For 1984-87 Pontiac Fieros using '90 Chevrolet Beretta Brake Hardware
Randy T. Agee  - The Fiero Ranch
January 1999
Revised & Updated May 2000


The brakes on the 1984-87 Pontiac Fieros are four wheel disk.  They utilize a solid, unvented rotor and have a set of rear calipers that can be actuated mechanically as well as hydraulically.  The mechanical actuation is used for the emergency brake.  Pontiac redesigned the Fiero brakes in their last year, 1988.  This upgrade is NOT for the 1988 model year cars.

The stock 1984-87 brakes will safely stop the car, but for performance and safety oriented Fiero owners, they leave a lot to be desired.

Several methods of improving the brakes are available.  This one uses readily available, off-the-shelf parts that can be bought at any autoparts store.  The mechanical difficulty is what I would call intermediate, meaning that anyone who can overhaul the stock Fiero brakes can easily accomplish this upgrade.  The only complex part that needs to be sent out is the machining of the old Fiero front rotors to create a new rotor-less hub.  Still, due to the low cost of the parts used, the upgrade can be less expensive than using remanufactured Fiero parts.

Please note as you review this article that I am not a brake professional.  I am just a normal (?) Fiero hobbyist who has completed the upgrade described and is willing to share what I learned.  The results you may receive if you decide to upgrade your Fiero brakes may be entirely different.  I cannot attest to the overall safety or long term reliability of the project.  In short, complete the following upgrade at your own risk!


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January 1999

The brakes were not too swift on our 1987 GT.  There was a small right front caliper seal leak.  It was due for a brake job.  The best way to describe the stock Fiero brakes on this car was SCARY.

I made the decision to do the Beretta *FRONT* brake upgrade.  At the time I decided not to do the rear brakes since in Virginia we are required by our state inspection laws to have a working emergency brake.  A price check also showed the Beretta parts were less than half the cost of Fiero parts at AutoZone. 

I did what research I could.  Much of what I found was general information difficult to visualize and missing the specific data my brain required.  Being a visual learner, I wanted pictures.  I couldn't find any.  So, I decided to proceed, learn what I could in the process, and document the whole thing with lots of pictures.

The 1990 Beretta/Grand Am rotors are the same diameter as the front rotors on the '87 Fiero.  The major difference is that they are vented, consequently thicker and obviously less prone to heating, warping and fading.  New rotors from AutoZone were only $13.99 each.  Hard to believe, isn't it?

calipers are those used on a '90 Beretta (see Update #5 below)  Physically, they look a lot like the Fiero front caliper.  But, the distance between  the piston side and the outer pad side is wider (it has to be for the increased rotor width).  The piston in the Beretta caliper is about 10mm larger in diameter.    AutoZone sells remanufactured calipers for $12.99 each, plus a $20 core charge.  The replacement calipers are made of cast iron and will rust (the stock Fiero is alloy).  So, spray with brake parts cleaner to remove any oily film and paint with a high temp engine enamel before you mount them unless you like rusty brown showing through your wheels.

=s standard semi-metallic brake pads for the Beretta (Albany brand) are $13.99 for a two wheel set.  AutoZone has carbonmetalic available for about $26, which are a better choice for the difference in money.   The carbonmetalic pads do not produce as much dust and bite well both cold and hot.  AutoZone also offers a "Z" rated pad for $54.95, but these have not been tested.

I took two old Fiero front rotors, pulled the bearings out and removed the wheel studs.  I dropped off the Fiero front rotors, along with BOTH Beretta rotors, at our local machine shop with instructions to cut off the Fiero rotor so the remaining hub would fit inside the Beretta rotor.  I carefully explained what I wanted to do with the parts so the machinist could do the job correctly.  The machinist did an excellent job.  He took $50 from my wallet as I walked out the door. 

If you have an air chisel, use it with a pointed tool to remove and later reset the wheel studs - it works great!  If not,  a hammer and big punch will do the same.

