brake caliper piston orientation

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miker
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brake caliper piston orientation

Post by miker » Fri Apr 05, 2019 8:07 pm

Here are two new rear brake calipers with 38mm pistons. It looks to me like piston on the left in the photo has the piston with the skinny groove on the bottom, and I think it should be on the top like the one on the right. Am I right?

If so, should I screw the left piston in or out to orient it correctly?
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MikeR (mirafiori.com since 1995)


1977 Fiat 124 Spider
Previously owned:
2012 Fiat 500 Prima Edizione #236 (now owned by my son David)
'86 Bertone X1/9
'81 Fiat Spider 2000 #236
'78 Fiat 131 four door
'76 Fiat 128 4 door
'74 Fiat 128 4 door
fp55scca
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Re: brake caliper piston orientation

Post by fp55scca » Fri Apr 05, 2019 8:16 pm

--Yes Mike the reference line should be on top. Doesn't matter if you turn clockwise or counter clockwise as long as you can fit the pads. If too tight to fit the pads, then turn clockwise (in) until they will fit, always stopping with the reference line on the top.
Jim Scurria
Norfolk, VA

1972 Fiat 124 Spider
1971 Spider - SCCA FP-24
1974 CSA Abarth Replica
1981 Fiat Spider Ratrod
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miker
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Re: brake caliper piston orientation

Post by miker » Sun Apr 07, 2019 12:57 pm

Thanks! It makes me slightly nervous that they didn't leave the factory in the correct orientation.
MikeR (mirafiori.com since 1995)


1977 Fiat 124 Spider
Previously owned:
2012 Fiat 500 Prima Edizione #236 (now owned by my son David)
'86 Bertone X1/9
'81 Fiat Spider 2000 #236
'78 Fiat 131 four door
'76 Fiat 128 4 door
'74 Fiat 128 4 door
spider2081
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Re: brake caliper piston orientation

Post by spider2081 » Sun Apr 07, 2019 1:33 pm

then turn clockwise (in) until they will fit, always stopping with the reference line on the top.
I have purchased rear calipers that did not have the piston screwed into the emergency brake rod. Now I move the lever and make sure the piston moves out and then back in following the levers motion. If the threads are not engages the piston can move out but stays there when the lever is released. Easy to check before installation. If not engaged turn the piston clockwise while pressing in. Once the piston is all the way seated it can still be rotated it just doesn'r move in any more.
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