89 Iroc Z

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The aftermath, I have created a full how-to with bracket designs, part numbers, etc at my website:
http://lukeskaff.com/projects/car/th...brake-upgrade/

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After a lot of research, I discovered that the Baer brake spindle mounting bracket has the same bolt pattern as the 88-96 corvette caliper carrier. This would make a pretty sweet swap to use C4 brakes brakes on our cars for a cheaper price then 1LE.

Since Baer (PBR) makes the C4 setup there should be many GM and Baer’s parts that are interchangeable.

What would be needed:
- The Baer caliper mounting bracket, I can get the dimensions, my brother has Bear brakes on his car so I can make a template off it and get some machined. (My brothers car has the Baer Sport which has a thicker rotor. The C4 setup is similar to the baer SS kit)
EDIT: It turned out that the Baer caliper carrier is slightly different (explained in depth in this post). So I modified the Baer bracket and posted the dimensions.
- Modify the stock spindle the same way you would for a 1LE swap, except cut of the steering bump stop also. (If you are using my bracket design)
- Two stock thirdgen rotors to machine down into an hub, if using the C4-HD 13-inch setup you will need to use 1LE rotors which have a larger offset

When you do the above, you should be able to mount the 88-96 C4 12 inch NON-HD or C4 13-inch HD brakes to the thirdgen spindle.

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If you are looking for 1998-2002 Camaro “LS1” 12 brake swap goto my other post CLICK HERE. The swap will use the same setup as the C4 swap just different spindle mounting bracket.
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Thanks to everyone who have helped with this swap. Here are some common questions that are asked about the C4 swap and there answers.

Q: What brake options came on the C4 corvette
A: There are four brake setups that came on the C4 corvette. The first is a fixed caliper design that came on the 84-87 corvettes which I will not discuss swapping because they are not worth the effort. In 88 GM put a 12-inch brake setup with a dual piston aluminum PBR caliper on the C4's. This setup is called the C4 NON-HD setup or non heavy duty. Then later in the production of the C4, GM came out with an optional 13-inch brake setup for the Corvette which is called the C4 HD or Heavy Duty. The final brake packet found on a limited number of Corvettes is the Grand Sport or GS setup. The GS model features a beefier caliper. Though the GS rotor is the same as the C4-HD rotor.

Q: Will the C4 setup clear my stock 15 inch wheels
A: The 12 inch NON-HD setup will, the HD 13 inch setup will not.

Q: Will my stock spare clear the C4 brake setup
A: No it will rub.

Q: What proportioning valve and master cylinder combo will I need with the C4 brakes?
A: You will need the 1LE Master cylinder and proportioning valve combo. For part numbers and more information CLICK HERE

Q: Will I need different brake hoses?
A: No, the stock hoses will work. I would upgrade to braided hoses while you have everything off.

Q: What year and model corvette can I get these brakes off of?
A: You need to get them off a 1988-1996 Corvette.

Q: What is a hub?
A: If you look at the pictures on this page of the post you will see a side by side comparison of the F-body rotor and the C4 rotor. As you can see the C4 rotor does not have that center section. That center section is physically part of the F-body rotor and mounts on the spindle. To mount the C4 rotor on a thirdgen you much machine down a F or G body rotor to just that center section then you can mount the C4 rotor on this.

Q: What outer diameter should I mill my rotor "Hub" down to?
A: Baer’s hub has a diameter of 5.95 inches where the rotor mounts. I recommend you get as close to that as possible.

Q: What is the difference between the 1LE and C4 brakes?
A: The C4 NON-HD brakes have thinner rotors, 0.81 inch, then the 1LE (1.1 inch) rotors. The C4 NON-HD caliper also has a smaller rotor opening to accommodate the thinner C4 rotor. The C4 HD 13 inch brakes have about the same thickness router as the 1LE but have a 1 inch larger diameter.

Q: Can I use a 1LE rotor so I don’t have to fabricate a hub?
A: No, the C4 NON-HD caliper has a smaller rotor opening then the 1LE caliper. The C4 NON-HD and HD caliper carrier is not bent like the 1LE so it will not clear the 1LE rotor. For some pictures comparing the two calipers and caliper carries CLICK HERE T

Q: What about the spindle bracket?
A: For the C4 13 inch HD setup you will need to use my bracket design. For the C4 12 inch NON-HD there are 2 designs you can use; Alloy's or mine. Both are discussed and pictures in this thread. You should use Alloy's bracket if you would like to use C4 front rotors. If you use my bracket design you will need to use C4 rear rotors. I posted dimension and CAD file of my bracket design on the bracket design page on of my website: Bracket design page on my website

Q: What is the difference between the C4 front and rear rotors?
A: The C4 12 inch NON-HD front and rear rotors are about the same except for offset. They are the same thickness and there shouldn't be a noticeable performance difference between the two rotors. The rear rotors allow for more room for a bracket so they will work with my bracket design. If you want the 13 inch C4 HD brakes you will need to use the C4 13 inch HD front brakes.