In the process of having the
old rotors lathe cut (the machinist called this Aparting off@) I learned a few things that you should consider.  The replacement Beretta rotor will not align so that it will spin in a perfect circle UNLESS the new hub is a pretty tight fit.  You see, the center hole where the wheel bearing cap sticks out is too large, and the holes for the wheel studs are much larger than the studs themselves.  So, if the rotor is machined too much, it is possible for the Beretta rotor to be "off center."  In my humble opinion, you should ask to have the old rotor machined  between .015 and .020 inches smaller than the inside of the Baretta rotor.  You might want to ask the machinist to remove the excess length from the face of the new hub to the back edge so it equals the depth of the Beretta rotor.  While this is not necessary, it looks neater.

The new front set-up moves each wheel out 9mm further than stock.  That is the thickness of the Baretta rotor at the hub.  I Installed
new wheel studs that measure 54mm in length.  The originals were 42mm. These were a buck each at Advance Auto (AutoZone did not stock them).  Stock studs will work OK since the rears on the Fiero are also 42mm long and have a similar rotor placed over the stock rear hub, but since I was installing new studs, I went for the longer pieces.

I decided to spray the modified Fiero front hubs with high temp engine enamel before I assembled the parts to help reduce rusting. I smeared a thin coat of antiseize on the inside of the Beretta rotor that goes over the Fiero hub as well.  I have some fears of time and rust making a semi-permanent bond between the two.  Hopefully this will slow down that process.  Care must be exercised with any release agent used - we don't want to contaminate the brake pads!

I also purchased a
new glide pin set for the Beretta rotors. You could reuse the Fiero pins (bolts?).  But, the heads are larger on the Fiero pins and stick out more than I liked.  Still, they do not hit or interfere with anything, so it is your call as to what to do.   AutoZone stocked them for $3.95 a set.  Lightly lube the pins before you put them into the slides with some brake part's grease.  Do NOT lube the outside of the slider tube that fits inside into the rubber bushing.

You must file or grind some metal off of the inside of the caliper mounting bracket.  If you don't, it pushes against the inside of the rotor.  I took mine off to do this and used a 4" hand grinder.  The original thickness at the mounting points was 21mm,  I cut them down to 18mm.  Using washers as spacers between the knuckle and bracket to achieve the same result will not work as this will cause the caliper to be too far off center.   A few drops of Locktite 202 on the bracket bolt threads and on the ends of the glide pin bolts are necessary.  Don't forget to clean the threads with spray brake parts cleaner first.  Also please note the excess metal is removed on the INSIDE of the bracket.  NOT on the outside where the caliper mounts.

The stock Fiero brake hoses work fine, but you will need to open the clamp around the center of the hose enough to slide/turn it a bit.  I used a pair of Channel-Lock pliers to open the bracket a tad.  The hose will need to be twisted 90 degrees to fit the new caliper.  Don't forget to clean the bolt that attaches the hose to the caliper with spray brake parts cleaner and to use the new copper washers that come with the rebuilt caliper.  The larger diameter copper washer goes on the outside, the smaller on the inside.  Also remember you have a left and right side caliper.  The brake hose holes go UP, not down.  Better braking performance can be achieved with new hoses - remember, yours are at least 12 years old.  Braided steel hoses give extra protection from damage and a firmer pedal - might be a good time to upgrade these as well.

The brake splash shield will most likely rub the inside of the Beretta rotor.  It will need to be bent back a little to provide clearance. 
I had to cut a small piece off of the top tip of the shield to clear the Baretta caliper when I bent it back.

I replaced both inner and outer wheel bearings.  The outer Fiero bearing looks like something out of a wheelbarrow.  Next time you rocket down the road at 100 mph, remember those cheesy little outer bearings.  They should be serviced every time you change oil anyway.  You will also need a new inner grease seal. 
The right tools make this a simple job It is nice to have a seal remover, driver and grease packing tool.  I used Mobil 1 Synthetic High Temperature grease in the front bearings as a little extra insurance.  If you don't have the right tools, buy an extra seal or two.  You will most likely distort them trying to do the install with a block of wood and a hammer.  This is defiantly one place you do not want grease to leak out and get on the brake pads & rotors!  The spares will come in handy.

