Brake booster valve question?

[brigond]

In previous posts I changed my booster and master cylinder. The original brakes worked fine but the booster, hose,and vaccum valve were corroded . The MASTER Cylinder was leaky and also corroded.

After replacing both , the brakes were super sensitive. So I changed the master cylinder again and it helped but didn't eliminate the sensitivity . The car stops great and straight but I have to control the pressure I apply on the brake pedal.

Since the parts change , the little rubber cap on the brake booster valve has popped off twice leaving me with very little stopping power. This cap blocks off the unused line. I guess its there for other applications. I replaced it with a tighter fitting cap and it seemed to work fine until yesterdays test drive.
It popped again .

Why does this rubber cap keep coming off?

Is it related to the sensitivity of the brakes? Could it be a bad proportioning valve ? Maybe I just need to secure (bond) the little rubber cap better?
Sent from my PC36100 using proboards

[Nacho-RT74]

the cap on the tee is just to block the Vacuum port to other purpouse ( Cruise control and stuff like that on laters )

I can't think on a fail related to the cap popping off, except a backfire

( I'd like to get "sensitive" brakes... My car gets everything working nice but brakes are not so fine to my taste yet, althought the ceramic front pads and drilled/slotted rotors, with rear metallic shoes )

[odzking]

Mine is like that because I have speed control on mine. That is the tap for the control.
And mine popped off once ... yep, no brakes. My solution was simply to find a much smaller and very stiff plug and jammed it on there.
However what I would suggest is go to NAPA (will be cheaper except for the $10.00 Mopar one below) and get one that only has 1 or 2 "T"'s on it like:

www.ebay.com/itm/1970-1974-Mopar-Bendix-Style-B-E-Body-Brake-Booster-Check-Valve-Seal-/200879879282?pt=Motors_Car_Truck_Parts_Accessories&hash=item2ec55fb472&vxp=mtr

www.ebay.com/itm/New-Mopar-Brake-Booster-Vaccum-Valve-2-for-One-Money-P-N-4240504-/271262178610?pt=LH_DefaultDomain_0&hash=item3f287c5d32

[brigond]

I have another cap. I think I'll go Bobbish and silicone the cap on.

Yes Nacho, it did backfire when it popped off.