Three questions re changing brake fluid

[rationull]

I've just hit the 3 year recommended brake fluid change interval on my Civic and I had three questions, since I've never changed brake fluid before:

1) The service manual only has instructions for bleeding the brakes, not changing out the fluid. Is the change out just an extended bleeding, pumping until clean fluid comes out at each wheel, or is there more to it than that?

2) Is it worthwhile to get a power bleeder or some other "one person" solution or is it better just to get a helper and use the normal "open bleed screw, pump brake" method? (The car has ABS if that affects the answer.)

3) I believe the manual only references brake fluid, not the clutch fluid. Is it generally recommended to flush the clutch fluid at the same time, or not mess with it?

 

[jstutz]

personally i love the little mighty hand vacs. There about 25 dollars and they work great for bleeding brakes by your self and its nice and clean. I will never bleed brakes the old way again.

 

[hate2work]

Can you give a brief description of how they work? I need to flush several rigs this summer, and have been looking into how to do it.

 

[rationull]

Do those just work by applying vacuum at the wheel cylinder instead of pressure at the master cylinder? Can they cause any problems with ABS systems?

 

[brandini]

They work great, you never want to apply pressure to brake fluid (with air).

Here's why:
http://www.stoptech.com/tech_info/wp_howto_bleedbrakes.shtml

Somewhere in there it states that pressure bleeders can force air to dissolve into the fluid (bad).

 

[mechtech2]

There are all sorts of very good methods of changing your brake fluid.

For a one man operation, a vacuum type bleed is VERY good. A Mity-Vac or similar [copy] vacuum device is cheap. No adapters are required.

First rule:
KEEP YOUR RESERVOIR FULL! It is easy to let it go down to far and you'll suck air and have to start over. This applies to ANY bleeding/flushing.

But all you do with a vacuum bleed is to loosen the bleeder with the hose attached , while keeping moderate vacuum applied. Close the bleeder while there is still some vacuum.
Of course, empty the collector/container as necessary.

And yes, do your clutch a favor and get it too while you are at it. Whether or not it shares the reservoir with the brakes, just do it.

Brake fluid eats paint. Spills on the body or other paint seem like nothing. 2 days later, the paint is lifting. So clean up spills right away.

 

[XCELERATIONRULES]

I usually use Teflon tape on the bleeder threads to help keep air out during the process.
The only headache is constantly topping off the master cylinder.
The brake system doesn't hold much fluid at all.
Be sure to use the correct fluid,usually dot 3 or 4.
They are all not compatible with each other.

 

[The_Jeff]

I'd find a honda forum and make sure the ABS doesn't need a special procedure. Some GMs do and they get real squishy pedals if it goes wrong.

 

[Kiwi_ME]

1. Yes
2. Yes, either a vacuum or pressure type - your choice. The vacuum pump is easier to attach but I prefer applying 5-10 psi to the reservoir, which requires a fitting or adapter.
3. I would do the clutch even more frequently. It gets dirtier more quickly for obvious reasons.

 

[bigmike]

http://corp.advanceautoparts.com/english/youcan/asp/ccr/ccr20011001bb.asp

I always do a 2-man brake flush. It costs me nothing, as I drag my wife out there to help me, and it works flawlessly. Besides, all that shouting "up" and "down" does something for the relationship.

 

[rationull]

OK, now I'm confused. I've read the following at various places:

- You shouldn't use pressure bleeders because they can force moisture into the fluid.
- Vacuum pumps and even the standard "helper" approach can collapse your clutch master cylinder, and you must pressurize the system externally to fix it.

The service manual for this car recommends the "helper" approach for both systems, and recommends using a piece of wood to block the clutch release fork's movement while pressing on the clutch pedal.

If the vacuum pump isn't going to work for the clutch then I'll either go with a pressure bleeder or just find a helper.

 

[donny939]

I just changed the brake fluid on my civic not to long ago. Buy the craftsman bleeder. Works great and is cake to use. I had my clutch fluid changed at the dealer when they did the transmission fluid.

 

[rationull]

If I'm going to take it somewhere I'd probably just have them do the brakes and the clutch both. Rather just do it all myself or not bother with any of it.

