Is There A True 12" Rotor That Will Fit A Stock Spindle?

[Blown&Injected]

Seems like if one digs deep enough there is something about all the swaps involving a different spindle so is it possible to just put a 12" something on the stock spindle and then just modify it for a different caliper?

Thanks

 

[turbofish38]

Yes. That is exactly what GM did with the 1LE brake option for the 3rd gen F-body. Okay,even though the F-body is Mac strut most of the brake and suspension is shared with the G-body. The F uses a modified G spindle and knuckle. What GM did when they made the 1LE is take the stock spindle and cut off the caliper mounting ears. The two holes that the old stock single piston caliper mounts on the spindle were than opened up so that an adapter bracket could bolt on the spindle. The PBR caliper brackets than bolted onto the adapter. The 12" rotor was a B-body piece drilled for the 4.75 wheel bolt pattern. Pretty slick way of doing it using off the shelf parts. The calipers are from the C4 Corvette. Unfortunetly the road race crowd has pretty much cleaned out those parts so if you want to duplicate what GM did than you'll have to scrounge around for them. There should be some links to eBay auctions of people making those adapters if you do a search. The rest can be sourced used like the calipers and brackets or through the aftermarket as new like the rotors and also the calipers. I'll try and find a pic of the 1LE spindle and adapter to give you an idea of how to do it.

 

[Blown&Injected]

Eric, thanks for helping me understand this.

I noticed in another post - and here too - it was mentioned that the 3rd gen F-Body spindle, as far as the caliper mount is concerned, just has the mount holes opened up and tapped M12 and maybe something cut or ground down.

So if the 3rd gen F-Body rotor will go on the stock GN spindle - then it sounds like the only thing left to do is modify the stock spindle to accept the F-Body caliper - right?

Is it just an adapter that bolts to caliper on one side and the modified spindle on the other side?

Is it just a piece of plate steel that one with access to a Knee Mill could easily make?

 

[BlackMetal]

Yup you just need to modify the stock spindle and then fab up a bracket that will put the caliper in the proper position.

 

[novaderrik]

i'm not 100% sure, but the 1LE rotor might use a bigger outer wheel bearing with a bigger center hole for the bigger B body spindle.
if putting 12" brakes on a G body was as simple as a stock Camaro rotor and a couple of simple modifications to the stock spindle to mount a stock Vette caliper, then no one would bother with putting the HD A body spindles on their cars.

 

[Blown&Injected]

Yup you just need to modify the stock spindle and then fab up a bracket that will put the caliper in the proper position.

From what the directions look like on Wilwood's site, it sure does look like that is all that is needed.

However, byt the time ya buy the calipers and rotors from Summit, the price is as much or more than the Wilwood kit - wilwood said that they would substitute the big rotor for the Regal Kit but told me I would need to fabricate a bracket for the caliper

 

[Roger]

The Baer 12' uses the stock spindle, which they modify. You have to return your original spindles for Baer to have cores on hand.

 

[Mark E.]

But why use the stock spindles? Use a B-body spindle and tubular upper control arms. The Global West Negative roll kit was my favorite mod to my car. Drives so nice normal and great when you need to throw it through a corner. I liked it so much I did it to my 65 Vista Cruiser also.

Just throwing that out there. Not too much cash if you do the work and go to the junkyard for parts.

 

[chopped39]

That is what i did. My friend was junking a 78 camaro. took the spindles with all the brake parts. the brakes were brand new.The only kiiller money was the global west arms. What about the s-10 brake conversion. Does this really work?

 

[Blown&Injected]

I think those spindles place the tie rod end in a slightly different position causing bump steer.

Thanks for the Baer Brakes swap info. The mod to the spindle looks extremely easy but those spindles have taken a beating over the past 1/4 million miles - a few of'em harder then the others so I would not mind getting some that have been checked over - assuming they don't just cut them and clean them, but actually have a testing jig of some sort.

 

[Mark E.]

I think those spindles place the tie rod end in a slightly different position causing bump steer.

Thanks for the Baer Brakes swap info. The mod to the spindle looks extremely easy but those spindles have taken a beating over the past 1/4 million miles - a few of'em harder then the others so I would not mind getting some that have been checked over - assuming they don't just cut them and clean them, but actually have a testing jig of some sort.

I've never been bothered by the bumpsteer. I just notice the cars handle like my old 75 Formula Firebird. :biggrin:

Both my swaps used junkyard spindles. I did not worry because it is a pretty robust piece.

Baer's are better. I am on a budget.

 

[Blown&Injected]

Another TB.C member that did the swap also told me that he did not notice anything bad about the bump steer or that is was even doing it.

I also think there may be an issue with the control arm shaft when it comes time to align, but I have read about so many different possibilities that I may be confusing the issues I have read about among all the possibilities.

Right now I'm thinking about just some 12" (or as close as they come to 12") rotors and calipers and doing the mod and fabricating a bracket for the spindle/caliper.

 

[turbotman]

I did the B-body spindle and Global West swap 3 years ago and have never had an issue with bumpsteer. The factory 12 inch rotors make it stop great and actually work awsome with the powermaster , as many full-size wagons that weigh in at about 900lbs heavier than the GN, came with this system.

 

[Blown&Injected]

Since I am going to do the G-Body Parts control arms, maybe the shim/bolt length/shaft issue will not be an issue with the B-Body spindles

However, for the cost of just the rotors and calipers from Summit, I can get the Wilwood kit that has rotors and 4 piston calipers, plus new bearings, seals, bolts...(they said they will substitute the 11.75" rotors in the Grand National Kit and went on to say that all I need do is fabricate a bracket for the caliper)

Sounds like it is just an aluminum bracket with steel inserts - it also looks like an easy bracket to make for one with some basic machine skills and access to a Bridgeport Knee Mill and tooling - I might be coming out with a bunch of new Buick parts
Dynalite Pro Series Front Hub Kits