Below is a picture of the Baer spindle mounting bracket used on the 12-inch baer setup.

91dubZ28

That sounds like it could work and would cost alot less than the 1le's. Too bad about the hub issue tho. If I had time, money and free access to a machine shop i would love to try it out. But for now I am stuck with my stock set up.

erictheviking

If you've read some of my previous posts,you'll notice I'm heading in a similar direction.Machining down a camaro disc down to leave just a hub is straightfoward for a machine shop.I'm open to any suggestions but I think I've narrowed it down to 2 options.A company in the UK can produce hats in any shape and size which will then bolt straight onto your hub.Get some custom brackets,throw on some 4-pot calipers and your away.This company make kits for most cars and the one which catches my eye is a complete front setup with 12" rotors and 4-POT AP racing calipers for £900!!!Alternately Willwood make universal bells(hats) to do a similar thing.Either way someone who is reasonably switched on could make a top Johny brake setup for a fraction of what Baer etc. charge.I'm very surprised more people haven't seized on this way of thinking and built their own system.I'm going to make this setup happen if it bloody kills me(it might do if it doesn't work).Keep us posted on your progress Cheers.

Checkout Godspeed brakes on the net to get an idea.

89 Iroc Z

I don't have any money to do it right now, but around Christmas time I will probably be able to try it out.

Eightyninef

my 96 C4 takes the same brake pads all around as my 1LE firebird.

the calipers look idential, but have different part#'s for some reason. maybe the bleeder is different or something irrevilant like that.

Larry

Redbird87

Did I read somewhere that the C-4 rotor and the 1le are different thicknesses or has old age struck again?

Eightyninef

it may, and that may be the reason why the calipers are different. but the pads are idential. #412 and #413 or something like that.

I swap my race pads from F-body to C4, no problem.

Kory-88Iroc 350 tpi

iTrader: (1)

I'm interested in this also. I have an extra set of spindles, some old rotors. What parts do I need to buy. I have been thinking about something like this for a while.
Kory

89 Iroc Z

C4 rotors are thinner then 1LE rotors so C4 calipers will not work with 1LE rotors. That is why you have to make a hub to mount the C4 rotor on, then you would be able to use the C4 calipers. Also C4 calipers have the wider bolt pattern that the Baer brakes have.

http://home.cfl.rr.com/shuhy/brakes.htm

If someone who works in an auto part store is willing to measure random GM rotors that have hubs built into them (that could possible be milled down into a hub) from G-boys etc. there might be one with the right width that is need to make this happen.

Here is a picture of my brother’s Baer’s hub; this is the width that is needed.....

89 Iroc Z

Another note: Baer’s SS package for thirdgens uses the same width rotors as the 12 inch C4 corvette rotors and I am almost positive the calipers are the exact same as the ones off a NON-HD brake package C4.

Here's the picture oh the Baer hub I talked about in the above post...

NOTE: MEASUREMENT IN PICTURE IS INCORECT, it is 1.91

89 Iroc Z

When I go home from college thanksgiving break I should be able get all the dimensions off the Baer caliper mounting bracket for anyone who want to try and do this.

camaro6spd

basically, all we need to fab up is a hub and a bracket? if someone could get more dimentiosn off the baer bracket and hub, i could draft up a design and talk to my friend and see if he can machine it, he has access to CNC machines.....there for, mass produded and i could sell them to you guys just to cover the cost. THe braket is a stright foward deisgn, i don't know y we have not be able to get that made up, the hub, i dunno i need to look into that, but i need dimensions for that before i can do ne thing....so if i could get more pictures like the above one that would bee cool, mesuments are prefered in MM or CM.

camaro6spd

ne one?

IROC_Canuck

what exactly is a hub? im just confused exactly what it is, what if you took C4 rotors and calipers, would you only ahve to mod the spindle then?

where does this hub go and waht does it do?

89 Iroc Z

Everything is explained about the modifications of the spindle and all.

The difference between the corvette rotors and the Thirdgen rotors is the Corvette rotors don't have a hub built into them. This means you have to fabricate a hub to mount the C4 brake setup to an F-body. The hub is what you mount the corvette rotor on. My first attachment is a picture of the one Baer sells.

See picture in post below.....