 

[mechtech2]

Unless you are a real brake bleeding team, expect failures from the pumper.
They will always do one bad movement as you relay you orders, and you have to start from scratch. And you may not know it, which is worse!
Teflon tape is not needed. Who cares is it leaks a little when under pressure or vacuum?

 

[bigmike]

Keep the hose in a bottle of fluid, preferably as clean as possible. No air will travel into the line, which will result in you only having a little contaminated fluid entering back into the line. This means you don't have to start from scratch, but merely bleed a little more back out.

I agree, you usually do have a few moments of this happening. I like to bleed my brakes twice over a few days of driving. Pretty easy on the truck, as I don't have to jack it up or put it on ramps.

I use a 1/4" washer line hose and a clear plastic cup. I used to use a jar, but if it falls on the garage floor, I don't want glass going everywhere.

 

[Paul B.]

I have flushed brake stystems in a variety of ways, here's my opinion on different methods I've tried:

Pump pedal method: Works fine if two people are available - take care to block last couple of inches of pedal travel to keep from damaging master cylinder with grunge that may have acumulated at bottom of cylinder bore. A pain in the neck if you don't have a second person and resort to using a cinder block on the brake pedal.

Mighty vac: It works mostly, but it's not very aggresive for removing air trapped along the walls of the brake system. I have coated bleeder valve threads with antigallant to prevent air leakage when drawing a vacuum.

Power bleeder: Works fine if your adapter fits the top of the master cylinder tightly. If it doesn't you have an enormous mess on your hands with leaking brake fluid. Dissolving air in brake fuid not a problem if you don't shake up the fluid or leave it under pressure for hours at a time.

Speed bleeders: This method uses a replacement bleeder valve that has a self contained check valve in it. You loosen it quarter to half a turn (attach a hose run into a jelly jar to catch old fluid) and get in the car to pump slowly with pedal blocked like normal pedal pump method. After 5 or six pumps, tighten the valve and you're done. The valve remains in place until next time. total cost of valves uner $20.

Agree that clutch should be done too.
I have had no problems doing it every 2 - 3 years with cars that have gone 150,000 - 200,000 miles before I sold them.

If you aren't starting with a spongy pedal, I don't think you have to worry about trigering the ABS system to get old fluid out. Just make it work a couple of times after you're done and any old fluid will migrate out in to the sytem to mix with the new fluid.

 

[Kiwi_ME]

To add to that, it is also practical to use a pressure flush with air only, removing the risk of spillage. Naturally you have to keep the reservoir full - same as with every other flush method.

I run 100ml through each back brake and about 75ml through each front, leaving enough out of a 500ml bottle for clutch and top-up.

I've been able to bleed the clutch system with gravity flow only, just takes a bit of patience.

 

[andyd]

If I am replacing lines , I remember to keep the reservoir topped off. This should keep the ABS quiet, as it has seen no change. This resulted in a gravity bleed that gave a harder pedal than any 2 person bleed. I also have rigged a bottle of fluid and a hose to the bleeder, making an airlock. You need a good seal at the bleeder threads. I use a dab of grease to prevent air from sucking in. I prolly should be flushing the brakes on my cars this spring.

 

[artificialist]

Originally Posted By: XCELERATIONRULES
I usually use Teflon tape on the bleeder threads to help keep air out during the process.
The only headache is constantly topping off the master cylinder.
The brake system doesn't hold much fluid at all.
Be sure to use the correct fluid,usually dot 3 or 4.
They are all not compatible with each other.

DOT4 can be used to replace DOT3, in fact I find that it lasts much longer in a DOT3 application.

But never put DOT3 in a DOT4 system, or it will easily boil the fluid.

 

[highmilegeguy]

I usually just use a one man system of connecting a check valve tube to the bleeder screws. Works great.

The only other point would be to empty the reservior first to the bottom and clean inside the reservoir. You'll have a good film of grime that you want to clean before you refill with new fluid.

Brake fluid absorbs moisture so always use a new bottle that hasn't been exposed tp air and humidity.