Intermittent power brake loss CPP MC / Booster

[curvedglass]

I have the CPP front disc conversion and power brake master cylinder / booster setup.

My issue is that about every 8 to 10 stops it feels like my power brakes are gone. The trucks stops fine - just needs a whole lot more leg. The fluid level is fine and i do not hear any sort of vacuum leaks. When I installed the system I spliced the PCV line from the intake. Could that be fouling my booster? any help would be greatly appreciated.

[geezer#99]

It's not fouling it, just reducing the vac supply.
Seperate them.

[Captainfab]

Your vacuum booster needs a dedicated vacuum source. How much vacuum does your engine produce at idle?

[curvedglass]

Originally Posted by Captainfab

Your vacuum booster needs a dedicated vacuum source. How much vacuum does your engine produce at idle?

Not sure. Friend has a gauge I can borrow.

I did this conversion 3 years ago and have about 20k +- on the truck since then. This just started about a week or two ago. 3 season daily driver / 80 miles a day.

The only vacuum hose on the entire truck is the line from the PCV to the intake manifold. Where would I find another port? I am running a a stock 230 with Weber 2bbl and HEI.

I am hoping it isn't a bad booster. That setup wasn't cheap and isn't that old -never know with CPP. I had a failed prop valve piece go bad the first year.

[chevy_mike]

If this has been fine for 3 years and is now a problem, I will vote bad booster.

My buddy has done two power disc conversions using CPP and both, new out of the box brake boosters were bad. We were able to get a solid pedal but it was hard to push, like no boost assist. In both cases CPP sent a new booster and after installing, they worked as they should.

If you haven't changed anything and the brakes are working, just needing a strong pedal push, booster is the fault. Don't overthink this.

[Captainfab]

I would have to say a bad booster as well.

[curvedglass]

Thanks all. I sent a note to CPP as to warranty etc. Doubt it because it has been three years. Doesn't hurt to ask. I also asked about exchange part numbers. When I bought my front end kit I asked about spare parts like wheel bearing etc in case they went out of business. Tech told me kit is based on 71-71 half ton heavy duty brakes. I was wondering if the booster and master cylinders were designed the same way.

[jweb]

Before replacing the booster, test the check valve on the front. I recently had a similar issue and it was just the valve.

Remove it and blow in both sides, air should only flow one way. If it flows both ways or not at all it's bad.

[curvedglass]

Yeah - those check valves are a whole lot cheaper. I will have to pull it out and check it. If it is bad can I just pick one up at the pep-boys etc?

[curvedglass]

I heard back from CPP. They are send me an RMA to send the booster back for repair. Will take about a week for them to fix it and send it back. Glad they are standing behind their parts.