Brakes?
Thread Starter
Racer
Joined: Mar 2008
Posts: 254
Likes: 0
From: Perth W.A
Brakes?
hi all
i am just wondering what the c4 brakes are supposed to be like?
My 1990 has a long pedal before feeling any bite, and even then is very poor, i have to push quite hard just for it to actually stop!
i mean yes there is assistance getting to the brakes, so i don't think there is any failure anywhere!
i am thinking it just the way they were back then! (single piston and all)
as i have a vl calais turbo (australian car) and the brakes are the same as on the c4! and those brakes were pretty pathetic and had same sort of feel to them!
i have seen upgrade kits(a few of them)
1: c5 larger rotors, but only have twin piston calipers
2: c5 upgrade kit that had 6 piston calipers(i think a bit overboard tho)
i think they are both 13" rotors!
has anyone done this upgrade
what ya think? thanks
i am just wondering what the c4 brakes are supposed to be like?
My 1990 has a long pedal before feeling any bite, and even then is very poor, i have to push quite hard just for it to actually stop!
i mean yes there is assistance getting to the brakes, so i don't think there is any failure anywhere!
i am thinking it just the way they were back then! (single piston and all)
as i have a vl calais turbo (australian car) and the brakes are the same as on the c4! and those brakes were pretty pathetic and had same sort of feel to them!
i have seen upgrade kits(a few of them)
1: c5 larger rotors, but only have twin piston calipers
2: c5 upgrade kit that had 6 piston calipers(i think a bit overboard tho)
i think they are both 13" rotors!
has anyone done this upgrade
what ya think? thanks
Race Director
Joined: Dec 2006
Posts: 10,383
Likes: 4
You are not describing a functioning brake system for any car let alone a Corvette.
Even the 12" front brake Corvettes can have excellent stopping power.
Before you go the upgrade route price out new rotors, pads, caliper rebuild kits, and master cylinder. Add in a few bottles of name brand full synthetic Dot 3-4 fluid.
Based on your description I would suspect there is air in the system and/or a master cylinder that is leaking back internally.
Can you pump the brake several times and get a full solid pedal? If so, can you hold it for several minutes with the same pressure and the pedal won't go to the floor?
Even the 12" front brake Corvettes can have excellent stopping power.
Before you go the upgrade route price out new rotors, pads, caliper rebuild kits, and master cylinder. Add in a few bottles of name brand full synthetic Dot 3-4 fluid.
Based on your description I would suspect there is air in the system and/or a master cylinder that is leaking back internally.
Can you pump the brake several times and get a full solid pedal? If so, can you hold it for several minutes with the same pressure and the pedal won't go to the floor?
Thread Starter
Racer
Joined: Mar 2008
Posts: 254
Likes: 0
From: Perth W.A
ok they do brake and pull the car up ok, but i just expected a little better from a sportscar!
but yes i will have to look into the master cylinder etc...
will have to try pushing the pedal with the engine off, and just see if it gets hard!, i am sure the system is fine! i just expect better from it! not used to having to push the pedal half way before noticing any braking happening!
my other car 1998 Holden VT has twin piston and brakes with to slightest touch of the pedal!
but yes i will have to look into the master cylinder etc...
will have to try pushing the pedal with the engine off, and just see if it gets hard!, i am sure the system is fine! i just expect better from it! not used to having to push the pedal half way before noticing any braking happening!
my other car 1998 Holden VT has twin piston and brakes with to slightest touch of the pedal!
Thread Starter
Racer
Joined: Mar 2008
Posts: 254
Likes: 0
From: Perth W.A
umm no not sure!
just assumed as if they are the same as my other car which had the same(or same sort of caliper) then they are single piston!
did any of the c4's come out with twin piston?
do the 1990 vettes have 12 or 13 inch rotors?
just assumed as if they are the same as my other car which had the same(or same sort of caliper) then they are single piston!
did any of the c4's come out with twin piston?
do the 1990 vettes have 12 or 13 inch rotors?
Race Director
Joined: Dec 2006
Posts: 10,383
Likes: 4
In 1990 one could get either 12" or 13" rotors in the front. RPO J55 is the 13" code and was included under other option packages but would still be listed as a seperate item on the console lid "build sheet".
Race Director
Joined: Oct 2005
Posts: 11,770
Likes: 175
From: Rolla Missouri
2021 C4 of the Year - Unmodified Finalist
St. Jude Donor '10 thru '25
If you have to push the pedal half way before noticing any braking action, then something is not right!
Even though the C4 brake system is not up to par with more modern systems, they were still plenty good enough to lock the wheels up when needed.
Thread Starter
Racer
Joined: Mar 2008
Posts: 254
Likes: 0
From: Perth W.A
I am not a brake expert, but I don't think your system is "fine".
