i've searched and all i found was regarding adjusting the e-brake.
now here's the scenario, i've had this car as a project for awhile, the rear rotors look fine, the pads are nasty. it's a 4cyl 5spd. i don't have a lot of experience driving standards but i knew something was wrong. well tonight i jacked the rear end up and started playing. i began by adjusting the ebrake, and playing with putting it on and off. the first thing i noticed is that no matter what the brake light will not come on, it used to. from the "feel" of things the ebrake is working though. however, i ended up going a step further and just detached the ebrake cable altogether. so i KNOW it's not the ebrake system alone, might still have something to do with it, i dunno.
so anyway, i jacked up the rear end, and put it in neutral. the wheels won't budge, i was actually able to break loose all the nuts on the wheel with it in the air, and i wasn't using an impact. so the back wheels are stuck, both of them, there is no doubt about that. but what i don't know is why.
i'm pretty new to brakes, so all help is welcome, but the car is pretty well undriveable right now and i need to figure this out. what else should i look for? is there a way to adjust the brakes? is there a way to disable the rear brakes temporarily? i ask this because the car needs a body integrity and a safety, and i'm not gonna bother working on the safety until it gets the body integrity.
any other ideas? other than the fact that the rear brakes are stuck, the braking system feels normal, no spongy brakes or anything like that.
thank you

There is (should be) a lever on the inboard ("back") side of the caliper, above the axle. The lever should have a big spring (at least 3/4" inch in diameter), pressing against the lever, tending to rotate it. The direction the spring is trying to rotate the lever, is the "release" direction. You should also find there's a cable running through the spring, that, when pulled, compresses the spring and rotates the lever in the opposite "apply" direction.

If the cable is rusted (or doesn't move freely for whatever reason), it's possible that it's keeping the lever rotated in the "apply" direction even if you've released the parking brake handle. If it looks like that's the case, you might try grabbing the cable end with pliers and unhooking it from the slot in the lever. Next see if the lever is fully rotated to the "release" position - the lever should rest on a "stop" feature cast into the brake caliper. If the lever isn't against the stop, grab it with pliers and (gently) rotate the lever in the "release" direction.

If all that doesn't work, you may have internal problems in the caliper itself. At this point, I would remove the parking brake lever on the caliper (the lever previously mentioned), and "squeeze" open the caliper using a C-clamp and protecting the parking brake shaft with a socket (see Ogre's Cave for details). If necessary, open the bleeder valve on the caliper.

That's all I can offer for now. BTW, it might help to let us know if your car is a 1988 model, or one of the earlier (1984-87) model years... the brakes on the '88s are unique. Good luck !

[This message has been edited by StuGood (edited 03-29-2006).]

Hi, right behind your hubs there is a e brake lever --you`ll see the cable going through the springs in that location, there will be a nut on the e brake lever, put a ratchet on it and move it back-n-forth a few times --it should break it loose for you....Good Luck

DONOT put a c clamp on the rear brakes!!!!!!!
repeat: DONOT PUT A C Clamp on the rear brakes!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

if you can't release them with the lever (which could be frozen), you should remove the caliper from the spindle, remove the pads, and rotor, the reinstall the caliper to the spindle snug, not torqued. look at the piston. you will see 2 holes about 90% of the way out from the center dimple. there is a tool to grab these holes and turn the piston back in to reset it when replacing pads. most auto parts places will have this tool for 10-20$, to do do the brakes correctly you must use this, or you will break the internal parking brake mechanism.(the fierostore has them)
follow your manual as to which way to rotate the piston to screw it in. this is done with the parking brake arm removed from the
back side. if you are lucky you can use a needle nose heavy plier held in tight and a vice grip, but don;t count on it.
pressing the piston back with a c clamp will damage the rachteting mechanism and royally screw up the ebrake.
you can use a c clamp on the fronts, but not the rear.
you need to leave the holes in a specific place too, the pads will have 2 small studs that lock into those holes to stop the piston rotation with pads installed, and allow the ratchet on the ebrake to engage.

ok, actually that spring etc i was trying to play with it. it looked like it was doing something. i removed the cable attached to it and tried to move it the other way, i figured that was the release direction. it is absolutely solid, so that's most likely my problem then correct? is there a way to remove/fix it other than just banging on it til it moves? i tried loosening the bolt behind it but it made no difference.
thanks for the help, at least i have some stuff to look at now

oh yeah, sorry i forgot, it's an 86 4cy, 5spd

[This message has been edited by fierce_gt (edited 03-29-2006).]

