Brake Piston Damage

[onefourk]

Hello All, I'm fixing up the seized rear caliper from my VFR400 and have managed to get the pistons out but I'm not sure if they are ok to go back in or not, so I thought I'd run it past the BCF collective. There's no major damage but there are some light scratches from cleaning off the corrosion.

https://i66.photobucket.com/albums/h272/agentb0b/78F468C5-C392-4794-87A3-F7CD9F6F2233_zpsdht7e4xt.jpg

https://i66.photobucket.com/albums/h272/agentb0b/18B415FC-F27B-47F9-99B6-07B83E00F3E0_zps4c55oa2l.jpg

Thoughts?

[Snod Blatter]

Are we looking at them with the open end up?
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1994 CB250, 1984 CBX250RS-E, 1989 K100RS, 1995 TRX850, 2016 Z250SL

[onefourk]

[Snod Blatter]

Strange damage then, but if it's still quite smooth to the touch I'd reuse them. Unless you have no material left on the pads that bit of the piston will hopefully not be near the seal, so it shouldn't be a problem at all.

In b4 "your brakes will save your life they have to be perfick I wouldnt dare your asking for trouble" etc.
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1994 CB250, 1984 CBX250RS-E, 1989 K100RS, 1995 TRX850, 2016 Z250SL

[kramdra]

I would polish them with diamond paste to remove the scratches but probably ok - they do still look a bit pitted. Which abrasive did you clean them with?

Rear brake, they will be fine.

[Fizzer Thou]

I have seen worse than that being reused without any problems,even on the front.
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Just talk bikes.What else is there?

Always have a 'Plan B'

[onefourk]

Thanks guys, it was some super knackered fine emery cloth I found in the shed, the corrosion that was on the exposed part of the piston was pretty well on there so I don't think anything softer than that would have done the trick. Like you say it's only a back brake so should be ok, but new pistons (with both seals) are only £16 each...hmmmm

[Fizzer Thou]

This is what I started with

https://i666.photobucket.com/albums/vv23/WiNot_Rhencullen/Workshop/Picture383.jpg

After a bit of elbow grease I had these to rebuild

https://i666.photobucket.com/albums/vv23/WiNot_Rhencullen/Workshop/Picture384.jpg

I used a brass wire brush to polish up the pistons as the soft wire did not damage the chrome plating.I have not ever used emery cloth but it will not have damaged your pistons.

£16 for OEM?Maybe for pattern parts but not for genuine parts.
____________________
Just talk bikes.What else is there?

Always have a 'Plan B'

[onefourk]

I think they must be pattern parts, but they're from renowned NC30 specialist Rick Oliver so should be ok, having said that I'll probably just go with replacing the seals.

[Fizzer Thou]

Unless the seals are damaged I would not bother replacing them.

My Exup 1000 has done over 55,000 miles and the original seals still look good as well as give decent braking pressure.
____________________
Just talk bikes.What else is there?

Always have a 'Plan B'

[Vincent]

New seals can be bloody expensive too
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Space Is Deep

[onefourk]

Thanks chaps, a full set of seals is £15 so might throw some on anyway, I'd hate to put it all back together and find the bastard is leaking which is almost certainly how it'd turn out

[Fizzer Thou]

https://www.hondascooterspares.co.uk/product/unbranded/717.24.22/brake%20caliper%20seal%20kit%20front%7Ccaliper%20service/repair?uid=0&model=HONDA%20VFR400R%20NC30

I realise that this is for a front caliper but it gives you an idea about prices
____________________
Just talk bikes.What else is there?

Always have a 'Plan B'