Front disc brakes will not release on 72 Europa Twin Cam

[marks]

The boosters are still hooked up; and I will have to check on the bore.  Thanks!

[jbcollier]

With dual boosters, the master has an 0.875" or 7/8" bore.  Without the boosters, they used a 0.700" bore.  Here's an article one fitting Spitfire master cylinders to Europas:

http://www.lotuseuropa.org/LotusForum/index.php?topic=1818.0

My advice would be to ditch the 50 year old boosters and go for a 0.700" master.

[rjbaren]

I bypassed my boosters in my 73 twin cam special.  I used a Tilton 74 series master cylinder 3/4" bore.  Part number 454-74-750U.  I bought it from JEGS.  It cost $75.65.  I did not need a proportioning valve.  The master bolts right up, you don't even have to change the bolts or the rod.  I did not use the remote reservoir.  I have driven the car for only 500 miles but the brakes felt good.  You will also remove about 25 lbs. from your car.  I put stainless bolts with stainless washers and stainless dome nuts in the six vacant mounting holes.  Plus, I now have extra room so I mounted a radiator over flow bottle connected to the swirl tank.

[jbcollier]

That's a single circuit master.  Nothing wrong with that.  I run one myself.  Just wanted to make sure Marks knew.  Lots of people sell Girling, or Girling-clone, single masters in sizes from 5/8 to 7/8.  If you go that way, I would recommend at 0.70 master.  It gives slightly longer travel than a 3/4" but is easier to modulate at the limit.

[marks]

Thank you very much for all the information!  You guys are great!  I am presently trying to unstick the front cylinder of the master cylinder.  I am keeping my fingers crossed; hoping that I only need to hone the front part of the master cylinder to get it operating without sticking.

[Clifton]

I would not run a single circuit master. Loosing your only circuit in a Europa is probably death.

I'm far from stock but I'm running a 5/8 front and 3/4 rear and then re drilled my pedal arm to get a better ratio and feel.

If you go unboosted with a larger bore you will need to increase the pedal ratio to get decent feel and modulation.