Proper method to change your brake fluid?

[Chris Meutsch]

Originally Posted By: mclasser
Honda says every 3 yrs, irrespective of mileage so that's what I go with on all my cars.

I've heard it said that bleeding the brakes via the pedal method can cause master cylinder failure, particularly on older cars since it's not good to let the pedal drop to the floor. I think there are TSB's for newer cars as well. Easiest & safest method is vacuum bleeding. Brake flushes are the only fluid change I don't DIY on my cars; it's nasty toxic stuff that eats paint. I gladly pay my indy to do it every 3 yrs.



This is exactly what I do.

 

[Colt45ws]

If any one is curious, These are the copper corrosion test strips I was talking about. They test the amount of copper in the brake fluid. A fleet study was done and determined that when the copper rose above a specific level, the chances of failing a master cylinder or wheel cylinder/caliper rose significantly.

Also, I sometimes drive my vehicle hard, and the reduced boil point of brake fluid that has absorbed water can become a problem if you use your brakes hard enough, often enough.

 

[HTSS_TR]

Originally Posted By: Colt45ws
I use a pressure bleeder. I used vacuum bleed for a long time, giant PITA. Hose always slips off the bleeder and then you have air, so rebleed time.
With the pressure bleeder, you just pressurize the master, and go around and open every cylinder until it runs clear. I typically use a quart bottle of oil to bleed into so I can monitor how much Im taking out, so I don't over do it and run out.

Simple and clean.

I have opposite experience.

I tried Motive pressure bleeder on my cars. The fronts were okay but it didn't do much for the rears of either LS400 or E430. I sold it on eBay.

I used Mityvac fluid extractor and it did excellent job in vacuum brake fluid without any air in the system for all my cars. The time it took to do 4 wheels was less than 5-10 minutes, the time I needed to raise/lower the car, take off/reinstall the wheels was more than 30 minutes.

I used Mityvac 7201 for change oil, ATF and bleed the brake, 1 tool to do several jobs, rather than several tools with each tool for 1 particular job.

 

[Charlie1935]

Originally Posted By: Doublehaul
I worked on cars professionally for a long long time and never heard of let alone saw people changing out brake fluid...and I am ASC certified in brakes!

In 1959 plus or minus a year British Motor Corporation recommended brake system flush at two year intervals.

 

[HTSS_TR]

Originally Posted By: Doublehaul
I worked on cars professionally for a long long time and never heard of let alone saw people changing out brake fluid...and I am ASC certified in brakes! Its absolutely true that brake fluid does absorb moisture...but in a closed system with very little fluid movement you may be looking for a problem that doesn't exist.

I get that BITOG is the most anal-retentive forum in existence but i guarantee you that nobody outside of a very select few change their brake fluid. Where are the catastrophic brake failures and TSBs? Is this a service thats recommended by any OEMs? Im not trying to be argumentative...just curious.

EDIT...i see the gent above me had a OEM recommendation to change every 30k. Maybe this is something I've honestly just missed over the years?

As always YMMV.

In all seriousness we should have a classified section for used car sales...we have the worlds BEST maintained cars!!!

Owner manual of E430 and S2000 clearly have maintenance schedule for brake fluid. MB recommends 2 years with DOT-4 and Honda recommends 3 years with DOT-3. Either one has unlimited mileage for brake fluid, just time.

 

[69GTX]

Originally Posted By: Colt45ws
If any one is curious, These are the copper corrosion test strips I was talking about. They test the amount of copper in the brake fluid. A fleet study was done and determined that when the copper rose above a specific level, the chances of failing a master cylinder or wheel cylinder/caliper rose significantly....


Those are the same kind of test strips that Monroe uses in their service centers. My 13 yr old brake fluid tested fine. They didn't test for % moisture.

 

[Colt45ws]

Originally Posted By: HTSS_TR

I have opposite experience.

I tried Motive pressure bleeder on my cars. The fronts were okay but it didn't do much for the rears of either LS400 or E430. I sold it on eBay.

I used Mityvac fluid extractor and it did excellent job in vacuum brake fluid without any air in the system for all my cars. The time it took to do 4 wheels was less than 5-10 minutes, the time I needed to raise/lower the car, take off/reinstall the wheels was more than 30 minutes.

I used Mityvac 7201 for change oil, ATF and bleed the brake, 1 tool to do several jobs, rather than several tools with each tool for 1 particular job.

Thats bizarre. Ive done the Mityvac for years before I bought the pressure bleeder and it was always a disaster. The hoses would fall off the bleeder if I looked them wrong. It was always a mess and took 10 minutes to do one wheel.

 

[Colt45ws]

Originally Posted By: 69GTX
Originally Posted By: Colt45ws
If any one is curious, These are the copper corrosion test strips I was talking about. They test the amount of copper in the brake fluid. A fleet study was done and determined that when the copper rose above a specific level, the chances of failing a master cylinder or wheel cylinder/caliper rose significantly....


Those are the same kind of test strips that Monroe uses in their service centers. My 13 yr old brake fluid tested fine. They didn't test for % moisture.

Yeah, thats all good then. For me, I like fresh fluid for, like I said, hard driving, and maintenance of my car is very much a hobby. I do a fluid change while Im doing a rotation and it doesn't take much additional time. For $12 I can have fresh fluid and not have to worry about it.

 

[threeputtpar]

I follow a fluid replacement schedule because in the very remote event that my life depended on my brakes working 100%, there's a much better chance of my survival than if the fluid is 4-20 years old.

