How to Access the Brake Fluid to Test It?

[PeterPan99]

The franchised dealer tells me that I should have the brake fluid changed in my 2020 Superb Estate (at a cost of £75).  However, when my previous car (VW Passat) was serviced over several years by a small independent, they would test the fluid for water content and only advise a change, if it was needed.   So, now I have bought myself a brake fluid tester, but the fluid level is too low for the probe to reach it, due to the yellow filter (I assume it is a filter) in the top of the Brake Fluid Reservoir.  It doesn't come out with a gentle tug - Can I remove it / How do I remove it, please?

[nta16]

Yes they seem to be a right pain, from what I've seen you just use needle nose or long nose pliers and work your way around to lift it a bit and then yank it out.  I'd watch out for brake fluid splashes.  I always had a moist cloth and bucket of water nearby when do brake fluid changes in case of drips.  Obviously you don't want any water to get into the brake fluid reservoir.

 

Your fluid looks very clean, which is good as it's not just the moist of brake fluid you want to check.

 

Some don't worry about brake fluid changes, others do as your independent and you and check for moisture and hopefully the state of the fluid.

 

I'm not so sure how good and reliable the cheap electronic brake testers are some say they're all you need, I take no chances with brakes are they are the most important item on a car, followed steering and suspension (all three include tyres), then safety electrics (lights, horn, blower, etc.) and glass (mirrors, windows) engine  is down the list.

 

You can get more expensive tester that may be more reliable or optical (refractometer) testers that don't rely on any electronics, just one example. - https://www.lasertools.co.uk/items/pdf/products/5519_Instructions.pdf

5519_Instructions.pdf 

 

HTH.

 

[xman]

My concern would be your car not only has ABS but other automated brake functions, hill/brake hold ASR, ESP, EDL etc. It is imperative that the braking system is kept scrupulously clean and fluid does not cause any internal corrosion.  In my experience, brake caliper pistons are prone to fill with crud and initial fluid discharged when bleeding tends to be dark and dirty, not sure how this happens. So contamination could build up after the ABS control block. Your reservoir may be clean and water free, but it may be a different story at the piston end.

 

Changing the fluid is called preventative maintenance. And it could save you all sorts of very expensive issues later, sticking caliper pistons, premature pad and disc wear, faulty ABS etc.

 

 

[nta16]

1 hour ago, xman said:

Your reservoir may be clean and water free, but it may be a different story at the piston end.

That's a good point as IIRC water goes to bottom and is absorbed and the observation and testing is at only one point but I've seen enough reservoirs with dirty and potentially perhaps contaminated old brake fluid in it but I've never tested any brake fluid for moisture as I prefer preventative maintenance approach, having put that without testing perhaps the fluid needs changing before the preventative maintenance change, or perhaps it could be done later.

 

In my limited experience black fluid is often from rubber seals.

 

@PeterPan99 in your photo isn't the brake fluid level above the yellow plastic cage enough to get the tip of the probe to as I thought that was all that was required or is that just shadow?

[nta16]

@PeterPan99 did you get it sorted, yellow catch-thing out and fluid tested and/or changed?