master won't work

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BWDart

BWDart

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I rebuilt the master cylinder cleaned it with alcohol blew out all the openings but now it won't pump any fluid, kit was the same as what came out and I did bench bleed it. Any suggestions?
thanks
Bruce
 
If you properly bench bled it, then it had to pump fluid by definition

How sure are you that you have the right piston? Did you check/ compare the two, and the depth of the pushrod hole?

How sure are you that it's put back together correctly?
 
I laid out the old pieces as they came out and compared, did not check the depth of the pushrod hole, have rebuilt many in the past without a problem.
 
This is why I don’t mess with rebuilding brake parts, where for a few bucks more one can get a brand new part.
 
BWDart said:
I rebuilt the master cylinder cleaned it with alcohol blew out all the openings but now it won't pump any fluid, kit was the same as what came out and I did bench bleed it. Any suggestions?
thanks
Bruce
Click to expand...

will the alcohol hurt the seals Bruce, and did you throw air at it after you
rebuilt it ? did you compare the kit very closely ? I seen one taken apart
for powder coating and never rebuilt one myself, but from what I seen I
don't think I would rebuild one... Good luck
 
memike said:
will the alcohol hurt the seals Bruce, and did you throw air at it after you
rebuilt it ? did you compare the kit very closely ? I seen one taken apart
for powder coating and never rebuilt one myself, but from what I seen I
don't think I would rebuild one... Good luck
Click to expand...

Mike, the kits can be gotten in two styles.
One is the cups (seals) and the other ia a complete piston with everything already assembled on the piston, and they are super easy to rebuild.

So easy that the only thing I can imagine is that one or more of the seals is a tad smaller than the original and that's why it wont work.
 
TrailBeast said:
Mike, the kits can be gotten in two styles.
One is the cups (seals) and the other ia a complete piston with everything already assembled on the piston, and they are super easy to rebuild.

So easy that the only thing I can imagine is that one or more of the seals is a tad smaller than the original and that's why it wont work.
Click to expand...

The one I seen was not a mopar MC, don't even know what kind it was and he had it all laid out and disassembled and it spooked me :D
Thank you for this info, know I think I could do a mopar MC if I needed to do one :coffee2:
 
I don't exactly know what year your master or if its power or manual or front disc so I don't know if this will help. But this is out of one of my Mopar manuals.

MoparForumMC.jpg

MoparForum2.jpg

MoparForum3.jpg
 
Thanks for all the help, the kit ( $5 at rock auto) came assembled, I'll go over the photos from the manual to make sure mine is assembled correctly, the car is a 72 w/power disc brake.
 
The rod in the booster may need to be adjusted to move the piston on the master cylinder far enough to get a good pedal.
 
Great info page, is your MC the same as PST posted for us ?
 
got a rebuilt from Orielly's $14.99 don't remember them being that cheap last time I looked.
 
I agree w/ 273. If you bench-bled it, then you verified it was moving fluid. What does "doesn't work" mean? Does the pedal sink to the floor? Do you feel no resistance?

I had a fairly new rebuilt MC fail once. A factory type 1-pot. Pulled the piston and found the lip seal was cut from a sharp corner in the bore. Looks like the rebuilders machined the bore and didn't round the edges of the ports.
 
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