Installed C6Z06 calipers and rotors on my ‘95 ZR1, with new braided hoses, while bleeding the brakes the first time I assume I let the master cylinder go dry.

Now after purchasing a neumatic power bleeder, and 3 additional bleedings including the ABS unit and a little over a gallon of brake fluid, I still have no brakes. When the car is started the pedal goes straight to the floor, but will pump up, but in a matter of seconds after letting off the brakes the pedal goes to the floor again. Also after cycling the Pedal the fluid in the master cylinder looks like champagne with tons of tiny bubbles.

I’m down to either removing the master cylinder and bench bleeding it and reinstalling or just replace with new, which is the direction I’m leaning.

Has anyone ever ran into this? I’m open to any and all suggestions.

Thanks!
Rob

 

I think you still have some air in

 

I am sure you probably already tried it, but I would pump up the pedal and loosen the lines right at the master cylinder. It sounds like you have air in the line right at the master cylinder.

 

Hi Rob,

Its air in the system. Heres how I would do it.
1. bench bleed the M/C
2. gravity bleed all 4 calipers
3. regular pump/hold crack bleeder/tighten bleeder method

You need to go slow when pumping the pedal. I have done many, many brake jobs and never needed any fancy power bleeders or even used a speed bleeder. Theres just no need in my opinion.

 

The best brake pedals ive ever gotten were with a hose, empty can, cheap dot 3 brake fluid, wrench, and someone to pump the brake pedal SLOWLY and hold till i closed the bleeder every time.
Start with the right rear, then left rear, then front right, and finish with the front left (drivers side closest to the MC).
Unless you have a broken line or hose that will fix it.

* don't let the MC go to low. Add brake fluid every 10ish pumps. Keep and eye on that.

 

this is best, Lowes sells clear pliable plastic tubing for pennies per foot. there is one size that is just perfect for going over the ends of bleeders. I use a small box end wrench to put the hose through to hold it down in the container.

additionally, regardless of using the hose or open air method, close the bleeder while the fluid is still squirting. that way you can ensure no air is leaking.

BEFORE anymore bleeding, double check all your fittings. make sure you tightened the banjo bolts good enough on the crush fittings.

lastly, the master cylinder can contribute, after all, it is 22 yrs old if it has never been replaced. brake fluid is hygroscopic, meaning it has an affinity for water. depending on how often the brakes were bled during the cars life, you could have roughness in the MC due to water corrosion. Old cars with cast iron based brake components suffered from the terribly. A whole business was based on stainless lining brake calipers for C2's and C3's.

BUT I would (for my 2 cents opinion and hearing my keyboard click) retighten everything and invest in less than 2 dollars worth of hose and bleed them out again, as the folks above have also said.

 

I've used the method drcook describes for years. always worked.

I have found that having the hose go as far up as practical before it turns down helps.
Air bubbles traveling vertically get farther from the bleeder faster than a hose that goes horizontal from the bleeder. So I tape or loosely zip tie the hose up on the body or frame.
you aren't going to push air down towards the catch jar so it needs a place to accumulate.

When I was buying the vinyl hose i grabbed a brass barb fitting to shove in the jar end of the hose as a weight.

Another homemade device I've seen is a hangable jar with the hose in the bottom. A line clamp was use to close the line for installation and removal. I think it was a clear plastic jelly jar.

 

Speaking of cheap DOT 3 brake fluid: I'm on master cylinder #3 because they all seem to leak at the back of the bore a few weeks/months after being installed. I've been using the Autozone brand DOT 3 brake fluid and I was wondering if there may be something in it that's eating the seals? I've run into the same issues as the OP with brakes. Vacuum bleed 5 or 6 jugs worth of brake fluid through the calipers and still have squishy brakes. It's one of the most simplistic systems on the car but feels like black magic to get it right.

 

I use a Phoenix Bleeding system on my 1988 Corvette. The real problems on these cars is at or near the ABS box behind the drivers seat. If you look carefully you will see the brake lines have vertical loops which is effectively acts like an air trap. Trying to push the fluid down towards the wheel is going to be very hard to do going through the air trap. If I had no other option I would open the lines on the ABS box and bleed the air out down there before moving on to the individual wheels.

