Okay after rebuilding caliper i opened bleed screws to gravity bleed nothing happened. yes,fluid in master cylinder. Then i ho oked up Mighty vac and all i receive is air bubbles on both inner and outer bleed screw with a excellent flow of fluid. Any suggestions?

 

you are sucking air through bleeder threads. common. I use your method too. If pedal is firm you should be okay.. If not, resort to the old two person method.
VS

 

This is why I push the air up and out versus defying gravity to push it down.

The bleeder screw has to be pretty loose to be able to pull that much air in around it. I think that you might be loosening them up a bit too much. I only cracked them open and bled them. Only open one bleeder screw at a time while bleeding the brakes. The only other place that it could pull air into the system would be at the Proportioning Valve or the brass unions used.

I tried the Speed Bleeders once and after I was done with them I bought a batch of new bleeder screws and they were much snugger in their threads, they didn't wobble as much as the original parts did. Sometimes it helps to just replace the wearable parts like the bleeder screws with tight new parts.

 

ctm

I'm gonna try your Phoenix method next time I change brake fluid! I made a rig out of a big veterinarian syringe on my Harley and it worked great.

VS

 

Never had much luck with the Miti-Vac method...for the same reasons you have expressed. When you crack the bleeder and SUCK fluid out, air is sucked in thru the threads on the (loose) bleeder valve. WT_?
Some folks have put clay around the threads of the bleeder to stop the influx of air; some ignore the bubbles. I just do it the "old fashioned" way.
You can't bleed BOTH rear bleeders at the same time (not sure that was what you indicated); inner first, outer last.
Good luck.

 

Triedtwo person barely had any fluid flowing let alone bubbles.

 

STOP!
C3s don't like anyone touching the pedal. You may have "tripped" the Prop Valve which shuts off half the brake system.
Turn on the key to IGN. Dash warning light on?

Your Mity Vac is pulling air past the caliper piston seals and pushing bubbles into your catch bottle.

 

A mity vac won't work on a C3 fullstop. I've explained this several times in the last week. It'll just pull air past the lip seals. Gravity bleeding is fine for fluid flushes but you can't get the system filled this way.
Believe it or not I've used the 2 man system many times on C3's with complete success. Yes I have the holding tool for the prop valve, most of the time I'm to lazy to use it. A quick stomp on the pedal recenteres it anyway.
Get the system filled and started using a large syringe or a Phoenix bleeder. Then if it's still not tight enough I'll go to 2 man. Then if it's really naughty, reverse bleed again.
All the above is maybe an hours job..

 

I've successfully used a Mity Vac to bleed the brakes on my C3 (1976) and on a host of other vehicles, including various motorcycles.

Jason

 

There's a guy on the C1 & C2 forum who also described getting just bubbles after numerous attempts to bleed his left rear caliper. He discovered that 1/2-3/4 turn opening the bleeder wasn't enough to allow adequate flow. Maybe you're not opening if far enough. If that doesn't work, try removing it completely to check the caliper's ability to flow.

 

A suction bleeder is almost always the go to tool on almost every car and motorcycle.
The fact that you didn't pull air past the lip seals in a C3? Got lucky? Maybe your seals are old and stiff? Or brand new and really tight? But, you got lucky.
Or, perhaps your car has upgraded (if you wish to call them that) O ring converted calipers.
But the honest truth is. Lip seals are designed to seal one way, being pushed against. Definitely not being pulled on. So suction will cause air to just be pulled under the lip of the seal.
Maybe ya got lucky, lucky it indeed worked for you. As per every other car and motorcycle, absolutely. Only the C3 Corvette as far as I know has lip seals.
And you may have noticed a unusually large number of threads on here with people having trouble bleeding the brakes on their C3's.

 

After reading numerous posts about loose fitting bleeder screws it's apparent that whoever is manufacturing these might be making them a bit on the small size.
I went to three different stores and basically purchased different quality in fitment. Some were just junk.
There should not be excessive play of the bleeder in the caliper when opened.

Or.
As posts mentioned years ago, when calipers are rebuilt, perhaps the thread-chasers job is over aggressive?

 

opened one at a time. thanks

 

i removed bleeder screw no flow, at all as car sits there. Does that show bad bleeder screw? Can you not test bleeder with just removing and blowing air threw IT

 

See post 7.

You used the pedal method to bleed.
You tripped the Prop V.

 

If the caliper is not flowing fluid with the bleeder completely removed (gently push the pedal rather than merely allowing gravity to work its magic), then the problem is not the screw. (Yes, you should be able to blow through the bleeder if it's not clogged.) Just an afterthought, do you have the master cylinder cap loose and just sitting on the master - i.e., not clamped with the bails? A well-sealed cap will cause extremely slow gravity flow due to the natural vacuum created.

Go to the wheel on the other side of the car and remove the outside bleeder - does this caliper flow well? If not, go to a front wheel and try the same thing. If there is a difference of flow, front v. rear, like HeadsU.P. said, you likely tripped the distribution block piston. If no difference, it's likely a problem in the master. If the problem only exists with a single rear caliper, you need to remove the inner bleeder to test flow. If no flow, test each section of line from the brass splitter block all the way to the caliper. If the inner and outer bleeders differ you've got something wrong inside the caliper.

Think of this as just a network of tubes and tunnels – with no restrictions anywhere you should lose all fluid in the master in maybe 30 minutes just by gravity alone. The only design restrictions in the entire system are the bleeder screws at the end of the tunnels (and the distribution/proportioning piston if tripped to one side).

 

If you are getting no brake fluid flow in the rear, it is because of a tripped distribution block shuttle valve or because of another form of plug in the rear brake line system (somewhere). The tripped shuttle valve is by FAR the most likely of those two.

 

Tow it to a shop. You lack the ability to follow directions.

 

How do i reset brake lite,i stabbed pedal while vehicle vvas running nothing.brake pedal goes directly to floor

 

Sounds like you let the M/C run dry and allowed air into the M/C.....is this the case? You'll have to go through the M/C bleeding process if you have let that happen.