If you have to push the pedal half way before noticing any braking action, then something is not right!
Even though the C4 brake system is not up to par with more modern systems, they were still plenty good enough to lock the wheels up when needed.
mine has abs so it shouldn't lock up, correct?
it does brake but the pedal feel is long and then gets harder, but needs to be pushed more than i thought it should!
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Race Director
Joined: Oct 2005
Posts: 11,770
Likes: 175
From: Rolla Missouri
2021 C4 of the Year - Unmodified Finalist
St. Jude Donor '10 thru '25
But you should be able to brake hard enough to activate the system (ABS light come on, and feel the pedal pulsing) without have to "stand on them so hard".
Thread Starter
Racer
Joined: Mar 2008
Posts: 254
Likes: 0
From: Perth W.A
ok i just tested the brake pedal with the engine off! and it was very firm on the first press! and then with engine on the pedal slowly sunk about 1/4 pedal travel, so that seems correct!
pressing the brake pedal while idling it travels about 5cm which is better than i thought!
haven't had a chance to drive it lately to test if it will lock up or not!
thanks for all your info!
pressing the brake pedal while idling it travels about 5cm which is better than i thought!
haven't had a chance to drive it lately to test if it will lock up or not!
thanks for all your info!
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
If you don't know when it was last done ; change the brake fluid ( flush old fluid out ) and rebleed the brakes. Brake fluid absorbs moisture
You can buy the HD 13" rotors locally (DBA / RDA ) from any decent brake shop and get the J55 calipers from the US.Bolt on conversion.
FYI ; the HD 13" rotors are 28 mm thick ; the std 12" ones are
only 20mm
You can buy the HD 13" rotors locally (DBA / RDA ) from any decent brake shop and get the J55 calipers from the US.Bolt on conversion.
FYI ; the HD 13" rotors are 28 mm thick ; the std 12" ones are
only 20mm
Safety Car
Joined: Sep 2002
Posts: 4,971
Likes: 9
From: The reason time exists is so everything doesn't happen at once
Thread Starter
Racer
Joined: Mar 2008
Posts: 254
Likes: 0
From: Perth W.A
If you don't know when it was last done ; change the brake fluid ( flush old fluid out ) and rebleed the brakes. Brake fluid absorbs moisture
You can buy the HD 13" rotors locally (DBA / RDA ) from any decent brake shop and get the J55 calipers from the US.Bolt on conversion.
FYI ; the HD 13" rotors are 28 mm thick ; the std 12" ones are
only 20mm
You can buy the HD 13" rotors locally (DBA / RDA ) from any decent brake shop and get the J55 calipers from the US.Bolt on conversion.
FYI ; the HD 13" rotors are 28 mm thick ; the std 12" ones are
only 20mm
i checked oil, and some plugs, oil was still nice clear oil colour! but i should change the plugs!
do you know what code they are in Australia? NGK ????
Are the J55 calipers the c5 caliper? or just 95/96 c4 caliper?
thanks a lot!
Safety Car
Joined: Sep 2002
Posts: 4,971
Likes: 9
From: The reason time exists is so everything doesn't happen at once
C5 brakes are just that, the brakes that came on the C5 (fifth generation Corvette). It is possible to upgrade the front brakes on a C4 to C5, but special adaptor brackets are required and you can't fit stock C4 wheels, except A-molds, over them.
Last edited by jrzvette; Jun 27, 2009 at 03:44 PM.
Pro
Joined: Aug 2007
Posts: 623
Likes: 0
From: BGM NY
hi all
i am just wondering what the c4 brakes are supposed to be like?
My 1990 has a long pedal before feeling any bite, and even then is very poor, i have to push quite hard just for it to actually stop!
i mean yes there is assistance getting to the brakes, so i don't think there is any failure anywhere!
i am thinking it just the way they were back then! (single piston and all)
as i have a vl calais turbo (australian car) and the brakes are the same as on the c4! and those brakes were pretty pathetic and had same sort of feel to them!
i have seen upgrade kits(a few of them)
1: c5 larger rotors, but only have twin piston calipers
2: c5 upgrade kit that had 6 piston calipers(i think a bit overboard tho)
i think they are both 13" rotors!
has anyone done this upgrade
what ya think? thanks
i am just wondering what the c4 brakes are supposed to be like?
My 1990 has a long pedal before feeling any bite, and even then is very poor, i have to push quite hard just for it to actually stop!
i mean yes there is assistance getting to the brakes, so i don't think there is any failure anywhere!
i am thinking it just the way they were back then! (single piston and all)
as i have a vl calais turbo (australian car) and the brakes are the same as on the c4! and those brakes were pretty pathetic and had same sort of feel to them!
i have seen upgrade kits(a few of them)
1: c5 larger rotors, but only have twin piston calipers
2: c5 upgrade kit that had 6 piston calipers(i think a bit overboard tho)
i think they are both 13" rotors!
has anyone done this upgrade
what ya think? thanks
Last edited by VETTEHIGH; Jun 27, 2009 at 05:01 PM.
