Front brake reservoir 'insert'

Sunny Jim

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Can someone tell me what's the point of the insert in the front brake reservoir, please?

Is it there to save on fluid ???

Ta
 
As far as I understand - its there as a seal and also to allow expansion/contraction of the fluid.
 
As far as I understand - its there as a seal and also to allow expansion/contraction of the fluid.
Yes, it's a diaphragm to allow fluid level changes such as pad wear/replacement etc. And also seal against fluid escaping from the cap and it helps to keep moisture out.

Sent from my SM-G935F using Tapatalk
 
Can someone tell me what's the point of the insert in the front brake reservoir, please?

Is it there to save on fluid ???

Ta

Do you mean the foam insert, rather than the rubber seal? The Haynes manual recommends changing it when the fluid is changed. I didn't as I'd already changed the fluid and bled the lines by the time I read that bit, so far so good everything is working ok. I'll replace it next time I service the bike.
 
Haven't bought it yet but yes, I think it's going to be a foam insert.
 
The foam insert is to take up space and stop the fluid from frothing.
 
my 2010 had the sponge, when Mikeyboy serviced the bike I got him to chuck it away :thumb
 
I don't know about the sponge but I always thought (assumed) the bellows/diaphragm thing was to fill the air gap between oil and cap to prevent splashing and bubbles forming which could then get pushed into the hydraulics. The bellows/diaphragm gets "sucked" down as the oil level drops as the brake pads wear so it's always sitting on top of the oil.

I assume the sponge does something similar. Perhaps any bubbles cling to the sponge rather than dispersing through the oil. Dunno. Making it up now.
 
Did a little bit of digging when I say my 2010 had one, and it seems that they only fitted the sponge on 2008-2010 bikes, and some have them, some don't.

I was told that it was because owners complained that they didn't like to see the brake fluid sloshing about through the clear reservoir :confused:

Not had a bike with a sponge in the reservoir apart from this one.... and that's why it's gone in the bin. The brakes still work :thumb2
 
As far as I understand - its there as a seal and also to allow expansion/contraction of the fluid.

Yes, it's a diaphragm to allow fluid level changes such as pad wear/replacement etc. And also seal against fluid escaping from the cap and it helps to keep moisture out.

Sent from my SM-G935F using Tapatalk

I don't know about the sponge but I always thought (assumed) the bellows/diaphragm thing was to fill the air gap between oil and cap to prevent splashing and bubbles forming which could then get pushed into the hydraulics. The bellows/diaphragm gets "sucked" down as the oil level drops as the brake pads wear so it's always sitting on top of the oil.

I assume the sponge does something similar. Perhaps any bubbles cling to the sponge rather than dispersing through the oil. Dunno. Making it up now.

Stop. You're all talking about something completely different.

Later reservoirs fitted with the sponge insert still have the bellows/diaphragm fitted as per normal.
 
My 08 has the bellows but never had the sponge. Brakes work fine.
I have a farkle cover over the reservoir to keep light fingers at bay so can't see the level.
 


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