JMatlock88

I REALLY enjoy reading these brake conversion threads. I beg someone to PLEASE make a tech article when they have successfully done the C4 or C5 brake conversion. Both articles would be great because many of us have 16s and many have 17s. I have seen the C4 & C5 brakes go dirt cheap on ebay!

91dubZ28

I was alittle confused at first after seeing the pictures, I bet any compitent machine shop could take an old thirdgen roter and machine into a hub that could accept the vette rotors. If some one had all the donor parts and cash to try it, I bet it would work with little trouble... just my $.02 Hopefully some one will figure it out, I plan on getting some c5 wheels for my car and I dont want everyone to see my litttle front brakes

IROC_Canuck

awesome, now i get it, when you make the hub, sot hat the c4 rotor will fit the spindle using the hub, is the hub welded to the c4 rotor?

JMatlock88

No, they'd be separate pieces. You'll be able to swap rotors without repacking bearings...another plus to this mod.

89 Iroc Z

Picture to show the difference in Vette and F-body rotors:

89 Iroc Z

Here is a picture of what a hub made by machining a brake rotor down looks like. This is what you would use to mount the corvette rotor on.

Hope this clears up any confusion.

89 Iroc Z

One last issue that may occur and a possible way to solve it.

Mounting a C4 rotor on a machined down F-body rotor, “HUB”, would make the wheels and the C4 rotor stick out a fraction of an inch more (the width of the base of the C4 rotor). To compensate for this, if needed, you could machine down the front surface of the hub to compensate.

JMatlock88

That shouldnt hurt anything at all... it wouldnt be necessary to mill on the face of the hub. I'm running spacers up front because my wheels are supposed to have gone on a 1le (Firehawk). The 1le's ran factory 16" wheels just fine. With this idea, I will no longer have to use my spacers. To give everyone an idea of what a big deal this is, I just saw all four C5 calipers and rotors sell on ebay for ~$195! We just need the front two!

IROC_Canuck

i relaly wish someone had a pick of the two together, but, let me see if i get this, the hub mounts to the spindle the way a normal f body rotor would, then thecorvette rotor fits over the bolts on the hub and then comes the wheel?

JMatlock88

Yes!

89 Iroc Z

I am not worrying about the wheel and tire sticking further then stock, I am worried about the rotor sticking out to far to fit properly in the caliper. The Baer adapter bracket that I would make a copy of to do the swap is setup for the rotor to be mounted on the Baer hub. If the hub I machine out of an F-body rotor is to shallow or to long then the rotor will not sit centered in the calipers range of motion.

JMatlock88

Oh, I see what you're saying. But what I'm saying is that you move the caliper out accordingly via your custom bracket. I wasnt under the impression that you already had one made/copied. If you were making your own, it could be as "thick" as it needs to be in order to center the caliper on the rotor.

89 Iroc Z

I haven't made any of the setup yet. I am trying to get the funds to start working on this swap over my spring break (I am at college now).

About the caliper centering, good point. That would work to just make the mounting bracket thicker.

355SS

iTrader: (1)

I am going to be doing a similar swap with porsche calipers and 13" 2 piece rotor. I have already put the front 13" corvette brakes on the rear of my camaro by making custom brackets.

LYV18F

any news on this conversion? i'd definitely be interested since my front rotors need to be replaced.

Scott_92RS

Check out the post titled "C5 Brakes". Same concept, but uses
C5 Corvette rotors and calipers :hail:

I've already bought some spindles and rotors to hack up to make the hub, I'm going to try my hand at making my own caliper adapter, and finding C5 calipers and rotors wount be too hard.

LYV18F

i would definitely want to use the c5 rotors, but i want to keep my stock wheels so that c4's would probably be the way to go.

also, check out corvetteforum.com for some used c4 or c5 parts

89 Iroc Z

Yea the C5 brakes are 13 inch rotor, so they won't fit under stock wheels. You may be able to get them to fit under stock 16 inch wheels if you grind off the cooling fins on the C5 caliper.

I got my full C4 12 inch setup for $120. That includes rotors, calipers, caliper mounting brackets, C4 brake lines, and pads off of the corvette forum classifieds. The corvette guys will practically give the C4 12 setups away. The C4 brakes seem to be identical to the Bear SS kit so it's a good deal.

I am going to start the swap in the next few days I have a spindle laying around that I can test the setup out on, just have to get my rotors milled down into a hub.

alloy

iTrader: (16)

I'm also interested in the brake conversion. I own a machine shop and it's fairly easy (but time consuming) to chuck the rotors up on a manual lathe and remove the rotor part and just leave the hub. That's a lot of material to remove, and the rotor itself is hollow with fins in it. Most shops will use carbide insert tool holders with solid carbide inserts to do this kind of job, and the carbide inserts DO NOT like interupted cuts like going through the rotor. They just shatter if pushed too hard. So, it's slow going with interupted cutting.