I am a big believer in bleeding in reverse ever since I bought my Phoenix Bleeder Pump kit. The Phoenix bleeding system is a small hand pump that forces the air and brake fluid in through the normal bleeding point. When you push brake fluid up from the wheel it forces the brake fluid and air out of the ABS system as the air is trying to go up and out of the system at the master cylinder. You do need to keep a close eye on the master cylinder as it has a small capacity for holding fluid. I put a catch pan under it with towels around to be sure that the fluid does not end up on my paint.

The Phoenix Bleeding system belongs in every Corvette Owners tool box. If you have a hydraulic clutch then there is another reason to have one. On my old pickup truck with the hydraulic clutch I had a horrible time getting the air out when replacing components. I have watched mechanics spend hours trying to solve the problem of getting the air out.

It makes sense to do it in reverse as you are simply helping the air out of the system by pushing brake fluid up behind it.

I hope that any of you having problems bleeding your air out might consider the "Other" way of doing it. Using the Phoenix kit you can bleed in either direction and it came with all the adapters needed for my old Yamaha motorcycles hydraulic brake systems as well as many other adapters for other cars. Mine gets plenty of use in my garage.

Good Luck getting all that air out of the loops!

 

I agree with those who say you have air in the system still.

There are a plethora of ways to push it out as detailed above; forward, backward, pressure, vacuum, etc.

I like gravity bleeding b/c it uses no tools. On the rare occasion that air gets trapped in a "loop" or high spot (as mentioned above), a very effective way of working around this is to pump the brake pedal with the bleeder screws open. This forces fluid (and air) through the lines, pushing the air out to the calipers...and out the bleeders.

Fast, effective, cheap and easy.

 

As I said above... the simple method seems to work best.... has for me more times than I can remember.

 

DOT 3 is DOT 3.

 

Try bleeding again. You may have gotten air into the ABS. IF so, it might be simpler to go to a dealership that has the Tech 1 to pulse it.

 

Are the bleeders at the top?

 

I also use a rubber mallet and whack the calipers etc. Helps dislodge stuck air bubbles. If it is in the ABS, as AKLIM said, you may have to go to a stealership or find someone with a diagnostic tool that will trip the ABS. I just scanned my son's and tripped his to bleed the system on the 93 Suburban he just got.

I had to go to the stealership to have my 04 2500HD bled when I put in all stainless lines. Had to have a Tech 2 to cycle all the valves.

There is a "poor man's Tech 1/2" trick. If you have a gravel or dirt road nearby, try locking them up so that the ABS is triggered. That has worked for the later model trucks sometimes.

 

Thanks for all of the suggestions, I think I’m going to remove MC and bench bleed it, reinstall, and give it another round of bleeding, I started at the ABS, RR, LR, RF, LF, I’ll update once I give it another shot.

 

I agree with aklim. If you have air in the ABS it can be very difficult to get rid of !!!!

You can try the reverse bleeding (or find a way to pressurize a reservoir of about a quart of brake fluid to about 10 psi - hook a hose to the reservoir and connect the hose to the bleeder screw - then open the bleeder) - but I've never had any real luck with vacuum bleeding - as air always seems to get in around the bleeder threads & I would expect reverse bleeding to give me the same problems - but hey - it might be worth a try....

You may end up having to take it to a dealer or someone who has the ability to pressure bleed the system WHILE cycling the valves n the ABS Unit (which is how they bleed the system at the factory).

I can tell you a friend and I were doing a brake fluid flush before a track day on his C4, and we got a bit of air into the system when we let the reservoir go a bit too low. We bled the system, and got a pedal - but it was spongy. We went out and drive the car - and actuated the ABS - then re-bled. About three iterations of that - and the pedal felt normal again.

On thing - if you say that the fluid in the reservoir is filled with air bubbles after repeated pedal applications - get a turkey baster and suck it out then refill with fresh fluid before doing anything more.... Aerated fluid is NOT your friend !!!

 

Check this. First time I installed calipers I got them swapped. Tried everything to bleed them but nothing worked. Finally noticed bleeders were not at top. Swapped calipers side to side. Quick bleed and brakes were fine.

 

Like I always say, calipers are like *****, you want the nipples pointing up.