Anyone running C5 Rear disc brakes?

[V6UnderPressure]

I'm ordering a custom 12 bolt rear from Moser with Ford 9inch Torino housing ends. They originally come in the same track width as stock. I am also getting a rear C5 disc kit to fit the Ford ends. I know alot of rear disc kits require the shocks to be relocated due to it hitting the caliper. However, Moser can make the ends longer (just not shorter due to the lower control arm mounts). I am just curious if anyone has done the C5 brakes on their GN Rear, and what type of clearance they have with the calipers. If I can get the rear end slightly wider to avoid relocating the shocks, I'd like to.

 

[83hurstguy]

I'll know hopefully in the next week or two... in the process of putting a Kore3 kit with parking brake on now. Waiting for calipers to come back from powdercoating. Preliminary measurements looked promising.

I have an LS1 backing plate caliper to help compare the offsets.

 

[V6UnderPressure]

The LS1 brake rotors are actually 1/2" taller than the C5 rotors. So I'd imagine that the caliper would definitely be inside more with the LS1 brakes. Clearance should be a bit better with the C5's.

 

[83hurstguy]

Yeah I measured 1/2 - 5/8" improvement in clearance over the LS1's based on some preliminary mockups.

The only downside is that trying to use a parking brake is a pain in the ass. Kore3 does sell the kit to work with C5/6 rears with a parking brake for 9 inch ends (friend is doing that swap right now on a 12 bolt with Ford ends), but your axle flange to housing flange measurement has to be 2.25" to work right if I remember correctly. You may need to adjust housing width to account for an odd axle offset requirement for the brakes if you want to hold your axle flange to axle flange width to the stock value.

G-bodies have less axle "stick out" than the earlier A-bodies or F-bodies. Mine were 2.65" and 2.75" (different due to C-clip axles and shimming carrier for gear pattern), where earlier cars were 2.75-2.81". You need 2.75" minimum to get the parking brakes and caliper abutments to center over the rotors correctly without doing some creative milling. I'll have pics probably towards the end of next week as it all goes together. Should have ordered a 0.100" extra long axle from Moser for one side, would have been a much easier/cheaper solution. I'll quit ranting now....

 

[SFI Cutlass]

Not sure if they will fit but what i have seen Kore3 makes a setup that you can Install the caliper in front of the axle or behind regardless if you are using e brakes or not. If your kit doesn't fit and you have to use a bracket for the shock, personally i would prefer to relocate the shock with ridetech shock relocation bracket that goes on the axle they use for the coil overs. They look good and strong.


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[V6UnderPressure]

Yeah I measured 1/2 - 5/8" improvement in clearance over the LS1's based on some preliminary mockups.

The only downside is that trying to use a parking brake is a pain in the ass. Kore3 does sell the kit to work with C5/6 rears with a parking brake for 9 inch ends (friend is doing that swap right now on a 12 bolt with Ford ends), but your axle flange to housing flange measurement has to be 2.25" to work right if I remember correctly. You may need to adjust housing width to account for an odd axle offset requirement for the brakes if you want to hold your axle flange to axle flange width to the stock value.

G-bodies have less axle "stick out" than the earlier A-bodies or F-bodies. Mine were 2.65" and 2.75" (different due to C-clip axles and shimming carrier for gear pattern), where earlier cars were 2.75-2.81". You need 2.75" minimum to get the parking brakes and caliper abutments to center over the rotors correctly without doing some creative milling. I'll have pics probably towards the end of next week as it all goes together. Should have ordered a 0.100" extra long axle from Moser for one side, would have been a much easier/cheaper solution. I'll quit ranting now....

Kore3 is the kit I went with. It has to be 2.5" between the flange and hub. Moser will accomodate that. If they need to move the axle outward an inch, they will also move the flange out an inch, which is nice.

 

[V6UnderPressure]

Not sure if they will fit but what i have seen Kore3 makes a setup that you can Install the caliper in front of the axle or behind regardless if you are using e brakes or not. If your kit doesn't fit and you have to use a bracket for the shock, personally i would prefer to relocate the shock with ridetech shock relocation bracket that goes on the axle they use for the coil overs. They look good and strong.


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I forgot about the Ridetech kit. I wonder if the ridetech kit gets you enough clearance for the calipers.

