Splitting Calipers pros/cons?
06-23-2006, 12:23 PM
#32
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Pesty-
1. First you will need an air compressor to blow air into the lines -
2. Second cover all exit ports except the one you are going to use to blow air into -
3. Get 2 blocks of wood that are narrow enough to fit down between the two caliper halfs and leave about a 1/2 inch of play for one block and about an inch for the other block
4. Set air pressure to a low setting - Set the first block of wood in the caliper and blow air into the port
5. The calipers pistons should each pop out a little until they come in contact with the block of wood.
6. Remove the first block of wood , replace with second block of wood and reduce air pressure further - then blow air into port- pistons should come out further.
7. At this point you should be able to remnove the pistons by hand.
8. Odds are that you will distroy several of the dust (seals) covers in the next process . The dust covers tend to get stcuk to the caliper - I used a small screw driver that I have filed down and rounded the tip so it is smooth. Gentle here but go around the outside of the dust cover looking for apoint to get under the cover with the screw driver an gentle work the cover free. Here the dust cover may stick or tear as you try to remove - so be careful - they are fitted into a small grove around the piston area and pressed into place.
9. The seal for the piston should come out with the piston so ther eshould not be a problem getting the seals out.
10. Removing the pistons - they are very tight, so be careful not to twist and jam sideways as you remove. DO NOT GRAB the outside of the piston with any metal tool unless you plan to repace.
Use the lip that the dust cover fits into as point to pull on - but use a plastic bar or plastic clamp to help-
Hope this helps .
1. First you will need an air compressor to blow air into the lines -
2. Second cover all exit ports except the one you are going to use to blow air into -
3. Get 2 blocks of wood that are narrow enough to fit down between the two caliper halfs and leave about a 1/2 inch of play for one block and about an inch for the other block
4. Set air pressure to a low setting - Set the first block of wood in the caliper and blow air into the port
5. The calipers pistons should each pop out a little until they come in contact with the block of wood.
6. Remove the first block of wood , replace with second block of wood and reduce air pressure further - then blow air into port- pistons should come out further.
7. At this point you should be able to remnove the pistons by hand.
8. Odds are that you will distroy several of the dust (seals) covers in the next process . The dust covers tend to get stcuk to the caliper - I used a small screw driver that I have filed down and rounded the tip so it is smooth. Gentle here but go around the outside of the dust cover looking for apoint to get under the cover with the screw driver an gentle work the cover free. Here the dust cover may stick or tear as you try to remove - so be careful - they are fitted into a small grove around the piston area and pressed into place.
9. The seal for the piston should come out with the piston so ther eshould not be a problem getting the seals out.
10. Removing the pistons - they are very tight, so be careful not to twist and jam sideways as you remove. DO NOT GRAB the outside of the piston with any metal tool unless you plan to repace.
Use the lip that the dust cover fits into as point to pull on - but use a plastic bar or plastic clamp to help-
Hope this helps .
06-23-2006, 01:13 PM
#34
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Dave - Am not really sure - I just turn the adjustment screw down until it feels right - Sorry -
I guess I would recommend starting low - like 25 psi and then increaseing until you get the pistons to move - once they sart moving back off - re adjust as they will move faster once started - but you may need more pressure to start. The big thing here is make sure that ALL 4 PISTONS MOVE OUT - don't leave one still in the cylinder as it will become a nightmare to get out. This is why you use the fist block of wood that only allows the psitons to travel a little way out. You keep the seals working in your favor.
I guess I would recommend starting low - like 25 psi and then increaseing until you get the pistons to move - once they sart moving back off - re adjust as they will move faster once started - but you may need more pressure to start. The big thing here is make sure that ALL 4 PISTONS MOVE OUT - don't leave one still in the cylinder as it will become a nightmare to get out. This is why you use the fist block of wood that only allows the psitons to travel a little way out. You keep the seals working in your favor.
06-23-2006, 02:04 PM
#36
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Thanks Gus I wish I'd read your post before I started
but time was pressing on and Im an impatient bugger.
all the pistons came out eventualy but it was a fight using G clamps and pieces of rubber to cover the holes when only one piston came out.
After messing the first two calipers up I worked out a method that was basicaly as u suggested but I used 2 brake pads instead of wood as that was the only thing I had availabe at the time. Im a slow learner and was never good at puzzles. Gave all the guys at work a laugh anyway.
No seal came off with the pistonds they all stayed in. tried to remove a dust cover before I saw you post and bent it all to hell
so I left the others. I will give your method a try next week.
but time was pressing on and Im an impatient bugger.all the pistons came out eventualy but it was a fight using G clamps and pieces of rubber to cover the holes when only one piston came out.
