New Master Cylinder Install problem

[sstrickland81]

Converting my 2000 ES for SCCA ITB racing. Installed a new master cylinder (brake pedal had been a bit weak), ss lines, etc. Also removed the four ABS sensors, as ABS must be disabled per IT rules.

Now I can't get the pedal to hold any pressure so I can bleed the brakes. Have put MC's on other cars (admittedly w/out ABS), have been bleeding brakes for many years (I'm an old showroom stock racer), so I don't think it's the bleeding technique. The MC is full of fluid, but it doesn't seem to be going through the lines.

Wondering if disconnecting the ABS is the problem? Any suggestions w/be appreciated.

TIA

 

[kudakev615]

sounds like there is air in the abs module and lines. id try hooking back up the abs stuff and then bleeding out the system.
edit: guessing you did bench bleed out the m/c prior to install?

 

[sstrickland81]

Nope, didn't pre-bleed. Never did in the past, probably part of the problem now.

To clarify, I just disconnected the ABS senders, otherwise left the ABS lines installed (to avoid this same problem...)

thks

 

[slavrenz]

Nope, didn't pre-bleed. Never did in the past, probably part of the problem now.

To clarify, I just disconnected the ABS senders, otherwise left the ABS lines installed (to avoid this same problem...)

thks

IMHO, you should always bench bleed the master cylinder before installing.

Go get a vacuum pump and bleed the brakes that way.

 

[kudakev615]

yeah i figured you just disconnected the sensors but what i was saying that get the abs system BACK to operating properly and then bleed out the brake system. that way the abs motor energizes and the gets all the air outta the abs module and the lines coming of it. once you get a good pedal again THEN go back and disconnect the abs wheel speed sensors. after that you should be good to go(hi)

 

[sstrickland81]

Gotcha- that'll be job one this weekend.

Good tip- thks.

 

[sstrickland81]

kudakev615- hooked the ABS back up and presto, was able to get the system bled.

Great tip- my thanks.

Steve