929 MC bleeding problem, geyser into reservoir?
 

Hey guys,

Just got a new reman 929 MC hooked up, bench bled it without any issue, then did a 2 man bleed today. The rears worked out fine, but as I moved onto the fronts, things got kind of weird.

Compared to the rears, the fronts moved very very little fluid, about 1-2cm of fluid per pump. I went through maybe 1/4 of the reservoir for both sides (front) before calling it, didn't see any air bubbles come out through the calipers. Then I noticed that every time the brake pedal was pushed, fluid would basically geyser into the reservoir. The pedal also has 0 pressure, I'm assuming bc all the pressure is going back into the reservoir.

Some details -
- I pressed the pedal all the way to the floor, i figured it was ok since it was a Mazda reman
- The prev owner had the clutch line going to the brake reservoir so there's some buildup of some dust crap that I haven't been able to completely clean out. It's since been separated into its own reservoir.

Any ideas?

Ok when I replaced my stocker with a 929 master this is what I did and definitely worked. Start at the wheel furthest (in hydraulic-circuit terms) from the master-cylinder and progress toward the closest. The correct order for the 3rd gen RX-7 is right rear, left rear, left front, right front.

Took that info out of Rob Robinette web page.
Brake Bleeding

If it is gushing into the reservoir, then there is something wrong with the piston seal.
As it moves forward it will block the line hole to the reservoir, compress the fluid and force it out the brake line hole.

There is a failure there. Take it apart or return it.
I have had a 929 MC for over 15 years without any problems.

The order really does not make a difference as the front and rears are on separate circuits. It does not even make a difference with old brake systems.

I had a rebuilt one do the same thing.

Swapped it for another one, and it bled immediately.

I just started the exchange process, I'm waiting for the new one to come in now. I'll post updates once I get that one installed, thanks for all the input guys!

Ive bought a 929 mc from Ray at Mallow Mazda which was bad and wouldnt bleed. Returned it for another one which worked fine.

What does this tell us?
Get a rebuild kit and do it yourself!