Can't Bleed the Brakes

[FY1Cuda]

Thanks again to everyone who weighed in so promptly on my master cylinder problems.  I ordered a new one.  Hopefully that one will be better, and, yes, I promise I'll bench bleed it.

[bc3j]

I've had good luck using a bleeder kit but put epoxy into the plugs to seal them. Screw the plugs into the master cylinder.  I install the mc on the car, fill about half way and hand push the brake pedal slowly about 3/4ths of its travel while a helper watches the air bubbles in the mc. As air is displaced the pedal travel reduces and gets harder to push and no air bubbles are present. After about a dozen or so pushes the pedal is hard and barely moves. Then finish filing the mc and remove plugs and install brake lines. Easy to do. Need to hand push slowly on the brake pedal so the fluid in the mc doesn't shoot out. Found it easier the looping lines back into the mc.

[FY1Cuda]

Thanks for the tip.

[FY1Cuda]

OK, so I got another master cylinder: a Raybestos 36283 (front power disks, rear drums).  When I got it, the piston was sticking out of the back about 1/8" like the other one.  Put it into the vise and was bench bleeding it.  I also moistened the cylinder with a little brake fluid.  When I pump it, the rear larger chamber circulates the fluid fine, but the piston doesn't return all the way back. It comes back to about 1/4" from  the rear surface.  If I pull it back all the way with my finger and then pump, the fluid in the front smaller reservoir circulates, but the piston won't return to protruding out, and when I depress it again, the front reservoir isn't doing anything.  Both chambers only work when I pull the piston all the way out.
Situation is just like my May 27 post and pictures.
Is this master cylinder a loser or am I missing something here?

[Falbz]

It took me a couple masters to get one working. I did notice the same issue with the piston not returning past the housing but everything worked fine with piston flush on housing.  I adjusted the pedal rod accordingly.  I understand your frustration though 

[Falbz]

I ended up using this from brake best as I had a lot of issues with the 36283  I tried at least 2 from classic industries made by Centric brakes.  Both had same issue and I returned them.


http://www.oreillyauto.com/site/c/detail/OBH3/101326/01292.oap?year=1970&make=Plymouth&model=Barracuda&vi=5143929&ck=Search_01292_5143929_3576&pt=01292&ppt=C0066

[FY1Cuda]

It is frustrating. I thought I was being pretty smart returning the first one (which I think was a Centric) and ordering the Raybestos from Amazon for $25 less. Actually they look identical, so I'm thinking they both come out of the same Chinese factory.  A friend was told that master cylinders have a definite shelf life and if you get one that has been sitting for a while, the internals might not be the best anymore.
As for the O'Reilly's MC, it has a 1" bore but I was told I should have a 1 1/8".
I'm considering the Napa MC, but I'm wondering if its just another Centric in a different box.
http://www.napaonline.com/Catalog/CatalogItemDetail.aspx/Brake-Master-Cylinder-Remfd/_/R-NMBP1955_0358914877
An additional bummer is that the first MC i bought had no core return needed so I recycled it.  So now after I deal with returning the second MC to Amazon, the ones I see at O'Reily's or Napa have a core charge

[Falbz]

If you need that bore size then look up a m/c for a 1976 Chrysler Cordoba  When I went through this nightmare it was for my 69 Charger that I added disc brakes too.

[FY1Cuda]

Thanks for your help. I'm giving the Raybestos 36283 one more try.  I can return this one to Amazon and get another with free shipping both ways, so I think it warrants one more attempt.  With Rock Auto, Amazon ,and a number of Ebay sites selling this particular master cylinder, there must be good ones out there.

[Falbz]

Good luck - keep us posted 

[burdar]

Is the piston supposed to stick out the back like that?  I'm pretty sure my master has a snap ring at the back to hold the piston in.

[FY1Cuda]

Some MC's have retainers on the back surface, but this one doesn't. I really don't know how the piston is held in or how you'd disassemble it.  All the pictures of this MC show the piston protruding a little.

[roadman5312]

Some MC's have retainers on the back surface, but this one doesn't. I really don't know how the piston is held in or how you'd disassemble it.  All the pictures of this MC show the piston protruding a little.

                 That doesn't look right to me.   

[72rtchallenger]

I dont think the 70 style has the retaining ring as the later ones do , I know the 72 has a retainer ring style ,

[mopar jack]

There is probably a set screw on the bottom of the MC or in the reservoir that holds the pistons.