UKISF

Hi guys,

Recently acquired an 09 IS-F. I've got a few things to do to it, and this forum has been a great resource so far, in particular, many thanks to Lobuxracer is his efforts to spread the word on the tensioners tick.

My rear right calliper (part number 47830-0W010) is weeping brake fluid. My plan is to take both rear callipers off and rebuild them. I've found replacement boots and seals but I'm struggling with pistons.
I haven't taken apart the callipers yet, but I would rather have replacement pistons on hand, should I need them, than having to wait for them to arrive.

I'm in the United Kingdom where IS-Fs are few in number (less than 200 now) so finding a spare calliper is rather expensive, used or new, and I would rather rebuild.
Also due to my location it is hard to order parts from your typical US retailers (centricparts etc), both in time and cost. So I would prefer to get a more local supplier. There are many retailers on my side who stock replacement Brembo pistons but I cannot get a clear answer on the ISF's piston dimensions.

On Racingbrake's website they have is as 42x32 piston in the rear callipers, I read this as 42mm in diameter and 32mm deep. A company called Frentech have the following piston (P42020A), I'm going to email them, but in the meantime would anyone able to confirm all the other dimensions are correct for a replacement?

Piston diameter - 42.00mm
Piston total height - 31.90mm
Bottom to collar - 24.60mm
Piston head diameter - 38.50mm
Piston collar diameter - 34.60mm
Centre hole diameter - 25.30mm
Centre hole depth - 27.00mm

Potential Rear Calliper Piston Replacement

Failing all of the above, I'll measure them when I take the callipers apart and report back!

Rickna

iTrader: (3)

Deleted-oops

lobuxracer

iTrader: (2)

Here's what Lexus says about the rear caliper:



Rockauto shows a 2004 - 2007 Subaru Impreza using the same rebuild kit, so it would seem if there are Subaru parts available, they MIGHT fit as well. The only thing 100% certain is the pistons are the same diameter. The rest of the dimensions are anyone's guess unless we have someone here familiar with those model year Imprezas.

Might be worth a look here, UK seller too: https://www.ebay.com/itm/for-SUBARU-...1733025?_ul=IL

UKISF

Thanks for you reply Lobuxracer, I ordered that replacement kit and a managed to purchase a used rear caliper.

I took apart the used rear caliper to rebuild it, on inspection, the pistons, dust boots and seals were fine, but better to know, than put another weeping caliper on the car.

What I did find is the OEM pistons are 32mm high, so the ebay rebuild kit pistons are short by 2mm. They would probably work, as they look identical in every other way, but would prefer not to take the chance, so I'm placing the OEM ones back in and replacing the seals and dust boots.

Using Vernier calipers here are the dimensions for the OEM rear caliper pistons, I may be off by .2 of a mm on everything but overall height and width:



The OEM dust boots have the Brembo model number on them: 20.4872.44 / 20487244, these seem to stem from Porsche 996 products, which may be similar for the piston themselves, not sure.

No model/order/stock number for the piston seals, the ones that came from the ebay kit do fit. I imagine a Brembo 36mm piston seal will work.

This piston look promising: Addiction Motorsport 36mm x 32mm Brembo piston, I'm currently looking to order, or have the retailer confirm the dimensions.


Comparison images of the pistons, grey is the ebay kit (BKP333S), silver is the original OEM:

lobuxracer

iTrader: (2)

That's very helpful information. Thanks for the follow up, we don't often get the rest of the story when members have questions/issues like this!

Rickna

iTrader: (3)

Is there a possible cross-reference with another application?