Bench bleeding help

[gbarber]

I'm wrapping up a Granada brake swap on my '66, and I'm trying to bench bleed the master cylinder using bleeder tubes. I'm using a MC from a '70 Mustang with power front discs. I bought a new MC from NAPA. The directions say to use 3/4" to 1" strokes to bleed the MC. They say to continue the process until the piston cannot be depressed more than 1/8" and no air bubbles are visible in the fluid.
Is 1/8" accurate? I can't get anywhere close to that. Actually, the piston did become tougher to push after the first few strokes, but it is nowhere close to preventing me from pushing the piston in an inch. I have worked on this for hours. This is the second MC I have tried.
If I'm only trying to get the air out, I have done that, but if I need to get the piston to where it will only travel 1/8", I don't know what I'm doing wrong.

 

[mustangdave]

I've never heard the 1/8" thing before so I think you are o.k. It could be a misprint or maybe they mean that as you push the plunger in 1/8" you should not see any bubbles.

 

[rbohm]

what dave said. never heard the 1/8" thing either. however you do not want to move the pistons too far as you can cause other problems. it sounds like you have done a fine job though.

 

[ForceFed70]

Those instructions are bunk. Without lines on there, it'll never build up presure to prevent you from pushing in the plunger.

FWIW: I always bench-bleed with the master cyln on the car. Much easier to just use the pedle instead of some rod/dowel.

 

[Edbert]

FWIW: I always bench-bleed with the master cyln on the car. Much easier to just use the pedle instead of some rod/dowel.

Ditto, just don't spill the fliud on the paint!

 

[gbarber]

Great. Thanks for the help. I thought something must be wrong when I pumped the thing a couple hundred times and nothing changed.

 

[2nd Mustang]

Okay, and now for the down and dirty method. I installed my new mc, booster, calipers, soft lines, etc., basically just connected everything up. I then tied an old towel around both fittings on the master cylinder after I loosened them up. Gave the pedal a few pumps, topped off the fluid and a couple more pumps with the pedal, making sure the reservoir didn't empty out below the level of the lines. Yes, it was somewhat messy, but not too bad. Tightened up the lines then proceeded with the normal bleeding of the four wheels. That was three years ago and haven't had to touch the brakes yet.

My engine bay is not a show item, so it really didn't do any damage.