i have heard that the only difference between the disc and drum spindles is about 5/8 " more material on the top of the casting? Has anyone milled off the offending material on the drum spindles to make them into disc spindle? I have a milling machine at work, is this too simplistic?

 

I haven't, but check out this thread. Joe P has a link to a site with information on what your asking. John

https://classicoldsmobile.com/forums...-question.html

 

No it's right on the money. The link John gave you has more info.

 

wow, if he's doing it with a hacksaw and grinder, I should be a regular Chip Foose using a mill? It seemed so simple I don't know why it isn't done more often ? I'm surprised someone isn't milling down drum spindles on a regular basis...... hmmm? (maybe someone will if they turn out good)

 

I think mostly because a lot of people are just buying the aftermarket drum to disc conversion kits. All new parts, bang bang bang and you're done. Still nice to know there are some of out there with skills.... You should take before and after pics of this machining so everyone can see it. Start a new thread about "How to machine drum spindles for Disc Brakes" or something like that. You will be a popular guy with others asking you to do the same for them??

 

I did this last year, there are photos of the process in the suspension forum that i posted when i did the project.
The search feature can be your friend :-)

Just be sure you have the right year spindles. The early ones have a smaller upper hole (in the boss that you trim down) and you will have to drill it out and tap it to the correct size to use the spindle mounting brackets.

and if you switch to later year spindles, be aware that the early steering arms had a smaller diameter bolt attaching them, so to attach them to the later spindles, you'll need to install a bushing/sleeve of some sort to take up the slack, or drill out the holes in the steering arms to the larger bolt size.

There used to be considerable savings potential by sourcing all the parts for a disk brake swap separately vs buying the complete kits... But then the kits have kept dropping in price over the last 10 years... Now, unless you are re-using a bunch of original stuff, the kits are considerably cheaper than buying the stuff individually.

 

I have tried the search thing, I always end up with TOO MUCH information, and not what i was looking for. I'm not a big forum person but it has proven to be very helpful. I figure someone will set me straight one way or another. I did ask about aftermarket VS factory and factory seemed to be the way. I would rather machine my drum spindles down than buy some china crap, then throw mine on the shelf for 20 yrs ? if i screw up, then I lost nothing but time. (and if i'm doing it at work, well.............)

 

Yep, only difference is the mounting pad on the top.

Let's see here...modifying a stock spindle to accept disc brakes, or buying some cheap *** Chinese made aftermarket spindles. I know what I would do.

 

well, after some garage redecorating and some other misc projects I dove in and started to "learn" the differences between the disc/drum spindles. I already knew I got taken on some GM parts I bought, but they are valuable in the sense that the spindles have the small holes, well, one does, the other is a drum anyway. I bought another PILE of parts off a guy who was going to swap to GM disc, and went complete hochkiss route. So I bought a complete drum setup from a driving car with upper and lower "A" arms AND the complete disc setup with torched off upper and lower arms, bleeder master, booster, calipers and old American made Rotors. Of course in my haste I didn't notice one disc spindle had a spun bearing. Yay Anyway, I tore into the "left" side only so not to confuse myself with piles of parts that I'll have to figure what goes where (car is storage so nothing to look at) The disc parts I bought had the "big" bolt, and so did the drum parts (71-2 chevelle) I gave them a quick look over and I think I can bang this out with minimal stress. The one thing I was worried about was keeping the correct angle of the pad to be machined. Taking off 5/8" is easy, making it on the correct "plane" as it was, ads a slight challenge, but I should be able to adapt and overcome !! Luckily the steering arm mounts are on the same "plane" so I'll use those to mount and hold the spindle assembly while I take a mill cutter to it. I'll get some pictures once I get the jig made.

 

Yea, it looks a little hap-hazard, but I made it out of misc pcs and scraps I had around here. The large block came off a machine so it was already milled drilled and tapped before so it has some x-tra holes. Castings are not consistent so the crazy "V" block looking thing is just to keep "chatter" down during machining. I used the factory machine surfaces to bolt it down since they are true and flat and should be consistent between spindles (to a certain degree) Now all that left is to try it

 

Here are a few different shots