quote Originally posted by tjm4fun: DONOT put a c clamp on the rear brakes!!!!!!! repeat: DONOT PUT A C Clamp on the rear brakes!!!!!!!!!!!!!!!!!!!!!!!!!!!!! if you can't release them with the lever (which could be frozen), you should remove the caliper from the spindle, remove the pads, and rotor, the reinstall the caliper to the spindle snug, not torqued. look at the piston. you will see 2 holes about 90% of the way out from the center dimple. there is a tool to grab these holes and turn the piston back in to reset it when replacing pads. most auto parts places will have this tool for 10-20$, to do do the brakes correctly you must use this, or you will break the internal parking brake mechanism.(the fierostore has them) follow your manual as to which way to rotate the piston to screw it in. this is done with the parking brake arm removed from the back side. if you are lucky you can use a needle nose heavy plier held in tight and a vice grip, but don;t count on it. pressing the piston back with a c clamp will damage the rachteting mechanism and royally screw up the ebrake. you can use a c clamp on the fronts, but not the rear. you need to leave the holes in a specific place too, the pads will have 2 small studs that lock into those holes to stop the piston rotation with pads installed, and allow the ratchet on the ebrake to engage.

This must be a model year dependant procedure. My 1986 factory service manual calls for using the C-clamp procedure with a specific warning to avoid damage to the E-brake actuator screw. Using a socket with the C-clamp works very well to protect the actuator screw. I tried the piston rotator tool method, and it is completely useless on my 1986 rear brakes. The C-clamp metheod reccomended by the factory manual works great, AND the E-brake works better than it ever has since installing new pads according to the factory procedure.

-- Dave

I agree with Dave. I know at least for the 84-87 (owned one of each...no 88 yet ) there is no need to rotate them

Best regards,

------------------
~ Shane

Love it, admire it....tear it apart!

my 86 se had to be turned in. it wouldn;t budge with a c clamp.
and as far as the book, try reading it completely.
you can compress it far enough to remove the brake pads,ie barely loose and that;s it.
that applies to ALL model years.
if you compressed your piston all the way in with a c clamp, you have broken the e brake mechanism.
or someone already did it for you and you are gonna be the one to pay the price.
but you don;t have to believe me, or the manual, go take it to a good brake mechanic and ask him about it.

note, this does only apply to rear brakes. feel free to compress away on the fronts.
the tool is a common brake tool, all GM lever actuated disc parking brakes required it.

[This message has been edited by tjm4fun (edited 03-29-2006).]

Here's the GM procedure from the recall bulletin:

Piston Removal

• Remove shoe damping spring from end of piston.
  
• Remove park brake lever.
  
• Remove lever seal and antifriction washer.
  
• Remove piston by turning actuator screw with lever or wrench.
  

Piston Reinstallation

• Install new piston seal. Lubricate seal and bore with brake fluid.
  NOTICE: Make sure that seal is not twisted.
  
• Install new lubricated boot onto new piston with inside lip of boot in piston groove and boot fold toward end of piston which contacts inboard brake pad.
  
• Install thrust washer on actuator screw with copper side of washer toward the piston assembly and gray surface toward the caliper housing.
  
• Install lubricated shaft seal on actuator screw.
  
• Install actuator screw into piston.
  
• Install new balance spring into piston recess.
  
• Guide lubricated piston assembly into lubricated bore of caliper.
  NOTICE: Excessive force is not required to install the piston assembly into the caliper bore. DO NOT ALLOW PISTON TO **** IN BORE AS SEAL WILL BE DAMAGED.
  
• When resistance (seal engagement) is met, rotate piston assembly back and forth to ensure it is square to seal.
  
• Use #J-22269-01 to install piston through piston seal. Shake tool to align piston to the seal while gently turning the jack screw to push piston through the seal to the bottom of the caliper bore. See illustration.
  
  
• Install lubricated antifriction washer and lever seal over end of actuator screw.
  NOTICE: The sealing bead on the lever seal should be against the housing.
  
• Install lever on actuator screw. Rotate lever away from stop slightly and hold while installing nut to 48 Nm (35 lb. ft.). Then, rotate lever back to contact stop.
  
• Seat boot into caliper housing counter bore using new Kent-Moore tool #J-38898.
  
• Install new brake pad dampening spring (included in kit) into groove on end of piston.
  

The piston tool with pins should be used to rotate the piston enough to make the holes align with the brake pad pins.

[This message has been edited by spark1 (edited 03-29-2006).]

quote Originally posted by tjm4fun: my 86 se had to be turned in. it wouldn;t budge with a c clamp. and as far as the book, try reading it completely. you can compress it far enough to remove the brake pads,ie barely loose and that;s it. that applies to ALL model years.

