reverse bleeding question.

[bryant]

when using a reverse bleeder like a phoenix, does the master cylinder need to be bench bleed?
ive gone through the instructions and their is no clear answer on it. ive see several vague references to reverse bleeding to get air trapped in the master but no clear statement of reverse bleeding will not need bench bleeding of the master cylinder before hand.

the idea of pushing air up through the master cylinder that has just been bench bleed seems counter productive.

[Apogee]

In my experience, yes, you still want to bench bleed the master cylinder, preferably with the plugged-port method. The reason being that while line bleeding in general is good for removing air from the lines, the air trapped in the seals of the MC can be particularly difficult to bleed with no/low-pressure methods. Low-pressure bench bleeding tactics like the recirculation method aren't even all that effective IMO, so normal line bleeding should be no better, and I don't know why reverse would be any different.

Tobin
KORE3

[MonzaRacer]

In real world service industry I like Tobin recommending plugging the master too bleed it. I have Phoenix Systems bleeders, On my third unit (wore one out, other is due for rebuild and since they use my email quote and photo I got a freebie unit.
I like to reverse bleed the master cyl. THEN I like to use the plugged method for finishing up my bleeding. Before I fully install it I try to reverse bleed to the master cylinder then tighten the fittings. This way I can get most of old fluid out and all of the air out.
I love my Phoenix Injector and since out brake flushing machine has an issue with the drain pump, I can still flush ,albeit messily with my Phoenix Injector. I use the adapters from flushing machine and hook up either it or my Mighty Vac to push fluid through.
Works very well.

[bryant]

ok i did the plug the mastercylinder and pump it bench bleed thing. it was instantly a hard pedal. it would get about 1" of pedal travel. on a 6 to 1 pedal ratio that 1/6" of travel at the push rod. also ford has slop in the pedal to push rod joint for the brake light switch. so their is still some piston travel but not much at all. i did put eyes on the the piston/push rod and it is a visible amount of movement but it would not reduce with pumping of the pedal. i then put a pressure bleeder on the mastercylinder and bleed a lot of fluid through the system. still has spongy pedal. i clamped the rear hose off and still spongy. that tells me the air is in the fronts. i cant clamp the fronts due to steel braid lines. ive pressure bleed the fronts a ton and no change. im going to try the reverse bleeder next.

[MonzaRacer]

Use short line inverted flare union and plug with front lines disconnected.
If you find this works try a 2 psi check valve in front line from mastercylinder to where ever your connection is.
ALSO look for any movement in the front calipers. Also you might plug off the front port on the Master cylinder.
Now let me state, for a fact that I have been doing brakes for years, as it is my job. And if you havent had it down the road too seat in the pads you MAY still have a spongy pedal. Had this go on too many times, pedal stays low till I get it few hundred feet down the road.
Also where are the pads from,,,,,cheaper pads=more break in time.

[bryant]

i have wilwoods on all 4 wheels and all the pads have plenty of miles on them. it feels like air in the system. it will stop, its just a bit squishy. ill give the reverse bleed a shot the next chance i get.

[MonzaRacer]

Like I suggested maybe you need a 2 psi check, Wilwood has them.

[bryant]

ill try that.