Why does the clutch lose pressure after take off.

BOTH THE CLUTCH MASTER AND SLAVE CYLINDERS. ARE CYLINDERS

THEY BOTH HAVE A "PISTON" OF SOME SORT INSIDE OF THEM

WHEN THE MASTER PISTON IS PUSHED---IT PUSHES FLUID---WHICH IN TURN PUSHES THE SLAVE PISTON

THE PISTON IN EACH ONE, SEALS AGAINST THE CYLINDER WALLS, WHICH THEY ARE CONTAINED/ OR RIDE WITHIN. USING "O"-RINGS OR A SUCTION CUP "LOOKING" TYPE SEAL

IF THE SEAL IS NOT SEALING---FLUID LEAKS BY AND THE PISTON "BLEEDS DOWN" OR YOU MIGHT SAY "BLEEDS BY"

SO IT'S SORTA LIKE A HYDRAULIC JACK WITH A "BLEED BY" ISSUE. IT HOLDS FOR "X" PERIOD OF TIME (DEPENDING ON THE LEAK'S SEVERITY) AS IT SLOWLY ALLOWS THE PLUNGER TO FALL

BEINGS THAT THE "SEALS" TO THE "OUTSIDE WORLD" ARE STILL GOOD OR INTACT. THERE IS NO FLUID LOSS. THE NEXT PUMP OF THE PEDAL SORTA "RELOADS" THE FLUID, AND IT'S ON IT'S WAY TO DOING IT AGAIN!

SOME PEOPLE REFER TO THE SITUATION AS IT HAVING AN "INTERNAL LEAK"

HERE'S ANOTHER POSSIBILITY--SOMETIMES AIR IN THE SYSTEM MAY HAVE THE SAME SYMPTOMS

SO. ONE OR THE OTHER "CYLINDERS" IS HAVING A PROBLEM

BLEEDING WOULD BE THE 1ST THING TO TRY. TO GET AIR OUT OF THE SYSTEM. ESPECIALLY IF THE SYSTEM WENT DRY (RAN OUT OR LOST IT'S FLUID) AT SOME POINT

THE OTHER, WOULD BE TO REPLACE THE "BAD CYLINDER"

I'VE SEEN PEOPLE ATTEMPT TIME CONSUMING TESTS TO TRY TO SEE WHICH ONE IS THE PROBLEM

I'VE SEEN THEM REPLACE THE "EZist" ON TO GET TO AS A TRIAL AND ERROR TEST. SORTA HOPING THEY "LUCK" INTO REPLACING THE RIGHT ONE

THEN THERE ARE THOSE WHO REPLACE BOTH AS A SET--- THEIR THINKING IS THAT THE SEALS IN BOTH ARE PROBABLY THE SAME AGE---MAYBE BOTH ARE "BATHING" IN THE SAME POSSIBLY CONTAMINATED FLUID---IT WON'T BE LONG BEFORE THE OTHER HAS A PROBLEM

I KINDA FAVOR THE "EZ" TO TO ONE 1ST. IF YOU WERE NOT LUCKY. THE OTHER WILL GET REPLACED DURING THE PROCESS

SO. EITHER YOU FIXED IT WITH A "CHANCE OF LUCK" OR YOU REPLACED BOTH PARTS DURING THE PROCESS OF ELIMINATION

THIS IS EXACTLY WHY I REALLY LIKE MY TWO JEEP'S SYSTEMS (1977 AND 1946) ----THEY ARE BOTH MECHANICAL CLUTCH LINKAGES---ONLY "METAL PARTS" CAN WEAR OUT, I HAVE IMPROVED ON THEM USING ROLLER BEARINGS

THE MEDIC