I'm asking for a friend who put a Pacbrake on a 12v 8.3. His truck weighs 25k and he has to go down Loveland and Vail at 12 mph. He said he was warned that e-brakes don't work good on 12Vs but he got one anyway and it barely makes a noticable difference. He also put on the heavy valve springs. I suggested he check the back pressure. I think he also needs to call PB. Anyone else have similar problems? I wonder if valve timing has something to do with it. TIA! Craig

 

Mine works great on my 12 valve auto but it only works when the torque converter is in lockup and for me that only happens above 35 mph or round about's

You don't say whether he has an auto or standard trans here?

 

That would make a big difference if he is running an auto and doesn't setup the signal for the TC to stay locked.

 

Also there are two holes in the butterfly. one should be blocked off, with the heavy springs in.

 

Pac has excellent troubleshooting charts on their website> http://pacbrake.com/PDF/L5056.PDF
they also have very good customer service by phone.

 

The 8.3 has a 9 spd RR. Has anyone heard that the Pacbrake isn't as effective on a 12v 8.3 or 5.9 if they have the heavy springs and plug the extra hole? Do you know what pressure they hold back? I'll ask him if his has the extra hole and if he plugged it. He really needs to call Pacbrake. Craig