74 Charger brake issues

[Hijinx]

Hello,

I have a 74 Charger with a new Booster, Wilwood Master and proportioning valve, all new copper nickle lines, new hoses, calipers, rotors, and pads. Brakes suck, i can bleed them, pump them etc they get a little hard, but once you start the car it goes to the bottom.

The Master and proportioning valve where under warranty so i swapped them out with a second set. Checked all the fittings for leaks, none found. I bled them by attaching a clear hose to the passenger rear bleeder valve and the other end to the reservoir and pumped the brakes through 20' of hose until i saw no air. Did the same for the other 3 sides in order. The booster vac line is connected to the back of a Sniper 2 EFI system.

Any suggestions as to what i can try? Will extending the push rod (As posted on other threads) help? Currently my brake pedal is about a 1/2 inch above my gas pedal...

 

[70chall440]

A couple of questions;

You say "the brakes suck", does this mean no brakes at all or what?

You say that once you start the car it "goes to the bottom", I suspect this means the pedal goes to the floor? If so are you getting any braking at this point?

Is sounds like you either have the wrong parts (booster/MC), there is an abundance of air in the lines or possibly something is not adjusted correctly (such as the brake rod).

The brake pedal being 1/2" above the gas pedal sounds like you could move it up some to get more throw which might help.

Your brake bleeding technique is unique, I cannot say I have ever heard of doing it that way. So is someone opening and closing the bleeder or are you opening it, attaching a hose and then going and pumping it? I am not sure it matters but if you are doing the later (opening, putting the hose on and pumping) it seems like a pretty ineffective way to do it plus I would not be confident that I was getting all of the air out. Generally you want to close the bleeder once the pedal is to the floor (of course this requires 2 people).

On the positive side of things, this is a simple system and there cannot be too many things going on here. The brake rod has to push the booster rod in enough to push the MC rod to push the fluid. So you might want to start by removing the booster, have someone push on the pedal and measure the rod extension. Then you will need to (unfortunately) remove the MC and measure the distance the rod needs to travel to obtain a full stroke.

 

[Paul_G]

Is the bleeder screw on the caliper at the highest point of the caliper as it is installed?

 

[hanks73340]

This may be a silly question, but did you bench bleed the master until no bubbles?

 

[Hijinx]

A couple of questions;

You say "the brakes suck", does this mean no brakes at all or what?

You say that once you start the car it "goes to the bottom", I suspect this means the pedal goes to the floor? If so are you getting any braking at this point?

Is sounds like you either have the wrong parts (booster/MC), there is an abundance of air in the lines or possibly something is not adjusted correctly (such as the brake rod).

Brakes Suck = when bleed them, they get somewhat hard, when you drive it around the block the brakes get worst and sometimes bottoms out and you have to pump them a ton of times to get some braking back.

Brake Bleeding = Yes two people, pump the brakes until nothing but fluid is inside the 20' line which empties into the reservoir, when done we close the bleeder valve. Then for kicks we do it the old way, pump them until hard, open valve, when it starts to go down, close valve.

Brake rod = I was thinking of trying that. Stick a screwdriver into the Master to push the piston all the way down, then see if i can get my caliper in there to measure the depth. Then push the pedal down and measure the booster rod to see if it's going in enough.

 

[Hijinx]

Is the bleeder screw on the caliper at the highest point of the caliper as it is installed?

Yes all 4 corners... always.

 

[Hijinx]

This may be a silly question, but did you bench bleed the master until no bubbles?

Yes i did with the original, which i though might be the issue, every 5 pumps or so i would get a bubble of air from the rear reservoir, i was iffy on it so i got a new replacement, bench bled until no bubbles.

 

[70chall440]

That system is sucking air in from someplace OR you are not getting all the air out, however given your bleeding efforts I would say that you are getting the air out, so that leaves air getting in.

Point here is that if you bleed it and you have pedal BUT you lose the pedal then air is either in the system (we are saying it isn't) or it is getting air in. If you don't have any leaks visible, its possible the back of the MC is leaking into the booster.

 

[CHGRSE74]

Bleed the brakes tho old school method… start at the furthest distance from MC, which would be RR, LR, RF, than LF. If you don’t there is a possibility you could recycle fluid/air from one steel line section to another. All this after you bleed MC on bench. You don’t need all that hose, just work off the bleeder screws.

Was there a reason you changed components? Was there an underlying issue?

If you’re getting air into the MC when bleeding check the flair on your lines, they should be fairly tight, no cracks or uneven flairs.

If all this checks out I would be suspicious of the MC, check to see if fluid is being sucked into the booster as 70chall440 indicated.

Also I’m not familiar with the sniper 2. Are you drawing manifold vacuum from that port? I have a sniper 1, and booster gets source from large vacuum tee. Are you getting inconsistent pedal feel as driving progresses?

Keep us posted.