fly89gta

iTrader: (1)

just curious...would the front rotors/pads fit from a 4thgen fit a 3rdgen? just curious cause i can get em cheap...if not the pads..how about the rotors? thanks!!

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Check out MyGTA Nicknamed:The Big Red Machine
***AOL IM RiceEatinGTA***
Moderator at www.transamgta.com
"What does not kill us only makes us stronger"

Tony

Apeiron

I doubt it, at least not without modification.

PF Flyer

The 4th Gen uses a rotor that slips over the hub, whereas the 3rd uses a rotor with the hub. Won't work.

The calipers a 'uge on the 98 and later 4th Gens. I'd be nice to retro a set of these

onto a 3rd Gen.

fly89gta

iTrader: (1)

i THINK Steve Spohn is working on a conversion..he was a few months ago..not sure if he's still doing it..i haven't spoke with him in a while about it...

------------------
Check out MyGTA Nicknamed:The Big Red Machine
***AOL IM RiceEatinGTA***
Moderator at www.transamgta.com
"What does not kill us only makes us stronger"

Tony

grobb284

iTrader: (1)

Have recently made brake adapters for the C5 Corvette to the early C4 Corvette. We may be able to make adapters for the front calipers of the 4th Generation to the 3rd.

For the Corvettes we make these of stainless steel and Grade 8 components.

Should this be of interest, let us know.
Would like to have a car from the Dayton-Springfield, Ohio vicinity to be available for measurements. We may be able to adapt the C5 calipers if there is interest, or the 4th generation. What do most prefer?

I am interested in making the brackets available, as you can find the components inexpensively as new take-offs or from forum vendors. E-mail me if interested, grobb284@aol.com

PF Flyer

grobb284 - There is definitly an interest.

I have a 99 Camaro SS and a 90 Formula. I've rebuilt the calipers on both. The size doesn't even compare. The photo of the orange caliper in an earlier response is mine. These brakes are awesome.
If there was any way to convert, I'd be a knockin'.
Keep us posted. I'm sure that if you needed a test mule in that area, someone would step up.

PunXsRock

I'd agree. My 84 TA definetly needs a boost in braking power.

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Manny

84 Trans Am

brharris27370

I see some interesting stuff here. If someone can make the adapter to get the caliper to bolt on. Why can't we machine off our rotor so we only have a hub and put the 4th gen rotor over that hub. Fiero guys do that with Beretta brakes. Check out http://fierozone.tripod.com/realbrakes/index.html I did this conversion to my wifes fiero and there was a dramatic difference.

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91 Camaro RS 5.0L Black Convertible 700R4
** Added so far **
*GM Wonderbar,Alston SFC's,spohn LCA's and Panhard rod
*Turbo City Inj Spacer
*Dual Snorkel Air Filter
*March Performance Pulleys
*GM 3.42 Gears with OEM Zexel POSI
*Edelbrock headers
*3" High Flow Cat
*3" Dynomax Exhaust
*Walbro 255 lph Fuel Pump
***Future 330hp Vortec Crate with LT4 hotcam and 454 TBI

CPCamaro

Grobb824,

I'm in Columbus. Is that close enough for you?

My car is a C-Prepared Race car, so it being out of commision for a while isn't a problem.

fly89gta

iTrader: (1)

if a conversion like this is possible...and u guys can fabricate everything...how much would something lke this run??? i mean i'm sure if i posted this elsewhere people would be interested!

brharris27370

Machining a rotor off the old rotor to just give you a hub to put the 4th gen rotor on cost me $50 per pair. All we need is a modified or replacement caliper mount to mount the new 4th gen caliper on. This type of setup moved the front wheels out about 3/8 inch (thickness of the 4th gen rotor at the lug nuts). On my fiero project I had to get new lugnut studs that were 10mm longer than the originals to keep proper length with the new rotor on my newly made hub. So if someone can come up with an inexpensive mod for mounting the caliper updated brakes are within our grasp. Should be a considerably cheaper option than the 1LE swap with almost the same results.

