exhaust brake

[SRehberg]

I am getting ready to install a PacBrake for my 12V '96 automatic, and after talking to PacBrake, they indicate the stock springs (30lb?) are good for towing loads up to 11,000. I know it's recommended for maximum effectiveness to use the 60lb springs, but is anyone using one of these brakes with the stock springs and it works o. k. ? Our 5th wheel weighs approx. 8,000lbs.

 

[Joseph Donnelly]

You can expect about 35% better braking effort with the heavier springs.

 

[Joe G.]

The heavier exhaust valve springs allow you to have an exhaust brake with more back pressure without blowing the valves open. If you have a Pacbrake that is for the 35 lb springs and install 60 lb springs there will be no affect on braking unless you plug one of the holes in the butterfly valve in the brake or get the brake for the heavier springs. I think Pacbrake has a kit to plug the hole.

 

[dvaughan]

Originally posted by SRehberg

I am getting ready to install a PacBrake for my 12V '96 automatic, and after talking to PacBrake, they indicate the stock springs (30lb?) are good for towing loads up to 11,000. I know it's recommended for maximum effectiveness to use the 60lb springs, but is anyone using one of these brakes with the stock springs and it works o. k. ? Our 5th wheel weighs approx. 8,000lbs.

Why would you put an exhaust brake in with stock springs( are you sure they are 30 lb springs and not 40 lb ?) Go to bd web site and ask them, I run a bd exhaust brake and it works great on all the mountain passes through out British Columbia and we have some great one's. I pull a 26. 5' Bigfoot and its not lite and I hardly ever have to use the brake on the long and steep grades.

 

[SRehberg]

My understanding is the 12V engines came with the lighter springs from the factory, as where the 24V engines came stock with the 60Lb springs. I will eventually get the 60's but for the time being, is there a problem using the stock springs? I understand the beveled hole in the butterfly gets plugged once the heavier springs go in, but leave both holes open for stock, to provide a safety measure. I wanted to know if anyone is running the stock setup with the brake and having either good luck or ? It's always good to hear from users who use the brakes over the sales pitch that can sometimes be enhanced.



Money becomes a reality and these changes have to be made in steps. Thanks to all for any help.

 

[dalton4]

It is my understanding that our engines have 35# springs. The 30# figure is most likely the brake pressure setting for safety reasons to keep from floating the valves. If Pacbrake said the 30# setup was sufficient for a 11k trailer and you're at 8k, I would give the stock 35# valve springs a try. You can always put in the 60# valve springs later if required. Desired braking action will require you being able to keep tc in lockup while off throttle.



Jerry

 

[CPG]

With the addition of the 60 lb. springs, the Pac/Brake works more efficient in My "93" first gen. truck. This was reported by a few to be a waste of money, however it works very satisfactory on this old truck.

On either side of Donner summit I maintain My speed going down with My 26' Alpenlite 5th wheel trailer at 55 mph. This is in conventional drive.

This truck has the 47rh transmission & is not equipped with

a Loc up T/C, but it does very well.

Prior to this installation We used the service brakes a lot with a very uncomfortable feeling on this route. We are at ease now.

Its not the perfect set up, but does darn good. With the later

model trucks, it works much better. Get the 60 lb. springs.



Chuck Goode

 

[SRehberg]

I guess I'll need to get the 60lb springs a little earlier than I had planned, but suspose it's better in the long run. For locking up the TC, does the mystery switch seem to do o. k. , as buying the electronic controller as well, is out of my budget at the moment.

 

[Joe G.]

The mystery switch works just fine. However, you have pay attention to what's going on or you can break things in the transmission. If you need details e-mail me.