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So when the "BRAKE" light on the dash lights up....

I dunno, I just gravity bled my front brakes last week and I just opened the bleeder screw and waited for a few minutes for it to start flowing through the clear tube.

If that power bleeder allowed you to not have to bench bleed the MC, then I could see it being pretty useful.
 
Bunch of sissy's i swear. :D

I've always just manually bled my brakes with no issues. I use two people if i have someone handy to help me otherwise i just use a plastic coke bottle with the small hole in the lid with a piece of vacuum hose through the lid and fill the coke bottle half full of brake fluid now attach the other end of the hose to the brake nipple and crack the nipple open and slowly pump the pedal several times then move to the next wheel. The fluid and air gets pushed out of the system and when you release the pedal nothing but fluid gets sucked back in. The only downside to this method is if you have dirty fluid there is no way to "flush" the system.
 
Power Bleeder

Bigbadchev let me use his power bleeder. It makes it ridiculously easy to bleed brakes. I didn't bench bleed the MC and just hit the peddle a couple times to move the internals and let everything flow through. :D
 
Picked up the new MC today....

Hopefully I can get it swapped in this weekend. I live on a BIG hill, so if I wait much longer Trogdor will be a cautionary tale.


:usaflag:
 
UPDATE:

I got the new MC bench-bled and installed. When I removed the old one, there was a bit of brake fluid that seeped out from the rear where the actuator rod meets the piston....I don't think that area is supposed to have fluid in it.

I topped off the fluid in both ports and went out and bought a MityVac at the local AutoZone to try to quickly vaccuum-bleed the system, starting with the rear lines. For some reason the rear didn't want to flow out any fluid on the driver's side, the passenger side went fine and I filled the catch canister twice before the fluid was flushed through and running clear. I ended up cracking the bleeder valve on the driver's side with a length of hose, then I clamped the cover on the MC, started the engine and pumped the pedal a few times.....finally I started getting fluid out that corner. The pedal was/is REALLY hard to push.

The "BRAKE" warning light finally went out, so I guess the MC was truly the culprit...but at this point I am unconvinced that I've achieved a proper "bleed" since the pedal is still really stiff and it doesn't stop worth a crap yet.

The MityVac came with enough extra parts that I might be able to create a pressure-side bleeder with it....or maybe I'll just try Scott's idea and put the pedal at each corner the old fashioned way


:usaflag:
 
Does your proportioning valve have a little button that you can push in? I think that has to be pushed in to allow the fluid to flow freely to bleed it.
 
There is a thin metal pin at the very end of the prop valve sticking out of a rubber boot. It looks more like an electrical sensor than a button, but I've also got a sensor located between the two input ports across the top of the prop valve.

:usaflag:
 
I'm pretty sure one of those has to be pushed in to do a proper bleed - I don't know for sure though as my 69 doesn't have one and the one on the 70 didn't need to be messed with to bleed for whatever reason.
 
Photo for clarity... Wire and boot in center is "BRAKE" sensor. No idea what that pin on the far left side does?? :dunno:

DSC01549.jpg
 
Ah come on, can't you just make a cool tool to do it for you? :-) Actually, you supply the beer and I will come push the pin in for you.
 
Greg, it is rare that you ever need to push that pin in. If the pedal is hard then the booster is bad. The fluid you seen at the rear of the master when you removed it came from the seal in the bore of the master and will have leaked into the booster and brake fluid will ruin a booster diaphragm. :deal:
 
Scott,

Do you think the booster was the original part that failed (the reason for the BRAKE light) or was it collateral damage once the MC failed?

I'll trying screwing around with that button ('cuz it's free) and if I can't get any better results than I have now, it looks like I'll throw some more parts ($$$) at it..... I was hoping to have this fixed before the weekend, so I'd better get this diagnosed today in case I need to order a booster. Nothing is "in stock" in this little town!


:usaflag:
 
just do a vac test on it with your fancy new Mity-Vac! :wink1:

disconnect the vac line, apply vac to the booster and see if it holds vac... the diaphrams don't like brake fluid..
 
Do just what ryoken said. If the diaphragm is good then the booster will hold vacuum.

To answer your question, the MC can take out a booster but not the other way around. If the booster is bad it is probably from the MC leaking fluid into the booster.
 
Well, I tried again....

Pushed in that little button (it doesn't really move much) and re-bled the system from back to front. Got a helper to push the pedal and got good clean fluid out of all 4 corners.

I vacuum tested the booster by putting the suction-cup attachment on the Mity-Vac and pulled vacuum to about 15psi, and it seemed to hold fine.

However:

The brake pedal is still really hard to push (engine running) and the brakes don't feel like they're working very strongly at all. It doesn't feel like air in the lines, where the pedal goes to the floor and there's not much braking. In this case the pedal isn't moving much at all and the whole system doesn't feel like it's building enough pressure.

Could the booster be at fault even though it's holding 15psi? Should I disconnect it and see the braking feels any different? :dunno:

I starting to wish this was something simple like rust-repair.



:usaflag:
 
I think I just solved my own problem....

I went outside and pulled the vacuum line (and plugged it from the manifold) and drove it forward and backward like before. The pedal feels IDENTICALLY hard to push.

I unplugged the vacuum line and heard the "vacuum sound" from the hose and confirmed that it's actually pulling in air with my finger. Good. Then I plugged it into the booster while the engine was still running......but that sucking vacuum sound didn't go away. Sounds like the booster itself is bleeding vacuum somewhere or somehow. CRAP!

Odds of getting a new booster in this town just before a long weekend.... :thinking:

EDIT:

.....are GOOD! The local CarQuest says they can get me the Cardone #54-71007 booster by tomorrow at 8:30AM. That's some seriously good karma coming my way! :saweet:

$140 + core charges.





:usaflag:
 
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