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91 Camaro RS 5.0L Black Convertible 700R4
** Added so far **
*GM Wonderbar,Alston SFC's,spohn LCA's and Panhard rod
*Turbo City Inj Spacer
*Dual Snorkel Air Filter
*March Performance Pulleys
*GM 3.42 Gears with OEM Zexel POSI
*Edelbrock headers
*3" High Flow Cat
*3" Dynomax Exhaust
*Walbro 255 lph Fuel Pump
***Future 330hp Vortec Crate with LT4 hotcam and 454 TBI

fly89gta

iTrader: (1)

guys PLEASE keep this thread open...i'm interested and i have 2 friends that drive 3rdgens that i KNOW would be interested

MichaelRBrumm

So could 15 inch rims possibly work with that setup? I'm very interested in fourth gen brakes, but I love the 15 inch rims I have.

ebmiller88

iTrader: (7)

I'm in.

drain89

iTrader: (10)

What about being able to machine a new set of bearing hubs out of heat-treated aluminum that utilizes 1LE sized bearings? Then offering these in a kit that includes all the brackets and bolts, or as a complete kit with everything?

JJ

VERY interested, I've been considering 1LE but it is somewhat cost prohibitive for me at this time.

NC 91 Z28

Count me in, I too have been wanting 1LE brakes. But this sounds better and cheaper too.

PunXsRock

wow. 4th gen brakes on a 3rd gen......let me in on it.



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Manny

84 Trans Am

WOODY MCC

ME 2
87 GTA

PF Flyer

MichaelRBrumm - As with the 4th Gen cars, the minimum size rim used is a 16".

grobb284 - anything happening on this? CPCamaro offer up his race prepped ride as a test mule.

brharris27370

To answer some questions. The 4th gen brakes WON'T fit in 15 wheels. That is the main purpose of this endeavor to get larger rotors on our cars. I think machining the hub to accept larger bearings is a good idea if you work in a machine shop or have a cheap one nearby. I think it would drive the cost up too much for most of us. Anybody have a picture of the bracket that holds the caliper to the spindle of a 4th gen car. If I can find a way to get the caliper mounted to the spindle I might put together a kit.

Jim85IROC

iTrader: (2)

Grobb, as long as you're working on conversion kits, why not make a kit so the C5 brakes work on a thirdgen instead of the 4th gen brakes?

TorchTA

Sounds grand.
Count me in

-JT

german-motorsport

fly 89gta ...ouch you got up a post that really is a burner, did you get any funny mails yet?
After everyone was sworn in for a 1 LE swap!

brharris...took a look at your page ...made me smile seeing one of those silent 3.gen members doing a compl swap without tempting to be MR.PRO!
Good job on that Fiero Swap , passed on the info to the Fiero org in Berlin Germany!

drain89 alu hubs are also available at willwood if someone wants to jump on that.
They have all parts seperate. I wonder why they keep behind offering a real street set?
There other kits are around 600$ a company like willwood should be able to offer a kit 12" for 800$ !
When i see the brake upgrade posts in here this would be a big group purchase!

To the real low investers, i think getting away from the 1Le bearing and using one similar to that but cheaper in price and easier to get would make sense!
The 4th gen cars are getting into the junk yards daily so its wiser to use that instead of vette parts!
Dream would be for all to use parts everyone can get everytime with a small budget!

This post is not, not downgrading andys work on the 1Le brake upgrade but i hope it´s making way for a cheaper and easier to have mod!
I do wonder why this post have not been moved to the 1LE Board though.




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www.camaro-firebird.de

Rob P

iTrader: (1)

I'd interject and say go with 4th gen brakes. How many C5 set-ups do you see in the junk yard? I see pleny 4th gen brakes in the boneyards. Add "Corvette" to any part and the prices seems to increase. I'd kill for some 4th gen front brakes on my RS. The stock 3rd gen brakes are flat inadequate.

