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Bad brake master cylinder?

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So while im waiting on carb parts i decided i would mess with brakes today which i dont know much about. so old brake fluid was all thick and gross so i took the reservoirs out and cleaned them and then sprayed down in the master cylinder. Went to beed the master cylinder and i got nothing at all through the lines... no movement or bubbles or anything... i took it off and blew it out with air and cleaned it with brake fluid cleaner... put it all back together and nothing. What else can i check? Im kind of lost...

  • 2 weeks later...
  • 2 weeks later...

Yop are trying to bleed the two bleed points on the master cylinder?  You need to do this in the same way as bleeding from the calipers.  Do you have someone helping you? If not you can do this yourself by connecting a hose to the bleed nipple and putting the other end into a vessal of brake fluid.  Then you can pump the brakes yourself with the bleed nipple open.

 

cheers

 

Dirk

I have never had any luck using the hose into brake fluid trick because the threads leak a small amount.So first try the trick with a hose if not find a friend a bleed them like you would brakes.then bleed the brakes starting with the brake farthest away from the MC.

  • Author

had a friend trying helping and we went through the whole process. Never got anything. The pedal just goes straight to the floor with nothing. Is there a way to test brake boosters?

What did you "spray" into the MC. If this was an older car, they sometimes dont like to be bled by the foot method. A ridge develops inside the cylinder. When you press the pedal to bleed it you go past the pedals usual travel and tear up the cups inside the MC. I would replace the MC, its not a lot of money compared to what it costs otherwise.

What did you "spray" into the MC. If this was an older car, they sometimes dont like to be bled by the foot method. A ridge develops inside the cylinder. When you press the pedal to bleed it you go past the pedals usual travel and tear up the cups inside the MC. I would replace the MC, its not a lot of money compared to what it costs otherwise.

Interesting.  Thanks for this.  I had trouble bleeding my brakes only a couple of weeks ago after a major caliper rebuild.  They work OK now but are certainly not as firm as I expected.

Think Ill buy a new MC to eliminate any potential damage.  Old one is over 30 years old anyways.

 

Cheers

 

Dirk

 

BTW, nice to see you are still around Nipper.  I have been under the radar for a while but I'll catch up via the OT at some point.

Edited by Dirk

Yup! Just had a look.  Master Cylinder is bleeding out the back onto the brake booster.  Maybe time for a new brake booster too.

 

Barrett045  FYI it would seem that 'bench bleeding' the MC is a better way to go before reinstalling.

 

Cheers

 

Dirk

Interesting.  Thanks for this.  I had trouble bleeding my brakes only a couple of weeks ago after a major caliper rebuild.  They work OK now but are certainly not as firm as I expected.

Think Ill buy a new MC to eliminate any potential damage.  Old one is over 30 years old anyways.

 

Cheers

 

Dirk

 

BTW, nice to see you are still around Nipper.  I have been under the radar for a while but I'll catch up via the OT at some point.

Just been a very tough, very lonely and depressing year. i can always be contacted by a private message on here :)

 

Thanks.

Brake booster can be used if you get a trusted source. I never bench bled a MC myself, but I have always used one of those silly hand held bleeders myself.

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