88 rear brake calipers (Page 1/1)
swing69 JAN 30, 07:14 PM
I'm getting ready to swap pads on the rear, and I'm looking into "how" to retract the pistons.

I read many previous posts here AND Ogre's cave. In fact, some have said that Ogre's cave did NOT say....its confusing the hell out of me.

I know 88s are different than 87 and back. NORMALLY, the 88 type set up would require TURNING the caliper piston IN to retract it onto the ebrake actuator screw.
I watch a video by another member here, and he split the caliper and used a c-clamp to push the piston back, and you can see the piston rotate, as the c-clamp face on the screw is a ball pivot type.

SO: did the other member KNOW by design the piston would rotate? (I don't know). Should I bypass the clamp, use the block/pin tool and rotate it back????
Some here say READ THE FSM!!!! only rotate it back!!! Some say: use the clamp dumb @ss!

What is your position? and WHY?????? plus; how many have you actually done????
Notorio JAN 30, 10:52 PM
I bought some rebuilt ones, very nicely done too. If you end up needing to go that route just let me know.

While you are waiting for someone who has done it several times to chime in please post a link to the video you mentioned for our edification purposes. Also you can PM the creator of the video and if they are still on the forum you'll get connected.
Shho13 JAN 30, 11:11 PM
Super easy to do, remove the rear parking brake spring and cable, remove the single attaching bolt for the parking brake arm off the back of the caliper, then slide the arm off the caliper. Compress the piston back in like any other brake caliper, with a clamp!

If you remove that arm from the back, you don't need to "spin" the piston to press it back in.

When you re-install with new brake pads, make sure the holes in the piston didn't move and are still clocked up and down so that the little nubs on the brake pads sit inside them. Re-install the arm and pull it several times to ensure the calipers still self adjust and aren't internally seized. (If they happen to be, you will need to send your calipers out to get rebuilt... I sent mine out to Phoenix Caliper in Chicago to get rebuilt a few months ago, they do a great job!) Re-install the parking brake cable and spring, and you're done!

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"Discord"
Red 1988 GT under restoration!

Let's Go Mets!

( ͡° ͜ʖ ͡°)

[This message has been edited by Shho13 (edited 01-30-2021).]

theogre JAN 30, 11:16 PM
88 piston Is Same design but different outside diameter then "old" pistons.

If Piston Rotates w/ C-clamp method Something is way wrong.
Follow Cave, Clamp Method notes

GM had a special Rotate tool make to save time for Dealer Service. Search Ebay etc if you want one.
Rotate the piston w/ GM or other tools can tear the boot and/or main seal.
Boots piston edge can "weld" itself to the piston and tear when rotate to retract.
Main seal can stick some and stretch as piston rotated and have a leak fluid after.

Often Either have problems when piston is "bad" or don't use them right...
Search PFF but try resort by date clicking the small link in upper right.

Tip: Don't follow many to most YT videos...
Many to All on a given topic are made by people w/o a clue, self claim "experts" poseurs, or way worse.
Many are example of what Not to do.
Example: Many YT videos "How to Solder wires" creates more problems and joints made in them often fail for many reasons.

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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

oneinch JAN 31, 12:41 AM
There are inexpensive tools and kits to rotate the piston back in. Many Ford calipers work this way. There are others. Calipers that have the built in cable operated e-brake work this way. It is really quite simple to rotate the piston with there proper tool.

Here's the link to the kit I bought.

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Stanton
'88 Formula, red on gray

swing69 JAN 31, 12:02 PM
It makes sense to:
1) remove the spring and arm to compress the piston with a C clamp, as the center screw will just rotate freely....and when you align the piston, the screw/flats for the arm will be aligned.
2) IF just compressing the piston, it better rotate in if the arm is still attached
3) keep it all together and use the pin / block tool to rotate the piston back down into its bore, stopping in the properly clocked position.

Here' the video: I spoke with the maker (about other things....and he's a really good guy) I"m not slamming him at all, just trying to understand what is happening before I try to do the job....

Starts in at the 13 minute mark: https://www.youtube.com/wat...nel=LostNotForgotton

[This message has been edited by swing69 (edited 01-31-2021).]

theogre JAN 31, 06:20 PM

quote
Originally posted by swing69:
It makes sense to:
1) remove the spring and arm to compress the piston with a C clamp, as the center screw will just rotate freely....and when you align the piston, the screw/flats for the arm will be aligned.
2) IF just compressing the piston, it better rotate in if the arm is still attached
3) keep it all together and use the pin / block tool to rotate the piston back down into its bore, stopping in the properly clocked position.

Here' the video: I spoke with the maker (about other things....and he's a really good guy) I"m not slamming him at all, just trying to understand what is happening before I try to do the job....

Starts in at the 13 minute mark: https://www.youtube.com/wat...nel=LostNotForgotton

I don't care if "he's a really good guy." Video between 13:40 to 14:30 shows only incompetence and What Not To Do.

Again, Piston rotates while C-clamping then Something Is Wrong. This time more so...

It that Video:
1. Did Not remove P-brake lever and nut.
2. Did Not protect the P-brake screw.
3. Very Likely he wreck the pistons and/or P-brake screw or it's bearing "washer" doing this even if they weren't "dead" to start.
4. Many rear Pistons have "died" and blown out the back cover and "fake" retraction using a C-clamp w/ force applied by people w/o a clue.
5. Maybe even damage the caliper shell.

Big C-clamp can Destroy the Piston when used, more like Abuse, in the video above. And that's w/ or w/o # 4 "faking" retraction.

Shorter Terms... If pistons won't easily retract even following Cave directions, The piston and P-brake screw have Major Problems and are "Dead" even if seems to work before started a "brake job."

C-clamp method as shown in my Cave Does Not Need Force to Tighten! I never even use even moderate effort to tighten the clamp in 30+ years of brake work for Fiero and other GM cars w/ same rear Piston setup. IOW When piston needs more then Finger Tip effort to tighten a C-clamp I except to have piston problems and likely won't self-adjust after whatever is done like Pad Replacement.

And before you asked, GM tool is likely going to have problems w/ "dead" pistons too. Or Twist Tools may seem to retract but Piston won't Self-adjust after job is done because inner and outer pistons are full of rust etc. (See my Cave, Rear Piston notes)