CFeria

Want to replace my front calipers on a 91 vette I just purchased, after calling napa as well as other auto parts stores they ask if I have HD brake's or not? How can I tell? I know the caliper has 2 pistons.

Thanks!

Deakins

Heavy duty brakes have the larger 13 inch rotors on the front if I remember correctly. Hope this helps.

c4cruiser

This. Measure the rotor diameter. Stock brakes will have 12" rotors and the J55 heavy duty brakes have 13" rotors.

CFeria

Thanks so much, that's what I thought, BUT... since I don't have the front end apart yet and am trying to order all the parts for when I do, is there any way to tell other wise? like in the vin? If not I will have to remove one front wheel and see?!

Thanks!

92ragtop

Under your console lid, there is a label with all the RPO codes for that car. If there is no J55 code in that list, then you don't have them.

bassackwards

Remove a wheel and take a pic of the caliper and post it here.

Most auto cars had JL9 (12") and most 6 spd had j55 (13") but this is not 100%

CFeria

Excellent! I did check the list under the arm rest and there was no j55, I do think I saw a jl9 so thank you very much! It has been very helpful!!!

bassackwards

You can only trust the sticker if they have not been upgraded in the last 23 years. Lots of them have. Take a pic of the caliper and I can tell just by looking most of the time.

CFeria

actually I am 100% they are original, looks like nothing was changed in this car.

FASTAZU

If I'm not mistaken both the JL9 and J55 use the same pad the rotor and caliper are different.

GKK

You, are Correct!...