Can you say where in the factory manual that it says to use a psiton rotator tool, because figure 4 on page 5B4-4 only shows the C-clamp method in the 1986 factory manual that I have? Figure 12 on page 5B4-7 shows another direction compression tool (J-23072) to bottom the piston in the bore, but still no mention of a piston rotator.

I am not an expert, so I have to go by the factory manual and assume they know what they are talking about. Also, since I am not an expert, I do read the manual "completely" before I jump in and ruin something.

BTW, I did not need to move the piston to remove the old pads, I just needed to move it back in the bore to get new pads in.

--Dave

we're not talking a rebuild here. this is replacing pads.
you turn the pistons in on the threaded rod that is part of the parking brake actuator.
the direction is not what you would expect. that rebuild procedure in is the chilton manual.
if you have a chilton,go read pg 288, step 7, note for the warning.
on install step one: Bottom the piston into the caliper bore using tool J-36621. turn the left piston in a counterclockwise direction
and the right piston in a clockwise direction to move the piston back into the bore. the piston MUST be bottomed in the bore to install new brake pads.

Those are direct lifts from the factory manual. same instructions for all years.
somewhere there was a good picture on the mechanism that shows how it works and what breaks when you force it in.

I think GM changed their procedure at some point cause I’ve seen both methods mentioned in different manuals. Personally, I wouldn’t use either one.

The easiest way to retract the piston is to remove the e-brake lever, put a washer over the shaft and tighten a wrench onto the shaft where the lever was (use the removed nut). Then the shaft can be turned either direction without being sucked back into the piston. Just wind the piston back into the caliper. No fuss, no muss.

In the case that started this, I’d try loosening the bleeder screws first to make sure the caliper isn’t locked by residual pressure. Also, you want to have the bleeders open when retracting the piston to prevent back-washing crud up the brake lines.

quote Originally posted by tjm4fun:..... if you can't release them with the lever (which could be frozen), you should remove the caliper from the spindle....

Hmmm.... makes me wonder: How do I remove a caliper from the knuckle/spindle, if the brakes are stuck fast to the rotor ?

Anyway, I agree that you'd like to not mess up the caliper if possible, so go gently no matter what method you use to loosen them . If the internal mechanism is truly messed up, you'd probably want to replace the caliper with a rebuilt. Save that Ebrake lever, though, the rebuilts ordinarily don't seem to include that part.

I've thought about using backing the pistons in on mine via sparks method, but when mine were freezing up, i didn't want that to be a continual problem, so I just got rebuilds. they come with a lifetime warrentee, so if it happens again, swap! and I'm done. I guess that is a little bit of an expensive way to do it, but i like having solid brakes.

For what its worth at this point---if you rotate the piston, the L-H side is rotated counter clock wise & R-H side is rotated clock wise... From 88 GM service manual & personall experience..

quote Originally posted by tjm4fun: we're not talking a rebuild here. this is replacing pads. you turn the pistons in on the threaded rod that is part of the parking brake actuator. the direction is not what you would expect. that rebuild procedure in is the chilton manual. if you have a chilton,go read pg 288, step 7, note for the warning. on install step one: Bottom the piston into the caliper bore using tool J-36621. turn the left piston in a counterclockwise direction and the right piston in a clockwise direction to move the piston back into the bore. the piston MUST be bottomed in the bore to install new brake pads. Those are direct lifts from the factory manual. same instructions for all years. somewhere there was a good picture on the mechanism that shows how it works and what breaks when you force it in.

tjm4fun, I am really not trying to be argumentative here, but I can not find any information in the manuals that I have that require using a piston rotator tool to push the caliper piston back in it's bore. I do not have the Chilton manual, but I do have the Helm's official factory manual, the Clymer manual, and the Haynes manual. In the editions that I have, none of them call for a piston rotator tool to push the piston back into it's bore in the caliper. They all say to use the C-clamp method. So far, I have always found the Helm's official factory manual to be the most reliable, and it never mentions a piston rotator tool in section 5B4, the section for the Disc Rear Brake Caliper. That is why I used the C-clamp method even though I had bought the rotator tool.

BTW, The Ogre's web site contains a very large amount of information on the Fiero rear disc brakes, and explains why the C-clamp method is the prefered method for depressing the caliper piston. It also says "GM DOES NOT recommend the use of piston rotation to retract the piston into the caliper in the 84-87 Fiero. Only 88 model Fiero pistons should be retracted by rotating the piston." The Ogre goes on to say "For safety, I have to recommend that the clamp method be used to push in the pistons regardless of type."

