Delco ABS-VI brake questions....

ss wannabee · 04-10-2013, 01:14 AM

Changing a master cyl on a '98 Lumina sedan...Couldn't borrow a scan tool...

To simplify bleeding, BPMV modulator valves should be in "home" position...

Factory manual on one page says ..to turn modulator gears COUNTER-CLOCKWISE
to achieve "home" position....

On another page...it says to turn gears CLOCKWISE....

One is a mis-print or....?

Going to bleed manually....understand start with forward bleeder valve on BPMV...then do I do the rear valve on BPMV...or leave it alone now? Maybe later?

Next I think you do RF wheel...then LF...and then drive car 5 mph...or a little more?

Finish up with RR...and then LR wheel? Do I have that right?

Don't think traditional RR-LR-RF-LF sequence applies here?

Boy, do I miss the one-lung m/c days!

ss wannabee · 04-10-2013, 06:34 PM

Anybody care to comment? I've got to go ahead...time's running out...Might go with Counter-Clockwise...as it was mentioned TWICE...(going with law of averages!)

To get to the master cyl mounting bolts...you disengage the BPMV motor pack....which is under tension with the modulator gears...

I think I've read this whole job CAN be done without special tools...BUT bleeding MIGHT
be difficult...if the BPMV valves are NOT in the "home" position...(trapped air.)

TO make matters worse...NO pressure bleeder available...I asked around...NOTHING!

Anybody done this repair...VERY popular brake system on 1990's GM cars....

SUPPOSED to be "user-friendly" too.....

04-10-2013, 01:14 AM	#1
ss wannabee Senior Member Join Date: Jun 2005 Posts: 663 Likes: 0 Liked 5 Times in 5 Posts	Delco ABS-VI brake questions.... Changing a master cyl on a '98 Lumina sedan...Couldn't borrow a scan tool... To simplify bleeding, BPMV modulator valves should be in "home" position... Factory manual on one page says ..to turn modulator gears COUNTER-CLOCKWISE to achieve "home" position.... On another page...it says to turn gears CLOCKWISE.... One is a mis-print or....? Going to bleed manually....understand start with forward bleeder valve on BPMV...then do I do the rear valve on BPMV...or leave it alone now? Maybe later? Next I think you do RF wheel...then LF...and then drive car 5 mph...or a little more? Finish up with RR...and then LR wheel? Do I have that right? Don't think traditional RR-LR-RF-LF sequence applies here? Boy, do I miss the one-lung m/c days!

04-10-2013, 06:34 PM	#2
ss wannabee Senior Member Join Date: Jun 2005 Posts: 663 Likes: 0 Liked 5 Times in 5 Posts	Re: Delco ABS-VI brake questions.... Anybody care to comment? I've got to go ahead...time's running out...Might go with Counter-Clockwise...as it was mentioned TWICE...(going with law of averages!) To get to the master cyl mounting bolts...you disengage the BPMV motor pack....which is under tension with the modulator gears... I think I've read this whole job CAN be done without special tools...BUT bleeding MIGHT be difficult...if the BPMV valves are NOT in the "home" position...(trapped air.) TO make matters worse...NO pressure bleeder available...I asked around...NOTHING! Anybody done this repair...VERY popular brake system on 1990's GM cars.... SUPPOSED to be "user-friendly" too.....