69autoXr

From the Wilwood site, assuming I was looking at the correct master:

NOTE: Fabrication or modification of the pedal pushrod may be required on the 1” or 1-1/8” bore size to adapt this master cylinder
to some applications. Installation should only be performed by persons with experience in the safe and proper operation of disc
brake systems.

Did you compare the master cylinder pushrod hole of the Wilwood to the stock master? Specifically the depth of the hole?

76 sting

1 1/8 bore not factory. However, just to rule things out I went out and bought a new referb MC from auto zone bench bleed and same thing. I then used the motive again and got a few little bubbles, but very little..again nothing, no pedal.

I also did what you said disconnected the vac started it up and the pedal was hard as a rock so it seams that the booster is fine.

I have no clue what to do now.

completely lost!

76 sting

all is the same just measured.

I will move this to another thread since this topic was about boosters. please use this link to continue to assist if you dare.

http://forums.corvetteforum.com/show....php?t=1893871

Jud Chapin

If everything is stock with NO LEAKS ANYWHERE, and the pedal is still going to the floor (bottoms out), you either have a bad m/c or air in the system. I know you said you got another m/c, but I have seen bad ones come off the shelf. You also said you still got a few bubbles after the last bleed; you really shouldn't have any after all the bleeding you've done. In doing the m/c bench bleed, do you do it off the car with it level and in a vice of some type, and did the air bubbles stop completely before you decided the job was finished? It has always taken me quite a few pumps to get all the air out.

76 sting

This is the 3rd MC I bought. I purchased the wilwood becasue I thought the one I had was bad (pedal going to the floor) obviously it was not the case. I then just bought another one yesterday becasue maybe the Wilwood was bad, but no this is performing the same way.

I think I got a few little bubbles becasue of the new MC that I bought yesterday and may not have done a good enough job bleeding kinda hurried a little. This time I bleed the crap out of them using the Motive until no matter what I did not a single bubble came out.

Bench bleed everything off the car with a small level on it to be sure it was level. Yes, all the bubbles were gone and once they were I continued to bleed it approx a dozzen more times just to be sure.

Jud Chapin

Sorry I can't help you solve the problem. I still think air in the system is your problem.

76 sting

you may be right, but I have no idea how to get it out.

thanks for your help man.

69autoXr

Are you bleeding the rear inners first, then outers?

rponfick

I hope you don't have the same problem I had when manually bleeding the brakes on my '69. My wife was "manning" the seat and I was working the bleeder screws. Bled for over an hour on one wheel and never got much air out. My wife finally asked which pedal was she supposed to be pushing? You guess which one she was pushing.

Ralph . I figured you needed a little humor about now.

76 sting

correct

76 sting

that was good!! and much needed.

76 sting

OK update...but still have the same problem. However, I placed clamps on all the rubber hoses and started the car wahooooooooo and got a hard pedal. This is telling me that the booster and MC are ok and there is still likely air in the new calip right?

After bleeding them gravity, 2 man, motive, wacking it with a mallet, pulling in the brake pads while motive bleeding it....Still no pedal... I also put 15 lbs of pressure on the system left it over night came out the next morning and it was down to 10lbs, but dry everywhere.

Any ideas how to bleed a calip better?

stock76

You said "new everything except the booster". Does that include new flexible brake lines? You could get a soft pedal if one of the flexible brake lines are bad. You won't necessarily see a leak. One of them could be collapsing internally, or the opposite, expanding under pressure if weak. If they are more than four or five years old I would replace them and see if that works. If the lines are new, I'm at a loss too, as to how else air could be getting int the system. When you get it figured out, let us know what it was. Could be a good learning experience for others. Best of luck with it.

76 sting

All the lines are brand new. Someone told me that there is a system that uses a air tank with compressor that pulls the fluid through unlike the motive that pushes it... anyone heard of this??

stock76

Never heard of an air tank/compressor setup but a MityVac Bleeder pulls the fluid thru the system. It doesn't work too well on C-3 calipers because while you are pulling the fluid through the bleeder it is also sucking air in from around the base of the bleeder nipple. When you crack the bleeder nipple the threads aren't sealed and air can be drawn in by the vacuum action of the bleeder. You have to put some vaseline or grease around the bleeder nipple to try to seal the air from leaking. Doesn't work all that well and you use a lot of brake fluid trying to bleed your brakes in the process. The Motive is the best bleeder I have found for C-3 calipers because it "pushes" not "pulls" so no air is getting sucked back in. The MityVac is a great tool, if you have one with the vacuum gauge, for troubleshooting your vacuum system. It just isn't all that great as a C-3 caliper bleeder.

76 sting

That makes sense. However the Motive does the same thing, meaning I get tiny tiny bubbles coming out while using the Motive. Not all the time and if I wiggle the the hose connected to the bleeder it stops and then starts. Should I be concerned with those tinny holes?

Matt Gruber

do a few stops on grass or gravel and see which wheels lock.
don't be :
http://community.webtv.net/MATTGRU/bubba

76 sting

I know what your saying, but the last timeI tried to do that without a pedal I almost went through the wall in my house never mind the few stop signs My driveway is on an incline..steep and short and I almost did't stop. I can't take that chance, especially after my new fire paint job was just applied.

Matt Gruber

just jack it up
put in gear
hit gas
hit brake
if wheels stop; do test drive
and fix the e-brake!

76 sting

Jack it up!!! that's funny sorry it has been up on jack stands for over 3 months trying to fix this. However, I do like your plan

The e-brake doesn't work well and I will need to correct that soon, but I have to do baby steps.

I will attempt this either later today or tomorrow.