72 chevy c20 break booster trouble

[kelz702]

Hey guys and gals,
I'm having trouble again. I think I have a vacuum leak coming from the diaphragm in the break booster(I'm hearing a loud whistle at high seeds on the freeway, also sometimes im having "irregular" idle at stoplights). I'm ready to buy a new one but I'm not sure where to look. I've been searching for hours but I've been going in circles. All that comes up in Web searches is info on conversions. I need to know if there is a vendor that sells a booster for a 72 c20. Currently I have a Delco-Moraine brake booster on my c20. Any info would be greatly appreciated.
Thanks!
Kels

[Jrainman]

Are you sure the loud whistle is comming from your brake booster , I say this because the way you said it high speed whistle , (just when traveling at high speed ??? )

I had a high speed whistle comming from under the hood on my 68 it took me 3 weeks to find the sorce , it turned out to be my hood springs ,when the air passed through the spring at a high rate of speed it whistled , I packed the inners of them with some rubatex insalation, I think because they are old a weak from age they do this .

YourIdle condidtion can be a host of many issues including carb, timing , fuel related .

I think you need to giva a little more information and Im sure the guys here will chim in and get you fixed up

[toolboxchev]

I have had a Lifetime Warranty unit from Cardone. I has been replaced 3 times now since the original replacement 10 years ago.

I believe the problem resides in the rubber they use, todays ethanol eats them up. No wonder so many go for a more modern system.

[John H.]

I used power brake exchange in Portland, OR. Also search "Booster Dewey"

I have used him 3-4 times and very happy.

[John H.]

http://boosterdeweyexchange.com

[toolboxchev]

Thanks John, That is very good to know!

[custom10nut]

If your booster is bad, you'll hear a rush of air when you press the pedal and then it feels like manual breaks. It does sound like vacuum leak, but I would look at all your hoses first before you spend any money

[jocko]

Contact Frank http://67-72chevytrucks.com/vboard/s...d.php?t=581862
Or just go to Oreily Autozone or Advance. Ensure you specify C20. Check the line and plastic fitting first to make sure that's not the whistle source. You didn't mention anything about your braking performance being degraded(?) Agree with the above comments - need to do a little elimination first. If power aspect of brakes is working find, then it's likely not the booster. You'd likely notice the braking difference before you noticed the whistle, especially if you're going fast enough to make anything whistle...

[davepl]

I can recommend this guy, he even found me a minty core. If it's for a show truck at all be sure to pay the extra for a polished case to get rid of the pitting, but if its a driver you don't need that expense:

http://brakeboosters.com/

[kelz702]

Thanks for the replies guys. I'm not getting any whooshing sounds when stepping on the brakes. They seem to be operating fine. I've changed the valve, grommet, and vacuum hose. The reason I'm thinking it's the booster is because If plug the vacuum hose for the booster, it returns to normal idle. Maybe I'm wrong in thinking the booster is bad?

[scooterpimp]

If ya capped off the booster line & now runs better , i believe you answered your own question... peace.