Looking for brake system specs...
Thread Starter
Team Owner
Joined: May 2002
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Looking for brake system specs...
Looing for info on the different brake options offered. J55, 12", 13".... were the rears upgraded with the big brake option?
I can't seem to find this info. I need piston and rotor sizes mainly.
I can't seem to find this info. I need piston and rotor sizes mainly.
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From: No more yankee my wankee, the Donger is tired!
J55 88-96 Dual piston 13.0" x 1.1
JL9 88-94 Dual piston 12.0" x .75 it seems just by going the difference in the caliper throat
All 88-96 cars had the same caliper/rotor Single piston 12.0" x .75" rotor (not sure on the thickness, just going by what I remember being a joke)
84-87 Single piston calipers front and rear. From what I understand smaller rotors as well.
Unsure of the piston sizes, I used to have it written down before I went to the Big Reds trying to figure out fluid displacement.
JL9 88-94 Dual piston 12.0" x .75 it seems just by going the difference in the caliper throat
All 88-96 cars had the same caliper/rotor Single piston 12.0" x .75" rotor (not sure on the thickness, just going by what I remember being a joke)
84-87 Single piston calipers front and rear. From what I understand smaller rotors as well.
Unsure of the piston sizes, I used to have it written down before I went to the Big Reds trying to figure out fluid displacement.
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
It's always been my understanding that the optional brakes were strictly a front rotor size upgrade, which also takes a caliper with a wider opening. I'm not sure if the piston size in these calipers is different or not. All C4s have 12" rears.
Safety Car
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From: VA
Some of the info is here:
http://www.superchevyperformance.com.../c4brakes.html
Look at the C5 page also, it has pics of C4 rotors.
http://www.superchevyperformance.com.../c4brakes.html
Look at the C5 page also, it has pics of C4 rotors.
Last edited by VenkmanP; Jun 11, 2005 at 02:39 PM.
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From: VA
Originally Posted by Jeffvette
All 88-96 cars had the same [rear] caliper/rotor Single piston 12.0" x .75" rotor (not sure on the thickness, just going by what I remember being a joke)
Thread Starter
Team Owner
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Thanks guys! I also think there's some specs on brake line pressure w/ 100# force on the pedal. It's in either the dealer specification manual, or the brochure.
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From: Östersund Jämtland
Mastercylinder info? (hijack warning)
Originally Posted by CentralCoaster
Looing for info on the different brake options offered. J55, 12", 13".... were the rears upgraded with the big brake option?
I can't seem to find this info. I need piston and rotor sizes mainly.
I can't seem to find this info. I need piston and rotor sizes mainly.
Anyone of you gentlemen know the Mastercylinder info aswell? I'm looking for the bore and stroke for a 90/91 brake MC.
Kind regards, Hans B
Pro
Joined: Feb 2005
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From: Centerville OH
J55 front piston size is 1.47" (37mm). The base brake caliper has the same size pistons. Rear piston size also appears to be 1.47", but it's tough to get a good measurement. Just for reference, C5 front piston size is 1.54" (39mm).
Safety Car
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From: VA
Originally Posted by Z51L9889
Rear piston size also appears to be 1.47", but it's tough to get a good measurement.
Here's my rear piston.
Last edited by VenkmanP; Jun 13, 2011 at 09:47 PM.
Thread Starter
Team Owner
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Originally Posted by HansB
I'm sorry CentralCoaster if I hijacked your thread
Anyone of you gentlemen know the Mastercylinder info aswell? I'm looking for the bore and stroke for a 90/91 brake MC.
Kind regards, Hans B
Anyone of you gentlemen know the Mastercylinder info aswell? I'm looking for the bore and stroke for a 90/91 brake MC.
Kind regards, Hans B
I have the rear stroke, and the bore written down somewhere for my 85.
Pro
Joined: Feb 2005
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From: Centerville OH
Originally Posted by steve9899
That's odd. I'm pretty sure the JL9 and J55 rears are the same. Never seen different part #s for them.
Here's my rear piston.
Here's my rear piston.
I don't think that is the primary hydraulic piston -- I believe that is the plunger for the parking brake. I don't have a diagram in front of me, but I think the plunger sits down inside the main hydraulic piston when the parking brake isn't set. I measured under the dust boot right where it meets the caliper body.
Thread Starter
Team Owner
Joined: May 2002
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
How thick are those rear rotors? Seems like the integral parking brake would be a great way to upgrade the rear rotors... since it always involves tossing my drum ebrake.
Pro
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From: Centerville OH
Originally Posted by steve9899
OK, now that I'm looking at the right thing...
Looks like 39mm.
Looks like 39mm.
Safety Car
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From: VA
Originally Posted by Z51L9889
Thanks for checking the piston by itself. My caliper is still assembled and I estimated the measurement through the dust boot.
I did think it was a pretty weird looking piston, but hadn't looked closely enough to figure it out. Hopefully I would have noticed my mistake when I went to install the new seals, but who knows.
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From: Östersund Jämtland
stroke / bore?
Originally Posted by CentralCoaster
The stroke is difficult, since there's the primary and secondary piston. I don't know if they have the same amount of travel, the front might have more since the front pistons hold more...
I have the rear stroke, and the bore written down somewhere for my 85.
I have the rear stroke, and the bore written down somewhere for my 85.
Regards, Hans B