PeachParts Mercedes-Benz Forum - Using Pressure Bleeder to bleed brakes with no fluid?

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Using Pressure Bleeder to bleed brakes with no fluid?

On one of the other threads, a poster said that when using a pressure brake bleeder (a Motive Bleeder, for example) to bleed the brakes, he did NOT put any brake fluid in the bleeder.

He said he just pushed air pressure using the pressure bleeder which lowers the risk of blowing brake fluid all over the car. I'm planning on installing Amsoil DOT4 synthetic brake fluid in the 1991 560SEL using a pressure bleeder.

Question: If I follow his advice, how would I get the new synthetic brake fluid into the system? Would I simply add the new brake fluid to the master brake cylinder reservoirs?

Quote:

Originally Posted by HuskyMan (Post 3660021)

Use the air pressure to move most but not all fluid out of the reservoir, then remove the pressure bleeder, refill the reservoirs with your new fluid, apply the air pressure again and again use that to move most but not all fluid out of the reservoirs, repeat until the flush is completed.

There is little advantage and some disadvantage is doing it the way the other poster does when in your situation you are aiming to do a complete flush rather than a simple bleed.

X2 worked well. Be certain not to pressure/push the reservoir dry. You can also remove the reservoir to clean it instead of pushing the sediment in the bottom through the system and ABS. If removing the reservoir the seals underneath should be replaced.

Good luck!!!

This is a nice way to do it if you just swapped over a caliper or something. It prevents a mess and allows you to use some pressure. However you can run the reservoir dry. If you want to change out all the fluid its much easier to fill the pressure bleeder and run it at a low pressure.

I have been using the same type pressure bleeder since 1988 and have not had any issues with it at all. I keep the bleeder filled about half way and attach it to the adapter on the brake fluid reservoir, open the valve on the hose (if there is one) and then pump it up to about 10 psi. I then wrap a cloth fender cover around the whole thing ( to contain any possible leaks ) and then bleed at each caliper until new looking fluid comes out.

The bleeder I use came from a MAC tool truck but looks just like a fancy garden sprayer, in fact the guy I work with uses a converted garden sprayer and has had good success with it.

When using a pressure bleeder with fluid in the container, make sure that the seals for the fluid level sensors on the reservoir are in good shape. If not you can have fluid flying all over. Happened to me once but luckily I had the garden hose close by. One of my W124's has a Girling reservoir and I need to replace seal boots every 5 years or so because they crack down the sides.

Quote:

Originally Posted by Rick76 (Post 3660618)

Very true Rick76. I usually take the reservoir off to clean and replace the grommets and rubber caps you speak of if needed.