do LS1 rear disc backing plate fit truck 10 / 12 bolts?

[modular93fox]

Just wondering if the LS1 backing plate bolts up to a truck 10 or 12 bolt? Ive got an 87 silverado with a 10 bolt and I will be upgrading the brakes in the front to 13" rotors and 2 piston calipers and would like rear disc aswell. If someone has bolt patterns for the rear flanges I would like that too so I could lay something down in autocad for a spacer.. I'm sure I will need something to get the backing plate centered. Thanks

[modular93fox]

Well this is what I found from wilwood.com
http://info.wilwood.com/Images/BrakeKits/Installation_Drawings/Installation_Drawings-Large/Axle_Flange_Diagrams.jpg

I thought LS1's came with 10 bolts? If so does the 12bolt late camaro have the same bolt pattern. I see that the C-10 down there is different..

[modular93fox]

so if the bolt pattern is correct for the camaro 12 bolt and 10 bolt could the backing plate be rotated so that it caan be redrilled for the new pattern. This is what I got when I laid the 2 out in autocad and rotated the LS1 pattern slightly:

https://static1.pt-content.com/images/noimg.gif

After I closed the program down I should have saved it when the pattern was not rotated and just laid on top of one another. I will do that tomarrow and see how that looks.

[modular93fox]

Well after laying it out, looking at the LS1 backing plate bracket from
http://www.camaros.net/forums/showthread.php?t=161383

https://static1.pt-content.com/images/pt/2009/07/DSCN0784-1.jpg

I'm a bit unsure if its going to work... the backing plate bolt pattern is raised from the base itself. So when the new pattern is drilled the new bolt holes will be roughly 1/2 an inch off of the extruded portion of the backing plate.

Possible Solution:
Place 1 spacer between the axle flange and backing plate to center the caliper on the rotor
Place a second spacer on the "outside" to act as a giant washer/base so the nuts will have a flat surface to anchor to.
It sounds solid but I'm not an engeneer, just have a bunch of ideas and I dont want to make something unsafe.
Any opinions on this setup?
https://static1.pt-content.com/images/pt/2009/07/ls1c10overlay2-1.png

I think this spacer will be the ticket... (I dunno if the holes are 9/16 or not, but thats not a big deal at the moment).
What I would send to the cutter would be the pattern on the RIGHT. It has 2 lower holes pre cut out so the LS1 plate can be bolted to the backing plate. This would center the 2 together. Once tightened you could drill out the new C-10's pattern without any measurements since the 4 pilot holes have already been torched in. The left picture is end result after all 4 holes have been drilled.

What do you guys think?
clint

[modular93fox]

anyone happen to have exact measurements from the center of the 2 caliper mounting holes to the center of the axle bore?
Ive made templates so I can hopefully get somewhat of an accurate measurement. If anyone has a better idea on how to measure this I'm all ears.

https://static1.pt-content.com/images/pt/2009/08/ls1bracketmeasuringtemp-1.png

The one on the left will get cut out and mounted like a caliper and it will extend and point towards the center of the axle bore.
The one on the right will get mounted as if it were the axle flange (front and back of the bracket). As you can see the center of the bore is marked so I can place a toothpick or something similar so it goes strait up.
Hopefully with all of this I can get the distance of the caliper center line to axle bore.

thanks
clint

[modular93fox]

Update:
Well the axle flange pattern didnt to line up to the ls1 backing plate :( however the the center bore was correct. So I was able to secure it to the bracket and take a measurement.. the best measurement (with a tape measure, business card and the templates) of 3 13/32 - center of caliper mounting bolts to center of axle bore. It seemed to fluxuate depending on how I held everything together, but it seemed to be either dead nuts on 3 3/8 Or in the middle between 3/8 and 3 7/16 (which is 3 13/32). I do not have a metric tape measure so I will probally try 3 13/32 as the centerline when I make the first bracket. If everything bolts up as it should, I guess the best way to tell if its spaced correctly is to look at the pads after a few hundred miles to see if the pads had missed the rotor any. Do the ls1 rotors get a lip on the edge of the rotor when they wear or does the pad just barely make it to the edge?
If anyone is an engenieer and had a neat way (the correct way) to measure something like I am trying to measure and you would like to share it, please PM me!

