I have recently bought some 4 piston calipers from a 1984 Toyota 4x4 that I installed in my '72 240Z but I ran into into a problem. The problem is that my stock master cylinder doesn't apply enough preasure so that the calipers will squeze. Even after bench bleeding it thouroughly and bleeding the brake system it still doesn't grab. Im guessing that I either need a bigger master cylinder or a bigger brake booster. But from what car/truck will I get the master cylinder/booster from?

 

Make sure you don't have the calipers on upside down... easy to do if you put the right on the left and the left on the right side...

You should not need a larger m/c unless there is something actually wrong with your current one.


Someone mentioned about needing Vented rotors... that is needed for the conversion using the 88+ Toyota 4 runner front calipers (S12W) calipers... They use the larger 84 300zx non turbo front rotors... BUT even they need a small spacer.. not sure for the 240 but the 280z needs a .314 thou spacer to place the rotor in the correct position for the calipers.

BOTH calipers just bolt up to the stock location on 1st gen Z's.. The 1984 4x4 pickup truck calipers bolt on useing STOCK 1st gen rotors...becareful as there is a right and a left... make sure the bleeder nipple is facing down.....

But back to the question...

neither of the above mentioned swaps "NEED" a larger m/c...yes it may be a good idea, but it is not critical to make the system work... I have the larger vented rotors with the 4 runner calipers using my stock m/c with NO issues in the 5 years I've had them on the car.....

If you can't operate your brakes, they may not be installed on the correct side of the car..or depending on where you got them, you could even have two lefts or two rights....your system may not be properly or fully bled out.. etc...

Did your brakes operate correctly before the swap?... was there a problem there already?...