The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Armen on April 11, 2013, 06:02:11 PM
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I don't see the pistons for the brake calipers listed on Max's fiche. Anyone find another source?
thanks,
-Armen
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ATE or Brembo? When posting questions, please include bike model and year. PLEASE.
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The pistons are no longer available from BMW for the ATE calipers .
Someone posted about a month ago, that Motorworks in the UK had stainless pistons for around $45-50US each .
Motorworks has just started doing business with customers in the US .
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It's a '79 R65 with the ATE single caliper.
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I just redid my ATE single caliper on a 79'. It was pretty rusted, but I managed to use some steel wool and get them pretty smooth.
There is a post about 4-5 pages down on the list entitled "ATE caliper opened."
Someone posted this link: http://www.etypeparts.com/products/ate15-bmw1
Apparently, these would fit the ATE caliper, but no one could confirm this. I thought about trying them, but went ahead and cleaned the caliper, pistons, and replaced the seals / o-rings and now they work great. Probably cheaper and easier to just get a used Brembo as they will fit and are if you rebuild them, don't have the rusting problems.
Seems like you're intent on the 4 piston caliper, so good luck.
Jeff
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... Someone posted about a month ago, that Motorworks in the UK had stainless pistons for around $45-50US each...
Just yesterday, I looked over the Motorworks site and didn't see pistons nada for the ATE R45/65. Perhaps I missed 'em?
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https://www.motorworks.co.uk/vlive/Shop/Parts.php?T=5&NU=15&M=20&Ct=HA&SbCt=BA_15_20_HA_30&Sort=4
Pistons for ATE
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Might be able to use a Brembo piston, as long as the ATE shroud will fit it.
http://www.bmwr65.org/cgi-bin/yabb2/YaBB.pl?num=1311933847
The Brembo piston is a little shorter, but the same diameter. It is made of much better metal.
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https://www.motorworks.co.uk/vlive/Shop/Parts.php?T=5&NU=15&M=20&Ct=HA&SbCt=BA_15_20_HA_30&Sort=4
Pistons for ATE
See there, you found 'em all by yourself. And Stoner offered his assist on the Airhead list, too.
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The Brembo pistons appear to be aluminum .
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Caliper is back on. New seals and bolts.
It seems the seals are not symetrical. When I installed them, one edge seemed higher than the other, as if the inner face has a wedge/taper to it. I reasoned that since the inner seal is all that retracts the piston, it made sense to install the seal with the raised edge toward the bottom (inside) of the caliper so the piston would be force back into the bore by the rubber trying to flex back into it's original shape.
The ATE rebuild kit came with a completely useless instruction sheet with a picture of an automotive caliper and references to parts that don't exist on the bike calipers :(
-Armen
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When I did this last month, there was not a higher/Lowe portion of the inner o-ring. It did take a little brake fluid and massaging to get the o-ring to seat nicely. I used the end of a toothbrush so that I wouldn't damage the o-ring.
Did you have any problems getting the piston to seat into the caliper after you installed the o-ring before you installed the protective cover and the metal ring?
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I had some Brembo brake caliper grease that came with a Brembo rebuild kit (different bike). I used some of that and it went together without too much grief. And the inside of the caliper and seal cavity were spotless. Sometimes there is corrosion that causes raised metal.
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Hey Disco,
I wondered if I was seeing things, so I grabbed the old inner seals and cut a cross section of one. Looking at it under a lighted magnifier and holding a digital caliper against the surfaces, I can see about a .004" taper to the inner surface of the o-ring.
-Armen
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Interesting. I didn't notice, but that's pretty small. Will be interesting to see if the Airhead list offers any insight. I agree, the instructions included were terrible. Have you tried the brakes out yet?
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Cutter (airhead list) said I was right on.
Haven't ridden it, but the brakes work and the pistons retract well (wheel spins freely).
-Armen
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That's interesting. I've never noticed that they weren't square. I can understand the old seal being distorted over time because of the way they work but Just to be clear are you saying the new ones are not exactly square.
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Yup, definitely not square. Looked at the new ones under a lighted magnifier and there is a few thousands of an inch difference between one edge and the other.
Mentioned it to Tom Cutter on the Airhead list and he said he'd seen it before. Not many bikes do this.