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When I rebuilt my factory calipers I cleaned the pistons and bores until I was able to press them in by hand. When I started I could not remove many of them with a compressor and had difficulty even removing them with a tool I made to grab onto the ring the dust cover fits in and a hammer.
Are you trying to press them in while connected to the car to fit pads or are you rebuilding them. If they are attached to the brake line then they should be difficult to press in. A C clamp and a couple blocks of wood is a great tool for pressing them in.
Posts: 389
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Brian jogged my memory. I had a reassembly system of;
1. Place the seals in a tub of brake fluid so they can soak some up.
2. Place the pistons for the caliper to be assembled in a tub of brake fluid.
3. Install the seals inside of the caliper.
4. Make a ring of the caliper grease that came in the Porsche rebuild kits around the end of the pistons that will go in first. I have seen similar grease packets at automotive stores.
5. Push the pistons in by hand.
Then move on to the next caliper.
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No need to do anything to the caliper.
You may be able to push the piston back in by hand if you open the bleed valve. Brake fluid will come out as you push the piston in. Brake fluid eats paint so you do not want to get it on anything. If you have a motive power bleeder it will have a short tube you can place over the bleed valve and into a bottle. If not get some tube at a hardware store to use.
If it will not go in with your hand then a c clamp and blocks of wood to protect the piston and caliper body will do the trick. Although if the piston is out too far then you need to realign it in the bore. You may even be able to push it back in with a c clamp without opening the bleed valve.
If the piston is out too far then you need to realign it in the bore. Although I think fluid would be coming out if the piston was that far out.
Posts: 389
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You can see the bleed valve in this picture
It is the thing right above the 10" mark on the ruler with a black cap on top. If it is the same as the stock 968 bleed valve you will need a 11mm line wrench or atleast a 6 point wrench to open it. Opening one bleed valve on the caliper should be sufficient to relieve pressure and allow the piston to be pushed back in.
(This post was last modified: 10-13-2005, 03:14 PM by
BruceWard.)