Jacobs exhaust brake reduced performance

[Bryan Beamon]

Our Cat C9 400hp with a Jacobs exhaust brake is not performing as it has in the past. We use to decend a 6% grade in 3rd gear with light service brake applications. Currently we can not decend a 5% grade and hold 2nd gear without several service brake applications while beginning the grade at 25mph.
Is there  any maintenance required for a jacobs exhaust brake  similar to a Pac Brake which required a high heat lubricant occasionally?
Dave Atherton previously recommend we might need a speed sensor replaced in our engine. I'm not sure if this is related to my exhaust brake reduced performance.
Any thoughts on what to check on our jacobs exhaust brake?
Appreciate any help
Thanks Bryan

[Mike Groves]

C & B,

I can only say that CAT includes adjustment on this during the adjustment of the valves.  That's what I was told when I asked what was included in a C-12 Valve Adjustment.  So, that must mean they can go out of adjustment and perhaps that's the issue.

Just my 2 cents.

Mike

[Bryan Beamon]

Thanks  Mike, l will call Cat to check out their opinion.

[Edward Buker]

Bryan,

I do not have a C9 but I do believe that you have an exhaust brake on that engine as you mentioned. It may be electrical solenoid or air cylinder activated and most of these exhaust brakes requires some hi temp lube maintenance at some interval to keep them freed up but it would depend on your particular installation. Cat should help here given it was probably original equipment. They can test if the unit is being activated or not, and if it is freely moving or not.

The engine brake adjustment with the valves Mike is referring to is for a full Jake brake on a C12 which is not an exhaust brake and has internal head mechanicals that do get adjusted. That does not apply to your engine unless you have a full Jake compression brake.

Later Ed

[Bryan Beamon]

Thanks Ed l realized afterwards that Mike had an engine brake when l looked at his coach. I contacted Jacobs and they agreed  with your assessment  of a air leak or butterfly valve not working correctly. We are traveling to Texas this week and will look for a Cat dealer that will diagnose the concern. Any good Cat dealers in Texas you recommend?
Thanks

[Edward Buker]

Bryan,

This should be a relatively easy diagnosis and repair for a good Cat dealer. What I would look for is a true Cat dealer for trucks, the larger the better. There are places with Cat signs out that are not true Cat dealers. One sign of a good size dealership is if they have a second or even a third shift running. Those dealers have seen it all. I am not familiar with Texas Cat shops. Take a look on the web, you can google map and see how large the shop and lot is.

Smaller Cat shops may be fine also, just my thinking is there is more talent and experience to call on in the larger shops with lots of years of combined experience. I had a good experience at Patterson Cat in Denver if you happen to go that way.

Later Ed

[Bryan Beamon]

Thanks Ed will proceed with your ideas.