Brake piston size


Information and questions on GL1100 Goldwings (1980-1983)
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arseatea
Posts: 36
Joined: Wed Feb 22, 2017 10:37 am
Location: Beavercreek Ohio
Motorcycle: 1983 GL1100I Interstate

Brake piston size

Post by arseatea »



I've been cleaning all three brake calipers and never noticed that two pistons are smaller. I marked them as they came off the bike so they would go back on in the same order. But, I just discovered that the right front caliper has smaller (25.2mm) pistons than the other two (31.8mm). Sure wish I had noticed that before ordering 3 rebuild kits of the same size from CycleMax. One of the two larger is stamped F-22 and the smaller is F-21. Third one has no stamp. Cycle Max does not make any distinction as to right or left as they only call it a front caliper. I just called Western Honda and they want nearly $30 for just the 4 rubber seals for the smaller pistons, but it includes shipping. I don't think this barn find was any find at all considering the cost of minor parts.. I think I am getting too old for this..arseatea..


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bruce swaybill
Posts: 116
Joined: Wed Dec 11, 2013 11:26 pm
Location: farmington, ct
Motorcycle: .
1983 honda gl1100i interstate
2009 triumph bonneville t100

Re: Brake piston size

Post by bruce swaybill »

Your '83 has linked brakes, which means that the rear brake pedal operates the rear brake and the front right caliper. Your front brake lever operates the front left caliper only. The rear and front left caliper have 32mm pistons. The front right has 25mm pistons. My calipers were marked with a 32 and 25 in a circle on the front facing side of each caliper. The earlier years did not have this arrangement. The 82 had 30's all around and independent front and rear brakes. Most non-Honda sellers have no clue what they are doing. My Honda dealer had all the correct info, with the latest part numbers to rebuild the calipers. Btw, the Honda seals are worth the money.....

Bruce S.
Have a nice day! :)
arseatea
Posts: 36
Joined: Wed Feb 22, 2017 10:37 am
Location: Beavercreek Ohio
Motorcycle: 1983 GL1100I Interstate

Re: Brake piston size

Post by arseatea »

Thanks for that information. I knew that the foot brake worked both the rear and the right side front, but never realized that the pistons would be smaller and after spending hours cleaning them, I still did not recognize the difference. The parts I got from Cyclemax are genuine Honda parts and I have to take responsibility for the mistake as I just ordered on line and did not speak to a sales person. Maybe he or she would have informed me of the difference in size. My wife is upset that I spend so much time surfing Honda Docs pages and YouTube and never saw anything about the different piston sizes. I will contact them Monday and see if I can return these parts for exchange. They have great prices on genuine parts, but their shipping cost is a killer..
Jag
Posts: 49
Joined: Thu Feb 09, 2017 1:22 am
Location: Pearlington, MS
Motorcycle: 1983 gl1100A Aspencade, 1982 GL1100 Interstate

Re: Brake piston size

Post by Jag »

I got my front caliper rebuild kit from partsnmore for my brothers 83 aspy. I was very pleased with it and it had all the correct size parts for the 2 different sized calipers. It was part number 29-0009 it was 48 bucks for it though... wasn't oem either btw


I hear you and agree with you about all the little parts and the cost adding up way way way to fast..... I have determined rebuilding older motorcycles has to be done for the love of it and them as it isn't a cheap way to a motorcycle.


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