After messing the first two calipers up I worked out a method that was basicaly as u suggested but I used 2 brake pads instead of wood as that was the only thing I had availabe at the time. Im a slow learner and was never good at puzzles
. Gave all the guys at work a laugh anyway.No seal came off with the pistonds they all stayed in. tried to remove a dust cover before I saw you post and bent it all to hell
so I left the others. I will give your method a try next week.
06-26-2006, 03:04 PM
#37
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The dust covers are a go slow process, depending on how tight they are pressed into the surounding grove. The very small screw drive (flat blade) with sharpe corners filed smooth and edges rounded off seems to work best for me . You can tear the skirt and still have a job getting the part of dust cover in the grove out - work slow/ drink little beer - more when the job is done - From my experience I would say you can probably count on replacing 2 dust covers per caliper ( given 4 per caliper ) - they are just hard to get out
07-11-2006, 05:38 AM
#38
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Thanks Gus,
Got all the dust covers out only damaged 2.
I am at work now and there are some outside contractors in who said that they will powder coat them for if I mask off the holes where the pistons/seals were.
SO I have 2 options either take them down to Big red and have them powder coat the calipers and spend cash or get them done for free
Ian I will still take the calipers to big red and have them check out for the seals
Anyone know how I can do the masking?
Got all the dust covers out only damaged 2.
I am at work now and there are some outside contractors in who said that they will powder coat them for if I mask off the holes where the pistons/seals were.
SO I have 2 options either take them down to Big red and have them powder coat the calipers and spend cash or get them done for free
Ian I will still take the calipers to big red and have them check out for the seals
Anyone know how I can do the masking?
07-11-2006, 09:00 AM
#39
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You are going to have to mask more than just the psiton holes - You will need to mask all mating surfaces to make sure that the caliper halfs mate back correctly. Any poder coating that gets on these surface areas needs to be removed. Use a good masking tape and a small sharp cutting blade to remove excess tape. make sure you get good surface contact with the tape so no paint gets under the edge of the tape. Seal or cover the dust cover seal areas as well as the powder coat will build up in the groove and you won't be able to install new seals.
07-11-2006, 08:36 PM
#40
Three Wheelin'
Thread Starter
Anybody know where to get the caliper bolts?
Metric M12x80mm 1.75 thread and M10x80mm 1.5 thread.
Can they be ordered through porsche? Somewhere else easy online? (in north america for me)
And as long as I am asking questions, what torque should they be when I reassemble, and with locktite or not?
I have to admit that with my engine rebuild happening I have dropped the ball on the calipers. The parts are out being powder coated and without them sitting there staring at me, they got pushed to the back of the list.
Kirk
Metric M12x80mm 1.75 thread and M10x80mm 1.5 thread.
Can they be ordered through porsche? Somewhere else easy online? (in north america for me)
And as long as I am asking questions, what torque should they be when I reassemble, and with locktite or not?
I have to admit that with my engine rebuild happening I have dropped the ball on the calipers. The parts are out being powder coated and without them sitting there staring at me, they got pushed to the back of the list.
Kirk
07-11-2006, 09:04 PM
#41
Burning Brakes
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On the old ones, is there are any marks on the head? If their strength can be determined you would know what to order from anywhere.
mcmaster.com has a good selection of bolts, even metric. I dislike their high strength metric stuff 10.9+), though, as you can't get it with a good anti-corrosion coating. Their 8.8's are fine though. If those bolts are 8.8's I'd just buy a box of them from mcmaster for around 8 bucks per pack of 10.
mcmaster.com has a good selection of bolts, even metric. I dislike their high strength metric stuff 10.9+), though, as you can't get it with a good anti-corrosion coating. Their 8.8's are fine though. If those bolts are 8.8's I'd just buy a box of them from mcmaster for around 8 bucks per pack of 10.
07-13-2006, 04:23 PM
#44
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I used stainless steel bolts and got them from a nut and bolt shop in West Georgia -
They have got to be available rather easily - I just called one of the race shops got the name and drove over to this shop and they had them in stock -
I will see if I can find the receipt - have you looked on line ?/
They have got to be available rather easily - I just called one of the race shops got the name and drove over to this shop and they had them in stock -
I will see if I can find the receipt - have you looked on line ?/
07-13-2006, 04:32 PM
#45
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What grade/finish? Have you looked at:
http://www.metricmcc.com
Another lister mentioned them, and they do seem to have a good selection.
Or, www.fastenal.com, under Socket Cap Screws
http://www.metricmcc.com
Another lister mentioned them, and they do seem to have a good selection.
Or, www.fastenal.com, under Socket Cap Screws