1968 gto rear disc swap from 98 to 02 s-10

[rosewood]

I have a 1968 GTO with BOP diff and was wondering if anyone had done an S-10 rear disc brake swap on one? I am curious if the bolt in axle will need a special spacer made for the axle bearing end play with this set up. It is supposed to be a direct bolt in, but.....

[cdrod]

I have done this very swap on my car ('72 Olds 442). You will need a 1/4" axle spacer to push the caliper mounts out so the calipers will be centered over the rotors. You can make these spacers or buy them from S-10 Warehouse. The Blazer caliper mounts are much thicker than the drum brake backing plates, so you will need to fabricate a bearing spacer to hold the wheel bearings and axle seals in place. You will also need longer mounting bolts. You can read up on my swap at my build page (post 68 & 89):

http://classicoldsmobile.com/forums/major-builds-projects/57404-72-cutlass-supreme-442-convertible-2.html

Here are some pics:

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[rosewood]

Can you send me a link or spec's for the split bearing spacer. Also I searched for the backing plate spacer but s10 warehouse only took me to Ebay. Thank you for the help it is just what I was thinking I would need.


I have done this very swap on my car ('72 Olds 442). You will need a 1/4" axle spacer to push the caliper mounts out so the calipers will be centered over the rotors. You can make these spacers or buy them from S-10 Warehouse. The Blazer caliper mounts are much thicker than the drum brake backing plates, so you will need to fabricate a bearing spacer to hold the wheel bearings and axle seals in place. You will also need longer mounting bolts. You can read up on my swap at my build page (post 68 & 89):

http://classicoldsmobile.com/forums/major-builds-projects/57404-72-cutlass-supreme-442-convertible-2.html

Here are some pics:

130812130813130814130815

[cdrod]

Rosewood,
If you have reasonable fabrication skills, you can make the spacers from 1/4" plate steel if they are no longer available. Just make template from the mounting plates at the end of your axle tubes. I bought my spacers on eBay from S10 Warehouse about 2 years ago. They were $35 for the pair. The bearing spacer is made from 1/2" aluminum plate; 2" ID, 3"OD. I mic'd all the stock parts to determine the amount of play in the OEM set-up (didn't want the bearings too tight) and added everything up to calculate the final clearance. I paid a local machine tool shop $30 to make me a pair of dounuts and I cut them in half with a hacksaw so they can be installed around the axle shafts. This left them just slightly loose when installed in the Blazer backing plate. Aluminum has a different thermal expansion coefficient and will "grow" more than steel when it gets hot so this allowed some wiggle room for thermal expansion.

130860

[rosewood]

Thank you for the information. I was hoping I could do this without taking it all apart first, but after reading your post I would be well served to take it apart, make measurments, draw blueprints and reassemble till parts are made. Either way you helped me a great deal. I have the skills just don't hve a machine shop I can use, so I will have to call in a favor and that may take more than a few days to get done.

[cdrod]

You are welcome. I've benefited so much from this site, I was excited to have the chance to give back a little. Good luck with your project.
Rodney

[rosewood]

Well my project is completed using your information. I only had to make the plates .125 thick to get the calipers to centert over the rotors though. I did the front with C5 corvette part's and core3 brackets. I used the stock drum master cylinder and booster and at this point I do not even have a proportioning valve. I am very pleased to say it stops on a dime and even in a full panic stop straight as an arrow, great modulation and even distribution. I don't know how I got so lucky. It seams the difference between the c5 fronts and s10 rears matched with the staggered set of tires I am running, make a nearly perfect balance. Coulnt be happier, thanks again for your help.

[cdrod]

Good to hear your swap turned out well. My brake calcs tell me the c5/s10 caliper combo should yield about a 60/40 bias front to rear which is a little heavily weighted to the rear and could cause the rears to lock up in a panic stop. What size are your back tires?

[cdrod]

I got to thinking about how you used the stock drum master cylinder for your 4-wheel disc set-up. Most stock drum/drum master cylinders have built in residual valves to hold the brake shoes tighter to the drums to avoid excessive pedal travel. The drum brake system also has springs to retract the shoes from the drums when you release the pedal. Your brakes may drag using a drum M/C because the calipers do not have this retraction spring and the residual valves will hold 2-3 lbs of fluid pressure in the brake lines. I spoke with Tobin from Kore3 about this; he recommended using a 1" disc/disc M/C from a C3 Corvette or 2001 S-10. Others have suggested a 15/16" M/C from Wilwood (PN260-13375). I've attached my brake calc spreadsheet if you care to dig deeper into the numbers.

[camuchi]

dang Rodney that is one cool spreadsheet you have there. are you a brake engineer? or just really smart!

[cdrod]

Camuchi:
Thanks for the compliment. I'm not a brake engineer, but I am an electrical engineer and I really hate to do things twice, so I built the spreadsheet to test different brake combos rather than throw a bunch of parts together and hope for the best. The blue numbers in the spreadsheet are the variables that you input, the yellow numbers are the results. This let me play with all the options on paper to see what works the best.

[Shawn01754]

Hi, would this process apply to a rear C-5 conversation of a 1971 olds 442?

[BBPanel]

Perhaps a little late to this thread but I used these retainer plates/spacer to setup S10 brakes on my 10-bolt Olds rearend. Not to take away from cdrod's elegant solution but it doesn't require any machining. -Bob
http://www.dutchmanaxles.com/hd-axle-bearing-retainer-plates.html

[Shawn01754]

Perhaps a little late to this thread but I used these retainer plates/spacer to setup S10 brakes on my 10-bolt Olds rearend. Not to take away from cdrod's elegant solution but it doesn't require any machining. -Bob
http://www.dutchmanaxles.com/hd-axle-bearing-retainer-plates.html
Do you think it would work with the c-5 brakes on the olds rear end. It's not to late. I'm just getting ready to do a full c-5 upgrade. I appreciate the help, Thanks

[BBPanel]

Sorry, I don't have any idea on the C5 application. But if you wanted to try it they are pretty inexpensive (the retainers, that is).

[Headhunter1974]

Been doing a lot of researching on this swap but have not seen anything about using 4wd backing plate/caliper mount. 2wd vehicles are a lot harder to come by in my area. Was just wondering if a 4wd backing plate would work, since I would be purchasing new rotors anyway and just buy a 2wd rotor. Just don't know if they are vehicle specific 2wd backing plate/2wd rotor, 4wd backing plate/4wd rotor. Any help would be appreciated