Topic: 1968 Shelby GT 500KR - Brake Master Cylinder

[dwdshelby]

Hi All, I have attached some pics of a NOS PBD master cylinder that I was told is correct for a 68 KR. It has the dimple on the drum secondary outlet. It has a screw stop but my understanding is that it should be an allen screw for the KR. It has the Bendix writing and a 2227091 code on the bottom. It appears to be a 1" bore and interestingly it has a shallow plunger depth designed for a manual disc/drum combo. I don't think it is correct but wanted to get some confirmation from the knowledgeable folks on this site. Any thoughts on what vehicles it would have been primarily made for? If the right internals were put in it for the power disc/drum combo would it work?

Thanks in advance.

Dave

[TLea]

I have seen both Allen and hex stop screws in 68

[Bob Gaines]

Hi All, I have attached some pics of a NOS PBD master cylinder that I was told is correct for a 68 KR. It has the dimple on the drum secondary outlet. It has a screw stop but my understanding is that it should be an allen screw for the KR. It has the Bendix writing and a 2227091 code on the bottom. It appears to be a 1" bore and interestingly it has a shallow plunger depth designed for a manual disc/drum combo. I don't think it is correct but wanted to get some confirmation from the knowledgeable folks on this site. Any thoughts on what vehicles it would have been primarily made for? If the right internals were put in it for the power disc/drum combo would it work?

Thanks in advance.

Dave

Dave ,I am not so sure that it is set in stone that the allen head style stop bolt is the only way KR's were equipped. It is my understanding that the hex head is the earlier style used in 67 and earlier 68.Not 100% but what I think until more conclusive info suggest otherwise. At the very least the changeover was near that time the KR's were being produced. I think dead nuts on has made up the allen head stop bolt. Interestingly if the item is NOS is that it doesn't have the typical bare circles where the plugs (and where are the rubber plugs for that matter) were installed in the unit to keep paint from contaminating the insides. It makes me wonder if it has been repainted because of that observation. Just what I have seen on NOS and survivor type units on cars. Just my thoughts.

[J_Speegle]

Rear brass seat/port may have been also repaired/replaced also - Just comparing the finish front to rear

[dwdshelby]

Thanks Guys, my car is a June 1st car so it could perhaps have had the hex bolt given the cross over from 67 to 68.  Interestingly, the Shelby Registry guys have paperwork that suggest the original was changed out as a warranty item in the first three to six months from sale so who knows what got in there from there. By the time I got the car in 2000, it had a NAPA special in it.  I agree that I think this one has been messed with but it also sounds like it is worth keeping for the car as finding good parts is becoming difficult. In that vein,  I figure that I should send it away to a knowledgeable vendor who can go through it and ensure it has all the correct seats, restrictors and internals for PBDisc/Drum. Any thoughts on who you would send this to to check out/restore? I have found the correct cap and gasket.
Blessings
Dave