I threw for a
Mighty-Vac one man brake bleeder kit ($25.00) to make the job a little easier and cleaner.  It is a welcome accessory tool.  I picked up two large bottles of Valvoline DOT-4 Synthetic brake fluid and completely flushed out the old fluid in the system.  I did this BEFORE I put the new calipers on.  The old fluid looked like dirty motor oil.  DOT-4 is a suitable replacement for older DOT-3 (which came in the Fiero).  DO NOT change your system over to DOT-5 silicone fluid.

I did the initial upgrade in three steps.  Driving the car after each change and noting the changes.  In step one I only changed the front brakes.  I used the stock Fiero master cylinder and left the rear brakes "as is."

I was very impressed when I first test drove the car after the step one upgrade.  The results were impressive, but the front brakes had too much pinch.  I was afraid that Nancy could get into trouble on a wet road.  Pedal travel was further than it used to be, but effort was considerably reduced over stock.  I noticed an unusual "catch" as the pedal passed the point where it stopped with the stock Fiero front brakes.  I suspect the original master cylinder had a lip or some sort of trash in the bore that caused this when the piston moved into virgin territory.  This bothered me, so I decided to proceed to step two.

In step two I replaced the stock master cylinder with a new master cylinder for a 1994 full size Blazer (about $40 at AutoZone - no core required).   This master cylinder has a larger bore and piston (1-1/8"), which moves more fluid for a given distance.  The outside is physically identical to the Fiero master cylinder and bolts right on.  The new master cylinder came with a larger fluid a reservoir.  The new reservoir needs to be replaced with the lower profile Fiero reservoir.  Just pull the new one off, and press in the recycled Fiero reservoir.

When I took the car for a test drive with the new Blazer master cylinder and the upgraded front brakes (remember-the back brakes have not been touched) pedal travel and effort were similar to the stock Fiero before the upgrade.  But, there was still too much front wheel pinch to make me happy with my bride behind the wheel.

So, I decided to go ahead and toss the emergency brake and put the Beretta stuff on the rear too.  The backs are a direct bolt-on.  No modifications are needed other than twisting the brake hose and storing the handbrake cables.

With new bakes on all four corners, a new master cylinder and fresh fluid, the little red car will stop on a dime.  There is only one word to describe the changes experienced. ****AWESOME!!!****  For me, It was worth every penny spent.  The overall cost was actually LESS than fixing and replacing the same parts with stock Fiero hardware.  It is not hard to do.

If you want an emergency brake, my advice is not to do the rear conversion.  While alternate methods of including an emergency  (or parking) brake can be created, all require additional brackets, machining and $$$.  Remember, this is an INEXPENSIVE, EASY upgrade using off-the-shelf GM parts.  To do otherwise defeats this conversions purpose.


A PARKING brake was created on a later manual transmission conversion using a Jamar In-Line Hydraulic Brake Lock (J.C. Whitney - 85XJ6592Y, $23.95).  This lock can be spliced into the existing steel brake lines by cutting and double flaring.   Depending on where you locate the lock, additional brake tubing may be needed.  The lock knob can be replaced with a fulcrum operated by the existing emergency brake cable to push the knob down while the brake pedal is depressed , or simply positioned in an accessable location - like protruding up through the driver's floorboard next to the seat.  This will lock the rear brakes by depressing the brake pedal and pushing the knob on the lock down.  When you depress the pedal again, the lock releases until the pedal is depressed again (also makes a great hill-holder)  If you decide to use the emergency brake lever to activate the lock, be sure to remove the ratchet from the stock e-brake lever next to the driver's seat  (I did not want to leave the Jamar knob locked down).  Other than that, you are pretty much on your own in making this work.  I have decided against giving any detailed instructions, but will advise you to be sure you have the proper tools to cut, splice, double flare and flush steel brake lines.  This is one project where sloppy workmanship or shortcuts just will not do!  BTW - the electric line-locks will not work, they require 12 volts to keep them locked, a sure prescription for a dead battery!  Also note that this is a PARKING brake, not an EMERGENCY brake solution.  Most likely, it will not satisfy state inspection emergency brake requirements.

