Brake fluid Q's?

[Carmudgeon]

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I'm still not convinced that the fluid in the brake reservoir will circulate down the lines to the calipers. I'm interested to see how this experiment turns out. Can you please post pics of what comes out when you finally bleed the system?

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I agree. There's so little displacement going on, and no looped circuit like there is in power steering hydraulics, the chances that the fluid inside the caliper cylinders is going to make its way back to the reservoir is virtually nil. The only thing a baster "flush" is going to do is freshen up the fluid in the reservoir, and perhaps the master cylinder, and give the owner a false sense of security.

A proper flush is a simple task, and easy to do with a pressure bleeder. It makes little sense to play games with such a critical system.

Advocates of the baster method might as well advise people to change oil by replacing the oil filter every 500 miles instead of a proper oil change by emptying the sump. It might work, but why bother instead of doing it the right way?

 

[Kestas]

I agree. Many are lazy and don't want to do it right. It's so easy to change just the reservoir. And they're justifying their action with palaver and not the scientific method I proposed in this thread. (Prove it - don't try to talk us down!) I actually proposed this a number of years ago. Nobody saw fit to carry this out.

It's not that hard to change the fluid properly. Drive the wheels up on the 2by10 miniramps I often talk about, and access the bleeders that way. No need to jack the car up and take the wheels off. The whole system can be flushed in your driveway in under 30 mins without breaking a sweat.

 

[y_p_w]

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Advocates of the baster method might as well advise people to change oil by replacing the oil filter every 500 miles instead of a proper oil change by emptying the sump. It might work, but why bother instead of doing it the right way?

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I don't do brakes myself. However - I've sent my car to a licensed mechanic, and seen a baster get used. Of course that was only to remove the fluid from the reservoir before adding fresh fluid and bleeding that through the brake lines until it came out clean.

 

[ewetho]

Really brake lines do not circulate. We do not run dual lines like Stock cars used to do in the 80's and early 90's. So the system is just dead headed. The only flow is up at the master and down into the line as pads wear. ABS will recirc some fluid but only at the top end of the line. One of the worst points is actually in the Calipers and Wheel Cylinders wear all the heat is and dirt from the seals moving. This is the fluid that MUST be changed first and foremost. So while we do service the Master Cylinder it is preparation for getting fresh fluid to the calipers and wheel cylinders. Much easier to get clean fluid without mixing the stuff up top with the old dirty fluid.

So clean it out as best as possible and then refill with clean fresh fluid. At this time it is time to do the most important part flush the lines down to the individual wheels.

 

[Doc8404]

another new thread, need advice
http://theoildrop.server101.com/forums/s...yxc6airmafkdji2

 

[Fester]

I just changed my Tundras brake fluid today, I used dot 3 synthetic.

I purchased a hose with a check valve and a hose clamp at AA, the clamp holds the hose to the zerk fitting, its a must to do a one man brake purge. shown on the right of the picture full of five year old brake fluid.

To remove the fluid from the reservoir I made the suction bottle, I drilled two holes on a Pepsi bottle cap, I got some tubing from work, the tubes fit tight one is longer than the other, Cost nada $0, by sucking on the short tube you can quickly draw the fluid out. I have a vacuum pump but wasn't really needed. shown to the left of the picture.

That is new dot fluid in the bottle to compare.

Heres the fluid from my 05 Civic, I think the body shop saves old brake fluid, this car only has 20k it wasn't that dirty till I got it back from the body shop.

 

[Kestas]

Fifteen years ago I made the same hookah setup. The problem is 90% of the time all I draw is air getting past the bleeder threads. Now I mainly use it to vacuum the master cylinder.

 

[Fester]

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Fifteen years ago I made the same hookah setup. The problem is 90% of the time all I draw is air getting past the bleeder threads. Now I mainly use it to vacuum the master cylinder.

