brake fluid change

[2006goldwing]

i have owned several Gw over the years (a few harleys too)my question is why do you have to all of a sudden have to change the brake fluid? i never have before and have put over a 100000 on two of them! did the fluid change or was i just lucky? Also why do you not have to change brake fluid on a vehicle? my Z71 has almost 150000!

[MikeB]

You have been lucky.

It is not an 'all of a sudden' thing. It has always been a necessity that the brake and clutch fluids be changed at least every two years on any vehicle.

Brake fluid absorbs moisture. Contrary to popular belief, the system is not sealed from the atmosphere. Air contains moisture. Air gets into the system. The moisture in the air is absorbed by the brake fluid. The combination of the moisture in the brake fluid degrades the fluid and will contaminate the master cylinders and brake cylinders.

[Rambozo]

Most brake fluid absorbs moisture in vented reservoirs. You can get a meter that measures the moisture content to see when it needs changing. Unvented reservoirs could go a long time without changing, but when brakes went to plastic vented reservoirs, the lifespan of the fluid became a lot shorter. Virtually every fluid in a vehicle has a lifespan. Run longer at your peril. You can see pictures of engines with 50,00 miles on the original oil.

[2006goldwing]

thank you for the info! i am going to change mine, bought all vacuum bleeders and honda dot 4 fluid etc!

[WingAdmin]

i have owned several Gw over the years (a few harleys too)my question is why do you have to all of a sudden have to change the brake fluid? i never have before and have put over a 100000 on two of them! did the fluid change or was i just lucky? Also why do you not have to change brake fluid on a vehicle? my Z71 has almost 150000!

First off, you should never have to ADD brake fluid - it's a closed system, so if the fluid is suddenly low, it means you have a leak.

As to why you need to flush and change your brake fluid, it's because that seals aren't perfect, particularly the ones in the calipers that get extremely hot from brake friction. Over time, they degrade and allow grit and moisture in. The moisture condenses into water and falls to the lowest part of the system, which is the caliper, where it can pit and corrode the caliper.

It's also a safety issue, as that water down in the caliper, if it gets too hot from the brakes, can vaporize into steam. Steam is extremely compressible, which means you could suddenly without warning find yourself with NO brakes at all until they cool down again.

Changing your brake fluid on a regular basis prevents this from happening. It's preventative maintenance.

[Limpy45]

Waay back in the 60's when I just started to work on cars, trucks and whatever fit in the door of the little shop I was employed at, we repaired lots of rusted out brake lines on older vehicles. Mostly old farm trucks and even some older cars. Water and such would rust out the lowest part of the line and I got very good at doing a double flare crimp on the lines and splicing in a new section for a couple of feet or so. Probably not DOT standard, but not many older vehicles had parts available so we improvised on them. Never had a leak or come back!! I was a rookie and 20 years old!

[Kingston]

you should never have to ADD brake fluid - it's a closed system, so if the fluid is suddenly low, it means you have a leak.
This statement is absolutely wrong. As the pads wear down, the pistons push out causing the area behind them to be replaced by brake fluid.
Also, when you put new pads on you have to push the piston back and that will raise the brake fluid in the reservoir. If you top-up the brake fluid when it was low, with the new pads in, it will be too high.

[MikeB]

you should never have to ADD brake fluid - it's a closed system, so if the fluid is suddenly low, it means you have a leak.
This statement is absolutely wrong. As the pads wear down, the pistons push out causing the area behind them to be replaced by brake fluid.
Also, when you put new pads on you have to push the piston back and that will raise the brake fluid in the reservoir. If you top-up the brake fluid when it was low, with the new pads in, it will be too high.

Actually the statement is correct. If you read it, it says suddenly low.

[scubarider1]

It’s very rare when a brake system actually leaks, but if it was suddenly lower, and you have a leak you would know it because the brake fluid would drip onto the ground and make a mess around the calipers. Of course, with the leak, you would also know because the brakes would not function correctly. Under normal conditions, brake fluid going down as simply because of pad wear. Have you ever experienced an actual brake system leak?