73 V8 Z Front Brakes

[JimieZee]

I have a 1973 V8 Z with a 327 Chevy/5 speed. It has full-length Hooker headers specially engineered for this swap. I've owned the car since early 1995 and have always had a problem with the front brakes. When the car is cold, they are fine. After driving around for a while, especially in traffic, they bind up. The pedal gets hard and the front brakes drag-very aggravating. I've put up with it long enough! Time to fix the problem. I figure that the brake fluid is boiling from the headers and adding pressure to the lines/master cylinder. I have also switched to a higher temp fluid with poor results. Will re-routing the front lines remedy the problem? Any suggestions would be greatly appreciated. Thanks.

I'm trying to figure out how to insert a photo....help?!

[Bambikiller240]

Insulate the lines from the heat, and/or "Jet Hot Coat" the headers?

[Bambikiller240]

How close to the brake lines are the headers? If they are really close, I guess I'd have to agree that re-routing them may be required.

[carguyinok]

Not sure if its the same but....

I have seen this on another V8 Z. With the lines running on the frame rail the header was real close. He pulled the lines up just enough to slip header tape under the lines and wraped them.

Another way would be a heat sheild. I would say put it on the frame not the header. Just some sheet metal bent over the lines should help.

For what it would cost I would do bolth. This would be worth a try first IMO before you try moving the lines.

[Daniel]

The first check I would make is the calipers.They may be locking up under normal use due to wear alone.Your heat theory makes since but, I would think the excess pressure from the heat would just cause the fluid level to rise in the master cylinder.I would think that would be the path of least resistance.Ever put your finger in the fluid for a heat test?Just a thought.Should you find the heat issue is the problem I suggest a shield or moving the lines. The Blanket wrap works until it gets hot then it holds the heat in.A shield with an air cavity would be my first test.I would use aluminum due to the rapid heat dispersal and ease of workability. Have fun!! Daniel

[2ManyZs]

I'm tending to agree with Daniel on this one.

I think the problem may be in your calipers or possibly in your vacuum hoses to the master vac, or it could be the master vac itself. You do have a check valve in the vacuum line to the master vac that is operating correctly right?

Having raced and boiled the fluid on more than one occassion, the pedal gets soft and goes to the floor, I've never had one get harder. The only time one got harder was when the check valve to the master vac failed and therefore the master vac was not operating at all.

So the first thing I would do it to pull the calipers, check your pistons and pad hardware to see if they are seized and/or binding. Then do a vaccum check on the line to the master vac, and verify the check valve is operating. The next thing would be the master vac itself.

When you boil the fluid due to overheating from whatever source, the air pockets formed from the vapor will displace the fluid in the lines. Air will compress easier than fluid, and you can compress a larger volume of air than fluid in the same space.The result is the pedal will travel further and easier with little or no braking being done, because it is compressing air instead of fluid.

[psimkin]

Move the brake lines on top of the frame rail behind a 1 inch heat shield sheet metaled screwed to the vertical part of the frame rail. A place to start, good luck

[260DET]

Boiling brake fluid usually reduces pressure in the brake lines. By all means insulate/protect as others have suggested but the real problem may be with your master cylinder itself or maladjustment of its actuating rod.

Rather than recon your existing components you may wish to do a big brake upgrade using new or reconditioned parts. Yes I know it will cost, but having great stopping power is almost as good as having great go power.:classic: