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Rear brakes won’t bleed - no fluid

Andy69 said:
Well that didn't fix shit. Still tons of air coming out and no pedal. I don't have any leaks at the metering block or the distribution block at the rear axle. Maybe my old metering block is bad? I have a PV4 that came with the original booster/MC combo I bought but it has to be one that is a direct replacement for the one that's on the car now because of the stainless brake lines. I hope they make one.

Beyond that maybe the booster? I already checked the calipers to make sure I didn't have them reversed. I'm at a loss here.
Click to expand...
I couldn't find any markings on my supposedly PV4 valve. Is it possible yours is a PV2 ?
Is it worth a try to bypass the valve and hook the rear brakes directly to the rear port of the master cylinder ?

I did find "PV4" on mine. It was very hard to see and it's on the bottom
 
Dbl check this but should be correct number for Napa 1968-197? Vette Power Disc/Disc MC
 

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The easiest way to tell the difference between a PV2 and a PV4 is the that the PV2 has a black cap on the end whereas the PV4 does not.
Another possibility, there was a hold-off valve in the rear brake line on some models
See this
 
Nashville Cat said:
The easiest way to tell the difference between a PV2 and a PV4 is the that the PV2 has a black cap on the end whereas the PV4 does not.
Another possibility, there was a hold-off valve in the rear brake line on some models
See this
Click to expand...
The POS 4 whl kit I bought from PJ had a PV2 and being out of old cars since the late 80’s I didn’t realize and pulled my Fn hair out trying to figure why a complete new including all lines stopped like an old worn out 4 whl drum system, if I were to start from scratch it’d be 2000 Camaro complete brake system front to rear
 
Booster wouldn't have anything to do with bleeding the lines. In the simple terms it's master to the block to the calipers. Are the calipers brand new in the rear? If you have a vacuum, start at the farthest point trying to vacuum out that line until there is no air. If you don't get a steady stream there is a block somewhere.

Try this out: Disconnect the master, put a rubber hose on the line going to the rear, then try to bleed the rear. If you get nothing then disconnect the block and try from there. If still nothing then inspect the caliper.
 
I think I'm done worrying about the stupid combination valve (proportioning valve). I'm discarding it.
4 wheel discs on GM models don't get enough pressure to the rear brakes. I've seen this a 1000X on youtube.
I found this 70-73 Corvette distribution block at inline tube. I'm sure it's cheaper somewhere else.
I can always add a proportioning valve to the rear brakes, but the LS1 setup has much bigger brakes on the front.
It would be almost impossible for the rear brakes to overpower the fronts.

1694647464835.png
 
Yep, that one,if it doesn't screw in, the valve isn't centered. You can also check your valve position doing a continuity check from the sensor to ground.....if it connects, the valve isn't centered.
 
Pulled the line at the MC, streams of fluid come out when the pedal is depressed. Disconnect it at the block and same. Going to try the rear line tomorrow as I ran out of daylight.

One thing is bugging me though. The pedal has like 2 inches of travel before it hits a hard mechanical limit which I assume is the piston hitting the back of the bore. Shouldn't it be going all the way to the floor? I don't think it is pushing enough volume.
 
Andy, I feel your pain.
I stopped on my 4 wheel disc conversion about 3 years ago when I couldn't get the rear brakes to bleed.
This thread has got me very interested as I need to finish my brakes.
 
Nashville Cat said:
Andy, I feel your pain.
I stopped on my 4 wheel disc conversion about 3 years ago when I couldn't get the rear brakes to bleed.
This thread has got me very interested as I need to finish my brakes.
Click to expand...

I’ve got a few things I’m going to try today. If they don’t work I‘m thinking about taking all that fancy crap off and going back to the drum/disc setup I had before. It’s not worth the BS.
 
kmakar said:
Like I said in my previous post you should have full travel of the pedal. I concur with Jerry, you have the wrong push rod.
Click to expand...
Or wrong Booster/MC kit?
Andy69 said:
I’ve got a few things I’m going to try today. If they don’t work I‘m thinking about taking all that fancy crap off and going back to the drum/disc setup I had before. It’s not worth the BS.
Click to expand...
Before calling it quits try a Napa 68-76 Vette MC, if it don't change anything return it :)
 
Andy69 said:
Ah ha.

Click to expand...
I also used SS brake lines (Wish I'd used NiCop) in 2010/11, one of the first things I did on the car, when I was having bleeding issues it was rec'd I Tighten fitting, Loosen then Retighten and that seemed to work, I forgot about that till watching this vid, if I were to do it again I'd use NiCop
 
I guessed I must have missed that you had SS brake lines. I'd heard many horror stories getting them to seal and never tried them. I just use standard steel lines and have never had a problem.
 
Shovelrick said:
I also used SS brake lines (Wish I'd used NiCop) in 2010/11, one of the first things I did on the car, when I was having bleeding issues it was rec'd I Tighten fitting, Loosen then Retighten and that seemed to work, I forgot about that till watching this vid, if I were to do it again I'd use NiCop
Click to expand...

I didn't realize that when I put them on. Two solutions that people use are tightening the shit out of them, which I'd like to avoid, and seating them 3-5 times. The issue is the stainless is harder and takes a bit more to get the two sides to conform to each other.

I'm about to go out there. If you don't hear from me in a few hours, call the fire brigade.
 
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