So I'm having some trouble with my brakes... they're kinda weak... as in I stomp the pedal and they don't seem to get any stronger the harder I push. They stop me fine, just not especially quickly. The calipers, rotors and pads are all fairly new. calipers are stock replacements from advance, rotors are cross-drilled and slotted from Summit, and pads are the carbomet ones from the Fiero store. I've got plenty of brake fluid and the brakes were bled fine. Could it be some other issue with the hydraulics? Maybe a bad master cylinder or brake booster?

what year? 84-87 brakes suck. 88's are supposed to be a little better.

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gt44ever,

Yes, it could be your booster. Best bet is to do the "$100 Brake Upgrade" and install an S-10 10" booster.

The carbomets are also part of your problem: though good pads when hot, they have a low co-efficient of friction when cold. Try Thermo-quiets.

Larry

quote Originally posted by ericjon262: what year? 84-87 brakes suck. 88's are supposed to be a little better.

84-87 do not suck. 20+ years and people pushing myths doesn't help.

First Check Booster Check Valve and Filter. (84-86 duke uses a small filter in engine bay on firewall.)

Yes, Wagner ThermoQuiet is very good and Works in any kind of driving. I love my brakes with ThermoQuiet pads.
Some pads are made for racing etc and needs higher heat to work. Normal driving lets the brakes to cool between stopping....

See my cave, brake section.

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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 (It's also at the top and bottom of every forum page...)

quote Originally posted by theogre: 84-87 do not suck. 20+ years and people pushing myths doesn't help.

I agree, saying that the brakes suck is really mis-leading because I think if I was buying my car new and it came with brakes that weak I wouldn't buy it. So therefore, when they were new it had good brakes, 25 years later, parts are worn and past their lifespan.

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Car Thread:
86 GT
https://www.fiero.nl/forum/F...ML/085541.html

On my stock 86, I can lock the wheels on dry pavement if I push hard.
If your car can't do that, something has failed in your system.

If it can and you are not satisfied with your stopping distance, you need tires that have a larger contact patch and/or are stickier.

[This message has been edited by 30+mpg (edited 03-02-2012).]

It's an 87 so no filter, which I guess would mean most likely source of issue would be the booster.

I always regret seeing guys spend relatively large amounts on the stock brake system. Even with all those expensive trick rotors and pads it just isn't as good as the Grand Am swap, which costs less and works better. Adding a Blazer booster will also improve it much more than buying slotted rotors. But, if you want to avoid fading, the vented Grand Am rotors do the job for a fraction of the price.

You can even add on the Seville rear calipers if you want an ebrake.

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I did the drill and slotted, that eliminated all my brake fade. But didn't seem to stop any better or not enough to really notice. Adjusted the ebrake as per the Ogre's cave brake section, that brought the pedal up,(before it got harder). Then got the stainless steel brainded brake lines from Summit. Again didn't seem to stop any better or not enough to really notice, but a bit firmer pedal. (Every upgrade with new pads, lifetime warranty) New master, no change. Different booster off of another Fiero, no change. Then did the grand am on the front, drilled, that seemed a little better but really not by a big amount, it lowered the pedal slightly(before it got harder) and made the pedal a little softer. I am sure each thing helped along the way, but nothing big each time. Then I did the bigger booster, big difference, softer pedal but more like a new car feel. I can lock up the brakes if I want, panic stop, but I can stop when I want. I have done bigger rotor swaps on other Fieros but nothing really as big of gain as the S10 booster, 50% increase. If you don't want to weld one up yourself, they can be bought Here

Is your pedal ?.....
really soft=air in the lines, leak
Avg hard=normal
Really hard=bad booster

Is your pedal really low before it get harder to push = ebrake adjustment

If you hold down the pedal then does it slowly sink to the floor = bad master

If you run the car for a min then turn it off, wait a couple of mins. you should be able to push on the brakes with normal effort at least once. if not booster or check valve leaks.
with the car still off pump the brakes untill they get hard and hold the brake pedal down and start the car, the pedal should sink under your foot. if not bad booster.

Hope this helps.
.
.

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"DRIVE IT LIKE A FIERO"
'84 Fiero, engine to be determined
'87Blue GT 3.4L Swap Completed!!!!!!!! Boosted!!!!!!!
^^^^ Now in the Construction Zone^^^^
Las Vegas Fiero Club Parts/Sales/Service/Club
Fiero Road Club Of Northern Nevada

The stock brakes on my 87 GT are very weak as well. I have replaced every component in the system except for the booster (strong vacuum and no leaks) and proportioning valve. At 30-40mph, I can stand on the brake pedal and they wont lock. Car gradually slows with almost no feeling like i'm gonna be thrown through the windshield. As the car slows to 5-10 mph, the braking force increases but still no lock-up. I am using Raybestos pads but not Thermo Quiets. It feels like the lines are plugged..but theyre all new and the braking feels the same as it did with the old parts. What you and I are experiencing is probably normal. Except Ogre can lock his brakes so, i dunno.

