87 GT Brake Woes (Page 1/2)
AndrewTHG AUG 24, 09:27 PM
I am getting around to doing the brakes on my 87 GT finally! Braking on my car has never felt great, and I don't think the lines have ever been replaced nor do I know the last time the brake fluid was changed. So I am putting in new hoses, fluid etc. and some questions have come up as I dig deeper, so looking for some help on these!

1. First, I ordered ACDelco Gold SAE J1401 hoses that seem identical to the ones that are already on the car. I assume the ones on the car must be original - they are old and crusty but I honestly don't see any leaks. Not sure if these could cause mediocre braking , but I am hoping the new ACDelco ones will help.

2. I have crazy uneven pad wear on both the front driver and front passenger sides. It is the outer pad on both of them that is worn down much more. I checked the bolts and sliders and nothing seemed seized, so not sure what could cause this. I did notice the piston sticking out on the inside but assume this was just to compensate for some pad wear.

3. Should I push the piston back in while I am doing all of this work? I believe I can just use a C-Clamp for the front rotors to push it back in?

4. Should I buy new pads to be safe? A shop a year or two ago replaced the front pads and rotors, but it is crazy the thickness difference between the inner and outer pad on each side. Perhaps the outer pad is draggin? But then what would that indicate? Sticking sliders? If I buy new pads, is it a necessity to get new rotors since I just got these ones and it seems like a pad issue mostly?

5. Can I just unhook the hoses and replace with new ones (and copper washers)? My plan here was pull some old fluid out of the master and top off with fresh fluid. Then disconnect the old hose and attach the new hose, placing a bucket under the hard line so that any fluid that comes out drips in there. I assume it is not going to come out fast enough that this is an issue? Any better suggestions

It's been too long since I have been able to work on this car, so I am enjoying getting back into it! Hopefully there will be an end though so I can finally drive it...or at least less working on it and more driving! Next up is going to be AC and deckled struts so stay tuned for more questions down the road, and thanks as always!
theogre AUG 24, 11:54 PM
1. New hose is supposed to look the same but is a lot better then OE. See http://www.fiero.nl/forum/Forum2/HTML/129208.html rubber brake lines vs stainless steel

2. Think Outer pad is thinner to start...
"O-rings" for sliders are "return springs" for outer pad. If slider grease is wrong type and often are when anyone takes them apart then O-rings don't work.
That's on top of binding pistons causing problems. Get new slider O-rings at min and use Permatex Green label brake grease.
See my Cave, Brake Service and rest of section.

3. push front piston back w/ any clamp, Big pliers etc. Should be easy unless pistons have crap in the bore and bind them.

4. Uneven wear see 2. May need new pads if near metal back on "glue mounted" friction. Rare but possible friction uses rivets and if true must have enough pad so rotors can't touch the heads.

5. Fluid won't run fast but you can't let MC run dry while fooling w/ hoses either. Wait to replace them unless old ones have problems causing piston problems.
Replacing hose then first step is try to open the bleeders. If they break... just get new front calipers and replace both then.
Note: Very Careful use of heat on frame end fitting of hose is often required to release the nut on hard line. You likely will boil some fluid and if hits you ouch is way understatement... You need Chemical Resistance Googles and other PPE when doing that. Safety Glasses, Googles w/ "screen" sides and related are not good enough.


------------------
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

[This message has been edited by theogre (edited 08-25-2022).]

TinaBeyer AUG 25, 07:39 AM
I am not sure, but I may have a problem realizing when it is enough pad that rotors not to touch the heads.
fierofool AUG 25, 08:42 AM
Andrew, I used Syl-Glyde lube on my slider bolts for years, but changed over to Permatex High Temp Brake Lube and I'm much more pleased with it. I not only pull the slider bolts out, but the sleeves, too. Clean, lube, and reinstall.

Old brake lines can start to deteriorate inside. Pieces begin to stand up like splinters or fish scales and depending on the direction they're still attached, can prevent fluid from going to or from the caliper. They act like a one-way valve. I had a brake fire when that happened to me. It was a new caliper but apparently bending the hose around while doing the job caused the inside to begin to come apart. It let fluid and pressure go to the caliper but not release.

