[67SS_MASS]

I bought new power booster and master cylinder and insalled it. yes, it did a bench bleed with the master cyl.

I Installed new master and bled brakes, before I pulled out of garage, they were SOLID.
I drove it and the breaks go the floor.
I took it home and had a buddy help me bleed the brakes AGAIN.
I drove it a few weeks and brakes were solid.
TODAY, the pedal goes down to the floor..

What else should I look for?

i am at my wits end with these brakes...

1967 Chevelle SS.. Discs up front, drum in rear.. I see no visible leaks, cracks, etc...

Could it be the calipers?

[Cam]

If you have the original style 4-piston calipers that were stock on the 67/68 Chevelles, there is a potential leak. Those piston seals can leak unless the bores are redone with stainless steel. Figure that there are 8 pistons in total up front so a little leakage times eight can add up to brake fluid out and air in. The wheel cylinders on the rear drums are another possible point of leakage. You say the lines are crack-free. Have they been replaced recently? Even if they aren't cracked they can still swell under pressure.

Usually when I hear of solid brake pedals going mushy after use I always think of more bleeding. If brake fluid isn't leaking anywhere I would think that it must be air in the system somewhere. How are the flare fittings? Any leaks there?

[67SS_MASS]

I do have the original 4 piston calipers. I have owned the car for 15 years and never replaced the bores with stainless steel. I do not see any leakage on the garage floor or inside the rims. Sounds like I have lots more inspecting to do..

Thanks for the reply, I appreciate it.

[zeke67]

Air is getting in somewhere. A crake in a line, a fitting, a caliper piston. Leak on the floor is more obvious than a slight wet spot on a line or fitting. It's there somewhere.

Other option is faulty new master. But I think it's a leak.

[OCTO13ER]

Is this the same problem as last year or a reoccuring issue? I think for the calipers to be the problem you would actually have to use them. If the car hasn't moved in a year then it's something else...see this post for help: http://www.chevelles.com/forums/showthread.php?t=239750

And, no John, I didn't search you. I've been a silent member of this forum for almost 2 years. When you asked your question on a Harley forum this is the first place I checked to try and help you. Your post was top of the list.

Like I said over there: Posting the question won't fix it; sooner or later you gotta' get in there and bust some knuckles. You've already gotten some good advice but how have you used it?

[67SS_MASS]

Adrian, I don't need your help.

By the way, I thought you told me your screen name was 66 El Camino. Why would you need to names on this board? You hiding something? Your a shady character.


Thanks to all others for your help.

[hpsherlin]

You are getting air or have air left in the lines.
Did you bleed the back right side followed by the back left and then the front right and finally the front left last?
Sometimes it takes a lot of pumping and bleeding to get all the air out especially after changing out stuff.
Good luck.

[Bad66Chevelle454]

I'm just thinking out loud here....so somebody please correct me if I'm wrong.

If you have mushy brakes now....what if you went and re-bled just the front drivers side wheel, to see if that makes them solid again? If not, then move to passenger side....then rear. My thinking is maybe if the problem is at the actual caliper or wheel cylinder, wouldn't this show where the problem is? If it's sudden firm after bleeding the drivers front, that would mean the air was trapped in that caliper, correct?

If the problem only goes away after bleeding all four corners, wouldn't that point to a cracked line or something of the sort?