KC John

I had a brake booster that was hanging up, so I purchased a new booster from Summit. As you all know, the only adjustment I had to make was the rod from the pedal to the booster and the rod from the booster to the master.

I went from brakes that would sometimes hang up a little, to almost no brakes. I adjusted the rod all the way in on the booster and the master slid on with no pressure. I lengthened the rod a bit and it took some pressure to seat the master, so I put it back where I had it.

The old booster was almost too sensitive and this one won't stop the car. I checked that I had a good vacuum at the connection to the booster.

When I start the car, the pedal doesn't go down at all and seems very hard. But when I step on the brakes the idle goes up a bit (200rpm), and then when I take my foot off the brake the engine idles down again to where it is supposed to be.

What am I missing?

66CorvetteCoupe

Bad check valve I am guessing?

steampunk c1

maybe leaking diaphram in booster. booster opertion test is to pump pedal with motor stoped hold pedal down and start motor and you will feel the pedal sink with the booster kicking in.

KC John

Mine doesn't do that.

dplotkin

You should be able to suck through, with your mouth, the source side of the check valve, but not blow through. I don't know if these can be hooked up backwards but make sure.

Dan