I don't think I've ever done a brake job on any vehicle that I found even pad wear. I just helped my son in law do his 2019 F150 and there was far more wear on the outside pad than the inside. When brakes are applied, the piston pushes and that draws the outside pad to the rotor. It doesn't back away as much as the inside pad when pressure is released. Unless you have serious scoring on your rotors there's no need to replace them again.

When changing calipers or lines, I use the rubber vacuum caps that you can find on the HELP rack at the parts stores. Use the proper size to cap the metal line.
theogre AUG 25, 09:03 AM

quote
Originally posted by TinaBeyer:
I am not sure, but I may have a problem realizing when it is enough pad that rotors not to touch the heads.

If the pads have rivets, again rare for decades now, you quickly see damage if the rotors touch just 1 rivet head. Most times that is let go long enough you need new rotors...

You might see some rivets going thru the metal on outer pad or not. If not, Pull the brakes and look at pads used.
AndrewTHG AUG 25, 10:05 PM
Thanks for the info everyone! So for the grease, I grabbed Permatex Silicone Ceramic Extreme Brake Parts Lubricant 80653. I am hoping/thinking that one ought to do.

And it looks like my one brake line was replaced and the others are original. The driver side has a rivet I drilled out, whereas the passenger was affixed with a bolt. Regardless, I am going to change them all out.

Good to know on the pads - I was hoping I wouldn't have to change them out already. They seem like they have ample thickness, it was just the unevenness that concerned me.

It's been...fun...so far. Every day I pick a couple frozen fasteners to tackle. The bleeders were a real treat today but I was able to get the fronts loose. I am just waiting for my luck to run out. We'll see what tomorrow holds!
hunter29 AUG 26, 09:18 PM
I would do the MC while your at it.
AndrewTHG AUG 28, 12:32 AM
Honestly the MC seems like it is in pretty good shape so I am going to hold off for now at least!

I did however tear one of the bolt boots on the front caliper that houses the T50 Torx bolts...unfortunate...but all things considered this could have been a lot worse so far.

Is there a way to replace this boot/seal? I haven't't seen anything and I don't want to trash a caliper just for that. If no replacement seals, I was debating trying some black RTV around the tear to seal it up.
fierofool AUG 28, 07:53 AM
Advance and Auto Zone are listed as selling the Dorman Brake Hardware Kit Part # HW5592
Disc Brake Hardware Kit
Application Summary: Pontiac Fiero 1987-85

The Snellville Auto Zone has it. https://www.autozone.com/br...sIgnoreVehicle=false

Or, you're close enough to go to the Pull A Part South Yard and pull some used ones off the Fiero that's located there.

BTW, Georgia Fieros meets on the 10th at The BBQ Place, 2365 Powder Springs Road, Marietta at 10 AM. Would love to have you finally join us.

[This message has been edited by fierofool (edited 08-28-2022).]

AndrewTHG AUG 28, 05:51 PM
Thanks fierofool! Exactly what I needed. At first I thought the seal was pressed under some sort of washer but then I realized it is just molded around it and once I saw that, I got the rest out with ease. So one casualty out of all of them isn't too bad. Now I need to clean them as well as the pins up (some 2000 grit sandpaper to remove a couple rust spots should do it). And I see it comes with the slider seals too which is awesome because I have a few of those I want to replace as well!

Popping the pins out definitely opened my eyes up to the braking issues I had been having. Passenger rear was almost frozen in place with minimal movement.

Unfortunately I had another casualty today though...I tore the upper dust seal on the front passenger caliper trying to clean the piston, and then popped the piston out. Any leads on the P/N for the seal/O-ring, and maybe the piston too? Mine seems like it is in pretty good shape but has some mild scoring (its the metal piston). If they don't have pistons, is it okay to hit this real lightly with some sand paper to remove any burrs?

And thanks for the heads up on the event! I will have to attend once the car is road worthy again. Right now its looking like it won't be until later in the year (my wedding weekend is actually that weekend so I will be busy for a while here). But once it's back on four wheels I will have to meet up! I see caffeine and octane was on the event list as well - sounds like a good plan to me!