Master cylinder sucked air

[bandit]

After replacing a collapsed brake hose in the back, I decided to flush the system and had the wife pressing on the pedal as I opened and closed the bleeders. Was running back and forth to keep the MC full but on one attempt(doing rear driver side), I heard it suck a little air as she let off the pedal. Refilled and kept going and thought I got all the air out but got a spongy pedal on the test drive. Going to attempt to re-bleed them again tomorrow but did I just make this a bigger job by letting that MC go dry on a pump?

Also saw a mention that the rear brake lines should go the the front reservoir. Mine go to the smaller back reservoir. Is this wrong? Previous owner changed from power to manual and this is his set up.

Manual brakes, disc front and drum back.

 

[Fran Blacker]

Rear brakes front reservoir . Disc brake need more fluid to work I believe.

 

[R/T Boy 67]

Drum brakes should be hooked up to the small reservoir, but that is normally on the front. The fluid level will drop on disc brakes as the pads wear, that is why the reservoir is bigger. What master do you have?

 

[69L48Z27]

All depends on what you’ve got as to where things get hooked up.

Regarding the MC. You should be able to get the air out with normal bleeding. If you can’t, try to block off both MC ports while installed on the car. Move the pedal back and forth until no bubbles come out of the bottom of the MC. Pedal should be rock hard. Hook the lines back up and re-bleed.

 

[Fran Blacker]

I bought E-Z bleeder liked them a lot. Just pump the pedal slowly with a hose on bleeder and watch when air bubbles stop.

 

[bandit]

Thanks! Was worried I may have trapped air in there or something. Thought I got all the air out today but going to go at it again tomorrow to be sure. I'll try to block the ports on the MC if rebleeding doesn't fix it. Def need to get one of those one man bleeders. Need to just buy one and not wait until I need it.

Not sure what MC it is. Plan on switching it back to power some day though.

 

[Nate S]

Last time I bled the system I did gravity only. Best firm pedal and easiest job I ever did. Back when I did this a lot I wasn’t aware you could do it that way.

 

[bandit]

Last time I bled the system I did gravity only. Best firm pedal and easiest job I ever did. Back when I did this a lot I wasn’t aware you could do it that way.

Interesting.... How do you know when all the air is out?

 

[Nate S]

Interesting.... How do you know when all the air is out?

Same as usual, when bubbles stopped coming out the wheel end. I used a piece of tubing to get the exit point lower and create a larger head pressure. Could see the bubbles in that pretty well. Same sequence as normal. Two big advantages are: I could do it by myself and the pressure from the pedal can't shove bubbles down a tube I had just bled.

 

[origcharger]

Last time I bled the system I did gravity only. Best firm pedal and easiest job I ever did. Back when I did this a lot I wasn’t aware you could do it that way.

I noticed I was able to gravity bleed my drum brakes the last time also, never could in the past, thinking its got something to do with not having a residual pressure check valve on the drum side like they had in the past.

 

[68Moparmaniac]

Eastwood has a bleeder that's not too expensive and makes it possible to bleed the brakes yourself. Handy tool in the box IMO
There are other more expensive bleeders out there but unless your making a living doing this kind of work, this tool will get it done for less $$.$$

Mityvac Brake Bleeding Kit
Item #49040

Mityvac Brake Bleeding Kit
$46.99

 

[bandit]

Tried to bleed the brakes again today but they are still spongy. A few micro bubbles came through but nothing significant. Did not mess with the master yet. Question, I have bleeders on my master cylinder, can you just run a hose from those bleeders into the reservoir and bleed like the brakes or is there a specific way to use those ones on the MC?

 

[69L48Z27]

Some GM MCs have the bleeders at the outbound ports. I don’t recall seeing any Chrysler ones that have this. You would pump the pedal and hold, crack those bleeders just like you would at the wheel.

 

[Ron H]

If the MC went dry during bleeding the MC should be bled then do the normal wheel bleeding process.

 

[bandit]

Some GM MCs have the bleeders at the outbound ports. I don’t recall seeing any Chrysler ones that have this. You would pump the pedal and hold, crack those bleeders just like you would at the wheel.

GM part!?!? What the....?!!!?!!? just kidding. Previous owner was getting creative I guess. Appreciate the info. Seems like an easy bleed. Crossing my fingers this takes care of it .

If this doesn't do it I'll try the full rebleed again before I start throwing tools.

 

[Ron H]

A lot of conversion kits use delco parts...it's what i have on mine.