so my jeeps brakes are horrible. yes, it's a jeep but mostly chevy, so i figured i'd ask you guys about the master cylinder.

I bled the brakes today and the pedal feel is definitely increased...doesn't go to the floor anymore....

but, it seems that there is an air leak where the reservoir hooks (with two bolts if i remember correctly) to the big round thing.

my question, is there a gasket that's worn out, or how can i fix that? brakes would be nice.

i'm not sure what mc it is or even what year, if it matters, but its on a 305

thanks a lot

hmmm, I'm far from being a brake expert, but the big round thing is a brake booster. Maybe pick up a cheap MC from a junk yard, but it on, bleed the brakes and see if there's any difference?

Sorry I couldn't be more help.

Vacuum boosters and master cylinders are two different animals living in the same world.

Think of it as a rhino and one of those cleaner birds that keeps the parasites and bugs off the rhino.

Usually two things will give that "pedal to the floor feel".

1. Air in the lines
2. Master cylinder is shot. (fluid bypasses shot internal seals)

It sounds like you fixed the sinking brake pedal issue.

The vacuum booster is there only to give "power" assist to your brakes.

If it leaks, it could easily affect the performance of your engine, ie. it will run badly at idle, because of the vacuum leak. If your brake pedal feels harder than normal, or feels like it does when you apply the brakes with the engine off, chances are, you have a leaking vacuum booster.

The only way to fix that is to replace the whole damn thing. No gaskets.

so my jeeps brakes are horrible. yes, it's a jeep but mostly chevy, so i figured i'd ask you guys about the master cylinder.
I bled the brakes today and the pedal feel is definitely increased...doesn't go to the floor anymore....
but, it seems that there is an air leak where the reservoir hooks (with two bolts if i remember correctly) to the big round thing.
my question, is there a gasket that's worn out, or how can i fix that? brakes would be nice.
i'm not sure what mc it is or even what year, if it matters, but its on a 305
thanks a lot



Air leak.....???

If there is fluid spewing out some where that is a good indication of a leak, should not have air in your brakes to begin with...

Sorry but the way you described the problem reminds me of my girlfriend, "there is this big thingy and some thing made this hiss noise and now the round part wont spin but the doodad is working still". :laughing::laughing::laughing:

Air leak.....???

If there is fluid spewing out some where that is a good indication of a leak, should not have air in your brakes to begin with...

Sorry but the way you described the problem reminds me of my girlfriend, "there is this big thingy and some thing made this hiss noise and now the round part wont spin but the doodad is working still". :laughing::laughing::laughing:


ah man you're killing me. lol. but i know what i'm describing doesn't make sense because i would think that escaping air would also carry fluid with it, but it's coming from where the reservoir attaches to the "booster"

these things can't be salty, right? thanks guys

if you had a seal cut there should be fluid leaking down the booster, unless you have an internal seal leaking at the MC

if your booster is bad, your pedal will probly be rock hard after about 3 pushes

all that was mentioned above, but i would check your linkage adjustment and throw a booster on it,

hm, the pedal feels really good after bleeding, but before bleed i had to pump for it to be good, then it would leak after like 5 seconds and with it owuld go my brakes. thanks a lot guys