Cummins/Jacobs Exhaust Brake

[KeithTaylor]

Watching these forums, I see that the belt driven vacuum pump on the Jacobs system has a bad failure rate; mine is dead. Has anyone changed the vacuum actuator at the butterfly to an air pressure actuator? I'm thinking of running an on board air compressor for air bags, horns, etc. and if I could change the system from vacuum to pressure, I would eliminate the whole belt driven pump headache . . . any ideas or comments?

Thanks,

Keith

 

[goodguys75]

Watching these forums, I see that the belt driven vacuum pump on the Jacobs system has a bad failure rate; mine is dead. Has anyone changed the vacuum actuator at the butterfly to an air pressure actuator? I'm thinking of running an on board air compressor for air bags, horns, etc. and if I could change the system from vacuum to pressure, I would eliminate the whole belt driven pump headache . . . any ideas or comments?

Thanks,

Keith

you should have went the cummins route, never have a problem with it... and it is made by the designer of the engine... .

 

[Shadrach]

you should have went the cummins route, never have a problem with it... and it is made by the designer of the engine... .

Huh ??? The Jake one is what Cummins sells. Shadrach

 

[Schrowang]

I've had mine on since 2007 and had no problems with it. It does exactly what it is supposed to do; slow the truck down on the down hill side of a steep grade.

 

[HBarlow]

Bad failure rate? I didn't think it was all that bad.

I had to replace one in the 60k mile range on my '06. After replacing the original pump I ran that truck another 170k miles with the second one. When I sold the truck with 230k on the odometer it was working fine.

 

[WStewart]

Does anyone know where to look for an upgrade for adding the jake to my '03?

Thanks.

 

[mwilson]

Watching these forums, I see that the belt driven vacuum pump on the Jacobs system has a bad failure rate; mine is dead. Has anyone changed the vacuum actuator at the butterfly to an air pressure actuator? I'm thinking of running an on board air compressor for air bags, horns, etc. and if I could change the system from vacuum to pressure, I would eliminate the whole belt driven pump headache . . . any ideas or comments?

Thanks,

Keith

That is something I have pondered myself. I think I will e-mail Jacobs and ask that very question. I believe that the actuator would be the only thing that would have to be changed, the solenoid and all other items should remain the same. Only thing may that might not work is the butterfly's design where it would have to be pushed rather than pulled open, that may shoot it down as there might not be room for the air actuator with the current configuration. I am going to be adding onboard air for my seats so it would make sense if the vacuum pump ever gives it up to change it to air operation if the numbers make sense. I will let you know what Jacob's response is, it would end my speculation no matter what the outcome..... :-laf



Mike.

 

[mwilson]

Does anyone know where to look for an upgrade for adding the jake to my '03?



Thanks.

Please fill in you signature so we know what transmission you have.

If you want the Jacobs brake purchase it from Cummins, pricing is much better than buying it from Dodge.

I can provide you with the correct kit number if you need it.

There are several other brands used as well, do a search or two and you will find all kind of info and opinions.



Mike.

 

[ENafziger]

I believe that the actuator would be the only thing that would have to be changed, the solenoid and all other items should remain the same.

Yep! I had the dealer install the Cummins/Jacobs exhaust brake on the truck when new. The first vacuum pump locked up at 35k miles. When it did, it immediately shredded the serpentine belt, snapped the tensioner pulley and sent it into the back of the radiator. All pulley grooves had melted rubber in them, and the fan shroud got broken in the process as well... all in the 30 seconds that it took me to pull to the side of interstate in rush hour traffic pulling a trailer.

The second vacuum pump went out at 71k miles. The bearings went out of this one, and it spit them out the intake port.

At this point, I was done with the Jacobs.

I ordered an inline 5" PXRB PacBrake unit instead. It has the benefit (in my mind) of operating off positive pressure instead of a vacuum. It also uses a variable orifice to help maintain constant backpressure with decreasing rpm, giving it much more low end hold back.

I just ordered the 5" butterfly itself, and wired up my own air compressor, tank, etc. I'm using the Jacobs wiring, stalk switch, etc. The only part I had to buy was a 12v NC solenoid, as the Jacobs vacuum solenoid wouldn't work.

