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> Stock rear brake questions
HalfMoon
post Nov 7 2014, 12:20 PM
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So which calipers (or the stock variety) are better? Late or early (and why)? Or does it not make much difference?
Also, and this may sound like an odd question....is there any reason why the rotors couldn't be drilled while on the car (other than the labor involved) and yes I have no plate.
Thanx
David
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Cap'n Krusty
post Nov 7 2014, 12:25 PM
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Drilled how?

The Cap'n
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HalfMoon
post Nov 7 2014, 12:29 PM
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QUOTE(Cap'n Krusty @ Nov 7 2014, 01:25 PM) *

Drilled how?

The Cap'n


Something like this
https://www.google.com/search?q=images+dril...2B4%3B225%3B225
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bandjoey
post Nov 7 2014, 12:35 PM
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Drilled for 5 lug or for cooling?
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Dave_Darling
post Nov 7 2014, 03:54 PM
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The stock 914-4 calipers are functionally identical. They change in how they mount, but the pad size and caliper piston size are the same. They all go over solid rotors, they all perform basically the same.

IMHO, cross-drilling solid rotors on a street car is a waste of time. On a track car, it's probably also a waste of time. On a track car with vented rotors (the thick ones with passages through the middle), it is worthwhile. Mostly because track cars get inspected thoroughly before and after every event, so the cracks that will eventually form can be caught early enough before the brakes fail catastrophically.

--DD
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HalfMoon
post Nov 7 2014, 04:03 PM
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QUOTE(Dave_Darling @ Nov 7 2014, 04:54 PM) *

The stock 914-4 calipers are functionally identical. They change in how they mount, but the pad size and caliper piston size are the same. They all go over solid rotors, they all perform basically the same.

IMHO, cross-drilling solid rotors on a street car is a waste of time. On a track car, it's probably also a waste of time. On a track car with vented rotors (the thick ones with passages through the middle), it is worthwhile. Mostly because track cars get inspected thoroughly before and after every event, so the cracks that will eventually form can be caught early enough before the brakes fail catastrophically.

--DD


Sage advice. Thanks for that.
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steuspeed
post Nov 7 2014, 08:47 PM
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PMB brake parts.

http://www.pmbperformance.com/914brake.html
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HalfMoon
post Nov 7 2014, 09:11 PM
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QUOTE(steuspeed @ Nov 7 2014, 09:47 PM) *


They don't sell ANY drilled rear rotors so I'm not clear on why you sent me the link.
(IMG:style_emoticons/default/confused24.gif)

Ammendment:
Duh. Because I never mentioned rears. My bad
So, back to the original question: Would drilling the REAR rotors have any positive effect given I already have vented 911 fronts?
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Dave_Darling
post Nov 7 2014, 11:31 PM
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The rear rotors are solid, like stock 914-4 front rotors. So no--no positive effect. Same reasons as I gave above. Additionally, the rears do much less work than the fronts do, so they build less heat in the first place.

The 914-4 rear calipers are all interchangeable, I think the only actual difference is that some have one bleeder (put it at the top!!) and some have two, one at the top and one at the bottom.

--DD
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HalfMoon
post Nov 7 2014, 11:55 PM
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QUOTE(Dave_Darling @ Nov 8 2014, 12:31 AM) *

The rear rotors are solid, like stock 914-4 front rotors. So no--no positive effect. Same reasons as I gave above. Additionally, the rears do much less work than the fronts do, so they build less heat in the first place.

The 914-4 rear calipers are all interchangeable, I think the only actual difference is that some have one bleeder (put it at the top!!) and some have two, one at the top and one at the bottom.

--DD


Awesome stuff Dave and thanks!
My plan is to keep em and git the PMB rebuild kit as I'm assuming (from all I've read) that they most likely aren't working (or barely) and are sorely in need of a rebuild.
911's on front and probably in need of a rebuild as well (although, in a different thread we've been talking about the possibility of 928 brakes for 3.5 spacing-must check mine tomorrow-doubtful they are)
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Mike Bellis
post Nov 8 2014, 09:54 AM
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For solid rotors, a groove to release gasses would be better than drilling. Drilling a rotor will make it weaker and prone to cracking if the drilled edge is not eased or rounded off.

BTW, if you try to drill rotors in the car, they will look like shit. It needs to be done in a drill press with a template.

(IMG:http://www.914world.com/bbs2/uploads_offsite/www.casmoedesigns.com-10496-1415462042.1.jpg)
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