Breaking in new pads

[firebob]

Just finished installing my new rear disc kit in the firebird. Had the adj prop vlv set in the middle to start. Made a couple of first gear runs to see if I could lock up. No go. After a couple of tries I was able to get one front to lock up but it was dragging a bit to begin with.
Question is...Is there a break in period for new pads and rotors? Should I expect them to get better with a little more time on them?

I didn't swap over to a disc/disc MC either. Still running the disc/drum MC and drum/drum metering block. Should I change out the MC for the 1 1/8" bore disc/disc type and swap out the metering block to a combo or work with what I have?

Robert

[protour73]

From Wilwood - http://brakepads.wilwood.com/03-tech...or-Beddin-6268

[firebob]

Cool. Thanks.

[a67]

You didn't mention what year Firebird it is. Did you pull the residual pressure check valve out of the drum side (rear brakes) of the master cylinder?

Bob

[firebob]

It's a 69,and no I did not. I looked but I did not see anything that looked like rubber at the rear brake port from the MC. If it's there, how do you remove it?

Robert

[a67]

It's a 69,and no I did not. I looked but I did not see anything that looked like rubber at the rear brake port from the MC. If it's there, how do you remove it?

Robert

Thread a screw into the brass seat and pry up under the head with two screwdrivers. Pulling the seat straight out. The residual pressure check valve is a small spring with a rubber cap on one end. Then press the seat back in.

Some use a sheet metal screw, can also tap the seat and thread in a machine screw.

Can check for the valve with something like a toothpick. Insert it into the seat through hole. If it stops about 3/8" of the way in that is the valve. If the toothpick keeps going for a ways then there isn't a valve.

As for the prop valve, the best way to go is to remove the stock one and install an adjustable. This way the system can be properly balanced. If there is a metering valve, for some reason I think GM used a separate piece in '69, it can stay. Although it may also be removed and the lines connected together.

Bob

[firebob]

I think I've decided on which way to go now. The MC seems to be leaking out the back so I figure I'll replace it. Brakes are power.

Do I need a disc/disc MC with a 1 1/8" bore to run frt/bk discs? Or can I run a 1" disc/drum MC?
Also, I'm going to remove the original "hold off valve" they had installed in 69 and I've ordered a new PV4 combo valve for it to replace the original disc/drum metering block. I'll leave the adjust PV in place until I find out if I need it or not.
Any other advice?

Robert

[a67]

Any other advice?

Robert

Do some serious research on braking systems.

Bob

[Yoda4561]

Even brand new street compound pads should lock your brakes up if the braking system is set up properly. If they don't, then something isn't right somewhere. If you have sticky big front tires and the brakes aren't huge, that would be the only time I'd say no lockup is acceptable, as long as they can still stop the car in a safe distance.

[firebob]

Obviuosly things aren't working up to par. Like most mods or upgrades, things aren't just an easy bolt on and go. Most time adjustments are necessary.
A67, thats kind of what I was trying to do.

Robert

[a67]

A67, thats kind of what I was trying to do.

Robert

Here is a good place to start:

http://www.stoptech.com/tech_info/te...e_papers.shtml

Part of the issue with the questions you are asking is that there isn't enough known about the rest of the system. Unless the caliper piston area, rotor diameter, pad compound, and type of booster (if any) is known, the M/C bore size can not be specified.

Also, don't run a combo valve with an adjustable prop valve in place. As a matter of fact, don't run a combo valve at all. It isn't required.

And if a separate metering valve is in place that too can be removed.

Bob