Brake pedal falls to the floor after rear brake line replacement

[gregp1962]

1964 1/2 convert.

I replaced the rear brake line because the old one got too close to the exhaust. The master cylinder is full of fluid. I can pull the pedal up and it falls right down to the floor. I can tell that it's not pumping any fluid or air into the lines.

What could be causing this?

 

[10secgoal]

Sounds like you pulled the pushrod out of the back of the master cylinder.

 

[gregp1962]

So, do I need to take to master cylinder off to put it back in?

 

[Rusty67]

Shine a nice bright light under your dash and take a look at whats under there. If you got it out without yanking the master then I'd imagine you could get it back in as well. It may be quite a bit easier to loosen the MC bolts and then put the pushrod back into place if it has indeed come out. Also double check to make sure that there isn't any fluid running down the firewall (assuming manual brakes).

 

[10secgoal]

You will need to fix the rod to make sure it doesn't happen again. The clip inside might just be worn. But you don't want the rod to fall out again when driving. It can happen.

 

[xoxbxfx]

dumb question...but did you bleed the brakes and or master cylinder?

 

[JDS68Stang]

dumb question...but did you bleed the brakes and or master cylinder?

Not as dumb a question as you might think.

At least the one post that asked another in a different thread "did you put trans. fluid back in" got an "oops" for a reply on a trans. issue

Come on Gregp1962, lets here the "oops",lol

Hey, we all make mistakes

 

[gregp1962]

No, I didn't bleed the lines. But, as odd as that sounds, that's not the problem. I can't bleed them. Pumping the brake pedal isn't doing anything. When I get a chance, I'll put the rod back into the master cylinder. Then bleed the master cyl and brake lines.

 

[DJCarbine]

When I bleed the MC in my car I took it out and bench bleed it. I put fluid in it, ran some brake line from the outputs back into the MC bowl and commenced pumping and pumping and pumping some more. After that, I pumped more. Then I took a break, and went back to pumping.

Did I mention the pumping?



While you are working on the brakes, now is good a time as any to take the MC and bench bleed it, especially since there seems to be problems.

 

[65fastbackresto]

Ok I gotta ask

What is bench bleeding the master cyl?

I`ve heard of this, but never done it. And....I just did a disc brake conversion on my car, of course I bled the brakes, and have a good firm peddle, but I didnt bench bleed anything. (other then my knuckles reaching under the dash)

 

[Tim65GT]

65fastbackresto
What is bench bleeding the master cyl?

I`ve heard of this, but never done it. And....I just did a disc brake conversion on my car, of course I bled the brakes, and have a good firm peddle, but I didnt bench bleed anything. (other then my knuckles reaching under the dash)

http://www.valvoline.com/carcare/articleviewer.asp?pg=res20020701bm&cccid=5&scccid=9

 

[65fastbackresto]

Tim65GT

Ya know from the info I`ve been picking up from you lately I`d have to say you been around the block or something. Thanks man.

Well obviously you know I didnt bench bleed my master, which was used off another mustang, but anyway ya think its neccesary to bench bleed it when I`ve got a really firm peddle (when I say firm I mean so much firmer then when I had the drum brakes on the front it almost scared me). The peddle is hard and at the top.


Good article, I appreciate it.

 

[Tim65GT]

65fastbackresto
Ya know from the info I`ve been picking up from you lately I`d have to say you been around the block or something. Thanks man.

Well obviously you know I didnt bench bleed my master, which was used off another mustang, but anyway ya think its neccesary to bench bleed it when I`ve got a really firm peddle (when I say firm I mean so much firmer then when I had the drum brakes on the front it almost scared me). The peddle is hard and at the top.

Your welcome.

Bench bleeding is usually only necessary on new master cylinders. If you have a hard pedal, I wouldn't remove and bench bleed it.