Hydraulic clutch release went pop

[fastfun]

Says your man who thought they were both 45,95mm

yep, as I said, you have to do the right maths

 

[R-III-R Turbo]

Found the correct photo, these are the ones I used.

The Viton ones that came with the Oberon slave cylinder ( the ones that are not compatible with DOT 4) were 46 x 2.2mm and 44 x 2.2mm by my measurement (difficult with a squishy o-ring).
And these ones are 46 x 2.0mm and 42 x 2.0mm, but they fit and work fine.
I couldn't find a 44 x 2.0, only a 44 x 2.5mm, which was too thick to fit right.

 

[R-III-R Turbo]

Update here for anyone interested.
The "EPDM" o-rings from ze Germans (Diehr & Rabenstein) must not be really EPDM after all.
Couple of years sitting in DOT 4 and they're hanging loose and passing fluid.

So current hypothesis is they are merely labelled EPDM but are probably common silicone or Viton or something not great with DOT 4.

It took a few years to find out.

So now I'll try a different supplier of EPDM rings.

 

[ant]

My plan was to purchase a complete seal kit from Oberon after they promised to send the O rings FOC.
After a few emails they sent me an invoice for £30 for a incomplete seal kit.
Oberon were not very helpful and wanted £149.99 for a new cylinder. After some searching on line i found on new
slave cylinder for £130.
Strangely it's fitted with red O rings.

 

[R-III-R Turbo]

Can the seller shed any light on why red rings or perhaps what kind of rubber they are?

I've wondered what the other rubber seals inside the cylinder are made of. If Oberon use Viton rings on the outside then maybe they use the same inside - and they are likely custom made / specific to that cylinder.
if that's the case then they could go same as the outer o-rings.
Wondering have they listened to the feedback and changed out the rubber type on all to EPDM or something DOT 4 compatible since.

 

[micromike1]

Can the seller shed any light on why red rings or perhaps what kind of rubber they are?

I've wondered what the other rubber seals inside the cylinder are made of. If Oberon use Viton rings on the outside then maybe they use the same inside - and they are likely custom made / specific to that cylinder.
if that's the case then they could go same as the outer o-rings.
Wondering have they listened to the feedback and changed out the rubber type on all to EPDM or something DOT 4 compatible since.

When i replaced the complete unit on mine i asked what type of o rings they are(they were red ) and told Silicon ,so i have flushed out my master cylinder and line and used Dot 5 Silicon brake fluid ,will see how that works out .

 

[R-III-R Turbo]

Little update here, havig replaced the outer o rings, my slave is still leaking but it's coming from between the piston and sleeve now too. So the inner seals are going it seems.

I spoke with Oberon on the phone re a replacement seal kit just now, and found that they have indeed updated both the material in the inner piston seals and the outer body o rings to one that is compatible with DOT 4 and engine oil.
But the exact grade is secret

So the good news is we have been listened to and feedback acted on.
Hopefully this new rubber holds up indefinitely now.

They said the slave is for a Buell but it was due to a steady influx of feedback and issues with the old rubber compatibility from Rocket III owners in the last few years (I.e. this thread and subsequent associated ones @ant @micromike1 @fastfun ) meant a revision of the product was needed.

Go team