Brake fitting in 15" wheels

[Skip Fix]

OK guys I have a question for you on fitting big brakes. So many of the aftermarket kits require 16" or bigger wheels for 12" rotors. GM put 12 " rotors on B body cars with 15" wheels. NASCAR requires 15" wheels and uses HUGE 6 piston calipers. Corvettes and early Camaros/Chevelle/GTOs used big 4 piston calipers in 14 and 15" wheels.Why the fit issues from the aftermarket?

Saw a article in newest HotRod of a girl who made custom brackets to fit the larger Wilwood calipers and 11.75 rotors in 15" Chevy Ralley wheels.

Why not kits using a bigger caliper/pad from Wilwood than the dinky Dynalyte? Baer's calipers are similar to factory GM 3rd/4th gen that aren't that tight in factory wheels.

[critter]

Skip, I often wonderd the same thing. Not everyone wants the cookie cutter Pro-Touring look (no offense, guys). Some of us like the resto-mod look that you and I have pursued with our cars.

You know I modified my stock spindles and used the Howe aluminum dual piston calipers. That was a big improvement. I think the 1LE upgrade with B-body spindles would have been better. Too gad someone doesn't make a reasonably priced kit for us.

[Skip Fix]

I also always wondered if the two piston PBR types if they have same piston sq in(force=PSI x sq in) of the factory single pistons are a real improvement or marketing.

Surely these other calipers don't stick outer diameter more than the factory calipers on the 15"s.

Guldstrand years ago welded a bracket on F/B spindles to take a Vette 4 piston caliper.

I've got some 1LE rotors and B body 12" spindles sitting around just pondering caliper choices.

[BonzoHansen]

This has been talked about much here and at nastyz28.com The stock calipers do have pretty big pistons. There are some upgrades out there, but some wheel clearance issues might exist.

The b-body swap is easy & cheap.

[Skip Fix]

So lets use a cheap B body spindle and 12" rotor and figure a easy caliper upgrade swap. Seems alot of options for the first gen guys, fewer for the second gen. I'll bet there are more second gen cars out there for potential customers!

[critter]

Skip, take a look at this and see if it gives you any ideas. I don't know how much space there is with B-Body and a 12 rotor but it might work.

http://www.arkansaspontiacs.org/tech...Brakestory.htm

[jake72ss]

Critter,

how do the Howe calipers compare with stock? I've considered using them or the single piston versions from wilwood or outlaw also. After doing the conversion did you notice any difference in pedal feel or travel? I have the Bbody spindle/ 1le setup on my chevelle with seville calipers in the rear, stock booster and master. My chevelle brakes awesome compared to stock disc/drum. I , like you two guys like the restomod look and prefer not to use stuff that limits wheel sizes below 15-16" range.

[critter]

There was more pedal travel because of the additional piston area. I did notice shorter stopping distances. That was tested with a before and after on a Gtech type device called a Varicom. I had 60 to 0 in the 120-130 foot range. That was with drum brakes on the back. I haven't tested again since adding the rear, 79 Trans Am, disc setup.

That said, I would not do this again. I'd rather go with the larger rotor and single piston caliper on the front. I think it would give the same results based on what I've read from other folks.

My real question is, what would this type of caliper do on a 1LE setup and will it still fit in the 15 inch wheel?

[Skip Fix]

I still have a Vericom also! I've had it 15 or so years.Did have it updated to do 1/8 mile stats inthe read out also.

[jake72ss]

critter, to answer your question I believe they would still fit the 15 inch wheel, I have had 15s and 16 inch wheels on my car with this set up using the stock caliper of course. The wilwood gm3 and the outlaw d52 style calipers both look to be a strait forward swap.

[critter]

I do know someone who's use the stock setup with the Wilwood calipers. Worked great for them. I might give the 12 inch setup a run since I already have the calipers. Another project for another day.

Skip, that Vericom belongs to my brother-in-law. We still use it and it's still amazing how accurate it is. I've never used a Gtech but I bet it's comparable.

[SHANE 73Z]

Hey guys,

I just thought I would chime in. On the front of my 73 I am running b-body/1LE with SSBC calipers. These are the 2 piston D52 replacements with the 38mm bores (same as C4 PBR). These were chosen to match with a 12" C4 rear conversion from touring classics.

I can tell you that the b-body/1le arrangement with STOCK calipers will fit inside stock 15" Z28 wheels. With the SSBC calipers there were issues. I am sorry to say that I didnt do any measuring to see wat it would take to make it work. I cannot say if the rear setup fits inside or not.

On another note the second gen cars that have both holes drilled in the pedal, the manual hole only provides about a 5:1 pedal ratio. This makes it extremely difficult to find a MC with a bore small enough to run these small bore calipers.

There is a gentleman on the NastyZ28 website that offers brackets that use a 13" wilwood rotor & superlite caliper that fits a 16" wheel. I believe he is also developing a bracket that would mount the same caliper with a 12" rotor that could potentially fit a 15" wheel.

I am hoping to upgrade to a Wilwood f/r package in the future.

Shane

[jake72ss]

Do you have a link to a post so that we can see what the guy on nasty z28 is offering? That setup sounds interesting.

[SHANE 73Z]

Here is a good thread:

http://www.nastyz28.com/forum/showth...hlight=wilwood

Shane

[critter]

Does anyone sell a B-body kit with everything except the calipers? I'm lazy enough to buy it rather than search the yards for the spindles.

[Skip Fix]

At one time Global had one also.
That's the kind of system I'm talking about!

[OLDFLM]

Scarebird has them...

[critter]

Has what? Spindles?

[TheMonkey]

scarebird makes custom brackets to convert to disc brakes. for one of my '61 pontiac full size B body cars, i bought scarebird brackets and it worked great.

buy the brackets (about $90; very well made), and he sends you the brackets & a shopping list). i kept my original spindles. for my application, from rockauto i bought 12" rotors for a '77 bonneville, calipers for a late model 1500 GM truck, new hoses for i forget what. i converted to 12" disc brakes up front for a few hundred bucks. another bonus was that my car came original with very expensive and crappy ball bearings; with the new rotors, it took the much better & less expensive roller bearings. any replacements in the future come from the corner auto parts store.

Mark from scarebird is very helpful and a fellow enthusiast.

i had the brackets powder coated with the rest of my front end and it looked super clean.

www.scarebird.com

[83hurstguy]

I would prefer not to put the B-body spindles on my car, as I would rather change the geometry with the stage 2 package from SC&C to avoid the bumpsteer...

I would also like to be able to run the stock 15" SSIII's that came on my car for some car shows...

Apparently, from reading on thirdgen, the Vette C4 brakes (non-HD) are 12" in diameter and fit a stock 15" wheel. The difference between these and the 1LE brakes are rotor thickness (1" vs. 0.82", 1LE is thicker), and the Vette brakes use a slip-on rotor. LIke I mentioned, I would prefer not to run the B-body spindles... seems like basically all I would have to do is make custom caliper brackets and get a hub to throw the rotor on.

Any input on the C4 brake setup?