The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Hard Pedal After Power Disc Brake Conversion

*JonnyC10* · 09-22-2014, 07:57 PM

Hey Guys,

I installed a CPP Grand Slam Kit and got it all installed. But now Im experiencing a hard brake pedal and stops just like it did when I had manual drum brakes. It hard to stop and I cant lock brakes up.

I called CPP and they told me to do a vacuum test on the intake and I am getting 15" at idle.

They told me to pump the brake and start the truck and see if the pedal goes down and it did, about a 1/4". He said that was normal. Then he had me let it idle for a few minutes, turn it off and pull the check valve out of the booster and see if I hear any air hissing, which I did. So he says the booster is working as it should but I am not getting enough vacuum. That I need 18".

So he recommends a vacuum canister or pump.

Any suggestions would be greatly appreciated. I read some threads on here about similar issues and majority say that the canister and or pump didn't produce any satisfactory results.

As far as I know, it has the stock cam. Just a plain ole 283 SBC.

09-22-2014, 07:57 PM	#1
JonnyC10 Account Suspended Join Date: Jul 2014 Location: NH Posts: 280	Hard Pedal After Power Disc Brake Conversion Hey Guys, I installed a CPP Grand Slam Kit and got it all installed. But now Im experiencing a hard brake pedal and stops just like it did when I had manual drum brakes. It hard to stop and I cant lock brakes up. I called CPP and they told me to do a vacuum test on the intake and I am getting 15" at idle. They told me to pump the brake and start the truck and see if the pedal goes down and it did, about a 1/4". He said that was normal. Then he had me let it idle for a few minutes, turn it off and pull the check valve out of the booster and see if I hear any air hissing, which I did. So he says the booster is working as it should but I am not getting enough vacuum. That I need 18". So he recommends a vacuum canister or pump. Any suggestions would be greatly appreciated. I read some threads on here about similar issues and majority say that the canister and or pump didn't produce any satisfactory results. As far as I know, it has the stock cam. Just a plain ole 283 SBC.