Replacing brake fluid

[joesmad4it]

My cupra tdi is 4 years old so as well as cam belt I been told the brake fluid needs changing too. I have heard it's not as easy as 'have your mate pump the brakes to drain the fluid' anymore and you need something that uses air pressure?! Is there a way of doing it myself as I'm not paying £65!

 

[rf860]

Is this the first time you are having to replace the brake fluid cos the dealer told me that i needed mine done and my car is 2 yrs old with 25k on the clock!? Still havent changed it cos due to get a service

 

[techie]

<2008 MY every two years
>2008 MY First change at 3 years and then 2 years after that

If your going to do it yourself get a Gunsons easibleed kit and follow the instructions.

 

[bubbles1]

Yes buy an ezebleed kit (halfords sell them) easy to use and a one man job!

Job jobed!

 

[joesmad4it]

Great stuff thanks I'll have a butchers and look into gettin one. I hear brake fluid should never degrade and the only reason it might is if it's been boiled (the brakes overheat) so really it shouldn't need changing?! I am going to however, as this seems far fetched but every 2 years sounds a lot.

 

[techie]

Brake fluid is hygroscopic which means it absorbs water.

As the brake fuild system isnt sealed it over time will absorb water. When water molecules get into the fluid this will boil up and create air pockets in the fluid which will compress unlike the fluid and thus effect braking.

 

[Neo]

Hi mate, as bubbles and techie said a Gunsons eezi-bleed kit will make the process easier - very important to read the instructions about pressure and sealing though.
Apparently doing the old two man pump-the-pedal method can knacker the seals in the master cylinder.

 

[NickyJam]

<2008 MY every two years
>2008 MY First change at 3 years and then 2 years after that

as techie said SEAT tried saying mine was due (currently being serviced) but showed them my manual said it weren't the case...at least i can save a bit for another year

 

[mgrays]

Hi mate, as bubbles and techie said a Gunsons eezi-bleed kit will make the process easier - very important to read the instructions about pressure and sealing though.
Apparently doing the old two man pump-the-pedal method can knacker the seals in the master cylinder.

Urban myth I really suspect... I did design and test these for a while and a lip seal is a lip seal is a lip seal. Careful standard bleeding will do it. No real need for a fancy kit or 2 people.. just a clear tube that fits over the bleed nipple and a glass jam jar with the tube held under the fluid level to stop air getting back in.

Yes it needs done.. and every 2 years is really too long but accountants will have their way. I always pull off a small cup full every time I change pads .. this is enough to remove the hardest working fluid and the fluid that is most contaminated (the rubber hoses let water into the brake fluid as they are too cheap to fix steel flexi with PTFE linings (i.e Goodrich hoses)).

But it is a safety issue so be safe and make sure you test you can stop.. i.e. pump brakes before you drive.. then 10 mins later do a slow test drive and make sure they stop and feel good.. if your pedal is sinking too far you have air in the system and should rebleed but really the only way to get the air in is to disconnect something or let the reservoir run dry (VERY IMPORTANT NOT TO LET THAT HAPPEN .. if at all possible)

But it is a basic hydraulic system .. not rocket science.

 

[Neo]

Urban myth I really suspect... I did design and test these for a while and a lip seal is a lip seal is a lip seal. Careful standard bleeding will do it. No real need for a fancy kit or 2 people.. just a clear tube that fits over the bleed nipple and a glass jam jar with the tube held under the fluid level to stop air getting back in.

But it is a basic hydraulic system .. not rocket science.

Yeah just something I was told by a vag guy once, and I`m sure I`ve read about it a couple of times too... just perpetuating the myth I guess.
know what you mean about basic hydraulics though, I work on an aircraft that has 3 hydraulic systems powering undercarriage, flying controls, brakes and hoist. Gets a bit sometimes!

 

[joesmad4it]

Great stuff cheers all. I noticed over the last week when putting medium pressure on brakes there seems to be points on the discs that contact better with the pads giving the car a jolty motion when slowing down. Will this be the discs or the pads? If I'm bleeding the brakes I guess it would be a good time for a pad change (if they are not too expensive)