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Rob P
89RSconvtZZ4TPI Edelbrock Intake
SLP Dual Cold Air Intake 1 5/8" Headers Semi-Siamesed Runners, IROC
suspension, alum shaft. Numerous mods.
92Z28convt5spd (stock)
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

brharris27370

I am removing a complete set of spindles, rotors, and calipers from my 91 RS parts car this week. Then I will take a closer look at what it involves to bolt a 98+ caliper to that spindle.

cy Z28

From what I understand the ZO6 calipers will bolt in place of the PBR's. I've seen it on a 96 vette. no adapters. I work at GM dealer in parts and one of the other parts guys put them on his vette. Looks really slick and they're red.

Just a thought.

brharris27370

Does the 98+ 4th gen caliper bolt onto a bracket that bolts to the spindle or does it bolt directly to the spindle like the 91 3rd gen ones I just removed last night?

Definitely going to require a lot of work to the spindle. It would be nice to have a 98+ spindle, caliper, rotor assembly to compare with my 91.

------------------
91 Camaro RS 5.0L Black Convertible 700R4
** Added so far **
*GM Wonderbar,Alston SFC's,spohn LCA's and Panhard rod
*Turbo City Inj Spacer
*Dual Snorkel Air Filter
*March Performance Pulleys
*GM 3.42 Gears with OEM Zexel POSI
*Edelbrock headers
*3" High Flow Cat
*3" Dynomax Exhaust
*Walbro 255 lph Fuel Pump
***Future 330hp Vortec Crate with LT4 hotcam and 454 TBI

MichaelRBrumm

Good news (I think).

Since no one seemed to be really working on this, I went out and purchased a 98+ 4th gen front brake (off a 1999 Firebird). I got everything from the knuckle to the calipers, and I have begun taking measurements and making comparisons with my 1991 Firebird.

(BTW, my total cost for my 98+ passenger side brake: $170, and that was with the knuckle and spindle!)

First, the idea from brharris27370 of turning our existing hub/rotor combos into just hubs by machining off the rotor is a very good idea. I am using this concept in my plans.

So, the only thing left is mounting the 98+ calipers. Fortunately, although a lot has changed between my 91 knuckles and the 98+ knuckles, enough has remained the same.

Ok, but the 98+ calipers mount a great deal closer to the spindle than the 91's. In fact... see those two closer holes where the dust backplate attaches to the knuckles? Those are almost exactly where the 98+ calipers bolts will need to go into the 91 knucles.

The 98+ calipers also need to mount on the outside of the knuckle, not the weird half-way-part-of-the-caliper-inside-the-knuckle way that the 91 calipers use.

So what is analysis? Well, I'm pretty sure that the 98+ calipers will mount on my 91 knuckles with a little cutting (to get rid of the extranious 91 caliper mounts that would be in the way of the pistons), a 1 centimeter spacing plate (to match the caliper's centerline with the rotor's centerline -- to have the pads fit on either side of the rotor), and a little drilling (in the knuckles and spacing plate) to make some mounting holes.

I will be continuing this in the next week, and hope to have a final verdict soon.


Some caveats:

Because those holes for the dust backplate I mentioned are so close to the mounting location of the calipers (they slightly overlap), they will likely need to be filled so that new holes can be drilled. I assume this could be done easily: screw a filler bolt in (maybe with some permanent-stregth loctite) grind off the bolt head flush, weld it in, and then drill the new hole. Other mounting holes can also be added for strength.

The double piston design of the 98+ calipers are quite a bit larger, so it is possible that they might not clear in the entire travel distance of the suspension and steering. I do not think there will be a problem, but I will not know for sure until I get the whole thing together and can load the suspension.

I have no idea if my base Firebird 91 knuckle is different from any other 3rd generation f-body knuckle... I assume 90-92 is the same. Is 82-92 the same? Base Camaros and Firebirds the same?

Some thoughts/ideas:

An interesting thought might be mounting the 98+ rotor inside the hub instead of outside it. This would eliminate the 9mm offset, but make mounting the calipers much more complicated, maybe impossible (since the mounting face for the calipers would have to be 8mm inside the knuckles).

