ABS unit cycling
Thread Starter
Drifting
Joined: Jan 2001
Posts: 1,408
Likes: 13
From: Dayton, Ohio
ABS unit cycling
Getting ready to do a brake fluid flush in the near future. When I do this, is there a need and a way to get the ABS unit to cycle in order to
flush the fluid in there also? Should I even worry about it?
I'm looking at going to braided lines, $110/set from MAD, Ecklers, C-Central.
Thanks in advance
flush the fluid in there also? Should I even worry about it?
I'm looking at going to braided lines, $110/set from MAD, Ecklers, C-Central.
Thanks in advance
Safety Car
Joined: Feb 1999
Posts: 3,504
Likes: 4
From: Mexico Beach FL
I think it may depend on the year of the car.
My '92 has a dedicated brake fluid "primer" pipe from the master cylinder reservoir to the ABS/ASR unit and a bleeder valve on the unit too.
The '92 shop manuals don't have anything in them about special procedures for bleeding/flushing the brake fluid separately through the ABS unit.
And, the manuals for the Vetronix Tech-1A don't have any instructions/features for opening the ABS valving for a flush on a '92.
But, I don't think later ('94 and up?) have this primer pipe.
Tom Piper
My '92 has a dedicated brake fluid "primer" pipe from the master cylinder reservoir to the ABS/ASR unit and a bleeder valve on the unit too.
The '92 shop manuals don't have anything in them about special procedures for bleeding/flushing the brake fluid separately through the ABS unit.
And, the manuals for the Vetronix Tech-1A don't have any instructions/features for opening the ABS valving for a flush on a '92.
But, I don't think later ('94 and up?) have this primer pipe.
Tom Piper
Last edited by Tom Piper; May 11, 2006 at 02:24 PM.
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
I flushed Mine using a Mityvac and did not cycle the ABS.It worked fine and improved my braking.The MC looked black before and is clear now.I guess that is the diagnostic aid. If it is black bleed time for sure.I used synthetic fluid too.
Safety Car
Joined: Feb 1999
Posts: 3,504
Likes: 4
From: Mexico Beach FL
According to my Ford shop manual, my Ford truck requires a scan-tool to open the ABS valves for flushing the entire system.
So, obviously, it depends.
The problem with not making sure the ABS unit is flushed/bled is:
1) If there is air in the ABS unit, the brakes will feel fine until the first time the ABS unit pump runs and the valves open during an ABS event, then the air will be pushed out into the rest of the system and you will have spongy brakes.
2) If the fluid in the ABS unit is contaminated with moisture or debris, the first time it is cycled that contamination will mix with the rest of the system.
Tom Piper
So, obviously, it depends.
The problem with not making sure the ABS unit is flushed/bled is:
1) If there is air in the ABS unit, the brakes will feel fine until the first time the ABS unit pump runs and the valves open during an ABS event, then the air will be pushed out into the rest of the system and you will have spongy brakes.
2) If the fluid in the ABS unit is contaminated with moisture or debris, the first time it is cycled that contamination will mix with the rest of the system.
Tom Piper
Last edited by Tom Piper; May 12, 2006 at 08:22 AM.
