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Discussion Starter #1
I’ve looked all over this forum and haven’t found anything on how to actually replace the front brake pads on my GT. I don’t really see any way to get them out.


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Opel Rallier since 1977
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I assume they are like for the Manta/Ascona: Look at each caliper casting from the outside and you will see 2 small holes in the outer edge, either side of center, and outside of right where the pads sit. These are the outer holes for some dowel pins that hold in the pads. Shoot some PB Blaster in those 2 holes, get a small diameter punch that fits in those 2 holes, and start tapping inward through the holes, one at at time. That will drive the dowel pins inward and they will loosen up and you can remove them from the inside of the caliper, and then slide the pads out.

Once the pads are out, then you have to get a wide flat pry bar and pry gently between the rotor surface and the pistons, one on the inside of each rotor and on the outside side of each rotor. Be gentle so you don't damage the rotors. You have to push these 2 pistons in each side back into the caliper body to get space for the new pads to slide in place. And once one is pushed back, insert a bit of wood, or a new pad, between it and the rotor so it does not get pushed back out of the caliper as you push the other piston in... hopes that makes sense.

Once the new pads slide in, then you put the dowel pins back in from the inside of each caliper, and gently tap them flush
the caliper surface. There are spring rings that will hold into the caliper. The pins look similar to these (and you can get new ones if needed from OGTS): Opel GT Source

If the caliper pistons won't push back, then you have to pull the calipers off and try something like a c-clamp to push the pistons back. If that does not work, then you are disconnecting the brake line to get the calipers removed, and or rebuild or replace the calipers, then bleed the system.

Keep all grease and/or oil off of the pads and rotors. Use some brake cleaner to clean the rotors off and any oil-grease that gets on the friction surfaces.
 

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Registered
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Discussion Starter #3
I assume they are like for the Manta/Ascona: Look at each caliper casting from the outside and you will see 2 small holes in the outer edge, either side of center, and outside of right where the pads sit. These are the outer holes for some dowel pins that hold in the pads. Shoot some PB Blaster in those 2 holes, get a small diameter punch that fits in those 2 holes, and start tapping inward through the holes, one at at time. That will drive the dowel pins inward and they will loosen up and you can remove them from the inside of the caliper, and then slide the pads out.

Once the pads are out, then you have to get a wide flat pry bar and pry gently between the rotor surface and the pistons, one on the inside of each rotor and on the outside side of each rotor. Be gentle so you don't damage the rotors. You have to push these 2 pistons in each side back into the caliper body to get space for the new pads to slide in place. And once one is pushed back, insert a bit of wood, or a new pad, between it and the rotor so it does not get pushed back out of the caliper as you push the other piston in... hopes that makes sense.

Once the new pads slide in, then you put the dowel pins back in from the inside of each caliper, and gently tap them flush
the caliper surface. There are spring rings that will hold into the caliper. The pins look similar to these (and you can get new ones if needed from OGTS): Opel GT Source

If the caliper pistons won't push back, then you have to pull the calipers off and try something like a c-clamp to push the pistons back. If that does not work, then you are disconnecting the brake line to get the calipers removed, and or rebuild or replace the calipers, then bleed the system.

Keep all grease and/or oil off of the pads and rotors. Use some brake cleaner to clean the rotors off and any oil-grease that gets on the friction surfaces.
Thanks a lot. I ended up needing a lot of force to compress the piston cause it was pretty seized, but I managed.


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Opeler
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You have to push these 2 pistons in each side back into the caliper body to get space for the new pads to slide in place.

I remove Master Cylinder Cap (on the Reservoir) to allow trapped air / fluid to escape while moving the caliper pistons back. Install master cylinder cap prior to pressing brake pedal, or you will have brake fluid all over engine compartment.
 

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Opel Rallier since 1977
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1,219 Posts
Thanks a lot. I ended up needing a lot of force to compress the piston cause it was pretty seized, but I managed.


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Yep often when the pads are really worn and the pistons move waay out in the calipers, the pistons move into areas where they can cock a tiny bit and seize up more easily, or move where rust and crud can lock them in place.

BTW, I would suggest very strongly that you bleed the brakes with fresh fluid. It wil have accumulated a lot of dirt and moisture; this will make things last longer.
 
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