brake problems - booster or master?

[danl]

I jumped in my 78 SC yesterday and the brake pedal went "guh-burr, guh-burr, guh-burr" nearly all the way to the floor. At that point there was some braking action, but I decided to put the car back in the garage. There was nothing leading up to this incident.

Does this indicate problems with the master cylinder or the power booster? My Bentley manual was no help on this matter, opinions sought.

thanks in advance,

Danno

[Bill Verburg]

probably a hydraulic seal let go.

look for a puddle or at least signs of dripping brake fluid. If a master seal goes it can collect inside the booster vacuum can

could be at the master or one or more calipers.

[danl]

I was leery about that power booster and it's location in the car.

After some prodding about it turned out to be a wheel cylinder leak. It made such a weird noise, it kinda freaked me.

Thanks,

[petrolblue83911]

just to be sure the master is ok, pull the drivers side carpet, and floor board by the pedals and see if all is dry back there

[Bill Verburg]

Originally posted by petrolblue83911
just to be sure the master is ok, pull the drivers side carpet, and floor board by the pedals and see if all is dry back there

Only on the '76 and earlier non boosted cars.

boosted cars leak into the booster vacuum can unless it is a hyd. boosted car.

[danl]

You guys are quick! I haven't even had a chance to go home from work and poke around some more.

IF the master is leaking into the vacuum assist, where will it show?

Into the passenger compartment or into the front compartment or onto my freshly painted garage floor?

[robertb]

when my master cylinder went out on my 79 sc the fluid went into the booster and was then sucked into my engine by the vacuum line. It turned my engine into a smoke machine as the brake fluid burned off. Was kinda weird, don't think this normally happens though.

[Bill Verburg]

If the m/c is leaking the fluid will collect in the bottom of the vac. can. Pull the vac. line off for inspection