Modify drum brake spindles to fit disc brakes [Archive] - Chevelle Tech

: Modify drum brake spindles to fit disc brakes

Mar 20th, 05, 1:16 PM
Modify drum brake spindles to fit disc brakes.
The top mounting boss is to long on drum brake spindles. If it is cut down or machined down 1/2 to 3/4 inch it turns drum brake spindles to disc brake spindles.
My question is does anyone know for sure the exact amount that has to be removed?
I have heard .610 and also .750
Is either one correct?
Thank You.

Mar 21st, 05, 11:55 AM
Good question. I'd also like to see before and after pictures of the mod.

Mar 21st, 05, 1:09 PM
Here are John's pictures

Cam Sweet
Mar 21st, 05, 3:38 PM
I've done this modification several times. I found the amount to cut off different on all the spindles. I attached the caliper bracket to the lower mount, snug but not tight and then rotated the bracket up until it touched the upper pivot bolt boss and scribed a line. I used a hacksaw to remove the majority of the boss and a Bridgeport mill to machine them flat. The flats on the backside of the steering arm mounts are plumb to the axle centerline and parallel to the surface of the boss. Oh, BTW, this only pertains to 69 and later spindles. You can modify earlier spindles, it's just a little more work.


Mar 31st, 05, 3:49 PM

Don't you have to bore the boss and retap it too? I was going to do this myself, but decided not to after reading several posts here saying that the hole isn't deep enough after you cut the boss. Or do -69 and up have a deeper hole than the earlier ones?

Cam Sweet
Mar 31st, 05, 4:11 PM
Yes, 69 and up have the correct hole/thread. Pre-69 do require drilling out the hole and retapping for the 1/2" bolt. Also on pre-69 the steering arm mounting bolts are smaller diameter so the you need to fashion a shim to take up the slop in the caliper bracket hole.


Mar 31st, 05, 4:38 PM
The later spindles seem to be drilled deep enough. On the 4 I cut, I did have to tap a little further with a bottom tap. However, the hole was deep enough to tighten the bolt into it.

Apr 1st, 05, 1:35 PM
Cool :cool: I just got through changing to disc brakes, so I have a set of drum spindles left over. I might give it a try just for fun.

Apr 5th, 05, 11:56 AM
hello,i have a 1969 chevelle, i would like to convert to disc brakes using the infomation you guys are talking about,but i am totaly confused. does anyone have a more detailed instructions for making my spindles work. i have the complete spindle assembly,roter,caliper off a 76 nova.exactly what do i do to convert.i am a mechanic and have all the tools i need. thank you. lance.

Cam Sweet
Apr 5th, 05, 4:50 PM
Well, Lance, I suspect that the spindle assemblies you have off of the 76 Nova classify as the "tall spindle" swap, of which I know nothing about. Your original drum brake spindles can be modified to accept the caliper brackets for a standard 64-72 A body disc brake setup. The brackets are available aftermarket from our sponsor, GroundUp fo like $95. The rest of the swap comes from your favorite parts house. I don't believe anything from your Nova setup is usable unless you do the whole tall spindle upgrade.


Apr 5th, 05, 8:45 PM
i guess i did sound a little confusing on my post. what i was trying to say is that i want to do the drum to disc swap using my exsisting drum spindles like they were explaning in the above post.i thought that since i had the 76 nova spindle setup, that i could use those rotors and calipers.

Apr 10th, 05, 10:40 PM

Are you guys saying that there is no other difference between the drum and disc spindles ???? Has anybody had them side by side to compare ? I am thinking about switching to discs and that would sure make it nice since my original drum spindles have been bead blasted and powder coated. All I would have to do is put them up in the mill and carve away :)

Cam Sweet
Apr 11th, 05, 10:21 AM
That's it, Bill. Like I previously mentioned, I get the amount to knock off by seeing where the bracket would rest by swinging it up attached only by the lower mount. I hacksaw off the majority of the boss and then clean it up with the mill. I clamp the spindle down on the table with the backside of the steering arm mounting ears on the 3 side of a set of 1-2-3 blocks. Man, I really ought to snap a set of pics... I have another set to do for a buddy. Hope this helps.


Apr 14th, 05, 1:25 PM
after you do this what rotor do you use and what caliper do you use? thank you.

Apr 14th, 05, 1:34 PM
after you do this what rotor do you use and what caliper do you use? thank you.

68 - 72 parts will fit.

Apr 17th, 05, 9:49 AM
I found this place in a Super Chevy magazine ad.

I'm looking to convert my 67 SS clone to disc. This one sounds almost too good to be true - $525 for a kit that bolts to un-modified original drum spindles, uses off-the shelf coponents, and (somehow) does not change wheel position.

Apr 17th, 05, 10:45 AM
I don't see any MC, Power Booster, prop valve, or hoses listed in this kit. For only $75 more you can also get all that with the kit. This is just a stock-type kit, nothing special except aluminum hubs. Don't really need those for a street car. By the time you add the stuff that's missing you will have spent much more than necessary.

Do a search on recent post by Olle in the past week. The source is listed. If you can't find it, PM Olle.

Apr 17th, 05, 5:31 PM

I have read a lot of posts where people are asking about where to buy a brake kit, but for some reason they don't get many replies from actual users. I hope the new review forum will take care of that.

I was very happy with my kit, so I e-mailed CR Customs and asked if it's ok to post his contact info here, and he said that it's perfectly ok to post it in any car forum. His service is good, parts are good and the price is right, so I'd say it's ok to post some feedback here without getting busted for advertising.

You don't have to buy a whole kit if you already have parts you want to reuse, you can e-mail him at for a quote on the parts you want. The parts are not perfect, but very good considering what you pay. I had the old brakes removed and the new ones (except for the plumbing) put on in one long afternoon. So even if I had to tweak some parts to make it fit, it was pretty painless. I'll try to post a review in the appropriate place later.