V40: - Brake Fluid Cap and Cushion

morrismen · Jun 29th, 2013, 16:36

This may seem like it's obvious, but I am gonna ask anyway.

The black cap on the V40 Brake Fluid container (where you fill up with brake fluid) has a flexi-cushion in the cap head which can be pulled down.

So, should this always be pulled down into the max brake fluid level (so as to reduce air in the Brake Fluid container) or should it be squashed or layered up so its retained in the cap head. With the latter, the brake fluid level can be seen easily and filled to the Max level.

Basically, I am not sure whether this flexi-black thing should be pulled down into the fluid, not least because then its lower than the clutch fluid feed and creates the illusion it's more full than it should be.

Feedback appreciated

happy diver · Jun 30th, 2013, 13:49

Layered up nice and flat kinda level with the top of the cap thread
with no wrinkles, run your little finger around about inside the fold.
If it is bulging down below the rim of the cap ish there is some sort
unwanted air sucking leak or bleeding action required happening
inside the system

morrismen · Jun 30th, 2013, 14:23

Thanks Happy Diver... that makes sense then. I'll push it back up and see the true level of the fluid then. I reckon previous owner just thought it was nice to have a bulge.

gatos · Jun 30th, 2013, 15:19

I was under the impression that the bulge should be there. It would be interesting to see if someone knows for sure as I would like to know.

Dog_Book · Jun 30th, 2013, 17:17

As the fluid drops in level the rubber cap expands filling the vacuum taa daa

happy diver · Jun 30th, 2013, 23:43

Filling the void due to vacuum sounds far more professional
than some unwanted air sucking

sensiblebutstupid · Jul 3rd, 2013, 21:29

Quote:

Originally Posted by happy diver

Filling the void due to vacuum sounds far more professional
than some unwanted air sucking

made me giggle that did, thank you

Dog_Book · Jul 3rd, 2013, 21:31

Quote:

Originally Posted by sensiblebutstupid

made me giggle that did, thank you

What? That in some way i could actually be professional?

morrismen · Jul 8th, 2013, 09:15

That is great deduction Dog_Book Watson. I reckon your analysis of the black puffy thing coming down with vacuum to reduce air in the brake fluid pot is a miracle of Volvo design and ingenuity, snarf.

But it does rely on the brake fluid cap being tight and air leak proof, which of course it won't be because its black plastic on clear plastic and the two will expand at different rates with heat.

However, the prize goes to... Dog_Book

cookie · Jul 8th, 2013, 09:27

snapped a picture, of mine other evening, this is how I set mine after replacing fluid

Jun 29th, 2013, 16:36	#1
morrismen Senior Member Last Online: May 3rd, 2023 13:02 Join Date: Dec 2003 Location: London	Brake Fluid Cap and Cushion This may seem like it's obvious, but I am gonna ask anyway. The black cap on the V40 Brake Fluid container (where you fill up with brake fluid) has a flexi-cushion in the cap head which can be pulled down. So, should this always be pulled down into the max brake fluid level (so as to reduce air in the Brake Fluid container) or should it be squashed or layered up so its retained in the cap head. With the latter, the brake fluid level can be seen easily and filled to the Max level. Basically, I am not sure whether this flexi-black thing should be pulled down into the fluid, not least because then its lower than the clutch fluid feed and creates the illusion it's more full than it should be. Feedback appreciated

Jun 30th, 2013, 13:49	#2
happy diver Active Member Moment Last Online: Apr 29th, 2023 05:58 Join Date: Jul 2012 Location: Brisbane: perfect for one day, asleep the rest	Layered up nice and flat kinda level with the top of the cap thread with no wrinkles, run your little finger around about inside the fold. If it is bulging down below the rim of the cap ish there is some sort unwanted air sucking leak or bleeding action required happening inside the system __________________ 20,000 leagues under the sea diving to adventure in a silent world with my ceiling the waves...Emile

Jun 30th, 2013, 15:19	#4
gatos Premier Member Last Online: Nov 15th, 2022 21:34 Join Date: Apr 2010 Location: London / Essex	I was under the impression that the bulge should be there. It would be interesting to see if someone knows for sure as I would like to know. __________________ Current car: 2002 S40 1.9D, 1992 240SE Nullius in Verba

Jun 30th, 2013, 17:17	#5
Dog_Book Idiot Last Online: Apr 21st, 2019 17:29 Join Date: Nov 2006 Location: Derby	As the fluid drops in level the rubber cap expands filling the vacuum taa daa __________________ Vectra VXR estate convert Experience = V40 1998 2.0 CD lots of mods Busy pestering the poor sods here now

Jun 30th, 2013, 23:43	#6
happy diver Active Member Moment Last Online: Apr 29th, 2023 05:58 Join Date: Jul 2012 Location: Brisbane: perfect for one day, asleep the rest	Filling the void due to vacuum sounds far more professional than some unwanted air sucking __________________ 20,000 leagues under the sea diving to adventure in a silent world with my ceiling the waves...Emile

Jun 30th, 2013, 14:23	#3
morrismen Senior Member Last Online: May 3rd, 2023 13:02 Join Date: Dec 2003 Location: London	Thanks Happy Diver... that makes sense then. I'll push it back up and see the true level of the fluid then. I reckon previous owner just thought it was nice to have a bulge.

Jul 8th, 2013, 09:15	#9
morrismen Senior Member Last Online: May 3rd, 2023 13:02 Join Date: Dec 2003 Location: London	That is great deduction Dog_Book Watson. I reckon your analysis of the black puffy thing coming down with vacuum to reduce air in the brake fluid pot is a miracle of Volvo design and ingenuity, snarf. But it does rely on the brake fluid cap being tight and air leak proof, which of course it won't be because its black plastic on clear plastic and the two will expand at different rates with heat. However, the prize goes to... Dog_Book

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