True C5 Rear Disc w/ internal parking brake in the works
 

Well I finally went to the bone yard to grab a spare rear end so I can start fabing up a rear kit with ebrake. I got lucky and found a 12 bolt... added bonus I guess. This past weekend I cleaned the rear end and probally lay some paint for in-progress pictures. The kit will use C5 rotors and C5 calipers, and C-5 parking brakes.. the cables will either be C5 or LS1... havent got that far yet.
First things first, buy a set of stock c-5 rotors and take measurements and have the stock axles turned down to fit.

As far as pictures, I have none yet, I just ordered brand new C5 rear calipers, and new backing plate assemblies with the e-brake shoes and actuator. Ive got the layout in the computer, and once I get the parts, I will start laying the bracket out on some acrylic plastic to get the spacing down. Once I get that far, its a matter of modifiying the factory ebrake cables which is an easy fix and has already been done by some f-body guys. Once I get that far, time to upgrade the membership on the forum :)

Once complete, the brakes could be upgraded to the z51 calipers and rotors or even the fixed caliper design and matching rotors, and maybe even build a hybrid bracket to adapt the C-5 calipers to the F-body rotors (smaller) so you can run 15" wheels.
till then,
clint

Re: True C5 Rear Disc w/ internal parking brake in the works
 

Dang, I have 2 73-87 12-bolts sitting in storage. I would have donated one for the cause ;) .

Re: True C5 Rear Disc w/ internal parking brake in the works
 

dang! I was seriously holding out on not buying one but hey...
As far as the cause, I am in need of:
1 - LS1 rotor (12")
1- C5 rotor - (12")
1 - C6 Z06 rotor (13.4")
1 - C6 Zo6 caliper/caliper bracket

The difference between the LS1 and C5 is the C5 (from what I've read) is directional, while the LS1 has strait veins for venting. The offsets are different too, so they dont interchange...

Whats the consensius on the board....
LS1 rotors - non directional -around 50$ at oreillys
- or -
Corvette - directional -around 80 bucks$ at oreillys

clint

Re: True C5 Rear Disc w/ internal parking brake in the works
 

here are some pictures I've found on the net to give an idea of the "look"...
C5 Rear Brakes

http://i91.photobucket.com/albums/k3...rsionweb25.jpg


C6Z06 Rear Brakes

http://i91.photobucket.com/albums/k3...ondiscweb4.jpg

Obviously the C6z06 brakes will look funny on our trucks w/o a front kit to match, but just throwing it out there.

Re: True C5 Rear Disc w/ internal parking brake in the works
 

Have you checked the bolt circle on the Vette pieces? I'm not up on the late models, but the older ones are 4.75". Are you planning on re-drilling them if necessary?

Ray

Re: True C5 Rear Disc w/ internal parking brake in the works
 

The rotors willl need to be redrilled for the pattern, Vetts and Camaros are 4.75x5. Once the axle is turned down by a machinist, you yourself can redrill the rotors with a supplied template. Becuase the rotor is going to be centered on the center register on the axle, the bolt pattern holes dont affect its center-ness.
clint

Re: True C5 Rear Disc w/ internal parking brake in the works
 

You 5-lug guys have it soooo easy! ;) I would go with the biggest brakes you can afford, so my vote is for the Z06 setup. :metal:

Re: True C5 Rear Disc w/ internal parking brake in the works
 

You drill those lug holes off center by as little as .025 and you are going to have vibrations out the wazoo ... regardless of where the rotor is centered.

Re: True C5 Rear Disc w/ internal parking brake in the works
 

If your center hole and axle are a tight fit, the lug hls can be a little over size. The center hole of the rotor is going to set the center of the rotor, not the lug holes.

Re: True C5 Rear Disc w/ internal parking brake in the works
 

Right, just like the McGaughys kit, the rear axle has to be machined down. One member got his done for around 80 bucks for the pair. I am going to search for a machine shop tomarrow (day off) and have them done. Since the axle's register will be machined down to 2.77 (center bore on the rotor is 2.776) the rotor will be perfectly centered.

