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Discussion Starter · #1 ·
It's time to replace the rear brake cylinders on my '64 122S (2-door, chassis #79137). I have three different shop manuals for this car, including the original Volvo factory ring binder, and they all say the rear cylinders should have 1" bores. But mine have 7/8" bores. It's very likely that the originals were replaced at some point in the past 55 years, and someone may have put in the smaller cylinders by mistake.

The VP Autoparts website also says the '64 should have 1" cylinders; IPD's website is ambiguous on the subject.

Should I install 1" cylinders, or stay with the 7/8" cylinders?

Thanks for any advice.
 

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Interesting. I did a bit of research and found out that:

Part # 667166 will fit a '62-'64 and looks to be 7/8"
671216 will fit a '65-'67 and looks to be 1"
670404 will fit a '67-'68. Back to 7/8"

I'd go with the first, assuming you have original components back there
 

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Discussion Starter · #3 · (Edited)
Thanks, Adrian L. I think I've solved this little mystery. According to the Haynes and Volvo factory shop manuals, some of the early Amazons had drum brakes front and back, and had 7/8" rear cylinders. Amazons with front disc brakes all had 1" rear cylinders, until 67-68, when the brake booster was added and they went back to 7/8" cylinders.

My '64 has front disc brakes, and originally had 1" rear cylinders. Looking through my file of parts invoices, I see that in 1993 I replaced them, and though I ordered 1" cylinders, and that's what's listed on the invoice/packing slip, I apparently received the 7/8" size. Since they look the same from the outside, and I had no reason to take them apart, I must have assumed they were 1". So I was the "someone" who put in the wrong parts.

I'm going to install 1" rear cylinders again -- I'll let the forum know if there are any problems.
 
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