If someone brought these rotors into my shop and wanted them cut down into hubs like what is pictured, I've grab my sawsall and remove most of the rotor before ever putting it on the lathe. This would cut the actual machine time down substantially.

Before taking these to a shop for machining, talk to them and see what they say about it. You may save yourself a bunch of money by removing most of the rotor yourself.

89 Iroc Z

Yup that’s exactly my plan. I am going to use a angle grinder or a reciprocating saw and take most of the disc surface off before I bring it in to be machined.

I was thinking I could just cut the rotor down close by myself and put it on a spare spindle I have, spin it up fast with a motor I have laying around and just run it against a sanding wheel on a drill press. But I want to make sure it’s balanced so my best bet would probably be a machine shop.

toddlsf

If the inside of the C4 rotor is the same size as the C5 rotor, you will have to machine the face of the "hub" also. You can see in the picture what I had to do to get the "hub" to fit in the C5 rotor.
Todd

alloy

iTrader: (16)

Well my idea was to "chain" drill the rotor itself around the edge where you want to have the hub machined, then you could take a hack saw or sawsall and easily zip around the chain drilling and drop the rotor off in a hurry. The rotor is cast and will drill like butter with a sharp drill bit.

The picture of what was done to the hub would be easy for someone that knows their way around a lathe. And machining the face shouldn't be a problem at all.

LYV18F

quick question, is there any reason why you can't use HD breaks?

89 Iroc Z

You can if you have aftermarket wheels they will fit them. The HD brakes are 13 inch rotors which will not fit stock 15 or 16 inch wheels. The non-HD brakes are 12 inch rotors and will fit under stock 16 inch wheels. If you want to do a 13 inch setup go with the C5 brakes. If you want 12 inch setup go with C4 or 98+ F-body brakes.

markus9

just recieved my c5 brakes today and want to get started on the brackets just wanted to know what is a good starting point for the size of the bracket , i know it's .500 thick what about the length and width . if i should take .300 off the front of the hub would the bracket still centre the caliper over the rotor . todd help me out and i'll back you! thanx

89 Iroc Z

This post is about using 12inch C4 brakes or 12inch 98+ F-body brakes. So this bracket will NOT work with 13 inch C5 brakes. There is another thread going about the C5 brake swap that you should post your question in.

Matthew91-Z28

Ok..sp let me get this straight:

I can use either 98+LS1 brakes or C4 brakes on this mod?

All I would need is the rotor, caliper carrier, caliper, machined stock spindle (1LE), machined rotor (for hub), machined bracket plus misc(pads/bolts)?

And about the hub. What was the decision about machining the face of the hub? Does it need to be done, and if so, how much should be machined off?

I am really going to do this.

LYV18F

if somebody can give me all the dimensions for the machined hub, i can make like an engineering drawing on my computer and post it so you could all take it to a machinist with like dimensions and tolerances and everything.

JMatlock88

I would be happy to post a 3D model and 3-view drawings as well

alloy

iTrader: (16)

Machining the hub is pretty straight forward, but a print would definately help.

The more important drawing would be of the brake caliper mounting bracket. I'd love to see this so I can machine a set up for myself and get started on this conversion on my car.

I'll probably have some time free this weekend to try and go grab some old front rotors to play with. I'll try and take some pics of what I'm talking about when I say "chain drill" the rotor to remove it.

LYV18F

if you send me pictures and dimensions for the caliper mounting bracket, i'm sure i could get you a 3d drawing and an engineering drawing with all the dimensions labeled and everything

89 Iroc Z

My roommate at college is awesome in AutoCAD so he is going to CAD that out, thanks for the offer though. I will have the dimensions posted in the next few days.

As far as the LS1 brakes the mounting holes on the LS1 brakes are the exact same size as this Bear bracket. I think it will work but can't be 100% sure. Once I post the bracket demission someone can try it out and tell me.

alloy

iTrader: (16)

Guys, honestly a 3d drawing isn't necessary. A 2d profile with the hole locations, hole diameters, thread call outs (if any), and material thickness is all that's needed to drill and profile a flat part like this. I make parts like this all day long, so no need to make it more complicated than necessary.

89 Iroc Z

It will be AutoCAD in 2D. I’m trying to keep it simple.

alloy

iTrader: (16)

I don't have a new version of ACAD to read your file, so can you give me a DXF drawing of the part?

And, to make it easy, drop a point in the center of any hole locations. My CAD/CAM software works best that way.