The Brake Master Cylinder is on the left side of the firewall (as you sit in truck) looks like a plastic container. It will have a black lid. There will be metal lines running off of it. Its about 8 inches long and 4 inches wide. The Clutch Master Clinder is on the same side and closer to the fender. Its round and about the size of your hand if you make the letter "C". Uses the same fluid as the Brake master clinder.
Sounds to me like your Vacum booster behind the master cylinder is weak or bad!
If there is a hydraulic master cylinder at the clutch lever (looks like the front brake) then...NO.
That is whats mounted to the side of the master cylinder and has electric connector pluged into it.
If it's not a new one, you should be able to get all the air out by bleeding all four corners beginning with the one furthest from the master cylinder. In other words, RR, LR,RF,LF A new master cylinder comes with instructions for bench bleeding before installation, but it doesn't sound like that is what you're asking about.
There is a gasket between the master cylinder and the booster of a 1990 Acura Integra. It is shaped like the side of the master cylinder with two bolt holes.
under the hood, directly in front of the driver. It is bolted to the brake booster which looks kinda like a bloated flying saucer.
Chevy did have a 4 cylinder in the S-10 but just like Ford does not offer 4WD with the 4 cylinder, Chevy may do the same. A search of "Chevy S-10 Specs" on Google will provide an answer.
vacuum leak at the master cylinder or vacuum line to the master cylinder
under the hood by master cylinder what does it look like
Sounds like you lost the vacuum supply to the controls. Check under the hood near the master cylinder area for cracked or disconnected vacuum lines.
== == It is necessary to bench bleed the master cylinder before installation, there is a good tech article at DenLors including a video showing a master cylinder being bled prior to installation, see the link to the left or go to DenLorsTools.com an look at the Tech Articles. look up "master cylinder bench bleeding" on google or something...you can get the kit at autozone or someplace like that...
In the past this use to mean that the brake master cylinder was low on fluid. Or the sensor inside the master cylinder (which is a float) is stuck on the bottom of the resevior.