Topic: Need Help Bleeding 4w disc

[10thAnniversarySearch]

Finally the brakes are complete, just need to bleed them.  I understand how to bleed them, but it doesn't seem to be working right.  I'm not seeing any bubbles from the bleeding tube.  Keep in mind I have replaced all the lines, calipers and the master cylinder. 

What do the experts have to say?

As a side note, is thee any trick to priming the fuel lines?  I have replaced all the fuel, return, and vapor lines as well as the tank and sending unit so everything is bone dry.

[eroc022]

Are you just getting a bad pedal feel or what's the issue?

As far as fuel lines just crank the motor for about 10-15 seconds at a time with about a 30 second break in between so you don't burn up the starter....

[10thAnniversarySearch]

Are you just getting a bad pedal feel or what's the issue?

As far as fuel lines just crank the motor for about 10-15 seconds at a time with about a 30 second break in between so you don't burn up the starter....

Thanks for the fuel line tip.

With the brakes, I've only filled the master cylinder once for the rear brakes, twice for the front.  When I depress the pedal and open the bleeder screw, I should get bubbles in the jar I'm bleeding into, right?  I don't get anything.  If I leave the screw closed and pump the brake pedal about 15 to 20 times, it begins to build firmness and if I remove the cove of the master cylinder, fluid is squirting back into the reservoir and fills it back up.

Would I do better to leave the brake line loose from the caliper to let fluid fill the line first?

I had trouble bleeding my 77 vette and years ago and finally took it somewhere to get it done.  Don't want to repeat that if I can avoid it.  I've managed to install all this stuff, surely I can get it filled with fluid!?

[termy1971]

If you have a new master cylinder did you bench bleed it?  If so fill it up leave the top off and open the bleeders and let them gravity bleed until you have solid stream of fluid coming out. This will fill the lines and most of the air will escape. Keep an eye on your M/C so that it does not run dry.
 Close all the bleeders put the cap back on the M/C and start at the right rear wheel first, then the left rear, then the right front and finally the left front. Have some one pump the pedal then hold it tight. take a rag and hold it over the bleed screw crack the crew with a wrench and you will see and hear air come out. Make sure the person holding the pedal does not let up until you have re-tightened the bleeder. Do this until just fluid comes out in the order above. Spray all the connections you did and calipers/rotors with brake clean then air gun off. Have some one put  ALLOT of force on the pedal and check for leaks. If your pedal is still low you may have to adjust the rear calipers. These brakes are horrible if the ratchet mechanism isn't working right or is not adjusted tight. Check the rear by applying the E brake if the pedal is tight and it locks the rear wheels you should be close. Let me know how this goes.

For the fuel line if its stubborn, hold and air gun with a rag covering it tight on the gas fill tube and put some pressure in the tank that will force gas through the whole system. (watch taking the rag off to quickly gas will spray back at you)

[TransAmconvert]

If you are working alone, it can be hard to pump brake then go over to bleed fluid out of brake cylinder. I found it lot easier to use one man brake bleeding tool without having to pump brake pedal. Termy1971 is right about master cylinder tasks.  Here is the tool you can find in local auto store or Harbor Freight where I got this tool. 

[oldskoolubr]

As Far as the fuel lines, you can put a temporary hose on the end then feed it into a 2 liter bottle so it doesn't spray or make a mess.  I also use a Large heavy clamp on the bottom (as a base) of the bottle to keep it from tipping!  I 2nd the Bench Bleeding and Gravity bleeding of the brakes, just keep topping it off at the MC as stated!  Good Luck!

[Angelo]

I did my 81 all wheel disc brakes with Russell Speed Bleeders, but the first step is to gravity bleed them as everyone else described with the original bleeders first. After that, I was able to bleed pressing down the brakes till I got bubbles out of the specific lines that still had them.

I bench bled my master cylinder as well, that took more time than bleeding the brakes. 81 is special year though, it uses the fast take up master cylinder and it will squirt fluid back up, its normal for 81+. I then read the lid needs to be on when ever your bleeding to keep the master cylinder side pressurised.

Make sure your parked in a flat surface. Rear calipers chamber needs to fill up before you can get bubble less brake fluid from them. Maybe a kinked rear hose? Check for leaks too.

[10thAnniversarySearch]

Thanks for all the tips.  I bled them all today and got really firm pedal.  Then  started the car and lost most of the firmness.  Is this normal?  Brake light is on too.

[Angelo]

If the brake light is on, you may have a leak somewhere or the proportioning valve is messed up. I didn't have this problem, but I did read on these forums (http://www.78ta.com/HTAF/index.php?topic=34548.0) about the prop valve not being balanced right which triggers the brakes light to think there's a leak in one side of the system. There's a tool you can install in place of the lead for the brake light that holds the position while bleeding.

When checking for leaks, check the rear calipers at the center of the piston (behind the inner brake pad), the plastic relief valve that's there may be leaking. Check the hoses too, you may have an old hose that is ballooning or something. You're going to need a buddy pressing on the brake pedal while you're under the car tracing this down.

Maybe jjr, Renovations and eroc022 can reply with more ideas, most of what I know is from reading their posts on the subject.

[Angelo]

Oh, and wear goggles under the car when someone's pressing on the brakes, you don't want brake fluid in your eyes.

[ta6point6]

There is no getting around it you have to bleed the cylinder first. You can do it while on the car. Most new master cylinders come with a bleeder kit and it can take some time to get bubbles out of the master cylinder. The best way to bleed calipers is the old fashioned way, 1 person in car pumping then holding and 1 person opening bleeder and then closing.
The best way to prime carb is pour fuel in the vent tube