Good morning. I have been working on my 68 cougar, it had drums in all 4 corners, so I decide to replace it with disc brakes. I bought the wilwood front and rear disc brake kits, along with a new wilwood master cylinder and proportioning valve. I bench bleed the master cylinder, and when I installed it, I try bleeding the lines, starter on the rear passenger wheel, we pump the pedal a few times but it kept going to the floor, but I had fluid coming up. We did this about 10 times, but every time the pedal kept going to the floor. So, I thought that the push rod from the booster was not long enough to make contact with the master cylinder, I order a little tool to measure the required length of rod, just to make sure that was not the problem. Well, I did that, and still the same thing. The pedal is all the way to the floor. No leaks on the lines.
So I tried the vacuum pump, I install it on the passenger rear side, when I apply vacuum, the vacuum is increasing but no fluid, but I heard bubbles at the master cylinder, which is weird since it has plenty of fluid.
If I open all bleed screws on the calipers fluid starts to come out,
So at this point not sure what could it be. Iām thinking of plugging the rear brakes and just try to bleed the front and see it that keeps a firm brake pedal.
Did you try pumping the Pedal to see if it firms up? If it does, you still have air in the lines. Since everything is new you may be pushing the slave cylinder pistons/Calipers closer to the pads when you have the bleeders closed. When they are open, you are not exerting any pressure into the slave Cylinders/calipers, hence the mushy pedal.
You still have a lot of air. Sometimesā¦it might take an extra bottle or 2 of fluid to get it done. If there are bubbles coming up to the masterā¦there is still a lot of air. Do you fill up the reservoir with the pedal to the floor?
Cap the brake lines at the master cyl and see if the pedal still goes to the floor. If it does, bad master cyl. Had that trouble with my Wilwood setup on the race car and they replaced it. About a year later they had a recall and replaced it again. This was about 4 years ago.
LSR Mike, I did try pumping the pedal and never got firm, it went to the floor all the time, did it a lot of times.
blue68cat, I did not try to fill it up the reservoir with the pedal to the floor, will need to try it. I have used one big bottle already and 2nd bottle is about 1/2 way gone.
BossElim69, thatās what I be doing next, I was going to cap the rear lines and try to bleed the front brakes and see if the pedal goes to the floor.
This is a long shot for you but I had similar thing and hereās what it was.
I installed a disc brake conversion that uses new calipers from a ā94 S10
These calipers mount in front of the rotor with this particular kit and brackets. One is stamped R and the other L. Of course I put R on passenger and L on drivers side.
Well since the S10 had calipers in back of rotor my bleeders where in the down position and no matter how many times I bleed it air was trapped.
I pulled my hair out for 2 days!
Swapped sides and all good.
Again long shot but are your calipers in the right side?
Iād try gravity bleeding all four wheels with vacuum hoses on the bleeders to make less mess. That should get you pedal. May take more fluid than you think since the system was empty. Keep an eye on the master cylinder level so as to not inject more air. Good luck
One other thing to check is whether there is another bleeder screw on the calipers that youāre not seeing. A friend of mine put Wilwoods on his car a number of years ago and it had bleeders on both sides of the caliper. He forgot about the āotherā side when he started bleeding. Took a little bit to figure it out. Also, if there are multiple bleeders on one side remember to use the upper/top bleeder. Good luck getting it figured out!