Rear caliper question...

budgetzagato

budgetzagato

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I've read that the rear calipers on a Scorpion, if original, are 38mm not 34mm bore like an X or Spider. Is there a way to tell what size they are from the outside? Does one have to measure the piston or bore?

I think I need new seals... :sigh:
 
Shouldn't the piston be sticking out...

of the bore a bit, if your brake pads are not brand new?

You would still have to take the caliper bracket off and the brake pads out, possibly dis-assemble the bracket from the caliper.

Once you get the pads out, you can gently press on the brake to make the piston pop out more, if necessary. Then after the measurement you would have to wind it back in. But that would all be a good opportunity to inspect for leaky seals.

Pete
 
Probably Pete,

But I was hoping to order seals before digging into it. The pads are pretty new also.

I'm pretty certain I have a leaking seal, so I might as well "rebuild" them both. It's always something.
 
Yup...

I'd offer to go get the caliper numbers off my Scorpion, but a) I'm not sure there are any, and b) I have no idea if mine are original either. :hrmph:

Pete
 
For the rears, the part of the piston that sticks out is not the full diameter:

Piston.JPG


If you screw the piston all the way in, you can remove the dust boot and measure the piston diameter (at least accurately enough to tell if it is 34 mm or 38 mm)

I have both my rear calipers sitting on the kitchen counter, so if you want I can read the casting number off them after work.
 
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Good point, I guess I should go pull a wheel and caliper and do some careful measuring. I don't need to be exact, as long as I can discern a 4mm difference. :mallet:

I'd rather get this done now while it's cold and rainy, than have to do it in the spring.
 
I believe....

I think the caliper has a different number on it. If memory serves correct, the Scorp/Monte calipers are off of a Fiat 130 which has a different housing ID on it.

Warren
 
Casting Part Number

If the casting part number starts with 124 then the piston diameter is 34mm, if the casting part number starts with 125 then the piston diameter is 38mm. The Scorpion / Monte Carlo rear calipers were borrowed from the Fiat 125 model.
 
And the answer is...

IMG_20140109_155036677_HDR_zps018ac40b.jpg


A Scorpion/125 specific caliper (38mm bore). So I'll order the seal kit for this type. Thanks again for all the pointers.
 
Make sure

Make sure both calipers are the same. I have seen where uninformed mechanics have put miss matched calipers on because they all looked the same and Fiat spider parts are plenty.
 
Good point... I'll double check for good measure. Seals are on the way, caliper rebuild will have to wait until my current cambox swap is complete, waiting on shims now.
 
If you want or need shims...

Volvo shims are the same as Fiat. Go to your closest Volvo dealer and ask for the thickness you need. (early Volvo, not sure about the newer cars)
 
Shims...

A fellow Mirafiori Fiat friend sent some to me, arriving today. And if I need some not in what I have between 2 engines and my friend's stash, then I can get some free w/trade in from the Mirafiori Shim Exchange program.

But, thanks for the tip.
 
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