Inexpensive pen brake and clutch fluid tester - only 12 bucks

[Garth Libre]

This business of flushing the brakes every two years always bugged me. I probably end up doing it every 4 years and I've never had a problem. I have a theory that opening the cap should only be done when you're low because you're letting moisture in. Now, I see there's a super cheap and easy pen tester that saves the trouble of buying brake fluid getting a friend or relative to pump the brakes, and then having to throw away a good amount of it because "once you open the bottle it goes bad quickly".

 

[Garth Libre]

https://www.amazon.com/Diagnostic-Hydraulic-Moisture-Analyzer-Indicators/dp/B08NH6FLXL/ref=sr_1_2_sspa?crid=1OQAHI8LINVBE&keywords=brake+fluid+tester&qid=1667139014&qu=eyJxc2MiOiI0LjE3IiwicXNhIjoiMy4zNiIsInFzcCI6IjMuMTgifQ%3D%3D&sprefix=brake+fluid+tester%2Caps%2C322&sr=8-2-spons&psc=1

 

[Garth Libre]

 

[19Walt93]

Both master cylinders are vented so air can get it as the fluid level changes. In NH with the cold winters, the amount of moisture condensing from normal hot-cold cycles would be higher than you'd experience but you'd still have some. If you're flushing it out every 4 years and the fluid isn't discolored, you're good. The discoloration is an indication of fluid contamination and rust, if your fluid isn't getting dark, OK. I flush out my brake fluid at least every 2 years to keep it clean. I replaced the complete brake system on my Mustang in August of 1990 and have rebuilt the front calipers and replaced the rear wheel cylinders once in 32 years because I keep the fluid clean. Maintenance pays.

 

[Shran]

I still have the original fluid in my F150 from 1986... I don't think it hurts to flush it, especially with ABS and stuff involved but I never have and it hasn't bit me.

 

[Roert42]

I subscribe to the school of, it will get changed when the brake lines rust out and need to be changed.

 

[sgtsandman]

I follow the 3 year plan for flushing the brake system with a hand operated vacuum pump kit. I feel it lessens the opportunity for interior corrosion issues, especially with the master cylinder seals getting chewed up from corrosion build up in the cylinder and a abnormally hard stop running the piston seals over the rough spot.

To each there own. There are people who have driven a vehicle for years with minimal issues and no fluid changes in the brake system.

 

[gw33gp]

I think I have flushed my brake fluid only once during the nearly 280K miles on my Ranger. I live in SoCal with low humidity most of the time, so moisture absorption into the brake fluid is very minimal. The brake system has never had any problems other than replacing brake pads (normal maintenance).

The fluid in my clutch system has been flushed many times.