Can you bleed RWABS with the truck in the air?

[TylerSteez]

In the manual for my 91, it says (something like) take that rubber cap off and press it in with a screwdriver or something. Air and fluid will come out, so have a rag handy. It firmed up my pedal that's for sure.
I'd highly recommend NOT doing the lift thing, but if you do...... PLEASE record it and post!!! Lol

sorry to bump an old thread but i have a 92 with the early abs system. did you do the bleeder facing the front of the truck or the bleeder underneath that faces the ground?

 

[Drunkcanuk]

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That one right there, so I guess the one facing the front.
And no worries about bumping an older one, at least it's not 10yrs old! Lol

 

[evilunclegrimace]

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That one right there, so I guess the one facing the front.
And no worries about bumping an older one, at least it's not 10yrs old! Lol

That is not a bleeder. it is the end of the centering valve.

 

[Drunkcanuk]

That is not a bleeder. it is the end of the centering valve.

Not doubting that. I just followed what the Haynes manual said for bleeding. It said take the rubber off, have someone pump and hold, stick a pointy doodad in there and fluid and air come out. I did it and my pedal firmed up.
Voodoo magic I guess.

 

[Schurkey]

That is not a bleeder. it is the end of the centering valve.

It's not a bleeder. It's not the end of the "centering valve". It's the stem of the metering valve.

Figure 2-12. Similar part, older diagram:

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[GoToGuy]

Not doubting that. I just followed what the Haynes manual said for bleeding. It said take the rubber off, have someone pump and hold, stick a pointy doodad in there and fluid and air come out. I did it and my pedal firmed up.
Voodoo magic I guess.

Your OE service manual is available here. You've seen the replies. If there was nothing else Haynes would help. It could also give incorrect info. I would be worried the metering valve had air and had shifted for some reason as it indicates a potential imbalance.

 

[Schurkey]

Your OE service manual is available here.

And a wonderful resource that is, too. Thanks, hatzie and other contributors!
www.gmt400.com/threads/88-98-service-manuals.43575/

88-98 Service Manuals

Over the years I have collected a bunch of GM service literature. Links to PDF Scans of service and STG manuals and a links to the Parts manuals. You'll need the FREE Adobe Acrobat reader to open these files. Get it directly from Adobe here {http://get.adobe.com/reader/} If you're not...

www.gmt400.com

If there was nothing else Haynes would help. It could also give incorrect info.

The aftermarket "service" manuals are so condensed as to be nearly useless.

I would be worried the metering valve had air and had shifted for some reason as it indicates a potential imbalance.

There was air in the combination valve as he saw it when it was expelled. However, you're thinking of the safety-switch valve, not the metering valve.

Combination valve has the proportioning valve (affects rear brakes only, by reducing pressure rise under heavy braking), the metering/holdoff valve (affects front disc brakes only, by preventing pressure to the front until the rear drum brakes have enough pressure to overcome the return springs), and they're separated by the safety-switch spool valve which reacts to input pressure imbalance between front and rear hydraulic systems.

 

[GoToGuy]

Ok, now I know I'm really tired. My fault I just glanced over it.

 

[evilunclegrimace]

It's not a bleeder. It's not the end of the "centering valve". It's the stem of the metering valve.

Figure 2-12. Similar part, older diagram:

You must be registered for see images attach

Yes that is the correct terminology. ya now the thing!