Wilwood  (http://www/ also makes a small add on mechanical
spot caliper.  For the energetic, auxilary brackets need to be fabricated to mount the caliper next to the main caliper and activated with the existing e-brake cable assembly.  Such an arrangement is somewhat complex and adds about $175 - $250 to the overall cost, but possible for someone with access to metal fabrication tools and good mechanical insight.

In retrospect, I have a very strong feeling that the extra front pinch might have been reduced had the stock rear Fiero brakes been in good condition.  The pads I took off of the rear of my car, while still thick enough to look good, were heavily glazed and had many cracks in them. 

Since I completed the first upgrade, many e-mails have arrived with questions and additional experiences from those who have also chosen to complete the upgrade.  While I hope that most of those questions have been answered in the rewrite above, I know some are not.  I will "TRY" to answer future E-mail questions where possible.  But, PLEASE remember - I am not a brake professional!  I am a Fiero hobbyist who wanted his car to stop better, and more safely.  I took the work others have done before me and tried to expand the project directions, adding little quirks I found in the process.  What I did is not the last word, or the absolutely best way to proceed.  I cannot tell you that you will receive the same results I did or be as pleased.  And most important, I can make no claims or promises for the safety of the brake upgrade over stock.  As it is often said, "Proceed at your own Risk."

The cost of machining the rotors into hubs seems to vary considerably from one shop to another.  I paid my machinist $50 for both hubs.  Others have reported paying up to $150 for a pair.  You might want to obtain an estimate of the machine shop cost BEFORE you give them the job.  But, keep in mind there is a fair amount of machine work required to do the job right.  My $50 invoice was apparently a real bargain!

The rotors available from AutoZone (made in China) seem to have a wide tolerance range on the thickness of the area the Fiero wheel studs slip through.  Some rotors have been reported to be as much as .050 thicker than others.  The rotors that are thicker in this area may cause the pads to rub since they set the rotor out further.  These thicker rotors should work fine on the rear of the Fiero.  You might need to remove some material from the caliper with a file to center the caliper if you encounter these rotors.  If you do need to remove material from the caliper, do it carefully so the flats are maintained.

For those who have asked for part numbers......  I hesitate to give these since it is MORE likely that you will get the WRONG part than if you ask for the part by the year, make and model of the vehicle the parts were originally used for.  Part numbers can vary greatly from one source or vendor to another.

For those who wanted to know why I did not use the Beretta rear calipers on the Fiero.....  There are none.  The Beretta used drum brakes on the rear!

As for the suggestion to use the rear calipers off of a late model Camaro....  They will not fit without an adapter bracket AND the actuation levers move in opposite directions. 

The correct parts were used on a number of GM vehicles.   From 1985 - 1991 the Chevrolet Beretta, Cavalier and Corsica and the Pontiac Astre, Sunbird, 2000 and J2000 all used the same brake parts.  The Pontiac Grand AM used identical parts ONLY from 1985 - 1990 (NOT in 1991).   In 1992 the Beretta changed to 10.25" rotors.  While these rotors WILL fit on the Fiero and the calipers WILL fit the existing bolt holes, the larger diameter rotor rubs the caliper mounts on the Fiero.  Using these would require fabricating caliper mounting adapters.

Click here for additional photos of the front and rear brake assemblies both BEFORE and AFTER conversion.

Randy T. Agee
The Fiero Ranch
5046 Sandy Valley Rd.
Mechanicsville, VA 23111


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