I've read threads here that offer an alternative to replacing brake fluid the "old" way( by bleeding the brakes). The thread advocates a "topsider" type method.Pulling fluid from the Brake Fluid Reservoir. This sounds like a good Idea, So -
My question is a practical one. Will I be commiting a car crime by refilling the Reservoir with fluid from two different name brands ? - Just happen to have two bottles handy that are both DOt 4, but not same brand...
thanks

Using a Mighty-vac you pull the fluid through at the wheel cylinder fitting, NOT the master cylinder. That's the suction method.

A pressure bleeder (see here:http://www.falcotools.com/html/euro_kit.html ) pushes fluid through the master cylinder and you drain it at wheel cylinder fitting.

You are going to get under the car either way. No "Topsider" system that I've ever heard of. You can use a turkey baster to "freshen" the fluid, but that isn't bleeding.

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The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

jbaj007 wrote
"You can use a turkey baster to "freshen" the fluid, but that isn't bleeding."

thanks for the prompt response - I guess I am refering to the "refreshing the fluid" option.

What do you think about my question re mixing 2 different name brands - is that OK ?
thanks

If you have ABS, you need to use the pressure system. You can use the MityVac for pre-ABS systems.

Refreshing the fluid in the resevoir probably won't do much good because it's the fluid in the lines and calipers that needs to be refreshed.

NEVER use the old method of pumping the brakes. That was found to be the major cause of damaging master cylinders.

I doubt it would hurt to mix Dot 4 fluids so long as they haven't had an opportunity to absorb moisture.

someone had written here about a "graduall refresh" . The claim was that over a period of a few weeks they had replaced all the fluid in the system a bit at a time (going through the reservoir only). I was going to give this method a try. So I was double checking, to learn from the experience of other members.
we'll see how it goes.

I don't see how a reservoir-only refresh can properly bleed the brakes. It won't do anything to the fluid at the calipers which MUST be changed periodically to prevent caliper deterioration - where most of the corrosion damage occurs.

Could you explain more on this "gradual refresh" method that you read?

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95 E320 Cabriolet, 159K

The "gradual refresh" method you read about was probably related to the power steering fluid where it is recirculated throughout the system and Newton's method of approximation will lead to a 90+% change after a few empty/refill cycles of the reservoir. Brake fluid doesn't circulate, except by diffusion, so must be bled to be fresh at the caliper cylinders. You got to be on your back for the brakes, one way or the other (unless you have a lift ).

__________________
The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

I finally found that thread I had seen a while back about the brake fluid - It addresses all the stuff mentioned above.

Here it is, Changing Brake Fluid
thanks again

That thread talks about the two person method of changing brake fluid. I was told by Sears Imports in the Twin Cities that when they stopped using that method, they stopped having to replace master cylinders.