Used Pacbrake install

[gimmie11s]

@Gregturley i found something interesting.  There is a warning label on my brake telling me this unit i have (part number C14000AT) is for automatic trans trucks only and that using it on a manual would harm the engine.  My truck is a manual so that got me wondering if the brake you have is for an auto or manual and is there really a difference?

 

Both of these brakes (yours and mine) are for 12v trucks with the weaker exhaust valve springs.  Fair enough.  My bigger question was what is the difference between the two brakes?

 

Looking at your pictures, ive found the answer.  You actually have a manual trans exhaust brake.  The orifice on your butterfly that is NOT plugged with a bolt/nut is 31/64" and much larger than the same orifice on my butterfly.

 

Both brakes have 2 holes drilled into the butterflys.  One of the 2 holes is a beveled hole that can be plugged with a nut/bolt (like yours) for more braking power once the theoretical 12v truck owner upgrades his exhaust valved springs.  The OTHER hole is specific to the manual trucks and the auto trucks.  The auto trucks have much smaller 2nd hole (around 1/4").  That manual versions have a much larger second hole of around 31/64" like yours.

 

Long story short, i should probably plug my 1st hole and drill out the second hole to match yours.

 

You should weld and re-drill your 2nd hole to a smaller size for better braking power.

 

Here are a couple pics

 

[url=https://postimg.cc/PvYGcQJm][img]https://i.postimg.cc/rsY8DhLY/pbrake.jpg[/img][/url]

[url=https://postimg.cc/8FYXdf4M][img]https://i.postimg.cc/KzcX2ngq/pbrake-warning.jpg[/img][/url]

 

https://postimg.cc/PvYGcQJm
https://postimg.cc/8FYXdf4M
 

 

 

 

Edited April 6, 2020 by gimmie11s

[Gregturley]

@gimmie11s i wondered about the hole size but never got around to looking into it. Makes sense what you're saying. I know the Pacbrake instructions i downloaded that covered the 12 valves said DO NOT USE WITHOUT UPGRADING THE EXHAUST SPRINGS. SEVERE ENGINE DAMAGE WILL OCCUR. Their caps not mine. 

 I did read a little about hole size online but did not research it enough.

 Wanna swap butterflies?

And for some reason the 1st 2 pics didn't work for me.

[gimmie11s]

1 hour ago, Gregturley said:

@gimmie11s i wondered about the hole size but never got around to looking into it. Makes sense what you're saying. I know the Pacbrake instructions i downloaded that covered the 12 valves said DO NOT USE WITHOUT UPGRADING THE EXHAUST SPRINGS. SEVERE ENGINE DAMAGE WILL OCCUR. Their caps not mine. 

 I did read a little about hole size online but did not research it enough.

 Wanna swap butterflies?

And for some reason the 1st 2 pics didn't work for me.

 

 

Yeah, for some reason i coudlnt get the website to embed the pics.

 

Thanks for the offer on the butterfly, but i already opened my second hole up some.  I'll try it out and open more if necessary.  

 

If you end up welding your hole closed an re-drilling, my hole was 1/4" before i opened it up.  Shrinking the hole on yours should give stronger braking.

 

I also countersunk my bolt holes where the butterfly bolts to the shaft.  Then i went and bought countersunk bolts an nuts ... hopefully this will allow better exhaust flow through the pacbrake when not in use.

 

couple more pics,.. lets see if these will embed.

 

https://postimg.cc/7GgmdQ9x
https://postimg.cc/JHMPLcYj
 

 

 

Edited April 7, 2020 by gimmie11s

[gimmie11s]

@Gregturley any idea if it would be safe to run the brake through the ECM 20 pin without a relay?  Basically PIN 20 would be in place of the throttle switch that was included in the kit.

 

I got my brake plumbed and tested how quick it actuates using the throttle switch and it is basically immediate as you cycle the momentary throttle switch off and on.. ..I really like this.

 

My thought is running it through the relay once i wire it to Pin 20 is going to slow down the operation of the brake.

 

Thoughts?  Quick video below

 

 

 

 

[Gregturley]

@gimmie11s a relay won't slow it down. A standard Bosch style relay switches in milliseconds and you'll never notice it. A relay will protect the ecm from excessive current draw thats why its used. I would not hook to pin 20 without a relay. 

 Pin 20 will give a slight delay between closed throttle and the command for brake operation. On my truck it was about 1.5 seconds. Works fine for me. 

 

[gimmie11s]

16 hours ago, Gregturley said:

@gimmie11s a relay won't slow it down. A standard Bosch style relay switches in milliseconds and you'll never notice it. A relay will protect the ecm from excessive current draw thats why its used. I would not hook to pin 20 without a relay. 

 Pin 20 will give a slight delay between closed throttle and the command for brake operation. On my truck it was about 1.5 seconds. Works fine for me. 

 

 

TY sir.  Today I got mine fully installed using the relay per your write up.  My delay to brake engagement once throttle is lifted is about 1.5 seconds also. 

 

Works perfect!

 

Thanks again... you've been a huge help.

 

 

.

Edited April 9, 2020 by gimmie11s

[Gregturley]

Happy it worked out for you.