Thread Starter
Racer
Joined: Mar 2008
Posts: 254
Likes: 0
From: Perth W.A
J55 was the heavy duty brake package on C4s. It was an option (either stand alone or part of a package, for example ZR1 or Z07) until 1994. For 1995 and 1996 J55 was the standard brake package and no options were available.
C5 brakes are just that, the brakes that came on the C5 (fifth generation Corvette). It is possible to upgrade the front brakes on a C4 to C5, but special adaptor brackets are required and you can't fit stock C4 wheels, except A-molds, over them.
C5 brakes are just that, the brakes that came on the C5 (fifth generation Corvette). It is possible to upgrade the front brakes on a C4 to C5, but special adaptor brackets are required and you can't fit stock C4 wheels, except A-molds, over them.
are the c5 rotors 13'' or bigger! i have 17 inch stock rims from the 90 vette! i have read that they will allow the c5 brake upgrade kit!
well on ebay from a provider called Mr Spares, he sells a c4 c5brake upgrade kit for $1000 AUD, comes with everything needed ,brackets, rotors, twin piston calipers, even 6 piston if you want!(extra of course) pads, and lines!
not bad!
but may be easier to just buy 13'' rotors and j55 calipers! are these brakes pretty good!
Thread Starter
Racer
Joined: Mar 2008
Posts: 254
Likes: 0
From: Perth W.A
I just received my Baer EradiSpeed Plus 2 rear rotors and Baer Claw TRACK-PLUS front kit yesterday. Holy cow is this a set up. 13" front/rear rotors. Looks huge. Also, I have brand new OEM rear calipers. Sent them out today to be powdercoated in almost chrome look. I sent all my calipers to http://www.thepowdercoater.com/ I guess he is really good at what he does
should be a huge improvement!what was the cost of the brake kit if you don't mind me asking?
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 763
hi all
i am just wondering what the c4 brakes are supposed to be like?
My 1990 has a long pedal before feeling any bite, and even then is very poor, i have to push quite hard just for it to actually stop!
i mean yes there is assistance getting to the brakes, so i don't think there is any failure anywhere!
i am thinking it just the way they were back then! (single piston and all)
as i have a vl calais turbo (australian car) and the brakes are the same as on the c4! and those brakes were pretty pathetic and had same sort of feel to them!
i have seen upgrade kits(a few of them)
1: c5 larger rotors, but only have twin piston calipers
2: c5 upgrade kit that had 6 piston calipers(i think a bit overboard tho)
i think they are both 13" rotors!
has anyone done this upgrade
what ya think? thanks
i am just wondering what the c4 brakes are supposed to be like?
My 1990 has a long pedal before feeling any bite, and even then is very poor, i have to push quite hard just for it to actually stop!
i mean yes there is assistance getting to the brakes, so i don't think there is any failure anywhere!
i am thinking it just the way they were back then! (single piston and all)
as i have a vl calais turbo (australian car) and the brakes are the same as on the c4! and those brakes were pretty pathetic and had same sort of feel to them!
i have seen upgrade kits(a few of them)
1: c5 larger rotors, but only have twin piston calipers
2: c5 upgrade kit that had 6 piston calipers(i think a bit overboard tho)
i think they are both 13" rotors!
has anyone done this upgrade
what ya think? thanks
Racer
Joined: Feb 2009
Posts: 251
Likes: 0
From: pa
the brake pedal problem as stated sounds like your are discribing my 90. my 90's brakes are also pretty pathetic - period! so far, ive replaced the master cylinder (new ac delco unit), and installed stainless steel (flex) brake lines. i've blead the system at least 4 times. i'm confident there is not any air in the system. my rotors are original, and i did install a "cheap" set of autozone pads. my next step is to install a new set of rotors, and a set of hawk pads to see if that helps. when i hit the brake pedal, i can sense the brakes are engaging, but not much stopping power. this leads me to believe my pads are not very efficient, and/or, the pads/rotors are slightly glazed. as of now, i have to apply, what i consider, excessive pedal pressure, and my pedal travel is half way to the floor. as far as c4's go, the only other car i can compare my 90 to is my 85 which has super brakes - you know, "stop on a dime, and give you a nickel change!" brakes. i've considered a c5 upgrade, but that's pretty expensive. if i can get my 90 to stop like my 85, i'd be more than happy. keep me/us informed of any progress you have...
my brakes on my 93 works like yours, they don't work like they did before!! let us know if the pads work? i don't think they will, i think the booster is going bad
