Master cylinder leaks

[tommytmopar]

I had disc brakes installed on the front of my Roadrunner last summer. The master cylinder keeps spilling fluid out the top and down the side. I have removed the hold down clamp and using a vise squeezed it together to make a tighter fit. I cut down on the amount of fluid but still have some spill. Do I keep trying to get a tighter fit? Or is something else at play here.

 

[Car Nut]

I had a new bendix master cylinder do the same thing, took it off and chucked it. Bought a new Remaster from Baer.

 

[HALIFAXHOPS]

Check the gasket on the cover and also make sure it is flat to get a good seal.

 

[65-440]

Last 2 I've replaced did the same thing. Make sure master cylinder and rubber seal on the lid are absolutely dry before putting the lid on. Mine still seeped out a bit. Ended up wrapping a rag around the master for a few drives, been a few years now and no drips since. I've had the lid off a few times just checking fluid levels. I don't know, almost like a fresh coolant fill "self leveling" itself through the vent hose ! Either way good luck, hopefully yours stops.

 

[moparnation74]

Last 2 I've replaced did the same thing. Make sure master cylinder and rubber seal on the lid are absolutely dry before putting the lid on. Mine still seeped out a bit. Ended up wrapping a rag around the master for a few drives, been a few years now and no drips since. I've had the lid off a few times just checking fluid levels. I don't know, almost like a fresh coolant fill "self leveling" itself through the vent hose ! Either way good luck, hopefully yours stops.

The ole rag trick and I thought I was the only one that has done this in the past!

Key point here is the mating surface must be clean.......

 

[brian6pac]

Take the gasket off and put the lid on and see if it wobbles, adjust till flat then clean the gasket real good and put it back on.

 

[PurpleBeeper]

These guys are right. The rubber diaphragm gasket isn't sealing. Either the mating surface on the mater cylinder is not smooth, the cap is bent slightly or not smooth or the gasket/diaphragm is bad.

 

[tommytmopar]

Thanks everyone i give those ideas a try and see if I can get it to seal

 

[Car Nut]

Mine was also leaking into the booster.

 

[MarPar]

if it leaks into the booster, do you have to get the fluid out of there somehow??

 

[Car Nut]

I was lucky, the leak was minimal, hardly any fluid.

 

[Billccm]

I've had my front disc conversion on the car now for a few months. Brakes are great and had no issues for the last 200 miles of occasional driving.

Last week I noticed my front reservoir cap area was wet with brake fluid? Took the cap off and the level is correct (in both reservoirs). Wiped dry and cycled the brake pedal a few times and no leaks.

I read an old thread which Rick E said that the newer master cylinders produce a 'geyser' inside when the brake pedal is stomped and sometimes it will blow fluid past the seal. Sounds reasonable, but now suspicious.

I've put less than 300 miles on these new brakes.