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Comment by lttlrck | Hacker News Reader

When my spring broke I called a someone local (maybe via Yelp), he came out within 30 minutes, replaced it in 20 and charged me $75. This was only a couple of years ago.

Likewise with brake fluid changes. I can do it, but the risk/hassle just ain't worth it for the cost of a pro.

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After seeing the quality of work of "pros" with simple oil changes, I wouldn't trust one of them to properly change and bleed brake fluid, unless I was very familiar with their work.

I never replace the brake fluid. I do flush each caliper when changing summer and winter tyres. This means a selected offspring presses the brake twice for every tyre and the caliper has fresh fluid in it.

The fluid only degrades in the caliper, no need to replace it entirely, and no need for a computer when you do it like I described it.

It depends. Brake fluid absorbs moisture, which lowers its boiling point. You don't want it boiling from brake heat when you're really trying to stop. If you live somewhere humid then the whole reservoir can slowly absorb too much moisture and make the fluid unsafe.

Correct. Brake fluid absorbs moisture but the key is that DOT 3, 4, and 5.1 fluid then spreads that moisture evenly throughout itself, so that you never have a pool of water in your brakes but instead a dispersed low percentage of moisture in the fluid.

So even if water only enters the system at the caliper or reservoir, that moisture still spreads through all the fluid in the entire car. That's why you flush it all out when changing brake fluid.

No need to panic. An entire generation never refreshed this fluid and vapour lock was still a rare incident. Replacing 20% of this fluid every year is more than enough.

You are replacing the brake fluid though. Probably more ofent then almost every car owner.

What are the risks of changing brakes? Never thought of that as a particularly risky endeavor before.

The most common risk is not properly protecting against contamination of the reservoir or not bleeding the system and having air or water in the line.

Air will compress and you could have brake failure. Also water, less common but happens, as the brakes heat up, can boil into gas and then also again you have loss of pressure and brake failure.

This is why I comment technique for race cars, which always have the risk of possibly boiling their brake fluid, will give a slight pump to the brake before coming up to a corner to pressurize the master cylinder and make sure that it does have a little bit of pressure pushback While you still have a little bit of space to react and ditch if something goes wrong

I would assume "if you don't put them back together right, you can't stop, and cars are deadly enough with functioning brakes"

In addition to the other answers, brake fluid is toxic and removes paint.

Only the old dot3 does that.

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