When I made the pattern to drill my current rotors (13.8 1/2 Dodge 1500), zero problems.. no wired vibrations or anything, rotors centered on the axle register.
The pattern is super easy to lay on the rotor and make your marks. Then simply drill using a drill press. When I go to drill the rotors for test fitting, I will be sure to bring a camera.

Clint

Re: True C5 Rear Disc w/ internal parking brake in the works
 

I've already done this mod with Cadillac parts. I don't know what I'm talking about. Just trying to help.

Re: True C5 Rear Disc w/ internal parking brake in the works
 

its all good. It seems that there might be an even better solution to the rotor modification... I need to measure the spare axles OD and the one in my truck and compare it to whats offered. Theres a company that sells kits for camaros and trans ams and what have you. They sell plain C5 rotors, Crossdrilled/slotted C5 rotors with the 5x5 pattern, center bore machined to fit our axle bore, and the inside of the face machined so NO modificaitons is necessary for the axle. Plus they are about 5 bucks cheaper than Oreillyauto.com. Once I take some measurements and I get an answer on that, I will be placing an order for the rotors tomarrow.

nlped took a measurement and posted it up in another thread, his measurement came out to 6.57.. So far so good.

clint

Kinda did a running total so far. Rear Calipers, Rear rotors (modified to fit stock axles), Backing plates w/shoes, e-brake cables is right at 590.00 plus s/h... Whats lacking in that total is the brake pads and converison brackets... but just to get a running total started. In the end, Im sure the price will be close to McGaughys rear brake conversion - less costs of axle machining :)

Re: True C5 Rear Disc w/ internal parking brake in the works
 

Well, I my digital caliper doesnt read past 6.0" so I couldnt measure the O.D. of the axle. I could measure the O.D. of the axles register and that was around 3.08. Due to the studs installed onthe axle prevented me from getting a accurate measurement.
The rear C5 rotor modifed to fit another rear end application, doesnt quite fit this axles register. The register was opened to 3.063 (the 1980ish 12bolt register measured around 3.08). So I am going to order a set of A/C delco rootrs later on today. Should have the calipers Wedensday, Rotors on Thursday, and maybe I can have the machine work done Friday? I will take the axle and rotor down to a machine shop and see what it would cost to machine the rotor to the axle. I Think maching the rotor to fit the axle is better because the way the inside of the rotor is machined. The mounting pad of the axle flange would have to be about 6" roughly 1/2
smaller in diameter from original to fit the inside of a stock rotor.

clint

Re: True C5 Rear Disc w/ internal parking brake in the works
 

Trailblazer SS's have 6-lug. What about their parts?

Re: True C5 Rear Disc w/ internal parking brake in the works
 

Trailblazer SS has a 6 on 5" bolt circle instead of the old 6 on 5 1/2" pattern. You could use the Baer 99 and up 14" rear disc rotors they are 6 on 5 1/2" pattern...i used them on my old square body and redrilled them to a 5 on 5" pattern and the truck is still rolling around four years later with no vibation or problems at all.

Re: True C5 Rear Disc w/ internal parking brake in the works
 

FedEx droped off the first order:

http://a.imageshack.us/img689/7738/caliperebrake.jpg

rotors are the last thing I'm waiting on before I can start mocking up the brackets.

clint

Re: True C5 Rear Disc w/ internal parking brake in the works
 

Finally went from paper space in autocad to some 1/4 acrylic plastic... fine tuned the outline/shape of the bracket and voila:

http://a.imageshack.us/img188/8272/img0167bm.jpg

and the back side showing the acrylic bracket - for race applications lol...

http://a.imageshack.us/img299/4958/img0168b.jpg
There will only be 3 bolts holding the backing plate to the adapter bracket. One on the top (thats the one you can see the hole is drilled through), and 2 at the bottom that go through the e-brake actuator.

