You can prevent Master Cylinder Brake Fluid Loss from any/all open brake line(s) by blocking the brake pedal depressed before you start. It only takes an inch or two on the pre-ABS 240s. The ABS 240s need more pedal travel, like the 700/900 cars (in which case the bleeder needs to be open while pedal is being depressed).

I made a notched wooden prop that fits to the bottom edge of the pedal and bears against the 240 seat adjuster bar. It's handy for checking brake lights too. But remember to disconnect the battery or pull a fuse to keep brake lights off while the pedal prop is in place.

Also, before installing the rebuilt front calipers, you need to make sure the rebuilder didn't put them together wrong. Some times they get Left and Right halves of 240 front calipers mixed up. The inner half, where the lines attach, will have an opposite side outer half paired to it but it will be upside down!.

Check the TOP of each front caliper, near the mating joint between the two halves. The surface should be free of any punch marks or "dimples".

Then look at the BOTTOM of each caliper. You should see a good-sized "dimple" on each half, near the joint line (within 1/2" or so).

If you DO see a dimple on the TOP of an outer half, that caliper was assembled wrong, and has an unbleedable lower, outside passage. What appears to be the "Outside Lower" bleeder is really connected to the bottom of the Outside Upper cylinder, and it should be on opposite side of the car.

Here's an Art Benstein photo of what to look for.


Art also says,
"...it is now one of the inspection points when a caliper is put in front of me on the counter at the auto parts store.

I've stopped ordering remans on line, not because of the core shipping, but the returns. At the store I can look at the seats and threads in the line orifices, the bleeders, check for mismatched halves, or poorly matched universal dust seals. Bring an adjustable wrench -- the reman bleeder screws are not always 8mm across the flats."


--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.