Or maybe we could get a hub that was custom made with the rotor mounting 9mm closer to the knuckle. Then the spacing plate for the calipers would only be 1mm deep (essentially just some washers).

german-motorsport mentioned custom aluminum hubs from Wilwood, but I think those are for 4th gen spindles... am I right? Does anyone sell custom 3rd gen hubs (without rotors)?

Oh, and finally: MY 15 INCH RIMS WILL WORK WITH THIS SETUP. SERIOUSLY. So rasberries to all of you who said it wouldn't!

Scott_92RS

Awsome man, make sure to take pics of EVERYTHING you do in this project. Let everyone know how it works out. Thanks!

MichaelRBrumm

Yeah, I've got some photos and measurement guides I'll share with everyone soon.

Even though I'm sure it will work, I'm not sure I'm going to go this route. It is quite a bit of custom work, and I'm the kind of guy who likes everything to look perfect (even the nearly invisible 9mm offset bothers me).

So, I'm going to take my 3rd and 4th gen knuckles in to a bunch of machine shops near me and see what the cost would be to just make a new 3rd gen knuckle with the 98+ hub and caliper mounting holes. Seeing as how the calipers and rotors can be obtained for such a low price, I am willing to put a bit more money into the knuckles.

If I did that, would anyone else be interested in buying a pair (and hopefully reducing our combined cost)?

A funny thing about this is that it would also allow a C5 upgrade (just need LS1 to C5 caliper brackets)... Right?

Earl 87gta

I dont know if this will help or not but 67 vets use a 12in X 1/14 one piece rotor that have the hub and rotor cast as one piece I dont know if they will bolt derectly on the spindal or notthier may be some machine work needed for the barrings but it may be somthing that you can look in to.

98_1LE

This is what I have wanted for some time. Tahanks, and keep up the good work! Will the wheel offset remain the same, or will it take fourthgen wheels after the conversion?

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87 Formula 350 13.94@96.67
98 Z28 1LE 13.15@107.59
1LE Owners Association

MichaelRBrumm

>Will the wheel offset remain the same, or
>will it take fourthgen wheels after the
>conversion?

Well, if I design the knuckle, the offset will be the same as thirdgens. It is pretty easy to take a thirdgen offset, add a spacer, and get a fourthgen offset. But going the other direction is darned near impossible.

Another thing is that my planned design could allow you to use spacers on the knuckle for the calipers and spindle instead of on the hub. Having the spacer off the hub decreases the rotational mass (although I'm not sure it matters that much).

The knuckle would, of course, allow either types of spacers to be used.

>67 vets

Sorry, I'm going to stick with 3rd and 4th gen parts as they have a lot better price/performance ratio.


Ok, another thought... If I do things right, I could even allow the 4th gen ABS speed sensor to be mounted on the new 3rd gen knuckles, making a 3rd gen ABS system a lot easier to install. Even if I don't do it, I'd might as well make it possible. After all, with these gigantic new breaks, lock-ups are even more likely to happen during panic stops.

Rob P

iTrader: (1)

Michael.
If you can do the 4th gen F-body brakes to 3rd gen and keep the ABS I'm in. I've always wanted to put ABS on my 89 RS. I toyed with the idea of stealing an ABS system from an S10 pick-up since they used to use similar components to the F-body.
Keep us posted.

------------------
Rob P
89RSconvtZZ4TPI Edelbrock Intake
SLP Dual Cold Air Intake 1 5/8" Headers Semi-Siamesed Runners, IROC
suspension, alum shaft. Numerous mods.
92Z28convt5spd (stock)
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

LT90RS

I would love to see some pic's of what you have done so far.


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I think the Sun Visiors are still Stock,Anybody know were I can get some after market ones?

MichaelRBrumm

Just in case anyone wants an update, I've just finished replacing my rear drum brakes with 98+ disc, so I am now moving on to the front.

I looked at trying to modify a 3rd gen knuckle to accept an LS1 (98+) spindle/hub, but found that it required cutting off way too much material, so now my plan is to modify a LS1 knuckle.

