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Question: Those wimpy 12 inch front brakes!

Dan McKeeman

Member
Joined
Jul 8, 2015
Messages
5
Location
Simsbury, ct
Corvette
1994 convertible
A hard stop (standing on the brake pedal) should activate the ABS if the tires start to slip. The 12 inch brakes on my 94 C4 will not skid on dry pavement with the new sticky tires I have installed. My question is for those owners that have tried drilled and slotted rotors. Did you see an improvement in braking power?
Thanks Dan
 
Joined
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Messages
3,668
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Mustang, OK
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'13 427 60th vert - '21 Silver Flare Coupe - CTS V Wagon(4-door Vette)
Good question! I think someone will have an answer for you soon. I just wanted to say:

:welcome

:w
 
Joined
Mar 27, 2003
Messages
3,668
Location
Mustang, OK
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'13 427 60th vert - '21 Silver Flare Coupe - CTS V Wagon(4-door Vette)
Thank you for watching the new threads! Sometimes they go weeks without an answer.:)


Dan

Let's hope not.

My wife and I have owned 3 C4s, 2 with the standard brakes and one with the big brakes. Never changed the small brakes out for bigger ones or cross drilled ones however.

I do remember that when I put autocross tires on my '92 with the small brakes, I could not get the anti-lock system to cycle - it did stop like crazy though. Still, maybe the small brakes were not strong enough to cause lock up and make the ABS cycle. Wish I knew.
 

hcbph

Well-known member
Joined
Aug 30, 2013
Messages
260
Location
Minneapolis, Mn.
Corvette
86 Red Convertible
I have drilled and slotted rotors along with ceramic pads on my 86, but they were on when I bought the car so I can't compare to the original config. I'm no abs expert but as I understand the premise of abs is when one or more wheels break traction while braking the abs system kicks in. If you brake hard and don't loose traction on one or more wheels, it's not going to engage the abs as I understand. I think if you want to test it you're going to have to stage the situation, like brake hard on sand, wet pavement or something like that where it will intentionally cause braking inconsistencies between the 4 wheels.
I've only had a couple of times where I've stood on the brakes hard and there was no loss of traction on a wheel and have not noticed the abs engaging. Mine will stop hard and straight on dry pavement so I can't say how the abs reacts to that.
 

Dan McKeeman

Member
Joined
Jul 8, 2015
Messages
5
Location
Simsbury, ct
Corvette
1994 convertible
yes the 12 inch brakes are wimpy!

It looks like the stock 12 inch rotors really can't stop sticky front tires from rolling on dry pavement and set off the ABS. Now I need some feedback on drilled and slotted 12 inch rotors, I hope they are better, I just bought a set!

Dan
 
Joined
Jan 31, 2005
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422
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Somewhere in Red Wings land
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1989 Bright Red Convertible (gone) 98 Jaguar XK8
Hmmmm, I've had to lock up the brakes on my completely stock 89 and the abs came on and worked fine.
 

Hib Halverson

Technical Writer for Internet & Print Media
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CenCoast CA
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71 04 12 19
It looks like the stock 12 inch rotors really can't stop sticky front tires from rolling on dry pavement and set off the ABS. Now I need some feedback on drilled and slotted 12 inch rotors, I hope they are better, I just bought a set!

Dan


As far as inability to lock up the wheels, drilled and slotted rotors will make little or no difference.

Have you pressure bled the system? In what condition are the master cylinder and brake booster?

There is information about C4 ABS here on the CAC at:
Corvette Action Center | Tech Center | C4 Corvette Tech | Stop to Match the Go - All About C4 Corvette Antilock Brakes and Traction Control
 

Wegone

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Joined
Apr 9, 2002
Messages
516
Location
Atlanta GA.
Corvette
82,91 ZR-1,
I agree with Hib, Normal street driving you will never know the difference other than looks. If you were to track your car with lots of hard use you would see better brake cooling. Locking up the wheels is not a good thing as you have than loss the ability to control your car. The best thing you could do is go to a J55 setup with 13 inch .
 
Last edited:

Dan McKeeman

Member
Joined
Jul 8, 2015
Messages
5
Location
Simsbury, ct
Corvette
1994 convertible
My 12 inch brakes on a 94, C4

First, thanks to Hib for the feedback! I read your 2009 article and these ABS systems are more complex than I thought! I bought a complete Powerstop kit from RockAuto. It has 2 drilled and slotted plated rotors and a set of carbon ceramic pads plus all the hardware to go with them. I also bought caliper kits as I doubt the calipers have ever been serviced in 21 years and 70,000 miles. (all the parts were only around $170.00) When I get the job done and wear in the brakes I will report back on my braking improvement (or not)!
Dan McKeeman
 

Dan McKeeman

Member
Joined
Jul 8, 2015
Messages
5
Location
Simsbury, ct
Corvette
1994 convertible
The new Powerstop Carbon Ceramic pads!

Ok, Calipers are rebuilt (rubber boots were dry rotted so this is definitely the first time in 21 years). New rotors and pads are on. I did the initial break in on the rotors, as in burning off the zinc plating. Then I re-bled the system one more time. Not ready for any panic stops yet, the directions say to go easy for about 200 miles. I will report on the panic stop results when that's done.

Dan
 

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