Okay, so I started about 6 months ago designing brackets to mount 95 C4 Vette brakes to our 88 GT.

I posted drawings of the brackets I came up with in the thread 84-87 12" Corvette Brake Swap...

The good news is that the front brackets fit and were easy to make. The brakes look great and stop like mad.

The bad news though is that in order to mount the 12" Vette brakes on the Fiero I had to remove a bunch of metal from the ubutment brackets where they hit the mounting ears of the Fiero's hubs as seen here.



Actually the upper bracket is from a 13" set of C4 brakes but it looks just like my 12" set used to.

Unfortunately, the webbing definitely needs to be there. After the first session of hammering the brake pedal to bed the pads, a pop developed coming from the front right wheel. Upon inspection I found the abutment bracket to be bent. The two tabs that hold the pads (and thus the caliper) have spread. Evidentally that's what the webbing is there for... DUH!!! So now the pads have a 1/8 inch of slop in the brackets and that of course is not good.

But without removing the webbing, I don't know how you're going to make the 12" system work. The only other alternative would be removing a large amount material from the Fiero's hubs. Since this is where the brakes bolt to the hub, you see the problem... Perhaps removing some from both pieces would work okay.

All is not lost though. I also have a set of 13" C4 Vette HD brakes.

The adaptor bracket design remains the same. But since the abutment brackets and calipers are now 1/2 inch further out from center, there's almost no interference between the abutment brackets and the hubs' mounting ears.


Instead of removing material from the bracket I was able to remove a little from around the outside of the hubs' mounting ears and voila.







But you'd better have 17" or larger wheels.


I used to have wheel weights in here...


12" side-by-side with 13".


I will try to tweak the bracket design a little to get a llitle more clearance between the caliper and wheel. As you can see there's just a little bit of wiggle room here.


I will also gather all the info on what parts I used to put these on your 88.

[This message has been edited by 2002z28ssconv (edited 10-19-2009).]

Good job, What is the cost on this conversion?

I bought the complete 13" setup off the Corvette forum for $250 including shipping. I got front and rear calipers, rotors, hardware and banjo bolts. Be sure to get the banjo bolts off your donor car if at all possible. These are almost impossible to find. I reused the front pads but bought new pads for the rears. I don't know how much new abutment brackets would cost or if they are even available new. But if you bought everything else from Autozone it would be around $1,000 for front and rear. Throw in another $250 at most to find a set of junk yard abutment brackets. I made my front conversion brackets from standard 1/2" x 1-1/2" steel. The rears can be made from 1/2" x 2" steel. I had to buy way too much because the only metal supplier that was open when I went to buy it had a 40' minimum length.



This mod can be done for less than $300 if you find a used setup that's in good shape. But you'd have to do all the fab work yourself. I paid $100 for my hub alignment rings but you can probably find a shop to do it cheaper. Check with one of the guys doing these swaps kits for 84-87 cars. I just took my hubs and rotors to the shop and dropped them off so I knew they would be the right size.

Note that I have not changed the master cylinder. I still may. I will get the rears bolted up tomorrow and see how they feel before going for a new master or maybe just a brake bias adjustment.

[This message has been edited by 2002z28ssconv (edited 10-19-2009).]

Wow... that's exactly what I'm looking for; all of the part #'s. VERY good job! A couple of questions for ya
1.) Is the e-brake still functional?
2.) Did you use the stock master cylinder & brake booster?

------------------
-Chris
'85 V6 SE 4sp (SOLD)
'88 GT Auto (fun car)
'03 Sentra SE-R Spec V (Daily driver)

quote Originally posted by Chris_narf: Wow... that's exactly what I'm looking for; all of the part #'s. VERY good job! A couple of questions for ya 1.) Is the e-brake still functional? 2.) Did you use the stock master cylinder & brake booster?

You have to doctor with the end of the E-Brake cable a little bit but it will still work. I haven't done that yet. I going outside right now to do the back brakes.

Still the stock booster and master.

wow lot to do for YOUR set up! Looks like way tooo much taken off the calipers.
I put mine on without cutting the caliper. Suppy has a bracket made as well. the brakes are just like the stock brakes but with 12" rotors and the e brake works very well in the stock form!

Good job!

I took nothing off of the calipers. I'm confused...

I got the backs on this morning but had to leave at 10:00 to go fishing.

I think the parking brake is going to need a bit of creativity though.

I'll get everything finalized Sunday morning (minus e-brake) and go for a test drive.

It stops as expected. 10 times better than stock. But with the 13" rotors the fronts want to lock up if you get into the pedal too hard. I think I'll revisit the 12" setup again if I can find another set of 12" abutment brackets. Otherwise a brake proportioning valve is definately being installed in the near future.

Oh, and the parking brake is going to be tricky to say the least. The only safe place to run the cable past the strut puts it almost on the same plane as the parking brake lever. But it would need to push the lever downward in order to activate the brakes instead of pulling upward. I thought about reversing the calipers (left to right) but then bleeding them would be a nightmare because the bleeder would be at the bottom instead of at the top. The lever can't be fipped over to the other side of the caliper either.


So I'm thinking of possibly extending the cable to be long enough to go around a pulley mounted to the bottom of the caliper. That would reverse the cables pull direction but might lead to a problem with it not releasing if the cable or pulley sticks.

My other solution is to use a spring loaded lever (using a spring like the ones used on a carb's throttle linkage) at the bottom instead of a pulley. Then a second cable from the new lever to the caliper's lever. This might be too complicated though.

But hey, it's only the parking brake right? How many people are running around with their's completely disconnected?

What do you think? I know... I need some more pictures...

[This message has been edited by 2002z28ssconv (edited 01-05-2009).]

ok i have a question wont this add rotating mass? and bigger tires means higher gearing. shouldnt that hurt accleration?

Tires are same diameter as stock.

I'm sure there is a little more rotating mass due to the heavier rotors. But the slight decrease in acceleration / deceleration / suspension response is far outweighed by not having to put the brake pedal through the floor and still wonder if the car will stop in time. The stopping force available before was adequate at best. It's phenominal now.

quote Originally posted by Bremertonfiero: ok i have a question wont this add rotating mass? and bigger tires means higher gearing. shouldnt that hurt accleration?

Bigger rims. The tires would be thinner to make up for the difference. The rotating circumference would be the same if calculated correctly. Search for the "Miata tire size calculator" for more info.

example*: 225/60/14 --> 225/40/18

First Number/Second number/Third number

First number=with of the thread in milimeters (mm)
Second number=Percentage (%) of tire height to thread with (how tall the tire is)
Third number=size of the Rim in inches (")

____
* Note: I just threw out some numbers to illustrate a point. Didn't do the actual calculation to check if the ratio would work. Rim with also affects tire height. See "Miata tire size calculator" for details (either search PFF, or google)

[This message has been edited by Austrian Import (edited 01-07-2009).]

Update: The brakes have been terrific but I wasn't able to get the parking brake reconnected. So I think I'll pull them off again in the next few weeks and go back to the stock calipers on the 12" Vette rotors.

Do you have an update? Are you currently running the 12" or 13" brakes?

Yes update please!

Also what width and offset are your wheels?

Thanks.