Boxster Calipers, got them installed today! Options

[SirAndy]

About time too as my Carrera brake pads were down to the metal.

The idea was simple, get rid of the Carrera Calipers and mount Boxster Calipers all around using the mounting adapters from Rich Johnson.


Of course, nothing ever goes as planned: (IMG:style_emoticons/default/headbang.gif)

First, i failed to read Rich's instructions that clearly state that you have to use a 20mm 911 SC rear rotor.

Well, i have 24mm Carrera rear rotors. The Boxster Calipers had to be machined (2mm off each of the brake pad pins) and the adapters had to be milled to center the Boxster Calipers over the wider rotors.
(IMG:style_emoticons/default/smash.gif)

Then, after everything was bolted together, i recalled reading that the hard brake lines may not be long enough.
And sure enough (of course) the front brake lines were about 1" too short. Arrghhh.
(IMG:style_emoticons/default/rolleyes.gif)

McMark came to the rescue and we made two new lines. (IMG:style_emoticons/default/thumb3d.gif)

In the rear, i used banjo fittings on the Calipers (Thanks to Eric Shea for those!) and the rear brakelines were no problem.

Mark and i then bled the brakes. I was still getting some air in the front, but it was already 9pm so we decided to call it a night and i drove it home (40+ miles). The brakes actually felt fine, they seem to work great.
I'll go back to the OC shop next weekend and we'll bleed them again.
(IMG:style_emoticons/default/driving.gif)


And now for the pitchers:
(IMG:style_emoticons/default/beer3.gif)

[Aaron Cox]

I too have boxsters on my 914...

Question for you peeps...
did you orient the rear calipers so the larger piston was the leading piston? (i.e. LR becomes RR, and RR becomes LR, and you have to flip the bleeders to the top, and the x-over to the bottom).

Or did you just bolt them on, and let the smaller piston lead?

(I see a mix of the above on this thread)

[SirAndy]

Question for you peeps...
did you orient the rear calipers so the larger piston was the leading piston? (i.e. LR becomes RR, and RR becomes LR, and you have to flip the bleeders to the top, and the x-over to the bottom).

Or did you just bolt them on, and let the smaller piston lead?

(I see a mix of the above on this thread)

Just bolted them on and ignored the pistons. Mounted so the bleeders are on top.

I doubt it will make any noticeable difference ...
(IMG:style_emoticons/default/popcorn[1].gif)

[Aaron Cox]

Question for you peeps...
did you orient the rear calipers so the larger piston was the leading piston? (i.e. LR becomes RR, and RR becomes LR, and you have to flip the bleeders to the top, and the x-over to the bottom).

Or did you just bolt them on, and let the smaller piston lead?

(I see a mix of the above on this thread)

I doubt it will make any noticeable difference ...
(IMG:style_emoticons/default/popcorn[1].gif)

I would tend to believe that also.. but the fronts use the larger piston as the leading piston (or so i thought?)
did a little digging on the reason for stepped/differential caliper bores. Sounds like bolt them on and go!

Differential bore calipers -- As the surface of the rotor heats up, the clamping force of the pistons has to be increased to avoid brake fade. If the caliper has multiple pistons (or multiple pairs of pistons), the brake rotor surface is initially heated by the pistons pushing against the brake pad at the leading edge of the caliper, making the rotor surface hotter when it rotates back to the pistons closer to the trailing edge of the caliper. Therefore it helps if the pistons closer to the rear edge of the caliper are larger. Differential-bore calipers use smaller pistons up front, larger pistons toward the back

[SirAndy]

Differential bore calipers -- As the surface of the rotor heats up, the clamping force of the pistons has to be increased to avoid brake fade. If the caliper has multiple pistons (or multiple pairs of pistons), the brake rotor surface is initially heated by the pistons pushing against the brake pad at the leading edge of the caliper, making the rotor surface hotter when it rotates back to the pistons closer to the trailing edge of the caliper. Therefore it helps if the pistons closer to the rear edge of the caliper are larger. Differential-bore calipers use smaller pistons up front, larger pistons toward the back

In that case it seems the way i mounted mine is correct? (IMG:style_emoticons/default/confused24.gif)

On the rear, the smaller piston is on top. I have to check on the fronts. (IMG:style_emoticons/default/idea.gif)

(IMG:http://www.914world.com/bbs2/uploads/post-179-1330327130_thumb.jpg)

[Aaron Cox]

Differential bore calipers -- As the surface of the rotor heats up, the clamping force of the pistons has to be increased to avoid brake fade. If the caliper has multiple pistons (or multiple pairs of pistons), the brake rotor surface is initially heated by the pistons pushing against the brake pad at the leading edge of the caliper, making the rotor surface hotter when it rotates back to the pistons closer to the trailing edge of the caliper. Therefore it helps if the pistons closer to the rear edge of the caliper are larger. Differential-bore calipers use smaller pistons up front, larger pistons toward the back

In that case it seems the way i mounted mine is correct? (IMG:style_emoticons/default/confused24.gif)

On the rear, the smaller piston is on top. I have to check on the fronts. (IMG:style_emoticons/default/idea.gif)

Yep..sounds like you were right. bolt on and go!