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Old February 1st 2019, 05:20
H2OSB H2OSB is offline
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Join Date: Jan 2003
Location: Modesto, CA
Posts: 197
964 C2 rear calipers up front

There was a thread SOMEWHAT about this in 2009, but it's been too quiet around here, and many years of experience has been added to all the heavy hitters on here who fiddle with these things.

First off, I have successfully gotten 42mm 914 front calipers over 944 rotors by installing REAR M caliper spacers in the 914 calipers making them clear. However, I could only do this by turning down the rotors (and the hubs, slightly). After the machine work, the calipers are bolt-ons for my 944 spindles (on a '74 1303). I'm certain these will be all the brakes I'll need for my modest 125hp T4 2056. However, it doesn't sit well with me to modify consumable parts of the brake set up, so as an academic endeavor, I would like to see what could be done to fit C2 2-pot rear calipers to the front.

One thing I discovered while playing with this idea, the 924 spindle has the correct caliper mount spacing of 94mm to bolt the caliper directly on. I thought this would be a boon for 1303 owners because it shares the 15mm ball joint, unlike the 944 spindles, which use a 17mm ball joint (requiring Kerscher ball joints.....perhaps). The major flaw with this idea is the 924s stock rotor size of 257mm is FAR smaller than all of the 299mm rotors that have the correct 24mm width to use the C2 caliper. That's a difference of 42mm. I don't know how far the body of the C2 caliper places the clamping surface out from the center axis relative to a 924 caliper, but I think the rotors would need to be modified to clear, which defeats the purpose of this exercise, OR an adapter would be needed to space the calipers further out. This would be the preferred choice. Additionally, the 924 uses the same bearings as the T1s, so a hub would need to be made, perhaps from a redrilled T1 brake drum...or some of Lanner's wizardry.

How about using a 944 spindle? Can anyone throw some ideas out? Lotta ready made hubs for this, and the rotors go right on. Caliper bolt spacing is off, but an adapter could fix that.

I like the C2 calipers because they're very light and ridged. I like that they have 44mm pistons. They might be ever so slightly too large to go along with my 944 rear brakes, but I doubt it. And I could always try a more aggressive pad on the rear, or perhaps, switch the brakes to the Mk3 Golf caliper/914 rotor set up which has slightly larger pistons (and is probably a lighter set up over all).

Thoughts?
H2OSB
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johnL (aka H2OSB)
'74 1303, Outlaw sedan (with a GL flavor)
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