early ford juice brakes

offy19

Member
Someone prior to my ownership put 40 brakes on my 33 coupe, the problem is after installing a new master cylinder and bleeding the system, fluid leaks from the vent hole in the cap (squirts from it) after pumping pedal. (looking back I think the old master cyl was probably ok cuz it was doing the same thing which is why I replaced it) Stock pedals in place putting cylinder in floor, maybe too low, below wheel cyls? (check valve) Anyone run into this before?
 
My guess is air in system. Air gets compressed and upon pedal release the air decompresses and forces the fluid back to the cylinder with such force that it can not be contained in the reservoir.
 
On my Pontiac, if the level of the fulid is to high, it will come out the vent, but stops after it gets a litter lower. When the piston moves forward it has to move past a port, untill it does it shoots fluid back into the reservoir, and that's when it came out the vent on mine.
 
I did not bench bleed the master cylinder but when the brake fluid gets down about 1/2" from cap it stops leaking like "oldscouts" Pontiac, but I've never had this problem before so I'm going to re-bleed the system and re-adjust the shoes. I'll let you know what happens. Thanks for the input.
 
The fluid should be down about 1/4 to 1/2 inch below the cap. Are you filling it all the way to the top?
 
It is perfectly normal for fluid to squirt when initial movement of the piston causes the compensating port to be closed off, trapping fluid in the cylinder. All masters I have ever had any experience with have an expanding gasket that completely seals off the fluid from the air vent, and would prevent any fluid loss through the vent. Didn't the Lockheeds also have a similar gasket? If not, they should. :)
 
It is perfectly normal for fluid to squirt when initial movement of the piston causes the compensating port to be closed off, trapping fluid in the cylinder. All masters I have ever had any experience with have an expanding gasket that completely seals off the fluid from the air vent, and would prevent any fluid loss through the vent. Didn't the Lockheeds also have a similar gasket? If not, they should. :)

No, just a simple baffled vent, like the EIS replacement cap pictured.
 

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DONT bench bleed single circuit master cyls..
You really need to put a brick or piece of wood behind the pedal to prevent it going too far.
 
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