- Local time
- 3:27 AM
- Jan 10, 2021
- Reaction score
These are all great points. I didn’t realize that about the brake rod not fully depressing the MC when in the car. I guess I’ll just pull it out and start over. As for the brake rod, I’m using my original from the single reservoir that came with the car simply because it has the protrusion that hits the brake switch. When the pedal is fully released, it is pretty tight and I can’t really move it. Maybe that is causing the master not to fully release? I guess I can try using the adjustable one and if that makes a difference then I’ll install an inline pressure brake switch under the hoodJust throwing out my experience bleeding systems over the years, they suggest bench bleeding for a reason. The brake pedal won't bottom out the piston in the master cylinder like it will when doing it out of the car. If the piston wasn't bottomed out when bench bleeding there still could be air trapped. (You might have done this) Sometimes on rare occurrences air can find it's way out over a couple of days.
The 15/16" bore master cylinder creates more pressure at the caliper and wheel cylinders than the 1" bore. The thing is you'll have a bit more pedal travel with the 15/16" bore. Maybe up to an inch more than the 1". Using a synthetic fluid like Dot 5 will create even more pedal travel. (That's why I asked what you were using).
The way I check for a bad master cylinder (internal leakage/bypass) is to pump up the pedal till it's hard and hold the pedal firmly. As you're doing this, slightly release pressure and feel if the pedal starts creaping down. If you experience this then it could be leaking internally.
Of course peaking under the boot at the rear of the master cylinder and inspecting it for fluid leaking is a sign of a bad one also but in this case the master cylinder could be operating properly.
Another I have to ask...You do have the front brake line hooked to the large reservoir? (Not easy to do with most master cylinders having two different size fittings but you never know).
The brake pedal rod needs a little play just enough that it's not applying pressure on the piston not allowing it to return to it's most rearward position. That's another thing to check.