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Discussion Starter · #1 ·
I changed one side and everything went well but on the left side I can't get the piston to retract by turning that 4mm hex in the back, it turns but the piston doesn't move in either direction. Anyone knows what to do in this situation? Kinda need to know tonight so I can drive to work tomorrow :) Thanks a lot!
 

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Get a 'G' clamp, and press the piston back that way, it might be seized so you may need new, so even if you manage to get it back, make sure all works ok at slow speed before you going driving off at speed and things don't work
 

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I would certainly try the C-clamp first. Better yet, Autozone and O reilly's have a device that compresses and rotates simultaneously. This is what I would get.

Make sure the bleeder valve is open when you compress of course!
 

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oh I didn't get that you aren't compressing it with a C Clamp. If it doesn't move under compression then move back to what I was originally saying. One mans internet experience.
 

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It makes it easier to compress, right?
I guess so...Never thought of that....
Normally, in a SAAB 900, the brake fluid reservoir is adequate to wear out the pads on all 4 wheels before running low. Wear out front pads, squeeze fluid back into reservoir while compressing calipers....Same with rears. Exchange fluid at will or whim.
Rarely, there's a problem with fluid return. That's the only time I've opened a hydraulic system to retract/compress a piston.
I don't see where it could do harm, just never heard of it. I've seen paint jobs ruined when brake fluid sprayed out of an open reservoir while the brake caliper was squeezed....Then the guy went to lunch...Paint bubbled by the time lunch was over...Dealer bought new paint job...
Sorry, I'm old, I ramble.
 

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Discussion Starter · #9 ·
I used a C clamp and got it to retract with no problem, interestingly the other side I tried C clamp first and it didn't work but the screw in the back did. It breaks fine however makes the same noise as it did with worn out breaks. I'm going to ride a couple of days and see if it goes away.
 

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what's the noise it makes then, if it sounds like it's 'catching' each revolution you probably need a new disc, there is a min thickness the disc should be, as people think just the pads wear, but the metal wears away too, and when they are thin they can get too hot and warp.
 

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The c-clamp worked because the allen screw was backed out. If you didn't back it out on the other side the clamp wouldn't work so that was normal. The noise could be new pads 'seating' it could be the adjustment isn't right (allen screw turned in and then backed 1/4 turn) or it could be a bad rotor...or any combination of the three.
 

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Was there a ridge of crud/rusty, rough metal along the outer diameter of the rotor? Just above the upper edge of where the pads ride on the rotor. This will make for a scraping sound as it rubs the edge of the pads.

Rotate the rotor by hand while holding a metal edge like a prybar against the crud and scrape it off. You don't need perfection--just reduce the rough metal rubbing the pads.

Yes, turning the rotors would be the nice way to properly fix this EXCEPT the rear rotors on a 900 aren't thick enough to survive a machine shop turning them for you... (they'll be underspec in thickness and now prone to warping 'cause they have less mass to take the heat...)
 

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Discussion Starter · #13 · (Edited)
Was there a ridge of crud/rusty, rough metal along the outer diameter of the rotor? Just above the upper edge of where the pads ride on the rotor. This will make for a scraping sound as it rubs the edge of the pads.

Rotate the rotor by hand while holding a metal edge like a prybar against the crud and scrape it off. You don't need perfection--just reduce the rough metal rubbing the pads.

Yes, turning the rotors would be the nice way to properly fix this EXCEPT the rear rotors on a 900 aren't thick enough to survive a machine shop turning them for you... (they'll be underspec in thickness and now prone to warping 'cause they have less mass to take the heat...)
Yes it had the rusty ridge along the outer diameter just like you described! Pretty extensive one too. Alright I'm going to try what you said and report back. Thanks a lot! Could I use a grinder with a metal brush on it or not??
 

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Discussion Starter · #14 ·
The c-clamp worked because the allen screw was backed out. If you didn't back it out on the other side the clamp wouldn't work so that was normal. The noise could be new pads 'seating' it could be the adjustment isn't right (allen screw turned in and then backed 1/4 turn) or it could be a bad rotor...or any combination of the three.
You're right I did unscrew it all the way before using the C clamp. And I did turn it back in as far is it went (which wasn't far with the new pads) and then probably more like a full turn back rather than 1/4 :(
 

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Discussion Starter · #15 ·
what's the noise it makes then, if it sounds like it's 'catching' each revolution you probably need a new disc, there is a min thickness the disc should be, as people think just the pads wear, but the metal wears away too, and when they are thin they can get too hot and warp.
It makes the metal on metal rough grinding noise only when I break otherwise no sound.
 

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It makes the metal on metal rough grinding noise only when I break otherwise no sound.
Not to be a smart ***, but if you are using written communication as your only means, please use the correct spelling. Your car has brakes. After you get them fixed, you can take a coffee break.

Hats off to you for working on your own car.
 

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If you don't correctly adjust the pads after installation it will make a noise that sounds like 'metal on metal scraping' because the pads aren't making proper contact with the disc

Refer to the tech manuals in the stickies at the top of this forum, adjust the brakes and let us know how it goes
 

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Discussion Starter · #18 ·
Thanks for correcting me! English is not my native language. I scored in the top 2 percentile on the GRE's verbal portion of the test but it's the little things that get ya :)
 

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now hold on.

on these saabs there were two different braking systems. on your rear brake calipers do you only have one line/cable that goes to it? does it just bolt to the car and have one single hydraulic line, and no cable line?

some 900's, like mine, had the parking brake equipped to the front of the vehicle instead. if you do not have a parking brake system on the rear of the car, then just use a C-clamp and slowly compress the piston inwards. EVENLY.
 

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'88 and up the brakes were changed. His is a rear parking brake.
 
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