"NEW" Wilwood master cylinder (no brakes)

[jeh]

I just installed a new Wilwood master cylinder and brake booster on my truck, after bench bleeding and the normal brake bleeding for 2 hours the pedal still goes to the floor!!!! Everything worked fine with the CPP booster I took off, anybody have any suggestions.

[davepl]

Gotta be something basic, or possibly a defective master, but more likely air.

Are the calipers mounted with the bleed screws on the top? They can't be bled with them mounted such that the bleeders are on the bottom.

Note that with discs I found the first stroke or two of the pedal DID go to the floor until the pistons were full, then subsequent strokes were all high and hard. So if you only hit the pedal once, try it again...

Sorry, not much meat here, someone else should be along with more ideas soon!

[jeh]

Originally Posted by davepl

Gotta be something basic, or possibly a defective master, but more likely air.

Are the calipers mounted with the bleed screws on the top? They can't be bled with them mounted such that the bleeders are on the bottom.

Note that with discs I found the first stroke or two of the pedal DID go to the floor until the pistons were full, then subsequent strokes were all high and hard. So if you only hit the pedal once, try it again...

Sorry, not much meat here, someone else should be along with more ideas soon!

I never changed the calipers and everything worked fine with the CPP master and booster I had. The only reason I changed was the valve cover clearance with the big block. My buddy and I pumped and bled for around 2 hours today, I pumped the brake pedal so much my leg cramped!!! He has run a mechanic/hot rod shop for 20 years and he was stumped over this.

[ratty69]

If I read it right, you changed the booster as well as the master cylinder. Is it possible that the pushrod in the booster is adjusted too short? If so, you won't get full travel of the master even though the pedal goes to the floor.

[jeh]

Originally Posted by ratty69

If I read it right, you changed the booster as well as the master cylinder. Is it possible that the pushrod in the booster is adjusted too short? If so, you won't get full travel of the master even though the pedal goes to the floor.

That makes sense, I look into that. Thanks

[jeh]

I didn't spend much time checking into it today, but I did pull the master cylinder off and had my wife push the brake pedal to the floor. It looks like the rod in the booster only travels about 3/4" out. I don't know how much it should move but that don't seem like it's enough.

[low70c10]

thats not enough travel do you have the bushing installed in the end of the master for the pushrod to ride on?

[JustToxic]

One other thing to check, I see you have a adjustable prop valve. I've ran into issues with not having that set up right and causing issues while bleeding brakes. I know not much help but its something I've ran into.

[TexasLS1]

I'm signing on to see the outcome of this, I'm having a similar issue with a different mfr's booster/master. I'm frustrated enough that I had wished I bought the Wilwood. Reality is that I've likely looked over or missed something. I tried adjusting pushrod length but no luck. Keep us updated Jason, I'd like to know how this turns out...

[jeh]

Originally Posted by low70c10

thats not enough travel do you have the bushing installed in the end of the master for the pushrod to ride on?

Originally Posted by JustToxic

One other thing to check, I see you have a adjustable prop valve. I've ran into issues with not having that set up right and causing issues while bleeding brakes. I know not much help but its something I've ran into.

Originally Posted by TexasLS1

I'm signing on to see the outcome of this, I'm having a similar issue with a different mfr's booster/master. I'm frustrated enough that I had wished I bought the Wilwood. Reality is that I've likely looked over or missed something. I tried adjusting pushrod length but no luck. Keep us updated Jason, I'd like to know how this turns out...

Ok guys, this is what I done this morning, come to find out the rod that comes out of the booster needed adjusted in. When I would hold the m/c up to it to bolt it on the rod was holding it out, as I would tighten the bolts it was shoving the piston forward. I also lengthened the rod to the pedal to give me a little more travel before it hit the floor. Also while it was off I bench bled it till I was satisfied with no air bubbles at all, put everything back on, bled the brakes and now I have somewhat of a firm pedal. I think it could be better, I don't have time to mess with it anymore today, I'm leaving for work and won't be home for about a week or so.