Ever since I mounted a front disc set from SSBC I am experiencing a rather hard brake pedal when trying to do some serious braking. All parts are new, air is out, booster seems ok, connection rod is in lower hole of the pedal.

After reading a lot of posts I think my problem might be the diameter of the M/C bore. For the power version it should be 1" (or even less). It seems SSBC sometimes is somewhat sloppy in choosing the M/C they send out.

My question is:

Is it correct to assume that I can determine the bore diameter by loosening the M/C from the booster and measure the inside diameter of the end that fits inside the booster. Or do I have to take the M/C apart and actually measure the plunger?

Thanks

Rob

Originally posted by rusty66:


My question is:

Is it correct to assume that I can determine the bore diameter by loosening the M/C from the booster and measure the inside diameter of the end that fits inside the booster.

Thanks

Rob [/QB]Yes
-Kid

That's a quick and very positive answer. Saves a lot of work up front.

Thanks a lot Kid.

Rob

Rob,

You might need to go down a MC bore diameter. Note that your pedal travel and fluid pressure will increase as your pumped fluid volume will decrease.

Theo.

Theo.

You might need to go down a MC bore diameter. Does this mean you recognise my case; is this a fairly common change? I understand the increase in pressure and travel.

Thanks

I've had the same problem with my C4 front and rear brakes. The mechanic installed a 1 1/8" diameter MC and the pedal had almost no travel and was hard as a rock. He kept insisting that it was my front pads (Z-rated Performance Friction). I asked them to switch to a 1" diameter MC and the pedal was perfect! There was more pedal travel and great feel.

That's my experience. If I were you, I would go down one size MC diameter.

Keep us updated,
Theo.
'68 Chevelle.

P.S. I do not like the Z-rated PF pads. I switched to the Carbon Metalic ones and they are much better.

Guys, I just measured the M/C bore diameter and that turns out to be 1-1/8. Without having to open the brake circuit, this has become a simple check just by unbolting the M/C from the booster, pulling it about 1 inch away, holding a 1 inch reference (coin) inside the end of the bore and looking with a small mirror. This shows the coin being smaller than the bore. Thanks again Kid.

Theo, I will definitely go to a smaller bore, but I will have to get that one from the States. This will take quite a while for me. In time I will inform you of course.

With all of your help it has taken me months to figure this one out. Initially I doubted the booster, the pad type, the prop. valve (not to mention my own mind). A post in the Camaro site by davidpozzi finally set me on this track. I really love these newsgroups, great people.

Rob

Update. At Year One's site I noticed a M/C has a smaller bore when using semi-metalic pads, which my SSBC kit came with.

As a test I switched my pads and I think it helps some. It seems I need less effort. Because the pads are new, I just don't want to lock brakes yet.

Rob