zz90vette

I have a 1990 c4-with 12inch rotors. i have a set of grand sport calipers not yet on car, just the calipers. i might buy a set of c5 or c6 calipers instead what parts exactly do i need to do this thanksin advance guys, johnny

Dominic Sorresso

You need to swap spindles from the 84 to an 85-87. The 84 spindle has room for only a 12mm shank bolt attaching the caliper bracket. C5 caliper needs a 14mm shank bolt. IMHO, its one of the best upgrades you can do for the 84. I made my own adapters from SS. Upgraded brake lines to Russell SS.

You'll also need 17" wheels.

GT40_GearHead

i thought he said he has a 1990 C4...:|... does the 90 have 84 brakes ?!

zz90vette

no the 1990 has 1990 brakes

James93LT1

2 12455799 Caliper Bracket

1 88895129 -or- 12530682 Caliper

1 88895128 -or- 12530683 Caliper

1 10445856 OEM Brake Rotor
-or-
88926731 Durastop Slotted Rotor Rotor

1 10445857 OEM Brake Rotor
-or-
88926732 Durastop Slotted Rotor

4 10139097 Hose Gasket

4 12530697 Pin

4 12530703 Seal

1 12530681 -or- 88909667
(Or Non-OEM) Pad Kit

2 18039816
(Only required if using non-GM pads) Hardware Kit

C4 to C5 brake adapters

zz90vette

ok were do i get these parts mainly the the adapter brackets

James93LT1

Contact Forum members "jeffvette" or "wdo-mkr"

They make them for a reasonable price.

I was very happy with my braking improvement with the C5 upgrade.

silver84

unless the car is raced,
why bother?

Dominic Sorresso

You can never have enough brakes.
Sorry about the mixup. James LT1 gave you the correct info.

Sidney004

If your intent is to drive on the street and you already have Grand Sport calipers; you are in good shape. I race my 94 with the J55's and it works adequately even at Laguna Seca, which is murder on brakes. The pads are the key to good quick stopping on the street(and the track, although cooling is a main priority there as well.) My suggestion is: 1) Use the Grand sport Calipers, they look really nice and work well 2) Get used J55 brackets from the C4 parts for sale forum(probably $35) 3) SS lines(Goodridge is what I use ($100.) 3) Hawk HPS or HPPlus front and rear 4) Doug Rippie bias spring($25) 5) Speedbleeders ($40) 6) Through brake bleed with Valvoline or Castrol LMA brake fluid and the 7) 13" rotors(slotted or drilled if you want more bling for the street, but not for track use.)

Smooth

I have a 94lt1 a4 coupe I got a full set of c5 calipers in a great deal. I bought the brackets for the front up grade already. Can I use the back ones also? are they a direct bolt on? or do they need a special bracket as well? I can't seem to find this info.

Alan

Aardwolf

C5 in the rear would require lots of work yes and is really not needed. Only 30% or so of the braking is done in the rear and stock works fine.