Although I like the Pac Brake very well, I have questions someone here may be able to answer:
1. What causes the delay between when I drop the throttle and when the Pac Brake actuates?
2. What can be done to make the actuation immediate?

I do not want to change the shifting pattern of the transmission, which makes it go to 4th gear when it is safe to do so.

Bob, I think the "delay" is non adjustable unless it has to do with the linkage adjustment re: excessive "play" or the solenoid.

I will have to look at my manual tomorrow and get back to you.

OAN, I had a bit of delay (more than now) after we bought the coach but I purchased the PacBrake lubricant and lubed all of the required points which minimized the delay.

On ours, it seems directly tied to speed and gearing but the unit basically works off of a solenoid so maybe there are other options.

Ken

Ken,
Thanks.
I don't have a manual and would appreciate any guide you can give me.
FWIW, I lubed the brake and checked the solenoid. All is free and there is no real 'play' in the linkage.

I did not, however, check to see if there was a flow restrictor on the cylinder. If there is, it could be set to allow only a small bleed of the air at the rod-end, slowing the response.

I think I'll run 12VDC directly to the solenoid to see how fast the actuation responds. If it does so quickly, there must be something else governing the timing. Don't think I'll mess with that until I have more info.

Bob, don't have my manuals in front of me but I seem to recall reading that the Pacbrake will not kick in until the operating parameters for the next lower gear are in range. In other words, the pacbrake will not engage until the vehicle is slowed down to the top end of the next lower gear. I think your delay occurs when the vehicle is bleeding off momentum until it gets to the next lower gear operating range.

Try getting off the acclerator while applying gentle brake pressure until you feel the Pacbrake engage. At that point you will have reached the top end of the next lower gear (check the tranny display) and the Pacbrake should take you down through each succeeding lower gear until you get to "22".

Thanks Chief.
That makes sense and I'll give it a whirl.

I have been seriously looking at upgrading to the the PRXB model, which is supposed to be effective at the lower speeds. Any comments?

if it aint broke dont fix it.

Bob:

I looked at my manuals and my version, and possibly yours, does not have any adjustment. I believe Chief was right about how it actuates and that may be the reason for the "improvements" on the newer models.

I have found that there are times when I wish it would come on earlier and stay on longer but I have adjusted my driving style a bit to compensate. I give the brake pedal a very firm press to "kick-in" the PacBrake and then take my foot off the accelerator if I really want it to continue to slow down quickly.

The new model (PRXB) appears to have what you want but it runs from around $1065-$1300 for the parts alone. Below is an application chart from PacBrake and for my engine (C8.3), I see a note that my engine might require a set of HD valve springs so before I would buy this, I would see if there are any caveats for your particular application.

PacBrake Website

Ken

Ken,

Thanks for the reply.

The price I got from Pac Brake was right around $810.00, including new clamps and shipping. There was no mention of possibly requiring HD valve springs for my 330 ISC.

CW quoted the entire job at just about $900, including labor and new clamps. The biggest problem I have with that is the drive to get to the Amsterdam, NY facility.

Consequently, I believe I'll do the job myself. Heck, after changing my shocks, how much trouble can it be?

Regarding the delay; I found that I was using it in such a manner as to create the delay. I've since modified my driving style to allow quicker actuation.

Bob