[yellowtonka2]

well as far as bench bleeding the master cylinder goes. you just clamp in a vice gently and plug both ports or they used to give a set of plugs with little hoses attached to them to run back up into the fluid but keep them submerged. then take a blunt tool dowel rod or something and begin to push in the piston at the rear of the mastercylinder no farther than 1 inch with the hose set up do it till you no longer see air air bubbles if you just plug the ports do it till the piston gets hard to push and only moves about 1/8 of a inchthen reinstall on the car and bleed the lines from rr lr rf lf in that order till no air comes out.good luck

[rocky289]

Steve
Do the brakes work properly & is there a firm pedal?

[steve sturgin]

Hi Rocky,

The brakes seem to work fine, the pedal seems to have more travel than i would have thought normal but i don't have another mustang handy that is set up the same way to compair it with.

I must have bled the brakes more than 10 times now since these have been instaled so i was thinking a bench bleed wouldn't necessarily help.

By the look of the bench bleed process described by yellowtonka2 (thanks for that) it sseems like it would do the same as a normal bleed unless i am missing something.

Steve

[rocky289]

Travel, is the fluid moving to force the brake lining/pads against the drums/discs. As long as the pedal comes up solid at the end of the travel, then there shouldn't be air in the system. If you clamp off the flexable lines you can work out just where the travel is. This can also help to pinpoint the position of any air in the system.
If there is excesive travel you will be displacing more fluid in the system than is necessary.

[steve sturgin]

Hi Rocky,

I just got off the phone to Wayne, he is convinced that the master must be bench bled or presure bled. He thinks my pedal travel is far too much and that there should only be an inch and 1/2 max.

The test for this (i'll do it when someone turns up to give me a hand) is to take the lid off and push the pedal, if a stream of fluid shoots up it is the bench bleeding. I guess this is what is presurising the master and chucking fluid out the lid.

I kind of hope this is the problem because i am sick of it now and would like to get on with the buiseness of driving it like i stole it.

I will report back with progress ....

Steve

[rocky289]

Sounds promising, Wayne knows his stuff.

[The Greek]

When you bench bleed, the master cyl is sitting in a horizontal position and you'll get the air out. When it's mounted in the car it's tilted and there will be small pockets of trapped air that can't be bled out unless it's pressure bled with a pressure source from the top of the M/C.

I guess the choice is to either pull the M/C (no big deal) and bench bleed where the position isn't tilted or pressure bleed on the car. Wayne is correct about the amount of piston travel. There is a specification for the amount of pushrod length from the booster to the M/C. Are you aware of this?

[steve sturgin]

Good morning Greek and Rocky, thanks for staying with me on this one.

My son and i bench bled the M/C yesterday afternoon but we are unfortunatly still getting the same leaking problem. It is possible that when we put the MC back in tha we didn't bleed the air from the lines at the MC end properly and that some air has got itself back into the MC after driving it around for 20 mins'.

The pedal travel didn't change much even after the bench bleed. As Rocky said; perhaps too much travel in the pedal is contributing to the problem.

I think i will work on isolating the air problem (if there is one) by blocking the hoses as rocky suggested.

"a specification for the amount of pushrod length from the booster to the M/C". No Greek, i thought because all of this gear is new then i wouldn't have to get into this. When i put the Mc back on yesterday the rod from the booster seemed to touch the inside before bolting it back on.

Steve

[rocky289]

"a specification for the amount of pushrod length from the booster to the M/C". No Greek, i thought because all of this gear is new then i wouldn't have to get into this. When i put the Mc back on yesterday the rod from the booster seemed to touch the inside before bolting it back on.

Steve, this will have to be correct. Can't help with the specs though.
From memory there is some sort of adjustment on the rod.

[The Greek]

The power brake pushrod should extend from the face of the booster, (the surface that the M/C mounts to), .980"-.995" for the Bendix Booster. You can also figure the measurement as being in a fashion to where the pushrod should not move more than .015" as it contacts the M/C piston. No movement (exact contact) is ideal.

If the pushrod measurement is less than spec, you will have excessive pedal travel. If it is longer than spec, there will be brake drag.

[steve sturgin]

Good morning guys,

I took most of the pedal travel out by adjusting the rod at the pedal end, i also took a little more out of the rear brakes by nipping them up a little further. The pedal is at the top and is very firm now.

Not had a chance to bleed the system out again but i will report back when i have done this.

Steve

[rocky289]

Make sure you check that clearence the Greek gave you.

[steve sturgin]

Will do Rocky,

I bled the system dry by mistake so i'll have to do the bench bleed thing again, i will check the clearances once i have the MC out again.

Did a silly thing ..... i tried the clamping on the flexys on the rear first, i did it by feel in the dark first thing yesterday morning, i couldn't figure out why there was still some noise in the rear shoes. Turnes out i clamped the diff breather hose ....

Steve

[rocky289]

Be carefull you dont cut the hoses.

[The Greek]

I don't want to offend anyone, but crimping off the flex hoses can possibly delaminate the interior portion of the hose. I've never seen the need to do this. If a line needs blocking, plug or cap it off.