Now that my 77 is off the road for cold weather, I changed out the rear rubber brake lines which looked original and were ripe, and pads. I bled the brakes with the engine off, had a decent pedal, but when I started it I found with the power brakes that the pedal was much lower, in fact when you first step on the brake it went to the floor and the brake warning light came on. Bled the rears again, no luck the light comes on sporadically, pumps up and the light goes out. Seems to me like the master cylinder is shot, did not have this problem before I tackled the rear brakes. Any special trick to bleeding the rear? I read in a manual that the front should be higher, but have the rear on jack stands, slightly higher than the front.

 

There are 2 bleeders on each rear caliper, best to bleed the inners first then the outers.

Also you can relieve frustration and loosen trapped air by hitting the caliper with a hammer.

How are you bleeding the brakes? By foot pedal with a helper? If so pump the pedal slowly.

 

If everything was fine before, then you just have air in the rears.

Best way to bleed is with a pressure bleeder, but short of that you can do it yourself with some clear pvc tubing, 3/16" id I believe, so that it will fit tightly on the bleeder screw.
You can do it no problem with the rear jacked up.
It helps to put enough teflon tape only on the threads of the bleeder screw, so that it won't leak fluid or air around the threads when opened.
Using tubing about 3 ft long attached to a bleeder, with the master cover off and cyl full, hold all the tubing higher than the caliper and open the bleeder a turn. Stand up and slowly suck on the tubing and watch the bubbles come out of the bleeder into the tubing. When the fluid gets above the fender level stop sucking and let the bubbles rise to the top of the fluid level in the tubing. The fluid level will slowly lower until it levels with the fluid level in the master (same principle as a water level), but the bubbles will keep rising. You can also tap on the caliper to help. Repeat until no more bubbles. Then do the other 3 bleeders.
A little different method, but works well, uses a lot less fluid and not as messy.
On power brakes your pedal will always be lower with engine running.

 

Hi Noonie, seems like there would not be enough clearance between the caliper and fender area to use 3ft of pvc pipe. Does this need to be done with the caliper off the rotor for clearance?

 

I'm sure Noonie means clear soft tubing that you can get at Lowes.

 

get a power bleeder if you plan on keeping your vett... this will not be the last time you will have problems in this area.... and a power bleeder is almost essential with our C3's...

you still have air in the lines.

another thing you can try... speed bleeders.... they do help with the process and you can get them cheep at pepboys

 

Yes it's tubing, not pipe, I don't think pipe comes that small anyway.
available at Ace, Homey Depot etc, only a few cents a foot, so get plenty. Take a blleder with, make sure it's a snug fit.
Here is a pic of the tubing with the rear obviously jacked up.



A pressure bleeder is always best, but if only replacing the rear hoses or calipers, I don't bother hooking one up, this is much easier, especially if the fluid doesn't have to be flushed.
Never let the level of the hose drop below the bleeder, unless you want to drain it before detaching from the bleeder.

It also helps to plug the line to prevent as much fluid loss and/or mess as possible when replacing parts. Helps a lot with the bleeding.

 

Great thanks. Where can I find a pressure bleeder if I decide to go that route. I checked with O'riley here in Houston today and they do not carry them.

 

The best by far is a diaphram type, but far to expensive for DIY use. They don't emulsify the fluid. Won't hurt to take a quick look on craigslist etc.

The most common is a Motive, just google for the best for you, Summit and Jegs carry them I think.
Don't know how real this it.
http://www.autopartsdealer.com/motiv...tent=APD246671