 

[V6UnderPressure]

Yeah I measured 1/2 - 5/8" improvement in clearance over the LS1's based on some preliminary mockups.

The only downside is that trying to use a parking brake is a pain in the ass. Kore3 does sell the kit to work with C5/6 rears with a parking brake for 9 inch ends (friend is doing that swap right now on a 12 bolt with Ford ends), but your axle flange to housing flange measurement has to be 2.25" to work right if I remember correctly. You may need to adjust housing width to account for an odd axle offset requirement for the brakes if you want to hold your axle flange to axle flange width to the stock value.

G-bodies have less axle "stick out" than the earlier A-bodies or F-bodies. Mine were 2.65" and 2.75" (different due to C-clip axles and shimming carrier for gear pattern), where earlier cars were 2.75-2.81". You need 2.75" minimum to get the parking brakes and caliper abutments to center over the rotors correctly without doing some creative milling. I'll have pics probably towards the end of next week as it all goes together. Should have ordered a 0.100" extra long axle from Moser for one side, would have been a much easier/cheaper solution. I'll quit ranting now....

Let me know on your friends 12 bolt. that sounds exactly like what I am doing. Is his 12 bolt stock width?

 

[SFI Cutlass]

Found this just by doing a quick search.

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[V6UnderPressure]

I'm running 17x8 with 4.5 BS and 255-45-17 tires so I should at a minimum be able to get the rear at least a quarter inch wider on each side if not a half inch.

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[83hurstguy]

Kore3 is the kit I went with. It has to be 2.5" between the flange and hub. Moser will accomodate that. If they need to move the axle outward an inch, they will also move the flange out an inch, which is nice.

Yeah that's right... not sure why 2.25" came out of my keyboard yesterday.

Let me know on your friends 12 bolt. that sounds exactly like what I am doing. Is his 12 bolt stock width?

It's an A-body with a 12 bolt, so it's not going to be as applicable to our stuff. However, there is a lesson learned out there about distance from back of rear housing flange to the LCA mount. The kit requires you to insert 2" long bolts from the back of the flange, so if you shorten the housing, you can't fit the bolts in there without interfering with the LCA mount.

My calipers were waiting for me when I arrived home from work yesterday, so I mocked the rear end up last night completely out of car.

With the calipers mounted, there is distance of 47-1/4" between them at their widest points, without bleeders installed. The bleeders are approximately 1/2" tall when installed. I measured frame rail to frame rail with help from the wife, and got a value of 47". Therefore, the bleeders are theoretically on an interference path. The Kore3 kit clocks the calipers lower than the LS1 backing plates do, so that will also help with frame clearance. Here's a picture of where the caliper sits relative to the axle tube.

I had to disassemble it to get some plating done and the housing painted, hopefully next weekend (the 13th), I can have it in the car to validate frame clearance when it's on the bump stops. I'm pretty confident it won't be an issue. In your case, if you bump the housing flanges out 0.25" and leave the axle flange width the same as stock G-body, you shouldn't have an issue, and the plus side is it should fit any G-body with standard wheel combination.

Hope that helps a bit. If I have some time today I may bolt up the LS1 brakes and calipers to judge the relative difference. Don't have a rotor though to make sure the caliper is center for the measurement.

 

[V6UnderPressure]

Yeah that's right... not sure why 2.25" came out of my keyboard yesterday.



It's an A-body with a 12 bolt, so it's not going to be as applicable to our stuff. However, there is a lesson learned out there about distance from back of rear housing flange to the LCA mount. The kit requires you to insert 2" long bolts from the back of the flange, so if you shorten the housing, you can't fit the bolts in there without interfering with the LCA mount.

My calipers were waiting for me when I arrived home from work yesterday, so I mocked the rear end up last night completely out of car.

With the calipers mounted, there is distance of 47-1/4" between them at their widest points, without bleeders installed. The bleeders are approximately 1/2" tall when installed. I measured frame rail to frame rail with help from the wife, and got a value of 47". Therefore, the bleeders are theoretically on an interference path. The Kore3 kit clocks the calipers lower than the LS1 backing plates do, so that will also help with frame clearance. Here's a picture of where the caliper sits relative to the axle tube.

I had to disassemble it to get some plating done and the housing painted, hopefully next weekend (the 13th), I can have it in the car to validate frame clearance when it's on the bump stops. I'm pretty confident it won't be an issue. In your case, if you bump the housing flanges out 0.25" and leave the axle flange width the same as stock G-body, you shouldn't have an issue, and the plus side is it should fit any G-body with standard wheel combination.

