71 Brake Bleeding

[Duke W.]

YOU HAVE TO BENCH BLEED THE M/C!!!

Been there, done that - doesn't matter what your working on. If you don't bench bleed the m/c you can bleed until hell freezes over, and you'll never get a pedal.

Bench bleed the m/c and you'll be done in ten minutes.

Duke

[Duke W.]

YOU HAVE TO BENCH BLEED THE M/C!!!

Been there, done that - doesn't matter what your working on. If you don't bench bleed the m/c you can bleed until hell freezes over, and you'll never get a pedal.

Bench bleed the m/c and you'll be done in ten minutes.

Duke

[Tom Northcott]

Re: YOU HAVE TO BENCH BLEED THE M/C!!!

It seems bench bleeding is a must. Can someone advise me how to do it properly?

[Tom Northcott]

Re: YOU HAVE TO BENCH BLEED THE M/C!!!

It seems bench bleeding is a must. Can someone advise me how to do it properly?

[John H.]

Re: YOU HAVE TO BENCH BLEED THE M/C!!!

Go to the auto parts store, and you'll find a bench-bleeding kit in a blister pack in the "HELP" section. You can do it on or off the car. Select the plastic fittings that match your master cylinder outlet ports and install them, run a piece of the clear plastic tubing from each outlet fitting into the master cylinder reservoirs (below fluid level) - most kits come with a clip to hold the tubes in place. Then pump the master cylinder slowly (but full stroke) with a big phillips screwdriver (off car) or with the pedal (in car) and you'll see fluid going from the outlet fittings back into the reservoirs - when you don't see bubbles in the fluid in the tubes any more, you've got all the air out of the primary and secondary piston cavities and you're in business.

[John H.]

Re: YOU HAVE TO BENCH BLEED THE M/C!!!

Go to the auto parts store, and you'll find a bench-bleeding kit in a blister pack in the "HELP" section. You can do it on or off the car. Select the plastic fittings that match your master cylinder outlet ports and install them, run a piece of the clear plastic tubing from each outlet fitting into the master cylinder reservoirs (below fluid level) - most kits come with a clip to hold the tubes in place. Then pump the master cylinder slowly (but full stroke) with a big phillips screwdriver (off car) or with the pedal (in car) and you'll see fluid going from the outlet fittings back into the reservoirs - when you don't see bubbles in the fluid in the tubes any more, you've got all the air out of the primary and secondary piston cavities and you're in business.

[Wayne K.]

Re: YOU HAVE TO BENCH BLEED THE M/C!!!

I think my 67 has two bleeder valves on the master. Would hooking up hoses to them and running them back to primary & secondary and opening both up and pumping accomplish the same thing?

[Wayne K.]

Re: YOU HAVE TO BENCH BLEED THE M/C!!!

I think my 67 has two bleeder valves on the master. Would hooking up hoses to them and running them back to primary & secondary and opening both up and pumping accomplish the same thing?

[John H.]

Re: YOU HAVE TO BENCH BLEED THE M/C!!!

For all practical purposes, yes - except if you have a lot of air in the master cylinder, using the bleeders instead of the outlet fittings will still leave some air in the outlet cavity between the end of the drilled bleeder hole and the outlet fitting, but normal system bleed would remove that. What you're trying to accomplish with the bench-bleed is to remove air trapped in the primary and secondary piston/bore cavities, which conventional system bleeding may not remove. ALWAYS bench-bleed a new or rebuilt master cylinder.

[John H.]

Re: YOU HAVE TO BENCH BLEED THE M/C!!!

For all practical purposes, yes - except if you have a lot of air in the master cylinder, using the bleeders instead of the outlet fittings will still leave some air in the outlet cavity between the end of the drilled bleeder hole and the outlet fitting, but normal system bleed would remove that. What you're trying to accomplish with the bench-bleed is to remove air trapped in the primary and secondary piston/bore cavities, which conventional system bleeding may not remove. ALWAYS bench-bleed a new or rebuilt master cylinder.