Brake/bleeding issue

[malonejy]

I need some help from all you gurus out there. I found a leak in my brakes (at the rear axle junction) and tightened that up. It's not leaking there anymore but my brakes were still not working right so I figured I better bleed them. Here's the issue, I can bleed the rear just fine, but not the fronts. On the fronts, the fluid isn't getting pressure (barely any). In other words, I don't get any fluid coming out while the pedal is being pumped.

Does that mean my master cylinder is shot and only applying pressure to the rear brakes? Thanks.

FYI, it's an aftermarket hydroboost system, the same one Wild Horses sells. I actually replaced the master cylinder on it about 4 years ago after the master cylinder was letting air into the system.

James

 

[Jason72Bronco]

Likely your MC. Disconnect line at the MC front brake port and see if any fluid will pump out. Otherwise you have a problem further down the line.
Possible seized brake cylinder. (Assuming drums)

 

[malonejy]

Well I figured it out and it was exactly what I thought it was going to be. I just had to tear apart the master cylinder to verify. It may be hard to tell by the photos but one of the seals on the piston went bad. I think this is the second time I have done this but I never tore down the first master cylinder.

As far as the "why", I think it's because the brake pedal was very firmly pushed and held there for an extended amount of time. From my understanding that's not a good idea with hydroboost.

Now I just have to see if I can get the seal replaced so I can keep that MC as a backup.