C5 vs C6(Z51) rear calipers

[gort69]

Are they identical? I know the design of the fronts was changed slightly - not sure about the rears. Thanks for any info.

[Apogee]

The C6 Z51 calipers have a slightly smaller pistons at 42.5mm IIRC versus 45mm. As for the caliper bodies themselves, they appear to be virtually the same casting with only a casting number revision...maybe a tooling change or something. No additional material across the bridge to make it more rigid or anything from what I can tell and the scale appears to back me up on that.

Tobin
KORE3

[gort69]

Thanks for the info Tobin. Am I correct in assuming the front calipers (C5 and C6) have the same piston sizes? I'm planning on replacing my current C5 fronts with C6 fronts, and my current LS1 rears with C6 rears - while retaining the LS1 rear abutments, backing plates and rotors.

While I'm on the subject - will C5/6 rear pads work in the LS1 abutments? Or should I use LS1 pads?

Thanks very much.

[317millhand]

Thanks for the info Tobin. Am I correct in assuming the front calipers (C5 and C6) have the same piston sizes? I'm planning on replacing my current C5 fronts with C6 fronts, and my current LS1 rears with C6 rears - while retaining the LS1 rear abutments, backing plates and rotors.

While I'm on the subject - will C5/6 rear pads work in the LS1 abutments? Or should I use LS1 pads?

Thanks very much.

Im not trying to be a smart A$$, but i have to ask, why are you changing? Id doesnt seem like much of an upgrade to me.

[Apogee]

Al, you are correct that the C5 and C6 front calipers use the same diameter pistons at 40.5mm. The C6 front caliper is ~25% more rigid than the C5 calipers and about .16 pounds heavier due to the additional material across the bridge. Despite the additional material, they didn't increase the profile of the caliper so wheel fitment should be the same.

Both the C5 and C6 rear calipers are pressure cast versus the gravity cast LS1 units, so service life should increase and caliper spreading should be less of an issue. The LS1 and C5/C6 pads use slightly different FMSI spec backing plates, so if you want your pads to fit the abutments like they're supposed to (no grinding, slop, etc), I'd run the LS1 pads. You need to run the C5/C6 anti-rattle springs in the calipers since the LS1 parts won't snap into the bridge. The rear anti-rattle spring will need a little nip and tuck job so that it clears the tangs on the top of the rear LS1 pad backing plates.

Tobin
KORE3

[gort69]

Im not trying to be a smart A$$, but i have to ask, why are you changing? Id doesnt seem like much of an upgrade to me.

Valid question. I'll never notice the difference on this street only car. Mainly for aesthetics. I currently have the red Z06 C5 front calipers and I'd prefer the anodized black look. I got a good deal on some low mileage C6 calipers (all 4) and I'll sell my red Z06 set as well as my LS1 rears.

[gort69]

Al, you are correct that the C5 and C6 front calipers use the same diameter pistons at 40.5mm. The C6 front caliper is ~25% more rigid than the C5 calipers and about .16 pounds heavier due to the additional material across the bridge. Despite the additional material, they didn't increase the profile of the caliper so wheel fitment should be the same.

Both the C5 and C6 rear calipers are pressure cast versus the gravity cast LS1 units, so service life should increase and caliper spreading should be less of an issue. The LS1 and C5/C6 pads use slightly different FMSI spec backing plates, so if you want your pads to fit the abutments like they're supposed to (no grinding, slop, etc), I'd run the LS1 pads. You need to run the C5/C6 anti-rattle springs in the calipers since the LS1 parts won't snap into the bridge. The rear anti-rattle spring will need a little nip and tuck job so that it clears the tangs on the top of the rear LS1 pad backing plates.

Tobin
KORE3

Excellent info Tobin. Thank you very much.

[Motown 454]

Tobin glad your here I 've learned a lot from your posts. Thanks

[drb930]

Al, you are correct that the C5 and C6 front calipers use the same diameter pistons at 40.5mm. The C6 front caliper is ~25% more rigid than the C5 calipers and about .16 pounds heavier due to the additional material across the bridge. Despite the additional material, they didn't increase the profile of the caliper so wheel fitment should be the same.

Both the C5 and C6 rear calipers are pressure cast versus the gravity cast LS1 units, so service life should increase and caliper spreading should be less of an issue. The LS1 and C5/C6 pads use slightly different FMSI spec backing plates, so if you want your pads to fit the abutments like they're supposed to (no grinding, slop, etc), I'd run the LS1 pads. You need to run the C5/C6 anti-rattle springs in the calipers since the LS1 parts won't snap into the bridge. The rear anti-rattle spring will need a little nip and tuck job so that it clears the tangs on the top of the rear LS1 pad backing plates.

Tobin
KORE3

Tobin,

Any idea where you can buy the C-5 Anti Rattle Spring that snaps into the top part of the C-5 caliper?

[Apogee]

Tobin,

Any idea where you can buy the C-5 Anti Rattle Spring that snaps into the top part of the C-5 caliper?

Sure, you can buy them at any auto parts store as part of a "caliper hardware kit".