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Does anyone know. There is an appendage cylinder attached to the master cylinder and I cannot figure out is function. Its off a 40 110 convertible. Attached is a picture of this mystery object. thanks

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I believe it may be part of the accessory "No Roll" device. Another name some used was "Hill-Holder". If so, there would also be some linkage (or at least some remnants of some) to the clutch pedal.

Operation was once you were on a hill and brakes were applied, gravity would cause a small ball inside the device to roll back and block the fluid from returning to the master. That would keep the brakes applied. Once you started engaging the clutch to move the car, the linkage would move the ball away so brake fluid could return and brakes release.

That is interesting. There seems to be no linkage but instead terminal for an electric wire. Does that make sense? Attached is another picture of the mystery object. Thanks

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In the better photo, it does not appear to be a typical No-Rol. The lines to the wheel cylinders don't seem to be blocked by it so it wouldn't provide any help there.

Since it is electrical and seeing the same pressure as wheel cylinders, one other possibility is part of an electric trailer brake system. There were some units that had a hydraulic operated resistor bank instead of a hand operated application. On the hydraulic units, the more brake pressure used the harder trailer brakes were applied so you didn't need to co-ordinate manually. Those units usually had two or three component pieces. Any sign of a box mounted on the firewall or fender splasher or if a trailer hitch was ever on your car?

I think that you have solved the puzzle. I think I will eliminate it. I can add it to the car archeology of historical devices. thanks

I see the regular brake light switch but not a definitive terminal on the unit. Is that piece on the end top the electrical terminal and if not, what? Also, where or what does the small pigtail tubing hook into?

Reason for asking where the tubing hooks up is a year or so ago another poster had a strange item on his car. That item, instead of a No-Rol, I believe turned out to be some early line lock device typically used in racing. IIRC, his only prevented one pair of wheels from releasing. I think it also had a mechanical chain release but nothing would prevent a switch and solenoid from doing the same thing.

pm sent, please check your inbox on this site. I am curious about this item.