[Pete Munroe]

I concur with Rick about the alignment of the master and/or the slave relative the input/output of the work.

The more off centerline the slave or master is to the actuator/actuating rod, the more side thrust on the cylinder bore.

These cylinders are generally NOT sleeved, but a plain aluminum bore...wear to the seals and the bore will occur relatively soon if they are not mounted correctly.

I will try to post a picture of the incredible "aluminum paste muck" on the inside of a master cylinder off of a early Backdraft. We replaced this cylinder at about 10k+. Had problems for awhile, lots of bleeding out black fluid. The wear didn't happen overnight, but it was shot. (these cylinder are normally not rebuilt, just replaced) I suppose they could be sleeved, but may cost more than a new cylinder...may last longer with a steel sleeve for sure.

The master mount on some cars is WAY to far out of alignment for the pedal actuating rod and lots of input force just goes into scrubbing away the master/slave cylinder bore.

Better fluid may help if the cylinder is cooked by being close to the headers.

My ERA, with clutch/brake masters under the floor do not have discoloration of fluid at all...( I do flush the fluid every year or so).

Nothing on the ERA is in close proximity to the headers, but, lots of cars mount the clutch/brake cylinder just above the headers...most have NO heat shields or ventilation...so, the fluid cooks.

Use the grade 5 fluid and the fluid won't be a problem from boiling, but it will still turn black from aluminum filings and rubber seal degeneration.

Pete