Bleeding /Flush Brake Sys


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Golden Jubilee
Golden Jubilee

Posts: 739

Joined: Mon Sep 07, 2015 11:14 am

Post Wed Jan 17, 2024 3:06 pm

Bleeding /Flush Brake Sys

Best method for one person ?

Suck out old from master/ refill with new

Bottle hose submerged in fluid / open bleeder slow pump peddle for each wheel in proper order..
Keep master full as you go,


What say you? Details . Tips . :)

Golden Jubilee
Golden Jubilee

Posts: 8937

Joined: Thu Dec 27, 2012 12:45 pm

Location: Canada's left Coast

Post Wed Jan 17, 2024 5:27 pm

Re: Bleeding /Flush Brake Sys

All brake fluid other than DOT5 will attract moisture and rusting will happen in the master cylinder. This is called hygroscopic. The rust is always ahead of the master piston boot. SO, if the person pumping the brake pedal depresses the pedal and piston into the rust zone, the piston boot will be destroyed. Back in the day, it was common practice to place a short section of wood 2X4 under the brake pedal to limit movement.
NEVER SHAKE THE BRAKE FLUID CONTAINER. DOT 5 is the worst for holding air bubbles after agitation. DOT 5 should be left still for a day after the trip from the store. If you shake the DOT 5, allow a week for the trapped bubbles to leave. These bubbles are what give any brake fluid a spongy feeling in the pedal.
I use DOT 5 silicone brake fluid only. The rear brake line on my R120 rusted thin on the outside. A hard brake application caused the tube to burst. After 20 years, the inside of the tube looked like new.
DOT 5 will not combine with other brake fluids. The only problem is, fluid other than DOT 5 will continue to attract moisture and the benefit of DOT 5 is all but lost.
It is always a good preventative maintenance service to flush the system along with replacing the brake cylinder boots.
If you are replacing the soft rubber parts in the brake cylinders. Dow Corning DC5 is a good lube for this application
I hope I have remembered everything CB89 will correct me if I missed something..
I would rather have tools I do not need than to need tools I do not have
Thinking risks being controversial and possibly being offensive

Golden Jubilee
Golden Jubilee

Posts: 8937

Joined: Thu Dec 27, 2012 12:45 pm

Location: Canada's left Coast

Post Wed Jan 17, 2024 6:15 pm

Re: Bleeding /Flush Brake Sys

Suck out old from master.
Just a minor point.
Suck is often misunderstood. It is really a lowering of pressure in one area and the ambient air pressure rushes to fill the lowered pressure space and balance the pressure.
In modern common language, suck and blow have become nearly the same.
I would rather have tools I do not need than to need tools I do not have
Thinking risks being controversial and possibly being offensive

Golden Jubilee
Golden Jubilee

Posts: 8937

Joined: Thu Dec 27, 2012 12:45 pm

Location: Canada's left Coast

Post Wed Jan 17, 2024 6:15 pm

Re: Bleeding /Flush Brake Sys

edited out
I would rather have tools I do not need than to need tools I do not have
Thinking risks being controversial and possibly being offensive
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Golden Jubilee
Golden Jubilee

Posts: 739

Joined: Mon Sep 07, 2015 11:14 am

Post Thu Jan 18, 2024 1:04 pm

Re: Bleeding /Flush Brake Sys

Thanks

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