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1985 Alfa Romeo GTV6
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Discussion Starter #1
I've searched the forum but can't seem to find the info I'm looking for. Wondering if any of you might have some solutions.
Situation: I am rebuilding the front Brembo calipers on my 1985 GVT6

1) Once you get the two halves of the caliper apart, what is the best way to remove the piston if you DON'T have compressed air? Can you just pull it out with non marking pliers or something like that?
2) What is the best lubricant to use when putting it back together (for the piston, etc)? Should one just use brake fluid, or is something like Sil-Glide better? I know that people use Sil-Glide on calipers with sliding pins, but not sure what the best thing for pistons is.
3) Both pistons have a "C" shape on the end that pushes the brake pad, meaning that it's not totally flat. Is this how the piston is supposed to be? Both sides have it.
4) What can you use the clean road grime off the caliper housing without removing the black paint (i.e. not brake cleaner)?
5) Lastly, when you reassembly the two halves back together, what is the torque spec for the 10mm hex bolts?

I apologize if this info is already somewhere else. It's obviously not on the cardisc, and I can't seem to find where these steps would be. Any help would be appreciated.
Thanks, all.
 

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1) You pump the pistons out using hydraulic pressure before you separate the calipers.
2) Rubber grease intended for purpose.
3) The C shape needs to be correctly orientated with regard to the rotation of the disc
4) Proper quality brake cleaner does not remove paint
5) Tight.
 

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Yes, regarding #1... you gotta put the calipers back together, and don’t forget the little o-rings between them. Once they are back together, use pressure (I used an air compressor) to push them out. But... before you do this, insert a piece of wood between the pistons leaving about 3/8” gap on each side. The trick is that you want both pistons to be forced out TOGETHER! So use the wood to ensure they both are pushed out equally. If one pops out only, you’ll never get the second one out! Once they are 3/8-1/2” out, you can pull them out the rest of the way... good luck!
 

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1984 GTV6 (Maratona)
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Just disassembled my rear brakes to prep for re-plating. :oops:

IMG_1272[1].JPG

Let me know if you need any pictures of the individual parts, I'd be happy to send them to you or post.
 

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I've rebuilt many of these calipers. Hope the advice below helps.

1) If the pistons are not stuck, you can use two modified pry bars or screwdrivers to pry up the pistons (ground to follow contour of the piston) from the groove. DO NOT try this if they are stuck, you will simply break off the piston above the groove. If they're stuck, reassemble the calipers and get pistons unstuck FIRST.
2) ATE part number 03 99 0 205 242 OR the same brake fluid you plan on using. I prefer the ATE paste. DO NOT use SilGlide.
3) See image.
4) The calipers are NOT painted. They are anodized. These calipers are not the most resilient units. If they've been exposed to a lot of moisture, road salt, or neglect they almost certainly will be pitted. They corrode readily. The proper way to restore these calipers is have them media blasted, de-anodized, tanked, and re-anodized after removing all ferrous contamination from brake dust. Otherwise they will continue to corrode. If you're doing a quick rebuild, once they are totally disassembled you can use parts washer fluid that is alloy friendly if you are going to thoroughly clean all traces of it away. My final step before assembly is hot, soapy water followed by a bake in the oven at about 200 to dry them. Take your time on assembly.
5) No more than 37 ft lbs "dry." If using an antiseize or grease, adjust accordingly. And, they should be pattern torqued. Remember we are discussing steel bolts threaded into aluminum. If the bolts are corroded or damaged, REPLACE them.

I have some new, or re-plated bolts here if you need them. I also have lots of other Brembo caliper parts. Good luck.
 

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1985 Alfa Romeo GTV6
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100 Posts
Discussion Starter #7
I've rebuilt many of these calipers. Hope the advice below helps.

1) If the pistons are not stuck, you can use two modified pry bars or screwdrivers to pry up the pistons (ground to follow contour of the piston) from the groove. DO NOT try this if they are stuck, you will simply break off the piston above the groove. If they're stuck, reassemble the calipers and get pistons unstuck FIRST.
2) ATE part number 03 99 0 205 242 OR the same brake fluid you plan on using. I prefer the ATE paste. DO NOT use SilGlide.
3) See image.
4) The calipers are NOT painted. They are anodized. These calipers are not the most resilient units. If they've been exposed to a lot of moisture, road salt, or neglect they almost certainly will be pitted. They corrode readily. The proper way to restore these calipers is have them media blasted, de-anodized, tanked, and re-anodized after removing all ferrous contamination from brake dust. Otherwise they will continue to corrode. If you're doing a quick rebuild, once they are totally disassembled you can use parts washer fluid that is alloy friendly if you are going to thoroughly clean all traces of it away. My final step before assembly is hot, soapy water followed by a bake in the oven at about 200 to dry them. Take your time on assembly.
5) No more than 37 ft lbs "dry." If using an antiseize or grease, adjust accordingly. And, they should be pattern torqued. Remember we are discussing steel bolts threaded into aluminum. If the bolts are corroded or damaged, REPLACE them.

I have some new, or re-plated bolts here if you need them. I also have lots of other Brembo caliper parts. Good luck.
That's amazing info. Thank you! Btw- where did you get that pic? Is that from an old Brembo manual?
 

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1985 Alfa Romeo GTV6
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Discussion Starter #8
Just fyi- here is one of the calipers. My car has lived its whole life in CA, so no snow or salt. As far as I can tell, there is no rust on the caliper, but just road grime and brake dust. But there IS rust on the interior of the piston, which I'm assuming I can hit with a dremel wire brush (obviously not on any of the machined surfaces; just the interior). Does anything on the caliper itself look like rust to you?
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