88 Fiero Formula Brakes (Page 1/1)
Reborn756 SEP 16, 12:21 PM
Howdy folks, Darryl here yet again. Finally drove my 88 Formula around the block last week, and found the brakes are God awful. I'm talking, stand on the pedal as hard as I can, and roll to a stop from 20MPH awful. Time for an overhaul.

My question for you folks is, what are you using for brakes? I'd prefer to keep the stock system, but can't find new calipers or boosters/master cylinder kits. I am redoing everything: pads, rotors, calipers, and the booster and master cylinder. I'm not Sunday driving this car, there will be some spirited driving up and down mountain roads with no guard rails, and I'm not putting myself down over a 30+ foot embankment thanks to shoddy brakes.

Any recommendations on where I can find a new booster kit, proper rebuild kit (including the correct pistons) for my calipers, and good pads and rotors? Or a conversion that will require no or minimal modifications to the car? I am running the stock wheels with no intentions to change them.

Eventually I'll be engine swapping, likely to a 4.9 Caddy, so the system will need to handle that bump in power.

Thanks in advance folks!

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- Darryl

theogre SEP 16, 02:27 PM

quote
Originally posted by Reborn756:
in. Finally drove my 88 Formula around the block last week, and found the brakes are God awful. I'm talking, stand on the pedal as hard as I can, and roll to a stop from 20MPH awful. ...

You have to push hard? Even just pushing down a bit w/ engine running but tran's out of gear or in parked? This is often sign of Booster problems. Not the rest of Brakes except maybe MC...

check vac line good all the way engine to booster. Must not leak, be pinched, crushed, or plugged w/ crap.
Check the check valve where line connect to booster. If bad is harder to find because Vac Line and Hose is 1/2". Meaning 87-88 valve is bigger and ones listed to fit older Fiero won't fit this. Very few "stores" have correct check valve.

Still can't find problem then maybe diaphram(s) or control valve in booster.

rarely MC can "freeze" cause similar issue. Carefully loosen 2 mount bolts and try to push pedal. Watch pedal height change for hard pedal if you have bad MC. Caution! Pushing pedal now w/ loose MC hardware can bend or break the hard lines very easy.

MC can have problems w/ QT valve "hidden" in back section making MC to "freeze" like this Valve is block w/ crap. Might be cleaned in the car but have to pull the tank and valve and easy to get air inside the MC doing this. If air gets in, likely need to "bench bleed" the MC or if lucky jack rear of car so MC is level then bleed rear/front or both brakes. But really this valve is not make to clean/fix by anyone and if you mess up by scratching the MC etc then will need a new MC.
See my Cave, Quick Take-up notes and Bleeding MC notes

If 1 to all calipers are frozen from "rust," bad hoses, etc, and won't move w/o that much force... They won't release when you release the pedal and 1 or more Pad will drag big time and can cause big problems or a fire trying to drive.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

Reborn756 SEP 16, 02:32 PM
Thanks for the quick response Ogre! Pedal is stiff, though if I recall it's stiff until I start it, then it's pretty easy to press, the gets hard again when in gear and moving. I've moved the car all of three times though so I could be muddying up my details, I'll take it for a quick run tonight after work to verify.

Brakes are not sticking as far as I can tell, car runs good, all the wheels spin free when jacked up. E brake works great too.

Regardless if it may just be a service issue or not (car did sit for a while before I bought it), is there anything you can tell me about finding replacement parts for everything? New, not remanned?

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- Darryl

theogre SEP 16, 03:15 PM
New rotors, pads, and maybe MC is available new.
Booster is likely only rebuild.
30+ years and Fiero Calipers are only rebuild too. Many Fronts are sold w/ steel pistons but these are not made by GM and often causes problems. If lucky might have new rear pistons but they are rebuilt some companies and this part was not made for this so you want to deal w/ local store w/ good warranty. AZ warranty is good and track w/ phone # so any store can honor it. AZ AA and some others can get parts on-line then take to store for returns, cores and warranty.

wheel hoses get SAE J1401 rubber. See http://www.fiero.nl/forum/F...HTML/129208.html#p27 http://www.fiero.nl/forum/F...HTML/129208.html#p38 and other posts
theogre SEP 16, 03:40 PM

quote
Originally posted by Reborn756:
Pedal is stiff, though if I recall it's stiff until I start it, then it's pretty easy to press, the gets hard again when in gear and moving.

Pedal should work w/ engine off too...
Check valve should keep vacuum in the booster for days, often more, when parked. You get ~ 1 to 3 times to push the pedal use the reserve vacuum w/ engine off. Exactly count depends how much distance etc. After you're fighting huge booster spring(s) to push the pedal.

If can't keep vacuum over night then check/clean that valve. Do Not use strong solvents that can attach the plastic when cleaning.
Still won't seal have bad valve, gromet and/or a leaky booster that could leak anyplace often hidden inside.
DIY can't fix a iffy booster beyond check valve and its grommet. Even "pro's" and GM Dealers won't fix them even tho FSM tells them how because of legal liability and eats time etc. I don't think GM actually offer booster inside parts then or now. No-one I've seen in aftermarket offers the inside booster parts.
Reborn756 SEP 16, 04:31 PM
Good to know Ogre, I'll check that tonight and see what I come up with. Need to do the brakes, fix the rich condition, make sure the cooling system is working appropriately, get the leaves and other junk out of the cradle, and clean the interior, and then I can drive this dang thing. Plan working on this until it's 100% and then I'm keeping it.

Always loved the looks of the Fieros, especially the 88 Notchbacks. This is my first one. Hasn't been too bad to work on, even compared to big spacious vehicles like my M1028. Though I am quickly finding that 88 specific parts are hard to find.

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- Darryl

Reborn756 SEP 16, 06:21 PM
Just checked it again, and I did have some details wrong. Good pedal, just weak brakes. Very weak brakes.

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- Darryl

theogre SEP 17, 12:24 AM
Stuck pistons, sliders, and pads can do that.

See my Cave, Brake Service etc.
88 is different from slider drawing there but still need to lube sliders w/ Brake Grease or will have problems.
Wrong grease is bad or worse then no grease so don't believe BS push by many other including "pro's."

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave