Wilwood master cylinder/bleeding issues

[mike72nova]

I'm having an issue with my Wilwood master cylinder. The car also has the 4 piston Wilwood dynalite calipers.

Pretty much nothing comes out when its mounted on the car and the pedal is pressed.
Took it apart and all the seals and pistons look fine.

Not sure whats up, or if i'm doing something wrong.

I tried to bench bleed it again today.
Looks like I can actually get fluid to come out of the hoses. Bubbles would come out of the tubes that were going back in to the resevoir and stopped after about 5 minutes of manually pressing the piston.
Thought all air would be out so I hooked it back up on the car and nothing..

The pushrod seems to be the correct length aswell.

What exactly is the procedure to hooking up a bled master to empty brake lines and then bleeding?? If I depress the pedal and get someone to open the bleeder the fluid level doesn't go down at all. Wilwood 4 piston calipers with 2 bleeders on top. The instructions on the wilwood website seem to suck.


Thanks
mike

[LONE*STAR]

I'm having a similar issue with my new willwood master. I'm drawn the fluid to the rear of the car with a vacuum bleeder and I can't get any fluid to the drivers rear, even at 20-30 psi.

[Apogee]

First off, I'd suggest confirming that your master cylinder is fully bleed by plugging both outlet ports and pushing on the piston by hand with a dowel or something similar. If there is no air in the MC, it should hydraulically lock as soon as the seals clear the compensator ports in the reservoirs. If it doesn't, then you still have air.

As for filling a new system with fluid, I prefer pressure bleeders if I have access to one, otherwise I'll let gravity do it's thing and gravity bleed the system. Once you've got fluid at the all of the calipers, a typical 2-person (1 if you're running speed bleeders) manual bleed should work fine at that point.

Tobin
KORE3

[quarterbooty]

In addition to what Tobin stated, I'll provide an additional consideration that I stumbled across when I upgraded my braking system. I installed a Wilwood tandem master cylinder along with C6 Z06 brakes and a hydroboost on my car. I retained the stock combination valve, but I gutted it to eliminate the proportioning function (I installed an adjustable Wilwood valve downstream of the combo valve to reduce pressure to the rear). I bench bled the master, and I was sure that I had purged all of the air. I installed it on the car, and tried to bleed the system through Russell speed bleeders. I started with the right rear inner, and I got nothing. After dozens of pedal depressions, still nothing. I could tell I wasn't moving any fluid by the way the pedal felt. I took the master off and re-bench bled it. I pushed out a few small air bubbles and reinstalled it only to have the same result during bleeding. I replaced the speed bleeders with the conventional bleed screws and let the system gravity bleed. It took forever to get fluid, but it finally started slowly dribbling out. I tried to bleed with the tried and true two person method, but the pedal still felt mushy and very little fluid was being displaced. I was beginning to think that the master was no good, so I started to do some research. I stumbled across some information somewhere that said to make sure the combination valve is centered when trying to bleed the system. If the shuttle valve has shifted due to a pressure differential between the front and rear circuits, it will reposition and block off the low pressure side. As it turns out, this was my problem (the brake warning light was on). This condition is remedied by holding the button on the metering valve down to reset it (if it's a disc/drum valve), or by venting the high pressure side (i.e., the front circuit) to equalize the pressure. I was successful with the latter approach. I opened a bleeder on one of the front calipers and pumped the pedal several times until the brake warning light went out. During this time, I was actually pumping out the typical volume of fluid and the pedal felt like I was expecting it to during bleeding. When the valve was reset the front circuit was closed, and I returned to the proper bleeding order. Now the rear circuit bled like it was supposed to as did the front. This may or may not be your issue, but I thought I'd share my experience just in case.

[mike72nova]

Got it to actually work somewhat.
Not sure what the issue is now.
Gravity bled all of the calipers as I can't get the pos pressure/vacuum bleeder I borrowed from Canadian tire to work.

Brake pedal still has pretty much no resistance and the front calipers seem to be stuck now as I can't turn the rotor, wtf??

May try to bench bleed the master again. Last time I tried to bench bleed it I used clear lines going back to the resevoir. Every time I pressed the pedal, I would see air pockets go up the line but I couldn't actually get them to go out the end of the line. So when I let off of the pistons, the pockets just went backwards. Are you supposed to pinch off these lines when you let off the piston?

Quarter, Not sure if that would be my issue or not..

With the Wilwood master the front and rears are 2 different circuits.
Port closest to firewall>a junction> both front brakes.
Port closest to the front of the car goes to a line infront of the rear end> a wilwood prop vave>junction>rear calipers

[Apogee]

Front port = large reservoir => Front brakes

Rear port = smaller reservoir => Rear brakes

If you can't push an air bubble through a bleeder hose on the MC bench bleed process, then it won't effectively bleed the entire system. I would suggest plugging both ports and re-bench bleeding the master cylinder. If you tap on the MC with a soft mallet/hammer while stroking the piston, you should see bubbles escape through the compensator ports into the reservoirs. Do this until the piston hydraulically locks and cannot be depressed more than 1/8" to 3/16" and then reinstall and bleed the system staring by cracking the fittings at the MC while someone presses the brake pedal and then the usual sequence. There are lots of ways to bleed a car, but this has worked well for me in the past.

HTH,
Tobin
KORE3