'86-'87 Steering knuckle dimensions

TVaitonis

New member
Joined
Jan 3, 2013
Messages
4
Location
Upstate NY
Hi folks!
I'm doing my off season planning for a C5 brake upgrade for my '87 and I thought while I was waiting for Spring I'd get some homework out of the way. What I'm after is a drawing or sketch showing the distances of the caliper bracket mounting points to the center of the spindle. I've only found information for '88 onwards which has a wider spread between the holes. My big plan is to mock up the position of the C5 caliper inside my wheels as a double check for clearance. I have '89 17" 12 slot wheels and know it's going to be very close.....so close that I'll need to mind where balance weights are placed!
I figured what better forum to ask than one named Vettmod!
Thanks!
 
Yes, I have a drawing ready for fab of the adapter plates. It's crazy what they cost to buy and I have access to a machine shop so all set there. I had hoped to find a salvage knuckle and build a mock-up so if there was any fine adjustments to improve clearances I could roll those into the final machining of the brackets. Right now I'm sort of stuck since my Vette is in storage and not easy to get to. I found out that it was harder or more expensive than I guessed to score an orphaned knuckle so plan "B" was to get dimensions I could use to simulate the caliper position.
 
Yes, I have a drawing ready for fab of the adapter plates. It's crazy what they cost to buy and I have access to a machine shop so all set there. I had hoped to find a salvage knuckle and build a mock-up so if there was any fine adjustments to improve clearances I could roll those into the final machining of the brackets. Right now I'm sort of stuck since my Vette is in storage and not easy to get to. I found out that it was harder or more expensive than I guessed to score an orphaned knuckle so plan "B" was to get dimensions I could use to simulate the caliper position.

I thought you could use 88-90 knuckles on earlier cars but the a-arms were what was different. But 91 up knucles differed in how the abs pickup was so that is why 91-96 knuckles can't be used on earlier cars.

I've seen 84-87 knuckles and they look identical to my 90 knuckles.
 
Yes, I have a drawing ready for fab of the adapter plates. It's crazy what they cost to buy and I have access to a machine shop so all set there. I had hoped to find a salvage knuckle and build a mock-up so if there was any fine adjustments to improve clearances I could roll those into the final machining of the brackets. Right now I'm sort of stuck since my Vette is in storage and not easy to get to. I found out that it was harder or more expensive than I guessed to score an orphaned knuckle so plan "B" was to get dimensions I could use to simulate the caliper position.

I thought you could use 88-90 knuckles on earlier cars but the a-arms were what was different. But 91 up knucles differed in how the abs pickup was so that is why 91-96 knuckles can't be used on earlier cars.

I've seen 84-87 knuckles and they look identical to my 90 knuckles.

That would be where I'm getting tripped up due to the factory offering the "bigger brake" package which might have required different knuckles.
 
I've decided to go with C5 calipers so we have not only the 13" rotor size but also the thicker cross section of C5 disks. I considered getting J55 parts or even a Baer equivalent but honestly it was less cost to go with the C5 package. The real purpose of my original post was to get enough information so I can "dry fit" or mock up an actual caliper, disk and spindle hub inside one of my wheels and confirm the clearance. I'd rather get any surprises out of the way during the winter and while I have good access to the machine shop.
 
I've decided to go with C5 calipers so we have not only the 13" rotor size but also the thicker cross section of C5 disks. I considered getting J55 parts or even a Baer equivalent but honestly it was less cost to go with the C5 package. The real purpose of my original post was to get enough information so I can "dry fit" or mock up an actual caliper, disk and spindle hub inside one of my wheels and confirm the clearance. I'd rather get any surprises out of the way during the winter and while I have good access to the machine shop.

J55 will fit 17 inch wheels no problem, but I think with c5 you need c5 rims or Zr1 5 spoke wheels to clear c5 calipers.
 
Yes, I have a drawing ready for fab of the adapter plates. It's crazy what they cost to buy and I have access to a machine shop so all set there. I had hoped to find a salvage knuckle and build a mock-up so if there was any fine adjustments to improve clearances I could roll those into the final machining of the brackets. Right now I'm sort of stuck since my Vette is in storage and not easy to get to. I found out that it was harder or more expensive than I guessed to score an orphaned knuckle so plan "B" was to get dimensions I could use to simulate the caliper position.

I thought you could use 88-90 knuckles on earlier cars but the a-arms were what was different. But 91 up knucles differed in how the abs pickup was so that is why 91-96 knuckles can't be used on earlier cars.

I've seen 84-87 knuckles and they look identical to my 90 knuckles.

That would be where I'm getting tripped up due to the factory offering the "bigger brake" package which might have required different knuckles.

The knuckles were not different the abutment brackets were what made them fit.
 
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