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Brakes and power bleeding them. Using a motive power bleeder.
Last summer I redid my brake system, everything new. Lines,calipers, pads, rotors and master. bled the brakes by the pump method and everything was fine. Brakes worked great. Last winter I redid the whole rear suspension and also added Wilwood replacement calipers. Bled the brakes using the pump method and had a nice pedal. Pulled it out of the driveway brakes seemed fine. Drove a few hundred feet and stepped on the brakes and it went right to the floor. I figured maybe there was still air in the system. I ordered a Motive power bleeder. Pumped it up to 10 pounds and bled the brakes. Got a flow out of most of the bleeders, some squirted and others just dribbled out but there was no evidence of air. Checked the pressure and it was the same. But when I looked under the car there was a puddle of brake fluid on the floor. I tried it again and went around and bled the brakes. Same thing pressure held and puddle on the floor. I was using 2 welding/vice grip clamps to hold the top in place.
I called Motive and he thinks the rear seal on the master went. The paint on the bottom of the booster is gone like the master was leaking. I got another master and will put it on Thursday and yes I will bench bleed it.
I ended up using a couple of c-clamps to hold the lid on the m/c. I filled the motive bleeder the first time I used it, now I just use it as an air pressure source to the top of the m/c. Less messy.
IIRC, there's something odd you need to do with Wilwood calipers for bleeding. Like remove one of the mount bolts and tip the bleeder screw so it's 100% the highest point. Not sure, you might ask around. I'm sure someone has had to do that or something with the Wilwoods.
First problem you will have is the wildwood calipers on the rear of the corvette will never bleed all the air out. The angle of the calipers allow air to be trapped at the top of the pistons. The only way to bleed the calipers ( after a new install ) is to remove the caliper from the mounts, stand them upright , place a block between the pads 1.25" same as the width of the rotor. Then bleed them. Once all the air is out then you should not have to do this again.
As for the motive bleeding I use this method to pressure bleed.
Now to make sure I don't empty the MC, I have a 6 ft length of tubing attached to the bleed screws, I bleed the full length of the tube (follow the air bubbles in the tube) 3 times and then refill the MC.
Then once you have the calipers completed, you might try this since you replaced all the brake system at some point.
Like it or hate it...you'll have to place the rear caliper in a vertical manner to be assured all the air is bled out. Even under pressure of a bleeder the crowns of the pistons can retain an air bubble in the horizontal position. Tipping them vertical places the bleed nipple at the very top where it's most effective. *Place some wood between the pads for this exercise so not to extend the pistons. Future flushing won't require that- assuming no air has been introduced to the system you can "bleed" (ie. flush) fresh fluid horizontally.
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
with the dribbling instead of squirting, that is an issue. I would say the M/C is bad as you have a puddle and paint coming off from the leak. I would remove it and look for the leak, either rebuild it or replace it. They arent expensive which is nioce
Installed a new master today and bench bled it. Pressurized the system and the calipers were squirting now. Even the rear ones were getting a nice flow. None of the calipers had any evidence of air in the stream. Went around twice but still have a spongy pedal. I guess I will bite the bullet and remove the rear calipers. I will get to it Friday.
Took the rear calipers off and brought them vertical as much as the brake line would let me. Pressurized the system and bled everything. Pedal still spongy. Very frustrating. Next up rebleeding the master. I bench bled it but now will do it on the car.
Took the rear calipers off and brought them vertical as much as the brake line would let me. Pressurized the system and bled everything. Pedal still spongy. Very frustrating. Next up rebleeding the master. I bench bled it but now will do it on the car.
Sorry to hear that you still have a spongy pedal and yes, very frustrating.
Don’t know if it’s true for Willwood calipers but I’ve had issues with the cast iron ones with bubbles adhering to the surfaces. A little banging with a block of wood seemed to help.
Sorry to hear that you still have a spongy pedal and yes, very frustrating.
Don’t know if it’s true for Willwood calipers but I’ve had issues with the cast iron ones with bubbles adhering to the surfaces. A little banging with a block of wood seemed to help.
I tapped them with a rubber mallet. I got nice streams of fluid out of each bleeder. I'm going to redo the master.
Just FYI. I pressure bled my Wilwood calipers with my home-made pressure-bleeder filled with DOT-3 and pressurized to 10-15 psig. Bled just fine and pedal is still hard and firm 5 years and 9 months later. I haven't even gotten around to "vertically" re-bleeding the rears because they're so nice and firm. Just info to inform that I did not have problems bleeding wilwoods.
not that this would fix your issue, but I remember reading where a member had to raise the front end to get all the air out of the master cyl. It seems at normal ride height the master was slightly pointed down and there was still air trapped in the back of the master cyl. Raising the front until the master had a slight up attitude and then rebleeding it fixed his issue.
not that this would fix your issue, but I remember reading where a member had to raise the front end to get all the air out of the master cyl. It seems at normal ride height the master was slightly pointed down and there was still air trapped in the back of the master cyl. Raising the front until the master had a slight up attitude and then rebleeding it fixed his issue.
The other way around, lift the back end of the car like this.
Just FYI. I pressure bled my Wilwood calipers with my home-made pressure-bleeder filled with DOT-3 and pressurized to 10-15 psig. Bled just fine and pedal is still hard and firm 5 years and 9 months later. I haven't even gotten around to "vertically" re-bleeding the rears because they're so nice and firm. Just info to inform that I did not have problems bleeding wilwoods.
Before I tried the vertical bleed on my rear wilwoods I was also getting a nice stream out of them. I just did it to see if it would work. It didn't make a difference.
Pressurized everything today. Bled the master by opening the fittings. Went all around and bled every caliper. No luck.
Raised the back of the car and got the master level like in the video. No luck.
Little history...all new stock calipers. New master and booster. All new lines except the one that went from the front to the back. Brakes worked perfect. Also went from auto to manual brake pedal setup. Maybe the rod is not the same....just grasping at straws now.
Changed the calipers to the Wilwoods. Replaced the front to rear line. Can't get a pedal. Put another new master. No luck.
Went thru the brakes again. Took the rear ones off stood them straight up and gravity bled them, then power bled them, then had my daughter pump the brakes. No difference. Went thru this 2x.
Bled the front ones, gravity then power then pump method.
Put a new master on. Gravity bench bled it, raise the back up like in the video with the level and pumped it until all bubbles out. Installed on car, no difference.
The brake pedal is firm until I start the car once started it goes to the floor. I am going to try bleeding them with the car running.
I have been working on care for 45 years, professionally and my own stuff and have never had this problem with the brakes like this.
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
I just reread all your problems and its a difficult problem for sure. If you have a firm pedal and everything goes to hell when you start it I would look at the booster again.... maybe its miss adjusted or bad from the factory?????
Last edited by Rescue Rogers; 05-16-2018 at 04:22 PM.
I just reread all your problems and its a difficult problem for sure. If you have a firm pedal and everything goes to hell when you start it I would look at the booster again.... maybe its miss adjusted or bad from the factory?????
New booster. Bad booster would give you a hard pedal. Everything was fine, I had brakes when I had my stock calipers. I changed the calipers and the line from front to rear. All fittings are tight, if they weren't I would have a leak from it. The only thing that I didn't do was put teflon on the threads of the fittings into the calipers. But I called Wilwood and they said it shouldn't be a problem.
I don't know if the adjustment is needed. I went from auto pedal assembly top manual. I don't know if there would be a different rod or adjustment.
04-25-2018, 01:44 PM
Brakes and power bleeding them. Using a motive power bleeder.
