Brake Booster Bad??

[cris well]

I noticed today that the rubber boot (accordion-looking thing) is split and cracked on my brake booster on my 68 C-10.

The pedal is hard to mash and the brakes won't lock down but they still work (just not properly).

Does the boot seal the air/vaccum or is it just to keep dirt out of it?

[hugger6933]

The boot that you are talking about doesnt hold any air or vaccum just helps in keeping stuff clean. Now the problem you describe does sound like a bad brake booster. Can you hear rushing air as you depress the brake pedal? The hard pedal usally comes from a busted or leaking diaphram iside the booster. It is rebuildable but takes specail tools and is as cheap to repalce with a rebuilt unit

[hugger6933]

but before you condemn the booster make sure you are getting a vaccum signal to it . If you have heard the air rushing sound that would count as confirmation

[cris well]

It's getting plenty of vacuum and I can hear a little bit of air squishing but not much (not sure if that is normal or not).

I've put new calipers and a master cylinder on it already but haven't done anything to the rear but replace one leaky wheel cylinder.

[hugger6933]

Yeah, your hearing air get you a rebuilt booster put in on and enjoy the power brakes and stop working out that leg muscle

[cris well]

Another question:

It was changed over to 5-lug and disc brakes when I got it and I don't know if it had power drums beforehand or if they used the booster off the 71-72 model truck that the discs came off of.

The parts stores are showing 2 different part numbers from 68 and 71. How can I tell the difference or does it really even matter?

[weircc]

make sure your back brakes are properly adjusted it will make a huge difference just had this problem this week

[cris well]

Does anyone know if the brake boosters are different from 68 to 71?

I'm not sure which one is on it--can I tell from looking at it or does it even matter?