With a LS1 knuckle (modified to work with the 3rd gen suspension), I'll be able to mount the calipers and add ABS!

The LS1 knuckle's major differences:

1. no mount point for the strut
2. shorter arm on knuckle for tie rod mount point
3. slightly different angle on LCA ball joint
4. negative offset

solutions:

1. cut and machine top of knuckle
2. longer tie rod; perhaps a new tubular LCA to add some clearance
3. negligable functional difference, only visual; the suspension never expands that much, even when the car is on jacks
4. add spacer between hub and rim

A local machine shop said it would cost $400 to machine the top of the knuckles to allow them to use struts. I am currently in the process of measuring and specifying the cut locations and angles for him.

Jim85IROC

iTrader: (2)

Mike... have any updates for us yet?

Kersteae

ttt

91tpiTA

Does anyone know what size mm allen wrench that takes off the 2 front disc caliper bolts? This is stock, also. The biggest one I had was an 8mm, and it was too small. So I'm guessing a 9, 10 or 11mm allen wrench. If anyone knows, please chime in.

ebmiller88

iTrader: (7)

12 mm.

Ed

91tpiTA

Actually, an 8mm is too small, and I just went out to buy a 10mm one, and it is too big, so it must be a 9mm. Damn this running around.

chevy35086

i am definatly interested in this as i already have a set of calipers here for a 98+ fbody and i would bet the my 86z would love to have them on there. keep me updated thanks

Gumby

Awesome mod. I will try and dig it up but read an article saying that when you have the "slip on" rotors you must use a torque wrench to get the proper even torque so not to warp the rotor or cause brake pulse.

I am not 100% sure on the validity on this but its almost makes sense.

Blue1989RS

I have a 94 Z28 LT1... How are these brakes different than the 98+??? The only thing I noticed as different than my 89RS, is the front rotors are HUGE, and the rear disks are larger and different than my current 3rd gen rear disk setup.

Dave_Jones

'82-'92 non-1LE used a 10.5" rotor with a single piston iron caliper.
'93-97 used a 10.9" rotor, and a single piston iron caliper.
'98+ used a 12" rotor, and a dual piston aluminum caliper.

pre-'89 rear discs were only 10.5", iron calipers
'89-97 rear rotors are 11.7x0.81", aluminum calipers
'98+ rear rotors are 12x1", and use a drum parking brake and a different aluminum caliper with a slightly larger piston.

Dave_Jones

Actually, the regular 1-pc integral hub rotors are worse than the slip-on type in this regard.

Anytime you heat an unevenly stressed piece of metal, you're just asking for it to distort.

IMHO, part of the reason why you don't hear this mentioned more often is that most folks really don't drive hard enough to get the rotors all that hot.

ALWAYS use a torque wrench.

Blue1989RS

So unless you get the huge slip on rotors on your 3rd gen, is there any advantage of upgrading to 89-97 rear disks? Seems like they would be way overkill.

Are there any stock options for increasing the front rotor or caliper size on a single hub/rotor assy? Looks like unless I do a wilwood upgrade, I'm stuck with 10.5" front rotors... correct me if I'm wrong.

Dave_Jones

Not overkill at all, IMHO.

If you're concerned about the brake bias being shifted too much to the rear, note that the PBR rear calipers use a much smaller piston than the earlier Delco-Morraines, which keeps things in balance. But, the '89-97s are lighter, and dissipate heat better. In addition, since the same basic rear caliper setup were also used on the C4 vette and LT1 fourthgens, you have a much better selection of brake pads available with the PBRs. And even if you're not going to drive it hard, IMHO the PBR disc setup is more reliable and easier to work on than the old iron arrangement.

I wouldn't waste my time trying to do a caliper upgrade on the stock 10.5" rotors.

If you're set on using a single hub/rotor assembly, then 1LE front brakes are probably your best bet. But personally, I like having separate hubs. Being able to swap rotors without having to mess with wheel bearings is just nice, and there are other small advantages as well. C4 HD, C5, and LS1 setups are all proven winners and well documented here, if you weren't already aware of them.