Lotus Elan and Lotus Elan Plus 2 Forums

In case it's of interest, Lidl currently have on sale brake fluid testers for £6.99:

https://www.lidl.co.uk/p/car-accessorie ... ter/p54457

I last changed my brake and clutch fluid just over 2.5 years ago, and the water content was showing as > 4%...

Which brings up the question "What's an acceptable amount of moisture content?"

pharriso wrote:Which brings up the question "What's an acceptable amount of moisture content?"

Less than 2%. 0% is ideal. Moisture = corrosion.

StressCraxx wrote:

pharriso wrote:Which brings up the question "What's an acceptable amount of moisture content?"

Less than 2%. 0% is ideal. Moisture = corrosion.

also moisture boils when getting hot (100°C vs 250-300 or even more for racing fluid), causing brake fade during spirited driving...

Dreanog.

Many thanks, purchased mine today , need to change my brake fluid.....

John

Hi

Thank you for the heads up! To Lidl I go tomorrow........

Berni

Just change the fluid completely every 2-3 years (Porsche and BMW both say 2) and you'll not need the tester. And your brakes will be happier. I like happy brakes.

bitsobrits wrote:Just change the fluid completely every 2-3 years (Porsche and BMW both say 2) and you'll not need the tester. And your brakes will be happier. I like happy brakes.

Now I'm a sucker for buying the tools and toys, but this is what I do as well. The issue I see with brake fluid testers is that unless you bleed the brakes and test what comes out of the caliper, you're only testing the m/cylinder reservoir fluid.

All well & good but this is the most likely area to have a high water level because it breathes to the atmosphere. It's hard to see how moisture gets much further into the system. The fluid down the lines and behind the caliper piston will be different because it doesn't flow around the circuit until you bleed some out. Some will go from the reservoir to the m/cylinder as the pads wear so IMO changing fluid protects that part of the system.

Because my cars don't do a great mileage or wear through pads I tend to go with a 2 or 3 year interval. If it's been a while since doing any work and I need to bleed the brakes then I'll empty the m/cylinder & replace the lot before bleeding. It's cheap insurance.

Brian

UAB807F wrote:The issue I see with brake fluid testers is that unless you bleed the brakes and test what comes out of the caliper, you're only testing the m/cylinder reservoir fluid.

All well & good but this is the most likely area to have a high water level because it breathes to the atmosphere. It's hard to see how moisture gets much further into the system. .............

Brian

So what you're saying is that you are testing worst case... that is fine!

Will try to pick one up this weekend when I visit the UK.

Good luck getting it to fit between the Weber carbs on a Sprint ! Its a bit of a tight squeeze……..

My 1 year old fluid still came out at less than 1 %

Regards
Richard

richardcox_lotus wrote:Good luck getting it to fit between the Weber carbs on a Sprint ! Its a bit of a tight squeeze……..

That’s the advantage of lhd!

I guess with rhd you could extract some brake fluid with a turkey baster?
P.s. don’t tell the wife!

Bought one and just tested a a brand new, sealed bottle of DOT4: it showed 2% water content, so putting it kindly, the gadget is spproximate. !