Flushing brake lines
Thread Starter
Instructor
Joined: Jun 2001
Posts: 116
Likes: 0
From: Brighton MI
Flushing brake lines
I'm in the process of installing new calipers and a new master cylinder. Do I need to flush the brake lines to get any dirt or remaining fluid out? The brake fluid that was in there was kinda nasty. Should I use compressed air and blow the lines out? Any insight would be greatly appreciated. Thanks
Melting Slicks
Joined: Aug 1999
Posts: 3,123
Likes: 13
From: Hollywood, Florida
Re: Flushing brake lines (AV76)
You should definitely clean out the lines. Brake fluid absorbs moisture, even from the air, and this causes the gunk. After a while, the lines and calipers corrode, pit, Etc.
If your brake lines are sound, you can gravity flush the fluid before you change the master cylinder. Just remove the lines from each caliper, slide a piece of rubber hose on the line, stick the other end in a container and let gravity do the rest. This is how I just flushed mine last weekend. Naturally you have to keep refilling the M/C as its level drops.
If you are switching to silicone fluild, I was told that you need to flush the system with denatured alcohol. You also might want to change the rubber hoses while your at it.
[Modified by shoptek, 6:23 PM 4/27/2002]
If your brake lines are sound, you can gravity flush the fluid before you change the master cylinder. Just remove the lines from each caliper, slide a piece of rubber hose on the line, stick the other end in a container and let gravity do the rest. This is how I just flushed mine last weekend. Naturally you have to keep refilling the M/C as its level drops.
If you are switching to silicone fluild, I was told that you need to flush the system with denatured alcohol. You also might want to change the rubber hoses while your at it.
[Modified by shoptek, 6:23 PM 4/27/2002]
Melting Slicks
Joined: Dec 2000
Posts: 3,407
Likes: 2
From: Carmichael CA
Re: Flushing brake lines (AV76)
I recommend using brake fluid to flush the system by sucking out all the nasty fluid out of the m/c reservoirs and using chemical gloves to scrub the sides and bottom, then filling with fresh fluid and pumping fresh fluid though the system using the brake pedal (run the engine if it's power brakes).
Safety Car
Joined: Mar 2002
Posts: 4,411
Likes: 1
From: Okeechobee Florida
Re: Flushing brake lines (Rockn-Roll)
does the engine need to be running to bleed the brakes too? says nothing about that in the repair manual, but i DID wonder about that when we bled mine...thanx, gary
Burning Brakes
Joined: Aug 2000
Posts: 852
Likes: 0
From: Katy TX
Re: Flushing brake lines (AV76)
When I converted to DOT5 fluid I disconnected the lines at the proportioning valve and blew out all of the lines with air. I also followed with brake cleaner and more air until everthing was clean. It helps to have someone hold a rag over the outlet so you can see what comes out (and you don't want to be blowing break fluid and cleaner all over the place). Like you, I was replacing the master cylinder as well so you dont have to jack around with trying to clean that.