Like I said above, I regret seeing guys wasting their money trying to get the Fiero brakes to behave like a newer car.

The S10 Booster/Grand Am/Seville swap brings the brakes into the 21st Century

Arn

i was having the same problem, bought all new calipers, pads, ect. and brakes still suck. i just figured that the brake system in 1984 was bad compared to nowadays

I can lock up my front with any pad, not just ThermoQuiets. Not hard. Ferodo is one cheap brand I used. (Another Federal brand) And my uses left pedal accelerate (example similar to setup I use), I can't use two feet to push the brake pedal.

and Rebuild/remanufacturer does not = new.
rebuild/reman rear caliber = rebuild piston and many are bad right out of the box.
Pistons were build and sold a one time use part.

sardonyx247 said "Really hard=bad booster"
Maybe but sadly not...

Iffy booster can cause weak brake performance w/o hard pedal. Booster control valve has problem, like dirt and/or wear is making problem and control valve can't switch and deliver full air on command.

Tearing 1 diaphragm is another. Vacuum booster uses 2. If 1 tears then can hurt brake performance.

25+ years? Very likely either/both could be a problem. Vacuum boosters have parts that will wear out.
Some/most People saying Upgrade the Booster maybe comparing to a booster with a problem...

See How Power Brakes Work at How stuff works. They have animation on 3nd page.

And note, MC QT valve can cause high hard pedal or low pedal. Depend what issue...

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

ok, pedal is not hard, maybe a little on the soft side but nor sure as the brakes were seized when I got the car... wouldn't say its any softer than the 03 cavalier I've been driving and its still about the same as it was new. pedal might be low though.

pedal does drop on startup like its supposed to and pedal feel for the first pump after its been sitting is no different than running

I'm going to re bleed the brakes just to he sure there's no air and do the hand brake adjustment per the cave and see where that gets me.

the goal is to get properly functioning brakes at a minimum cost. I DO NOT plan on getting any parts unless necessary. I'm planning on working on other areas of the car soon and would like to keep the money for that.

thanks for the help, I should have an update in a few days

quote Originally posted by theogre: 84-87 do not suck. 20+ years and people pushing myths doesn't help. First Check Booster Check Valve and Filter. (84-86 duke uses a small filter in engine bay on firewall.) Yes, Wagner ThermoQuiet is very good and Works in any kind of driving. I love my brakes with ThermoQuiet pads. Some pads are made for racing etc and needs higher heat to work. Normal driving lets the brakes to cool between stopping.... See my cave, brake section.

I disagree, they overheat and fade rapidly. For stop and go traffic, they're fine, but anything else, I'll go on the record and say they're junk, even my 3rd gen camaro(non 1LE) performed better. I'm sure they can be made to work, but there are so many better alternatives out there.

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I’ve never had a problem getting my 87 GT to lock up when needed (fortunately it doesn’t happen too often). If you’ve got a car (any car) that feels like it’s hard to stop but the pedal feels normal I’d look at the Proportioning valve. When you jump on the brakes the weight on the rears is reduced so the proportioning delays them and reduces the pressure. Sometimes when they go bad the limit the amount of pressure applied and if this happens to the fronts the car will feel like it’s hard to stop.

Morning Guys,

The subject of whether and/or why stock Fiero brakes 'suck' is a subject which gets as heated as v6 vs v8! I am now convinced that there are two groups of people: those who can lock up the stock brakes and those who cannot. Those who can think the brakes are great (or at least adequate)...those who disagree.

Simply saying "Just FIX your brakes", is not particularly useful to those who cannot lock them up.

I come down on the 'sucks' side. Even my '87 GT which I bought off the showroom floor could not lock up the brakes. And, with all the "Just fix your brakes" responses I do not recall ANYONE who actually succeeded in doing so and reported that fact back.

I believe it is production variation in the stock booster, for what it is worth, and that is one of the reasons the "$100 brake upgrade" gets such wonderful reviews: folks are replacing the ineffective stock booster with a much more effective booster.

SO: If YOUR brakes suck, then first do a good brake job, flush the lines, use 'good' pads. Don't bother with drilled or slotted rotors (they will help with fading, but NOT with brake torque), do not use a larger master unless the pedal throw is intolerable (that will REDUCE brake torque). If they still suck (they probably will), do the $100 upgrade. If they STILL suck, then do the Baretta, Zettner, or 12" Vette upgrade (In order of effectiveness). Use stock '88 calipers if possible (they are light and increasing the number of pots does nothing to increase brake torque). In MY experience, YMMV, your brakes will no longer suck, but will never be as good as the brakes in modern cars....and you WILL be able to lock them up as desired.

But PLEASE don't just say 'fix them'

Larry

A. Check the rubber hose going to the brake booster, make sure it's in very good condition and sealing.

B. Carbomet pads suck when they are cold, and they do not get warm enough in normal street driving.

C. Brake pedal should not feel spongy at all.

replace the brake hoses with new stainless steel braided. We did on my car and it was the single best thing ever to happen! The hoses the Fiero Store sells are actually cheaper then OEM and look good too.

