Bleeding Wilwood brakes

[65 drop top]

I'm having a little trouble with my new brake system. It's a 65 Chevelle with a stock manual pedal ratio that is roughly 6:1. I'm using a new Wilwood 7/8 master which was recently rebuilt by them. I had polished the master a while back and got some water in the bore which rusted the springs, so I sent it back to them for a rebuild. Front calipers are Wilwood 6 piston and rears are Wilwood 4 piston. I bench bled the master and believe I got all the air out. When all the brake lines were empty the pedal was going down to the floor. As I bled the brakes to where it was consistently fluid coming out of the bleeders, the pedal stopped about 1" off the floor when a bleeder was cracked open. I'm not sure as to why the pedal doesn't go as far down as it used to when the bleeder is open. But the problem I'm having is that the pedal doesn't seem to create much pressure until about 1/2 travel to the floor. Once it creates some pressure at 1/2 way down, it seems a bit mushy. I've heard that the 7/8 master can feel a bit mushy so I'm not overly concerned there. But why so much pedal travel to get firm? I've bled around the car 6 or 7 times now and getting solid fluid. Do I still have air in the system? (I stopped getting air about 2-3 times around the car) Too much pedal ratio? Bad master rebuild? Any other ideas as to what I should be looking for? Thanks.

[JustJohn]

Try here:
https://www.pro-touring.com/threads/115296-Is-there-a-Wilwood-master-cylinder-pressure-bleeding-adaptor-can-someone-make-one?highlight=wilwood+justjohn

[Mach1_Ron]

I have the same Pedal Ratio and the 7/8 Bore MC on my Mach. I only have 4 Piston calipers. I made sure when I bled mine to have the Bleeder pointing straight up, had to unbolt the caliper and tilt it slightly. Also there are 2 Bleeder screws per Caliper...Go from furthest from MC to closest as always, but make sure to Bleed BOTH Bleed Screws... Maybe that will help?

[65 drop top]

I have the same Pedal Ratio and the 7/8 Bore MC on my Mach. I only have 4 Piston calipers. I made sure when I bled mine to have the Bleeder pointing straight up, had to unbolt the caliper and tilt it slightly. Also there are 2 Bleeder screws per Caliper...Go from furthest from MC to closest as always, but make sure to Bleed BOTH Bleed Screws... Maybe that will help?I have bled both top bleeder screws at each caliper every time I worked my way around the car. The rear calipers are mounted vertical. The front calipers are mounted at an angle maybe 20* or so. I'll pull the front calipers off tonight and hold them in a vertical position and bleed them there. It's worth a try. Thanks.

[cactuss4]

oh boy.. I've been here, as the forum will attest.. I tried everything, pressure, vacuum bleeders, the ole, pump it a few times hold , open, close, pump a few times etc.. None of it worked.

I finally took 2 bottles half full, a bit of tubing and something to weigh the tubing down so it stays in the brake fluid (can't get air if all it can take in is fluid), attached to my 2 outers in the rear and opened those bleed screws, and I pumped the **** out of my brakes, (I had some kind of bubble from hell that nothing until this point got rid of), after a bit of time I was getting good flow and once I stopped pumping, I could actually see gravity bleeding happening (which means you are in a good state). This is really old school, but it worked and after 2 brake systems and multiple weeks? I have great brakes.

Tory
66 Chevelle
Hydroboost
Wilwood 1"
Wilwood 6 pot front
Wilwood 4 pot rear

Give that a whirl and give the family member a break from sitting there pumping 2-3x "hold", are you holding? then okay release pump 3 more times "hold", are you holding? :))))

[65 drop top]

oh boy.. I've been here, as the forum will attest.. I tried everything, pressure, vacuum bleeders, the ole, pump it a few times hold , open, close, pump a few times etc.. None of it worked.

I finally took 2 bottles half full, a bit of tubing and something to weigh the tubing down so it stays in the brake fluid (can't get air if all it can take in is fluid), attached to my 2 outers in the rear and opened those bleed screws, and I pumped the **** out of my brakes, (I had some kind of bubble from hell that nothing until this point got rid of), after a bit of time I was getting good flow and once I stopped pumping, I could actually see gravity bleeding happening (which means you are in a good state). This is really old school, but it worked and after 2 brake systems and multiple weeks? I have great brakes.

Tory
66 Chevelle
Hydroboost
Wilwood 1"
Wilwood 6 pot front
Wilwood 4 pot rear

Give that a whirl and give the family member a break from sitting there pumping 2-3x "hold", are you holding? then okay release pump 3 more times "hold", are you holding? :))))
So when you bled the rears, you did the driver and passenger side at the same time? Also when you started to see the gravity bleed happen, will that drain the master and get air in the system? Or did you close the bleeders right away after you see it flowing? Thanks.

[a67]

But the problem I'm having is that the pedal doesn't seem to create much pressure until about 1/2 travel to the floor. Once it creates some pressure at 1/2 way down, it seems a bit mushy. I've heard that the 7/8 master can feel a bit mushy so I'm not overly concerned there. But why so much pedal travel to get firm? ... Any other ideas as to what I should be looking for? Thanks.

Check that there is a minimal gap between the pedal pushrod to M/C rear piston. Usually a gap of about 1/32" is OK.

The other one to check is to see how far the piston has to move before it covers the compensation ports. There have been instances where it has been excessive. This increases pedal travel before the M/C moves fluid.

Bob.

[analyte]

I'm a fan of vacuum bleeding with my air compressor. When I installed my new setup, front to rear, it was how I finally got all the air out of my system.

The bleeder canister is around $20 from Harbor freight with a coupon.

Kerry

[cactuss4]

So when you bled the rears, you did the driver and passenger side at the same time? Also when you started to see the gravity bleed happen, will that drain the master and get air in the system? Or did you close the bleeders right away after you see it flowing? Thanks.

No no, both rears.. But honestly you don't have to do them both, do a single if you want, always go from furthest back to front, so normally that means pass rear outer, pass rear inner, driver rear inner, driver rear outer, pass front outer, pass front inner, driver front outer, driver front inner (obviously depends on where the MC is obviously).

I could not get the vacuum bleeder to work..

Also yes you have to make sure the MC has fluid at all times. and you need to watch your brake fluid bottles to make sure they don't over flow as well!!