-- Dave

No arguements intended! this is for info only. I've been down this route before, thos instructions I put in before are an exact copy of the chilton book, even using the gm part number. it is the same for all model years.
This brake style is not unique to fiero's, many gm cars used it. All my car buddies biatch about the same thing with those calipers, they all have to be turned in to bottom. you can do a little tweak with a clamp to loosen the pads, but if you read all the setup specs, there is only .010-.020 gap on the pad if the ebrake is off and retracted. not alot of space, and that is basically with the piston back to the limit of the ratchet of the adjuster. any more than that is forcing the followers over the thread shaft.
As I said earlier, my 86 would not compress with a clamp, but turned in freely with the tool. one of my friend's sons had an 85 or 87, don;t remember the exact year, and he had the same results, no budge without turning in.
it may compress with enough pressure, but all';s I can say is that all my ebrakes always worked with no hassle, and I always turned them in. I don;t have the official tool, I use an old 1/2 socket that I ground down the sides and left 2 square pegs sticing up about 3/16th inch to grab the holes. works fine.
again, I wish I could find the pic of the mechanism, if you saw it youwould realize that compressing it is only going to damage it.

Here's the image. I agree that you will cause damage if you try to compress the piston without first removing the brake lever. But with the lever off, the shaft can spin freely. If you can't compress the piston with the lever removed, the piston has internal damage.

hehe, now I see why a c clamp kills em. I had my levers off when I spun them in. if that screw spun so easily, I should never have been able to spin it in.
by now look at your pic. now picture a c clamp. where is the anvil of the clamp? on the stud of the parking brake lever if it's centered, or even near center, and that stud is the actuator screw that is supposed to spin. apply pressure. lock the screw against the anvil, and it won;t spin. crunch. only might work if you had a large socke to cover the lever stud to allow it to spin.

just spin the things in, and you don;t have this problem.
I missed your post before on pulling them back in with the washer on the rear side. that is the easiest way and a very nice idea for folks that don;t have the tool.

I think there may be a level of confusion here on the gm manual too, they talk about a clamp, but it has a tool part number. the tool may have a cup on the anvil side to allow the actuaot screw to be spun. a c clamp will not allow that withous something to stop it from resting on that screw/stud.

as for the original problem, first remove the torx screws that hold the caliper asm to the knuckle. sometimes those pistons get frozen also and that makes it even harder to move the caliper. I've also seen metalic pads rust themselves to the rotor, tho a good smack will usually break them free. In this case you can try a c clamp, but only enough to ever so slightly compress the piston and free the pads, but leave that for a last resort

you could aslo try sparks method to pull the piston back, a heavy washer, put the nut back on and rotate it in the opposite direction of the lever normal pull. but don;t use too much force. you can shear off the stud.

For what its worth on ---88`s ---- rear only , if you don`t have that tool , they do sell them in help section, but I got stuck --late one night & cut the old brake pad up--so I would have the 2 studs to spin mine with that are on the back of the in board pad--just a thought , it works,but kind of a knuckle buster..

quote Originally posted by tjm4fun: hehe, now I see why a c clamp kills em. I had my levers off when I spun them in. if that screw spun so easily, I should never have been able to spin it in. by now look at your pic. now picture a c clamp. where is the anvil of the clamp? on the stud of the parking brake lever if it's centered, or even near center, and that stud is the actuator screw that is supposed to spin. apply pressure. lock the screw against the anvil, and it won;t spin. crunch. only might work if you had a large socke to cover the lever stud to allow it to spin.

Which is exactly what was said at the very beginning of this thread!!!
Also page 5B4-4 of the factory manual says "Do not allow C-Clamp to contact actuator screw"

quote I think there may be a level of confusion here on the gm manual too, they talk about a clamp, but it has a tool part number. the tool may have a cup on the anvil side to allow the actuaot screw to be spun.

Page 5B4-4 of the factory manual refers to an ordinary C-Clamp (with a picture included as well). There is no special tool called for in the pad replacement section of the manual, only an ordinary C-Clamp.
In the rebuild section on page 5B4-7 the special tool is shown. but it does not use the C-Clamp method to produce pressure. It has a plate that spans the center gap of the outer caliper section to apply pressure.

A piston rotator is NEVER called for in the GM factory manual rear disc brake procedures for 1986 Fiero. According to The Ogre's Cave web site, the rotator is only for use in a 1988 Fiero, and even then is not the method he reccomends.