I am lacking the rotors, so I do now know how far to space it just yet. The backing plate will be close to 5/8 away from the flange. The 4 axle flange holes in the backing plate adapter will be tapped just like the Ed Miller design. I am going to start on the caliper bracket now.. I am going to look at some C-5 pictures to see about at what angle the caliper is in...... and then compare it to the front of our trucks.. make it about the same angle.
clint

Re: True C5 Rear Disc w/ internal parking brake in the works
 

So a quick search shows that the calipers are setup just like our fronts, 90* and to the rear. There like how I set up the Dodge rear calipers on my truck now:

http://a.imageshack.us/img13/2985/dsc0809i.jpg

Uploaded with ImageShack.us

thoughts/opinions? Any case, the angle could be changed at any time with no problem.

clint

Re: True C5 Rear Disc w/ internal parking brake in the works
 

FedEx dropped off the rotors... after looking at it, the inside of the rotor is machined to about 6.25. Our axles are a tad over 6.5. While staring at the two, I was thinking instead of turning the entire axle down to fit the rotor, just turn the outer edge (of the face), like a chamfer that fits within the stock rotor. Along with that turn the center register to fit the stock rotor. Sounds like it would be better so there would not be any extra costs each time the rotor needs replacing. I am going to the machine shop tomarrow to see what their advice is and costs involved. ... anywhoo, I loaded AutoCad Inventor 2010 so I wll post up a 3d of what I had in mind.
clint

edit:
heres a rendering of the axle mod that I was describing..

http://a.imageshack.us/img13/5115/axle3d.jpg

and a view looking down

http://a.imageshack.us/img806/7505/axle3d2.jpg

Re: True C5 Rear Disc w/ internal parking brake in the works
 

Well, After going to a few machine shops, its not cost effective to turn the rotors down to fit a stock axle without doing large quantities of rotors. for 2 rotors, it would be 150.... yikes. I wish I had machine shop friends :( a few shops said they could turn the axles down for 180... im like dang. Called Moser for a estimate on their stock replacement axles for 245.00 and see how much it would cost to have the axle modified to fit the stock C5/6 rotor. I was like really? ... no additional charge.. wicked cool.
Now that I have found a simple solution, I will toss the idea on buying a set.

clint

Re: True C5 Rear Disc w/ internal parking brake in the works
 

I like the concept here, but I don't see that your heading for any big advantage in what currently available. If your going to spend 245.00 plus shipping for a set of axles the cost to build this goes up rather quickly. I don't feel thats a bad price, just adds too much to your bottom line.

Re: True C5 Rear Disc w/ internal parking brake in the works
 

yeah, thats one thing that I'm seeing... One good thing is that you can piece the kit together as $ is available. Im still confident the conversion will come close to McGaughys rear brake kit cost but with matched and modern components.
clint

edit:
quick quote on the axles and its 28 bucks shipping.. not as bad as I thought.

Re: True C5 Rear Disc w/ internal parking brake in the works
 

Frankly, I was astonished at your quote of $180 to machine the shafts. This job should be about a half hour max. What other work were you requesting besides turning the flange O.D. and the center register?

Ray

Re: True C5 Rear Disc w/ internal parking brake in the works
 

I know, another member here had both turned for 80 bucks. I went to 3 shops, some didnt want to turn it because its a saftey thing... and what have you but its their decision. No other work requested, just like the picture shows, a simple turning job... Its all good, maybe its time to bench build the 12 bolt with all new goodies, posi and 3.73 gears.
clint

edit:
Finaly found a place that will turn down the rotors... funny thing is I had them saved in my phone book when I had my ford 9" built years ago... lol.. they guy gave a rough quote of 75 for both.. now I can work with that. Going there tormarrow morning and he said I could wait on it... By this weekend, I should have everything besides the cables mocked up.

Re: True C5 Rear Disc w/ internal parking brake in the works
 

Got the stock 12-bolt axles turned down just like I had drawn up in AutoCad.... awesome, fits just like I had planned for. Now if I could only do something about getting the weekend to come any faster.. lol
clint