I believe that $10 of fluid every 3 years and an hour of my time is worth it. But chances are that I may never need to test this theory.

 

[deoxy4]

Lots of good advice here.

YouTube has a lot of great instructional video too. You might even find some vehicle specific videos.

 

[andyd]

The wheel cylinders or calipers are at the bottom of the system. For yrs, I draggoned one of the kids or MDW for pedal duty. When I replace lines, I use a gravity bleed. A system has to be open at both ends and tight in the middle to get a gravity bleed to work. To pedal bleed I rig an airlock out of tubing and a jar of brake fluid. I pump by hand,keeping an eye on the jar When there is a 1/2 cup in the jar, I top off the MC. You don't want to let air into the MC. If I was a pro, I would pressure bleed. The guys who race their BMWs or auto cross, change the fluid after every event.One thing driving old cars in the rustbelt, you get pretty OK with brake systems.

 

[Traction]

I have been using a air powered vacuum bleeder by OTC, and they are rebranded by other companies. So easy, just pull, lock on the trigger, and it will pull a pint of brake fluid in like 30 seconds. It is fast, and you have to be quick not to run the MC down though. You can bleed a completely dry system in 20 minutes. DO NOT worry about bubbles you see coming past the bleeder screw threads, it is after the fact, and can't go back in. It is all about moving a lot of brake fluid through the system quickly. Otherwise, it might take all day, plus help using other methods. A vac bleed, you can easily do all by yourself!

 

[Bud]

Originally Posted By: Doublehaul
Hate to say it guys...but I've never "changed" brake fluid...ive also never had an ABS or MC failure....and i keep cars a long time! Only time i remove fluid is if changing a brake line or a caliper etc and even then its only enough to get the air out.


Same here. In 53 years of driving I have never done it and never had a problem. But whatever makes you feel good.

 

[Rick in PA]

Yup, don't push the brake pedal to the floor when bleeding. I replaced a blown brake cylinder once. We were bleeding the system and it was getting a fairly firm pedal. Then we went a little too far and lost the pedal. That added a new master cylinder to the job.

Put your turkey baster in a zip lock bag labeled "brake fluid only" to keep it clean and reduce the chance of cross contamination.

I'm in the flush the brake fluid occasionally camp. The thought of an expensive ABS solenoid pack going bad concerns me, and brake fluid does get nasty over time.

 

[HTSS_TR]

Originally Posted By: Colt45ws
That's bizarre. Ive done the Mityvac for years before I bought the pressure bleeder and it was always a disaster. The hoses would fall off the bleeder if I looked them wrong. It was always a mess and took 10 minutes to do one wheel.

You're right.

Similar tools and totally difference results.

I use the hose that came with Motive power bleeder. When I hook up the hose to bleeder valve I twisted it 180 degree clockwise so that when I loosen the bleeder valve it is straight with the adapter.

The rears took about 2 minutes each, the fronts were about 1 minute each with 4 pumps on the extractor. I can speed up with few more pumps, but I took my time to do it right and a little slow is better so that the reservoir didn't get emptied.

One thing you and I are similar is we need 1 quart to bleed 4 wheels.

PS Trav, a very good mechanic, uses similar fluid extractor to bleed brake too.

 

[Wheel]

Put a block of wood under the brake pedal to keep it from bottoming out. Easy, cheap and it works.

Moisture in DOT 4.0 tends to form corrosive boric acid, hence the need for more regular changes. Cheap insurance in my mind.

 

[Leo99]

Originally Posted By: Bud
Originally Posted By: Doublehaul
Hate to say it guys...but I've never "changed" brake fluid...ive also never had an ABS or MC failure....and i keep cars a long time! Only time i remove fluid is if changing a brake line or a caliper etc and even then its only enough to get the air out.


Same here. In 53 years of driving I have never done it and never had a problem. But whatever makes you feel good.


My cars still have their original brake fluid. I got ambitious a year or two ago after reading one of these brake fluid threads on here and replaced an ounce or two in the reservoir of the Rav4 with a turkey baster. The turkey baster wouldn't fit in the Corolla so it was left alone.

 

[turtlevette]

Its funny that people that think the hygroscopic nature of brake fluid is no big deal, will go nuts thinking about the e10 in their car or boat. Like lose sleep over it.

 

[DBMaster]

So, get one of these - example only...

Brake Fluid Tester

 

[Colt45ws]

Ive heard of mixed results with those probes that are supposed to measure water content. Like failing new fluid mixed results. From what Ive read, the copper test is more reliable.
Originally Posted By: HTSS_TR


You're right.

Similar tools and totally difference results.

I use the hose that came with Motive power bleeder. When I hook up the hose to bleeder valve I twisted it 180 degree clockwise so that when I loosen the bleeder valve it is straight with the adapter.

The rears took about 2 minutes each, the fronts were about 1 minute each with 4 pumps on the extractor. I can speed up with few more pumps, but I took my time to do it right and a little slow is better so that the reservoir didn't get emptied.

One thing you and I are similar is we need 1 quart to bleed 4 wheels.

PS Trav, a very good mechanic, uses similar fluid extractor to bleed brake too.


For sure. I have no idea what I was doing wrong. I would use one of the little black adapters that seemed to snap firmly onto the bleeder. But I would still loose vacuum at some point in the procedure.
I always used a quart because what would I do with a partial quart? It would just sit there and inhale water. Might as well use it.