'd LIKE to have an additional (2nd) stage to our single stage exhaust brake....We really didnt need on our recent trip to Sedona (7% grades on i17).

Our single stage exhaust brake didnt completely hold the coach back (like it does on 5 & 6 % grades) we were able to manage the speed (let it gain 10 mph & then give it a good brake stab to bring it back down & let off so the brakes didnt get hot).

Gordy · 07-14-2015, 12:59 AM

What gear are you in when you say the Jake doesn't hold. It won't hold anything in high gear, you have to downshift it into probably 9 or 10 (with a 13 speed) to feel the hold.
When I got my C15 rerated I considered changing the Jake to operate with the cruise on but left well enough alone.

bushpilot · 07-14-2015, 01:23 AM

12th gear Gordy, in our Smart Shift, it does fine holding back the coach on smaller (5-6% grades) - but you make a good point - if it had been an issue i could have down shifted.

Bob86ZZ4 · 07-22-2015, 05:50 PM

Quote:

Originally Posted by Gordy

What gear are you in when you say the Jake doesn't hold. It won't hold anything in high gear, you have to downshift it into probably 9 or 10 (with a 13 speed) to feel the hold.
When I got my C15 rerated I considered changing the Jake to operate with the cruise on but left well enough alone.

My Jake functions in 10th gear (mine is a 10 speed autoshift). When I lift off the throttle or cut off the cruise power it kicks in and starts slowing.

Caracer13 · 12-31-2016, 12:24 AM

I just bought my 2002 fl112 with a c12 cat and the Jake doesn't seem to be working. Seems to be ano electrical issue as it works if I just hold the throttle to the floor then the auto shift makes it turn on to bring the rpms down but that is the only time I have noticed it working. Anyone have any ideas were to start?

Caracer13 · 12-31-2016, 12:27 AM

Forgot to add that it doesn't seem to matter were the cruise switch is and doesn't matter if it is high or low

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