2nd Gen Non-Engine/Transmission Required Maintenance - ISB Jacobs Exhaust Brake

[Thomas]

I've had the E-Brake by Jacobs on my 2000 Ram for 7+ years & 130,000+ miles, all trouble free. While hauling my TT several hundred miles from home recently I noticed that I had a dead pedal for about five seconds after being off the throttle for several seconds. The "dead" period ended with black smoke & skyrocketing EGT's. This led me to check the operation of my exhaust brake. What I found was that it was taking the exhaust brake about five seconds to totally release. I switched off the exhaust brake and drove without any problems.

I had time today to fix the brake. The problem was caused by a clogged sintered bronze breather filter vent mounted on the side of the vacuum solenoid assembly. The vent allows air to enter the system and release the brake when the vacuum solenoid switches to the brake off position. The almost totally clogged vent allowed air to enter the system very slowly. I removed the vent, cleaned the vent with lacquer thinner, and reinstalled the vent. Problem solved.

The exhaust brake butterfly now opens quickly, likely much faster than it has for a long time.

I'm adding a sintered bronze breather filter vent (McMaster-Carr - $1. 21) to my tool box. It can be changed in minutes.




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[WStrmiska]

Thanks Thomas for the heads up.

 

[n7gxz]

I just did the same cleaning about two weeks ago, such a difference with it cleaned.



Kevin

 

[Thomas]

Were you having problems with the butterfly opening?

I don't recall reading of a single problem with a properly installed Jacobs brake in more than seven years here.

 

[AndyMan]

I got and old brake assembley and a NEW solenoid, and mine does this EXACT same thing. How in the heck can you tell that the breather is clogged? The sintered brass/bronze filter/plug assembly is SO fine?



Thanks for the tip though... I'll be trying that tonight.

 

[Thomas]

. . . How in the heck can you tell that the breather is clogged?. . .

Watch the actuator on the exhaust elbow while the engine idles and a helper turns on & turns off the +12v. to the brake. With a clean filter and all else okay, the actuator should go from the butterfly-closed position to the butterfly-open position very quickly. With my almost totally clogged clogged filter it took about five seconds for the butterfly to completely open.

Another test would be to remove the filter with a 9/16 wrench and go for a test drive. If the filter is seriously restricting the flow of air into the system (opens butterfly) the change in exhaust operation will be apparent.

 

[Boondocker]

Good post! Thanks. Mine is very clean after about four years, but now I know to check.