PSA: Heard a guy at the NAPA counter say he's using DOT 3 brake fluid in a car that needs DOT 4

I overheard him telling the clerk his brakes felt spongy after a fluid flush last week and I had to speak up because mixing those two can boil the fluid and leave you with no stopping power on a mountain grade has anyone else run into people ignoring the reservoir cap specs?

2 comments

2 Comments

fisher.mason1mo ago

Man, that's the kind of conversation you gotta jump into before he walks out the door. Had a buddy do the exact same thing with his old Jeep Cherokee last summer, swore DOT 3 was "close enough" and the cap was just being picky. I finally convinced him to do a full bleed with the right stuff, and we took it up a steep logging road near Mount Baker the next weekend. Halfway down the grade, his pedal was solid as a rock while mine was already starting to get soft from the heat of constant braking. After we got back, I showed him a used set of pads I'd cooked on a previous trip where old fluid boiled, and that shut his argument down for good. Sometimes people just need to see the actual danger before they take a sticker on the reservoir seriously.

paul2331mo ago

Damn, that's a real bonehead move. Did he just not check the cap or did he think DOT3 and DOT4 were basically the same thing?