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Denise, Bristol PA (Ernie is my Brother) 86 SE, stock resto. Jasper reman, 5spd Isuzu

being able to lock your brakes up doesn't mean they are good.

------------------
there's a Group on 60degreeV6.com for us 660 Fiero owners!

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I know these lines Look crooked on paper, but I swear I've got them straight in my head.

Is it possible the caliper sliders are hanging up? Mine were and removing the bolt/pins, cleaning and relubing fixed the issue.

P

quote Originally posted by ericjon262: being able to lock your brakes up doesn't mean they are good.

Yes, If you lockup too easy then it's a bad sign. Any lockup can/will cause problems like flat spots on tires...

quote 87SM, Page 5-2: Test brakes at different speeds with both light and heavy pedal force; however, avoid locking the brakes and sliding the tires. Locked brakes and sliding tires do not indicate brake efficiency, since heavily braked, but turning wheels will stop a car in less distance than locked brakes. More tire-to-road friction is present with a heavily braked turning tire than with a sliding tire. The brake system is designed and balanced to avoid locking the wheels except at very high line pressure levels. This is done because best stopping distance and control is achieved without brake lock-up.

That said, Fiero brakes can lock in panic stop setting. Fronts can do it on dry pavement.

[This message has been edited by theogre (edited 03-05-2012).]

Ok, so quick update: I haven't gotten to making my adjustments yet, hopefully will get there later today, but I have noticed that the pedal will slowly drop while braking, which I believe indicates a faulty master.

And to address some other comments:
My goal right now is to get the brakes working well enough to stop effectively... or in other words well enough that I can actually feel the braking force, which right now I can't. It tends to make getting off the interstate a little more concerning than it should be.
I'm just using the ability to lock the brakes as a rough scaling of how much brake power I have since its a lot easier to describe "my brakes can't lock at all" than "my brakes aren't working good at all". Generally speaking, most cars are at least capable of locking their brakes, or at least every car I've ever driven is, so I felt that was a fair way to get an idea as to how much brake power my car can generate.

Hopefully that clears things up a little. I should have an update later today after I've had a chance to get some work done.
Thanks for the help

quote Originally posted by gt44ever: Ok, so quick update: I haven't gotten to making my adjustments yet, hopefully will get there later today, but I have noticed that the pedal will slowly drop while braking, which I believe indicates a faulty master.

Leaking fluid or bad mc...
Leaking will drop fluid level in MC tank.
No fluid level dropping then MC seal is bad. 3 of 4 MC seals can leak internally.

Fluid level doesn't change and I haven't found any leaks so it must be internal. Will look to replace the MC once I'm done with everything else.
thanks

I'm running stock brakes (rebuilt calipers) on my 85 and can lock it up at any speed.

I have the Grand Am upgrade on the 86 and it stops the car as well as stock. The only difference I can tell is my wallet when I replace the pads.

I have Grand Am rears, and stock fronts on the 4.9, and have no problems stopping it. (well, when it was running I had no problems stopping.)

If your brakes will not lock by pushing hard on the pedal they are not safe and need to be off the road. Seriously, that is a very bad problem and there is something wrong with your brake system somewhere. Stock brakes work great if they are properly maintained, or repaired. A "complete replacement" and your car will not "screech" to a stop when needed means something is wrong in your braking system.

I'm not attacking here, but calling the brakes on a Fiero "weak" or saying they "suck" is simply not true at all.

The Grand Am upgrade is good because it helps eliminate brake fade, and lowers replacement costs of parts, not because stock is unsafe. The fade is usually felt if you use your car on an autocross, or similar type driving where you brake hard and often. It does little to nothing to lower stopping distance.

Like I said earlier, I changed over to the Grand Am brakes on the 86 because parts are much less expensive. The 85 got rebuilt calipers because I wanted it to remain stock. When I was driving both of them they were almost equal in stopping, with the stock feeling a little better to me.


Brad

[This message has been edited by twofatguys (edited 03-10-2012).]

So, got the new MC installed today and then the real fun started. Turns out, my right rear caliper (the only one I didn't replace last spring) was super messed up. Went to start the bleeding procedure and found that nothing was coming out of the bleeder screw, even with it completely out. Then checked to make sure it was even receiving fluid, which it was, but the hole had been cross-threaded at some point so I went to fix the threads with a tap, but the tap handle wouldn't clear with the caliper mounted. Removed the caliper and low-and-behold, the cylinder was jammed out a good inch or so, having torn through the dust boot. This left me with basically no pad left and even bent the inner pad and has left some nasty gouges in my nice rotors. Now, I'm going to replace that rotor and swich the rear pads to thermo quiets, since there's nothing left of that set. All of the other brakes appear to be fine, other than the left rear probably needs to have the hand brake adjusted, which I will do once I get the new caliper installed next week.

Thanks for the help. Wish I had gotten to this point sooner. Might have saved me a lot of trouble.