Teach me 12inch brakes

[El Coolmino]

You can totally fit 15x4 rallys onto a b body 12" swap. Those rims don't hang far enough over the caliper to hit.

My 2 cents from experience on the 12" brake B cars themselves. 14s won't clear. All but one of the 100 different 15" rims I've installed cleared, but not by much. I think the one that hit was a generic cragar ripoff from the 70s, and it had a massive inner lip.

The comment about LS1 brakes needing 16" is correct too. The caliper is huge and barely clears 16s

The swap isn't that cheap with the arms required to correct the geometry. If cheap is your thing, consider the US brake overbored calipers.

Good Luck!

 

[HarrisonTX]

Whats advantages do the Ls1 brakes offer over the b bodies.
So you are saying that aftermarket upper controls are a must?
In one of my new car crafts, theres a place that has just uppers for $350, thats the cheapest i have seen, but that still seems crazy! iceman needs to get on it.

 

[Duts87ss]

Whats advantages do the Ls1 brakes offer over the b bodies.
So you are saying that aftermarket upper controls are a must?
In one of my new car crafts, theres a place that has just uppers for $350, thats the cheapest i have seen, but that still seems crazy! iceman needs to get on it.

The LS1 cars use a 12" rotor with a dual piston aluminum caliper.

When doing the B-spindle swap, you'll need aftermarket arms to correct the ball joint angle and static camber.

If the arms arent designed for the B-spindle swap they wont work for you. You cant just use a generic Gbody tubular arm to aquire the correct geometry when using the B-spindles.

 

[El Coolmino]

I've never driven a B-body swapped G body, but have owned and driven many B bodies with 12" fronts. One in my driveway now. The stock brakes, in good working order, will stop a train. With 275 front tires, passengers need to be belted in for panic stops, or they'll be laying on the dash. The G body weighs +800 lbs less, so it's not hard to imagine the effect.

So, knowing that, and having converted my 97 Z28 to "LS1" brakes, I would say that the B body parts are a much better fit for a G body primarily because of the caliper size and placement. There are pros and cons to both 12" swaps.

Currently use the overbore US calipers on my elco, they make the stock brakes work like they should have if GM had any sense. But also have B spindles sitting in the garage, because I view them as the ultimate street solution. Taller spindles help the geometry anyway, so there is additional benefit to the expensive hotchkiss/global west/etc route.

I question why you'd want 12" brakes with a 4" rim anyway. Can't even explore the full capabilities of your stock ones with that little contact patch, so why add rotating weight?

Good Luck either way!

 

[HarrisonTX]

well, cool, i guess im just uneducated.
I have always been taught that a hotrod isnt just all motor, it needs to be able to stop also. I see everyone upgrading, so i thought i needed too also.
Do you think i will do fine with my current brakes, and new fuild, with an oversized pad? You maybe saving me a nice chunk of change here, so please keep posting.
I forgot that tire size has something to do with braking. If i had monster 18inch brakes, and bicycle front tires, all that would do is lock them up easier, correct?
what do you suggest?
I rely greatly on other peoples advice, especially if they speak from expierence, i blame the military for that!

 

[Autometer]

Yeah I think a 15x4 would fit with no problem. I can lock up fronts when I run the 3.5 wheels so keep that in mind too.

The advantage of using the LS1 brakes over the B-body is still using your same control arm and spindle. Also you could probably pick up all the parts you need for the LS1 swap cheaper than the price of the B-body swap control arms.

 

[HarrisonTX]

Autometer, i guess i misunderstood you a few posts back, i thought you said i would need more backspaceing to do the b body swap, meanin my wheels wouldnt work.
Now i guess they will..
So a little run down
B-body swap, cheap parts, execpt for the Upper control arms, Not just any aftermarket uppers, specifically for the b body swap, those are pricy. New uppers are mandatory to get rid of the added bumpsteer issue.
LS1 swap, all cheap parts? i can retain my stock uppers and lowers, but the caliper is bigger so i will need different wheels?
If i can lock up the front tires as it is now, do i need to upgrade?
FYI, i am probably going to swap to manual brakes very soon.

 

[Autometer]

Yeah I since you a PM. I was going by an 8" wheel that you'll need to have a little more BS. When I go typing late at night, I'm not all that clear.

A friend is doing the LS1 swap do his GN. He found all the parts he needs for 350 bucks from a salvageyard. Oh the thing with the LS1 swap is that you'll have either buy a hub or make your own out of an old rotor.

 

[El Coolmino]

Harrison, You're right about hotrods having upgraded brakes. That's one reason I'm generally anti-pizza cutter tires for street cars. Your stock brakes should be plenty for that size contact patch. You're obviously not road coursing or towing and overheating the brakes, thus needing the larger brakes for heat dissipation. And the stock brakes will lock skinnies without much effort if they work properly.

At that point, I just question what you really gain with bigger brakes other than lots of hassle and expense. The ability to lock the tires if you breathe on the pedal? Is that even a good thing for driveability?

Now if you had 245 front tires on a 7/8 inch rim, different situation. Then you can explore the additional stopping power of 12" brakes by screaming BRAKE CHECK! and planting your passengers on the dash. :lol:

Good Luck!

 

[Scoti]

Where can I find out more info on the LS1 12" conversions? This sounds like what I will want to do.

I was thinking of the B-spindle swap but don't like the can-o-worms it opens (even though some notice, some dont). So I guess I'll do the tall BJ & shorter upper a-arm w/some LS1 12" brakes & might even swap to the Eradispeed rotors for looks.

I already have 2-sets of rear discs: one set from a 78~81 TA 8.5" rear & the other from a late 90's S-body Blazer. IIRC, the TA discs are 10.5 & the Blazer discs are 11" (I believe the Blazer discs are the same as the standard F-body rear discs).