Joined: Tue Mar 01 2011, 04:53PM
Location: Seattle
Posts: 39
1966 Chrysler 300, 383, Power Drum Brakes
So as I am getting through the brakes on the car (I am doing a comprehensive brake repair/replacement) I noticed a gasket between the master cylinder and the power booster. Specifically, there is the master cylinder, then a thin cork-like gasket, then a yellow-ish spacer and then the power booster.
The reason I ask is I am replacing the MC, and the cork gasket is destroyed (must have a slight leak developing in the MC) and wanted to know if I need to put anything back in other than the yellow-ish spacer?
Joined: Tue Mar 01 2011, 04:53PM
Location: Seattle
Posts: 39
Yes, that is the one. Mine is a white/yellow color, but the same design.
The spacer is in good condition still. In my case, there was a very thin gasket as well... I am not sure where that came from. My assumption only was that it must have been for the prevention/slowing of master cylinder leakage from the rear into the booster.
I think what I will do is not put another gasket in and just put the spacer in. I was going to check the Master Parts book (I have a CD copy of it... somewhere at home) just to verify.
Joined: Thu Mar 22 2007, 08:13AM
Location: In the workshop
Posts: 1063
I'm a bit surprised here. If we assume that your '66 power drum setup is identical to the one that was on my '65, then it went:
Master Cylinder, bolted directly to booster. After the booster came a spacer, then the bracket that holds everything to the firewall, then a gasket.
A gasket between the master and booster does not really matter. The pushrod is adjustable.
Between the booster and firewall, a gasket has to be used along with the correct spacer. Thats because the pushrod that attaches to the brake pedal is not adjustable. If its deleted, the booster will always be slightly on.
Of course, this assumes as I stated at the start, that '65's and '66's are identical in that area.
I just installed a Cardone 503500 booster with master cylinder combo on mine and didn't even check to see if this had it on there. I'll be at my car this weekend so i'll check,but there is also a foam gasket on the one i just took out. I'm assuming this is some kind of vent as i can't see any other kind of reason behind it. On my friends 70 Road Runner,it does not have this on there. I just took a front and back picture of the aluminum spacer,as i threw the old foam gasket out the other day as it was shot.
and
Here's a picture of a booster with all the trimmin's in place.
Joined: Tue Mar 01 2011, 04:53PM
Location: Seattle
Posts: 39
I correct myself:
The metal spacer shown by owatajrkiam I have as well.
There is not a spacer I remember between the booster and firewall, however I do not have the booster out. When I did, I made a new gasket for it at the time I removed it (gasket between booster and firewall).
I do have the metal spacer between the master cylinder and booster along with the yellow plastic spacer/thing. It is identical to the black spacer/thing mentioned above. It clips onto the metal spacer and oddly sits rather flush with it. The plastic piece sits into the metal and seems like it is supposed to be there.
I installed my booster/master assembly and never noticed that it did not have this on there (cardone # 503500). I have cleaned up my old one and am going to make something similar to the foam gasket that was original and install it between the cyl. and booster. I will go the fsm to get the correct measurement and readjust the pushrod. Cardone had the measurement exact,but with no spacer. When i bench bled the master,i got the bubbles out in about 10 pumps and the pedal feels firm without the other lines bled yet. I have heard the newer rebuilds are about a 50% good/bad ratio lately,so i guess i got a good one. I have just fired the engine for the first time and even with the Voodoo .494"/.513" cam,it's still got 12" of vacuum at 700 rpm. Booster feels good. I still don't know why that spacer is there? Any other guesses why it's on some but not others?
Joined: Tue Mar 01 2011, 04:53PM
Location: Seattle
Posts: 39
Here is the excerpt from the Chrysler Master Parts showing the parts. It is legitimate that the plastic cover, spacer and filter are all supposed to be there.