wnjlt1

it looks like your very frustrated. i also went through a simular ordeal this past spring with a complete brake caliper overhaul and can truley relate. from what i have read so far, it's not clear if it's a hardware issue / small leak or a tool not working properly. it's probably not a fluid issue so i would stay the coarse and not change to dot 4. i know...it's kind of expensive.
will have to agree with sixfooter, duke and cosmic about getting a motive pressure bleeder and also a good c-clamp. with the bleeder you can pressurize the system to determine if you have any leaks before proceding. that would be a great place to start with the process of elimination. good luck!

MarkV

I was able to determine that there was a small air leak (sucking air) at the distribution valve/rear break line (top). I tightened up the fitting & this took care of that problem. Then I was having a leak at the right rear caliper, as when I applied 25 in vacuum, I could hear something that sounded like air. I just rebuilt all 4 calipers with the 'O' ringed pistons & new seals so I didn't think they were the culprit. All I know is that there was way too many air bubbles coming thru that clear tube. I removed the brake line where it screws into the rubber line & shot low pressure (25 psi) compressed air into the brake line to see if the little black 'O' ring that seals the caliper halves was to blame. Even applied a little soapy water at the top of the caliper to see if it would bubble. No leaks. I removed the disc brake pads to see if a caliper seal was leaking. Dry as a bone. I reconnected the line, tried to apply some vacuum & this time it did as it was supposed to. I guess that maybe one of the caliper pistons wasn't seated well into the rubber seal & when I put the compressed air to it, it seated. Anyway, I bleed the brakes all around twice. I still have a soft peddle. I guess I'll take the plunge & purchase a pressure bleeder if I don't make one myself, as has been suggested. Yes, frustrated, but I'll get it straightened out. My problem is that I'm registered for the NCRS winter meet in Orlando Jan 18 - 21. My car will be there for Flight judging........not if I don't get these brakes working properly!!

Thanks for taking the time for responding!

stingr69

The Motive Products Pressure Bleeder with a big C-clamp and a block of wood will make the job SO much better you will kick yourself for not buying it sooner. It should come standard in any C3 owners starter kit tool box. Never needed one before I tried to do the Vette.

The only way to fly!

-Mark.

MarkV

Ordering one tomorrow. Never knew using silicon brake fluid would be so problematic. Hopefully it'll work as good as everyone on here says it will. This entire ordeal has been very frustrating. But, I'll get it straight soon enough.

Big2Bird

Hope they don'y knock off points for unathentic brake fluid.

MarkV

If they do, then 'Oh Well'!!!!

MarkV

OK, now to get a 'headstart' so to speak, when this pressure bleeder comes in, is there anything special or other tricks besides the large 'C' clamp & 1" X 4" X 6" block of wood that I need to know? Thanks for all the responses BTW!!!

stingr69

Heat the fluid in a stainless steel pot on your stove to drive off the air bubbles. This helps but can stink up the kitchen a bit. Other than that you should be stopping in no time.

-Mark.

MELVIN

Ive used so many suction type gadgets, and to tell the truth, Ive never had much succes with any of them. 70 Cuds, 77, 76 TA, 70 El Camino: None bled very well.

Then I went to Russel and got thier self bleeding bled screws. They have a tiny, one way valve or ball bearing in them. Crack the screw about one turn, and air will only go out, not in. Pump till nothing but juice comes out. No messy lines, vacum crap, catch bottle, etc.

Once bled, close it, move to the next. They cost about $4 each

Takes about 10 minutes to do the entire job

carbster09

I agree, we were having problems with my dad's vette and he bought some speed bleeders. I didn't rate them ... BUT they WORK! Autozone even had them. After that we found a leak, fixed it and bled the brakes in about 1/5 hours and started driving with a rock hard pedal...however DOT 5 will NOT give you a great pedal. Although my LS-5 has a pretty decent pedal with DOT 5 and VBP calipers. It could be better so I'll be upgrading to Wilwoods and DOT 4 in a few weeks!

carbster

MarkV

OK, got it all done. Actually had to re-bleed the MC again. Bleed the brakes twice with the powerbleeder. Went well & very easy. I've got a much better pedal now, but it's still a little softer than what I'm used to. I think I'll drive it some & then re-bleed at a later date. Any suggestions are welcome & thanks again for all the great advise!!

Big2Bird

So that's why. I thought you guys added eye of newt, or earnhart blood.

72 LT1

Not to highjack thread, but I just replaced MC, and all calipers and used DOT 3. Bled all calipers 4 times, have NO air bubbles, but pedal seems softer than it should. I have manual brakes and would have thought pedal would be pretty hard. Used "mighty vac" to pull fluid thru to start, then used "press the pedal' method 4 more times. I thought DOT3 would give a harder pedal feel than DOT5. Am I right in thinking that??

Duke94

If there is no air in either system there's no difference, as both fluids are incompressable. I have Silicone fluid in both Vettes and my 88 PU and all 3 have excellant pedals. You just have to not bleed at high pressures (push hard on the pedal and crack a bleeder screw) which will airate the fluid. Also, don't pour the bled fluid back into the master cylinder, always use fresh.