Master Cylinder leaking from the TOP

[ScottR 10]

Hey guys,

 

I've got a brake question for you. I have Power Assist brakes; front disc, rear drum.

 

I noticed that some brake fluid was leaking from the top of the master cylinder.

 

When I pulled the top off the cylinder I noticed the front resevoir was very full (almost spilling out) and the rear resevoir was over an inch low.

 

I got a new cylinder gasket, cleaned the outside of the cylinder up, topped off the brake fluid in the rear resevoir then re-installed the top. I tweaked the hold down clamp a bit so it would fit real snug.

 

After this I went for a ride.

 

When I got back I had mucho brake fluid seeping out from the top of the master cylinder. Most of it was on the front end (small resevoir side).

 

Is the Master Cylinder bad or is this something else?

 

I did the Power Booster test (pump brakes with engine off to dump vacuum then start engine with foot on brake) and the pedal did move down about and inch.

 

Thanks,

 

Scott

[LoneWolf2U 136]

Possiable air bubble in rear line or sticky shuttle in master cyl.

The large side is front brakes and small is rear brakes.

Large side level will lower as pads wear, your best indicator of amount of pad left short of squealing front brakes.

[shelbyshelby 52]

That is what you call a "gremlin". My only thought is pressure from the rear is escaping to front, maybe thru a crack??? I would do exploratory surgery unless someone chimes in with the answer.

[ScottR 10]

Thanks Mach1Rider. I'll check the front pad level and bleed the brakes as a first step.

[ScottR 10]

Thanks shelbyshelby. I'll check for a crack.

[Hendog 10]

I had that same problem with a fresh m/c. The hold down clamp was the culpret. Replaced it with a new one I got from NPD and problem solved. The bad clamp simply wasn't strong enough to seal the m/c.