Air leaking into brake lines Options

[jmargush]

I am wondering if I might be drawing air into my brake system somewhere. I have bleed the system atleast 6 times and done all the tricks with the proportioning valve. I got a really good high, firm peadal the last time I bled them. A few days later it wasn't quite as good. then went and autoxed on Sunday and by the end of the day they were about gone unless I pumped them.

Question, if it is drawiing air in somewhere after the master cylinder wouldn't there be fluid leaking? If this is correct and I don't have fluid anywhere, the only thing left is where the lines go into the master cylinder which could draw air in without leaking fluid. Does this sound logical?

[ArtechnikA]

when your brakes cooled after the AX, did any of the pedal travel come back?
when you bleed with the 2-person or pressure-bleeder methods, do you actually get air bubbles in the fluid ?
what is your rear caliper venting clearance ?

[jmargush]

Pedal didn't come back. the last time I bled them I got air out of the rear calipers. I haven't bled them again yet since Sunday will try thta tonight to see what I get. The vent ting clearance is set at what haynes calls for.

[ArtechnikA]

The vent ting clearance is set at what haynes calls for.

this is one of the places where Haynes has it wrong ...they call for 0.008" (0,2mm) but that's much too big - 0.004" works better ...

[jmargush]

I bled them again and the pedal never got really firm. If I push on the pedal really hard and hold it, it eventually moves toward the floor. This does not happen as fast as other bad master cylinders I have had but just wondering if this sounds like a bad master cylinder?

[SpecialK]

The vent ting clearance is set at what haynes calls for.

this is one of the places where Haynes has it wrong ...they call for 0.008" (0,2mm) but that's much too big - 0.004" works better ...

Never heard that before, but it makes sense.

Just curious, but is it required to periodically check/reset the clearance as the pads wear? Or is it only required when installing a new set of pads?

[ArtechnikA]

...just wondering if this sounds like a bad master cylinder?

does to me - i almost suggested that earlier. sounds like the seals are just starting to go...

don't even think about rebuilding them - they're cheap, and front-end damage is not ...

[ArtechnikA]

Never heard that before, but it makes sense.
Just curious, but is it required to periodically check/reset the clearance as the pads wear? Or is it only required when installing a new set of pads?

been discussed here in a few threads - search on 'venting' and i'm sure it'll turn up. be a good idea anyway, because i'm only 90% sure on the 0.004" number...

if your self-adjusters are doing their jobs, it's a new-pads-only thing. the venting clearance is basically the self-adjust rest-position baseline.