--Eric

 

[AH64ID]

I have over 55K on mine, and dad has over 60K on his without issues.

I did some talking with Jacobs and the main cause of failures is vacuum leaks. So if one fails on you leak check the system.

 

[mwilson]

I sent an e-mail to Jacobs at lunch time asking if an air conversion was possible and if so, what the part numbers would be.

Hope to hear back tomorrow morning.

 

[mwilson]

My reply from Jacobs.

Another great idea shot down in flames..... :{



"Jacobs does not sell any parts to convert a vacuum operated exhaust

brake into an air operated model. Jacobs does not recommend making that

modification.



Regards,



Jacobs Technical Support"





There you have it. .

Mike.

 

[CKelley1]

genosgarage.com sells the pump and the diaphragm. about the only thing harvy and i do not agree on is the jake. the bd and pac work a lot better than the jake we have several 06's and one has a jake still left on it. it is night and day difference between the two and i do not have as good of luck as harvey does. as my jake's vacuum pumps fail i convert them to bd. i prefer the bd over the pac but i think the pac has a bigger compressor and pack has a kit for what you want. just mount there compressor somewhere else. about 50% of my failures with the jake locks up the pump and melts the serpentine belt. i was driving one on a friday night loaded outside of pecos texas. it was tuesday before i got going again. and trust me, sight seeing on foot for four days in the summer in pecos texas is not what you want to be doing.

 

[KeithTaylor]

Thanks to all of you for your input! CKelly1, do you change the complete system to the BD system that mounts to the turbo like the Jacobs/Dodge/Cummins setup? I read one thread on TDR where a member installed an electric SSBC vacuum pump normally used for V8 hot rods with big cams that don't make enough vacuum to operate the brake booster. Money wise, I'm thinking I might go that way simply because everyone that has the Jacobs says they work great except for the belt driven pump. I'm very conservative with the brakes when towing and would really like to get this thing working. Again, thanks to everyone for your comments and hope everyone had a great Thanksgiving day . . .

Keith

 

[AH64ID]

All the variable brakes will have more mid range braking, from idle thru about 2400. From 2400 up they are all the same, as they all have to have the same peak retarding pressure.

 

[AABEN]

need more info. Auto or stick

 

[AABEN]

I have an 03 that had the jake put on when new still going good. It doer work very good with my stick. it will work as slow as 5 MPH .

 

[BrianJ]

I have been very happy with the Jacobs on my 2004. 5, with 85,000 miles of trouble free service. It will chirp the tires when downshifting if I don't ease into it.

 

[mroodzant]

Some will have trouble and some wont! its all about perspective right? on may way home I started to faintly hear the tell tale tick of another failed Vac Pump. Truck has 111,000 and this will be the 5th Pump that will be going in the truck over the past 8 years. Been a bad 3 months for my truck. replaced all 3 u-joints in rear drive line in Nov. just replaced power steering pump, gear box and brake booster in Jan. now this. Plus just changed every drop of every fluid in the truck except Brake system. But what else do you do. guess ignoring a bad Vac pump has more risks than just reduced braking ability, so guess I will reach deeper in pocket and fix it. Anybody know how hard it would be to do myself????

 

[AH64ID]

Some will have trouble and some wont! its all about perspective right? on may way home I started to faintly hear the tell tale tick of another failed Vac Pump. Truck has 111,000 and this will be the 5th Pump that will be going in the truck over the past 8 years. Been a bad 3 months for my truck. replaced all 3 u-joints in rear drive line in Nov. just replaced power steering pump, gear box and brake booster in Jan. now this. Plus just changed every drop of every fluid in the truck except Brake system. But what else do you do. guess ignoring a bad Vac pump has more risks than just reduced braking ability, so guess I will reach deeper in pocket and fix it. Anybody know how hard it would be to do myself????

I would guess you have a vacuum leak, which is putting too much of the load on the pump, and introducing contaminantes. According to Jacobs most recurring failures are due to vacuum leaks.