I found a guy selling something similar to what im trying to do but his setup consists of 11.5 impala SS rotors and 93-97 F-body calipers. The parking brake is integrated into the caliper which is nice, no 100 dollar set of parking brake shoes. I really want the ls1 or c6 rear disc in the rear becuase of their size. Im pretty much going for looks in the rear since the wheels I plan on getting are a 5 spoke 17". Drums and tiny discs just isnt attractive.

[modular93fox]

Anyone know the diameter of the bore on the LS1 rear calipers? Just want to compare them to the 93-97 rears. Alldata does not show a diameter for the LS1 cars. 93-97 shows to be 1.595"
thanks guys

[Gearhead Dude]

Can you share the source for the Impala setup? I'm looking for brackets for '67-72 Chevy trucks.

[gort69]

The LT1 (93-97 F body) and the LS1 both have a single 45mm piston. The LT1 rotor is 11.6 x .80 (going from memory) and the LS1 rotor is 12.0 x 1.02.

Both the LT1 and LS1 in stock form are about 1/8" shy of pad contact at the edge of the rotor.

The LT1 integral caliper parking brake works just "OK" The LS1 drum-in-hat parking brake is excellent.

[modular93fox]

awesome.. just courious becuase I realized it will be difficult centering the corvette prarking brake actuator on the bracket. Still trying but it will be a challange.

gearhead dude: link (http://67-72chevytrucks.com/vboard/showthread.php?p=2280058#post2280058)

[ScotI]

Can you share the source for the Impala setup? I'm looking for brackets for '67-72 Chevy trucks.Google 'Impala rear disc brake brackets'. You should see a link for 67-72chevytrucks.com. There's a board member there that makes the brackets (sans emergency brake).

[LUV2XLR8]

Does anyone know if the lt1 backing plate and the ls1 backing plates have the same bolt pattern to fit onto the axle tube?

[modular93fox]

yeah

[gort69]

Does anyone know if the lt1 backing plate and the ls1 backing plates have the same bolt pattern to fit onto the axle tube?
Yes they are the same bolt pattern

[modular93fox]

man what an old thread ... well I recently moved back to Houston and it hadnt been a week and I already went to the wrecking yard. Guess I happened to be in the right spot at the right time... I decided to try the Dodge Ram 1500 rear brakes. they are single piston PBR calipers with massive 13.8" rotors. They are a bit thinner than the camaro and corvette but this is no race truck. Also the parking brake shoes are 1/4 of the cost of the LS1's...
So got both calipers, flex lines, rotors and mounting brackets for 100 bucks. when he said 150 I was like nice... then I played the let me think about it and I'll call you tomarrow.. before I got out the door he said 100 bucks. woot woot.
I placed the rotors inside of the stock rally wheel and wow ... there is only 1/4 to 1/2" of room between the rotor and inside of the rim.. I measured the spacing of the axle flange and it measured out 88mm across side to side and 72mm top to bottom.. extremely close to the c-10 pattern were talking minimal work to get them to bolt up. Willwood shows their kits to use a 2.42" axle flange offset which would be factory stuff. I measured the dodges rear setup with everyhing bolted together and laying on the bench and using a digital caliper and measured roughly 3.02". The only way to make the dodge bracket work would be to put it on the inside of the axle tube and maybe use spacers to push it inwards.
I did something similar with my old 93 fox and the sn-95 rear brakes. I notched the bracket so it would slide over the axle tube. still retained all 4 bolt holes and worked fine for the time I had the car. Im still a few weeks away from tearing the rear end apart to get these brakes on so.. till then
clint

[xx_ED_xx]

Updates?

[modular93fox]

The ls1/corvette brake project is incomplete.. however I did get 2002+ dodge 1500 rear brakes on the truck.. stops great. 13.8", single piston calipers. No mods the master or prop valve. Havent had the new caliper bracket cut out. The new design would allow me to run the e-brake.

https://static1.pt-content.com/images/noimg.gif (http://img94.imageshack.us/i/brakebrackets.jpg/)

https://static1.pt-content.com/images/pt/2010/07/dsc0811tnth-1.jpg (http://img706.imageshack.us/i/dsc0811tn.jpg/)