I would like some brake system suggestions, so here is my story. In 2010 I upgrade all 4 corners to the Grand Am brakes, and added the S-10 master cylinder. My brakes were awesome compared to stock. However, in 2011 I did an 88 rear cradle swap, so I lost my rear Grand Am brakes and had to install stock 88 brakes. Now my brakes suck. My front brakes are the only ones really working it seems, and when thinking about it, it makes sense because the larger MC is clamping the larger piston Grand Am's in the front first, and not giving all that much to the back. Nothing is really "wrong" either, I bled it several times, newer pads in the rear, with no difference, so I know it's a system design flaw.

Now, to go about fixing this, I have several options, which is why I created this thread, I would like to know which fix or upgrade would give me the best brakes I can get with a limited budget and maybe 16" rims if I'm lucky. I could put 12" Corvette rotors in the rear, but I still would have the pressure issue and most likely wouldn't do as much as I would like. I could do the brake booster upgrade, but that would just make it worse, etc. Not sure what to do.
Thanks
Matt

Edit: I forgot to mention that I do not have an e-brake system and have front 88 calipers installed in the rear.

[This message has been edited by mattwa (edited 12-19-2011).]

the 88 rear brakes are all you really need back there .i would just buy a proportioning valve to send a little more pressure to the rear callipers .12 " brakes in the back is just adding extra unsprung weight .they look cool but are way beyond what you need back there .

[This message has been edited by wftb (edited 12-18-2011).]

There really should not be a noticeable performance increase between the vented Grand Am setup in the rear and the stock 88 setup in the rear unless there is something not quite right with your rear 88 calipers.

Does your parking brake work? A poorly adjusted parking brake assy will make the rear brakes perform poorly.

quote Originally posted by fieroguru: There really should not be a noticeable performance increase between the vented Grand Am setup in the rear and the stock 88 setup in the rear unless there is something not quite right with your rear 88 calipers. Does your parking brake work? A poorly adjusted parking brake assy will make the rear brakes perform poorly.

Even with the larger Master Cylinder? I would think there would be a reduction between the two because of the smaller piston size of the 88 caliper compared to the Grand Am.

Oops. I forgot to mention that I do not have an e-brake system and have front 88 calipers installed in the rear.

So that means that no brake adjustment will be happening on your car, and that the brake pistons are different sizes (front to rear). Sounds like the rear brakes would be doing nothing.

quote Originally posted by Gall757: So that means that no brake adjustment will be happening on your car, and that the brake pistons are different sizes (front to rear). Sounds like the rear brakes would be doing nothing.

No, the front and rear 88 calipers are exactly the same, minus e-brake hardware.

But I was looking at adjustable brake proportioning valves, and they aren't cheap, I found one I liked from Wilwood, but it's $83.

I was mis-remembering the piston size of the Grand Am thinking their was only 1mm difference... the piston difference is 9mm instead with the 88 one being smaller. With that being the case, you need to increase the rear brake bias to help balance out the brake system due to the smaller piston in the rear. Going from a 57mm piston (Grand Am) to a 48mm piston (88) will reduce the clamp pressure about 30% at the caliper.

[This message has been edited by fieroguru (edited 12-18-2011).]

Yea, that's what I thinking as well, would this work?
http://www.jegs.com/i/Wilwo...entProductId=1284815

EDIT: It seems like most aftermarket valves are adjusting to reduce rear braking pressure, not increase it. Makes sense for most cars, but not a Fiero, and definitely not in my case.

[This message has been edited by mattwa (edited 12-18-2011).]

I wonder how you set it correctly? Turn the knob a little and test drive?

quote Originally posted by Gall757: I wonder how you set it correctly? Turn the knob a little and test drive?

I'm guessing so.

I could do the brake booster upgrade as well.

Bump? Anyone else?

The rear brakes are adjusted the same way the earlier ones are, by periodic use of the e-brake. If your e-brake isn't functional, the calipers are probably out of adjustment, or need to be rebuilt.

quote Originally posted by RWDPLZ: The rear brakes are adjusted the same way the earlier ones are, by periodic use of the e-brake. If your e-brake isn't functional, the calipers are probably out of adjustment, or need to be rebuilt.

quote Originally posted by mattwa: Oops. I forgot to mention that I do not have an e-brake system and have front 88 calipers installed in the rear.

quote Originally posted by mattwa: Oops. I forgot to mention that I do not have an e-brake system and have front 88 calipers installed in the rear.

Oops, I missed the 'front' part.

If there was a way to install the Grand Am calipers on the 88 rear knuckle, I would just do that. But sadly it's not that easy. Really not sure what to do. And I'm not sure the stock sized brakes will be good enough for the 4.9/4T60e that's in this Fiero.

quote Originally posted by mattwa: If there was a way to install the Grand Am calipers on the 88 rear knuckle, I would just do that. But sadly it's not that easy. Really not sure what to do. And I'm not sure the stock sized brakes will be good enough for the 4.9/4T60e that's in this Fiero.

It would be easier to adapt the 88 caliper to the front of the 84-87 - that would restore the balance, but then you would also need to switch back to the stock fiero master.

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[This message has been edited by mattwa (edited 01-03-2012).]

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[This message has been edited by mattwa (edited 02-02-2012).]