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You are correct, the bleeder threads can leak, I had only one that did you can tell which one because fluid will leak through them threads just like the air will, my solution was to remove the Zerk and add Teflon tape to the threads, Its much easier with two people, but I dint have that luxury

 

[Auto-Union]

I think you'd contaminate it more than do any good. Brake system is more sensitive to that than PS.

 

[MGPD03]

I thought I'd resurrect this thread due to the fact that I finally bled the brake syatem clean during a wheel cylinder replacement.

Old fluid from the bleeder valve (versus baster method on page one)

Same fluid, but in handy dandy cups...

Since I found the old image in my photobucket account (to save you a click or two)...

Quite a difference in color and sediment if I do say so myself.

 

[V1]

So this is from your very first flush, MGPD? Approximately how many baster cycles would you say you've done overall? I must say it does look cleaner than the original dirty fluid you showed us. This also appears to be academic proof that regular "bastings" will improve the fluid in a brake system. BUT, it's still kinda dark.

I believe that the baster method works, and I respect the guy that conceived it. It just seems like a waste of time though.

Bleeding from the calipers seems undisputably more effective and practical. Like Kestas said above, you can bleed the system in as little as 30 minutes. How many baster cycles (and cumulative time) would it take to match that? There's no comparison!

 

[moribundman]

I change the brake fluid and bleed my brakes every two years. The only dirt I ever see is for the first first moment when I crack the bleeder. I use a 1/4" ID clear vinyl tube in a small soda bottle. The first inch or so of the fluid that exits the caliper is darker than what follows The fluid gets immediately lighter. I bleed about 200 ml from each caliper. I use a combination of pressure bleeder and pumping the pedal. Since I use the pressure bleeder I can pump the pedal myself without needing a helper: there is no risk of old fluid (or air bubbles) getting sucked back in.

I just did this once again last Saturday after replacing pads and rotors. I also rebuilt the calipers with new piston seals, piston boots, new guide bushings and new caliper guide pins.

 

[MGPD03]

Originally Posted By: V1
So this is from your very first flush, MGPD? Approximately how many baster cycles would you say you've done overall? I must say it does look cleaner than the original dirty fluid you showed us. This also appears to be academic proof that regular "bastings" will improve the fluid in a brake system. BUT, it's still kinda dark.

I believe that the baster method works, and I respect the guy that conceived it. It just seems like a waste of time though.

Bleeding from the calipers seems undisputably more effective and practical. Like Kestas said above, you can bleed the system in as little as 30 minutes. How many baster cycles (and cumulative time) would it take to match that? There's no comparison!


Yes, this is the first complete flush of the brake system since I've owned the vehicle (purchased with 50k and flush was at 127k).

The baster regimen consisted of emptying the resevoir once every 3-5 days for approximately 3 months.

The fluid from the bleeding was much darker and had some sediment as opposed to the dark-ish fluid pulled by the baster method.

I think I've changed sides and have become a proponent of properly maintaining the brake system via bleeding/flushing.

Since I am anal about overdoing things, I bled the system until I got new fluid at the calipers/wheel cylinders and then drove the car for a week or so and bled them again flushing through an entire 32 ounce bottle of fluid.

Overkill? Probably, but I enjoyed it.

 

[johnnyo4]

Originally Posted By: Lorenzo
I don't think the turkey baster method will work for the brake system like it would for the power steering. It's not likely that the new fluid will circulate all the way through the lines to the calipers.

You really should fully flush the brake fluid. It's the same process as bleeding, you just keep doing it and filling fresh fluid in the reservoir until all the old stuff is out.


I agree. I try to flush my brakes every other year. Last year, I could not flush the brakes so I just syphoned the master cylinder reservoir and refilled. My thought was that at least it would reduce the moisture content. It may have, but it did not get any dirt in the lines and calipers out:
I just flushed the brakes (a year later). The fluid in the master cylinder reservoir was clean. The fluid that came out of the lines and caliper was dirty.
So I think it boils down to a full brake flush is best.