tracing air

[Cornpatch MO]

64 Dodge B body. I installed disc brakes on the front with dual reservoir Master Cylinder and separate brake line circuits for the disc and for the drums.
I have air in the brake lines somewhere. Is there a way to determine if it is in the disc lines- or in the drum lines?
Do the right lines first and save brake fluid................................MO

 

[67 coronet]

first thing to check is that your bleeders are on top side of calipers and wheel cyls.common problem to install them upside down.they will never bleed that way.two person job to do correctly.start at rr and bleed to clean fluid and no bubbles.them lr and rf and lf last.only open bleeder when pedal is under presure,and pump pedal with bleeder closed after each bleed.if that dont work something else is wrong.

 

[Cornpatch MO]

first thing to check is that your bleeders are on top side of calipers and wheel cyls.common problem to install them upside down.they will never bleed that way.two person job to do correctly.start at rr and bleed to clean fluid and no bubbles.them lr and rf and lf last.only open bleeder when pedal is under presure,and pump pedal with bleeder closed after each bleed.if that dont work something else is wrong.

Yup, did all this. Getting a bubble free flow of brake fluid. But there is still air somewhere in one of the two circuits. Which one? Thanks.........................MO

 

[Hemi Rebel]

Did you bench bleed the master cylinder?

 

[Cornpatch MO]

Did you bench bleed the master cylinder?

Yes, I did it installed on the car. Un-hooked brake lines and attached short hoses that dumped back into the reservoirs pumped brake pedal slowly till air was all out--took a while. Thanks.........................MO

 

[HT413]

Could still be air in the mc. I've read several places saying bleeding an mc on the car is a bad idea because the brake pedal may not travel far enough to fully engage the mc, so air can remain trapped.

 

[Cornpatch MO]

Could still be air in the mc. I've read several places saying bleeding an mc on the car is a bad idea because the brake pedal may not travel far enough to fully engage the mc, so air can remain trapped.

Makes sense. I know that is the right way to do it, but I didn't want to remove from the car. Anyone have an idea , short of removing the MC, on how to get that air out, if it is in the MC?........................MO

 

[ws27]

Question, why do you say it has air? Could you problem be something else?

 

[Cornpatch MO]

Question, why do you say it has air? Could you problem be something else?

spongy brake pedal. everything is new including brake lines. To the best of my knowledge (limited) mushy brake pedal is always air in the MC or lines or wheel cylinders.......................................MO