Hope that helps a bit. If I have some time today I may bolt up the LS1 brakes and calipers to judge the relative difference. Don't have a rotor though to make sure the caliper is center for the measurement.

I'm pretty sure if I kick the flanges out .25, I would be good as far as frame clearance. My main concern is rear shock clearance. I would imagine yours will require your shocks to be relocated. What I am truly curious about is how much is the caliper in the way. If the caliper would clear the shock with an extra .25" then my problem would be solved.

 

[V6UnderPressure]

With the Kore 3 kit and 9 inch flanges, I also have the power to mount the calipers towards the front, in which case I'd only have to worry about frame clearance. When you get your rear end in, can you take a straight edge and tell me how much clearance you would have from the front part of the frame? I'd be curious. The kore3 kit clocks the C5 caliper at 90 degrees.

 

[V6UnderPressure]

Yeah that's right... not sure why 2.25" came out of my keyboard yesterday.



It's an A-body with a 12 bolt, so it's not going to be as applicable to our stuff. However, there is a lesson learned out there about distance from back of rear housing flange to the LCA mount. The kit requires you to insert 2" long bolts from the back of the flange, so if you shorten the housing, you can't fit the bolts in there without interfering with the LCA mount.

My calipers were waiting for me when I arrived home from work yesterday, so I mocked the rear end up last night completely out of car.

With the calipers mounted, there is distance of 47-1/4" between them at their widest points, without bleeders installed. The bleeders are approximately 1/2" tall when installed. I measured frame rail to frame rail with help from the wife, and got a value of 47". Therefore, the bleeders are theoretically on an interference path. The Kore3 kit clocks the calipers lower than the LS1 backing plates do, so that will also help with frame clearance. Here's a picture of where the caliper sits relative to the axle tube.

I had to disassemble it to get some plating done and the housing painted, hopefully next weekend (the 13th), I can have it in the car to validate frame clearance when it's on the bump stops. I'm pretty confident it won't be an issue. In your case, if you bump the housing flanges out 0.25" and leave the axle flange width the same as stock G-body, you shouldn't have an issue, and the plus side is it should fit any G-body with standard wheel combination.

Hope that helps a bit. If I have some time today I may bolt up the LS1 brakes and calipers to judge the relative difference. Don't have a rotor though to make sure the caliper is center for the measurement.

You said ur runnin ls1 rotors/calipers right? If so, c5 calipers/rotors will net about a half inch additional clearance per side due to the shorter height of the rotor hat.

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[83hurstguy]

You said ur runnin ls1 rotors/calipers right? If so, c5 calipers/rotors will net about a half inch additional clearance per side due to the shorter height of the rotor hat.

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No, those are brand new C5 PBR calipers, with DBA 4000 series C5/C6 base rear rotor. I was considering doing the LS1 swap, so I have the parts, but my car sits low and I was worried about frame clearance.

 

[V6UnderPressure]

So what kit did you end up going with? I'm just curious if you are using the stock 10 bolt rear. Did you hack off the top portion like most do and drill the two extra holes?

 

[83hurstguy]

Using their 12 bolt setup for C clip axles. Yep, had to cut the ends and drill the holes. Wasn't too bad to do. I'll probably do a build thread on it once it's completed.

 

[V6UnderPressure]

Using their 12 bolt setup for C clip axles. Yep, had to cut the ends and drill the holes. Wasn't too bad to do. I'll probably do a build thread on it once it's completed.

That would be a good idea. After seeing the photos, I'm not so sure an extra quarter inch will helo clear the shocks. At this point I think I'm more interested in the clearance you would have if mounted on the front side.

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[V6UnderPressure]

Any updates on your build?

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[83hurstguy]

Got slowed down the past two weeks with some other issues that I had to finish before the rear end goes back in, needed new upper control arms but they were delayed from the manufacturer... got them Friday. Planning on working on it more this week. I'm really hoping the shocks clear...

Have a few lessons learned from the friend's install. He had to notch the parking brake cable bracket due to bolt interference and is fighting some seal leaks now. In addition, if you use screw-in axle studs, make sure you get low profile stud heads, or the standard ARP ones will interfere with the parking brake actuator on the backing plate.