Brakes. WTF am I not doing / doing wrong?

[iamdub]

I can't say I've ever noticed anything like this. Are you sure that's the case for a 96?

Now that you mention it, I'm second-guessing myself on this particular vintage.

 

[thompsoj22]

Are you going all the way to the floor with the pedal? Try half strokes for one complete bleed sequence. I know it sounds impossible but try it and see, In fact since you feel the rears are the issue just do those and leave the fronts alone. ill bet the pedal firms up instantly. This is a big hail mary bet!

 

[96-2D-Hoe]

Are you going all the way to the floor with the pedal? Try half strokes for one complete bleed sequence. I know it sounds impossible but try it and see, In fact since you feel the rears are the issue just do those and leave the fronts alone. ill bet the pedal firms up instantly. This is a big hail mary bet!

Thanks for the reply/advice. I don't push the pedal all the way to the floor any more. I killed at least one MC doing that the last time I went through this. Probably about 1/2 way or so.

I only had about a quart fluid left so I just put it through. I got a couple bubbles from the passenger rear. Not sure about the rest as it's hard to tell when you're one man bleeding. About to return the spare MC to Autozone so I'll see if it's any different shortly.

 

[96-2D-Hoe]

Considerably better. Pedal was going past halfway. Now probably travels about half of what it did before. Finally got somewhere. And that is why I wanted to set the ABS off.

No problems returning the frankenMC to autozone. Bought the 4th gallon of brake fluid, and an additional ground cable to run from the battery to the frame with my free points money.

Didn't check the MC for fluid when I got back. Hoping it's dry tomorrow when I carry on.

 

[96-2D-Hoe]

Ahh well. Here's an update.

 

[96-2D-Hoe]

Lastly, there are a few threads about using newer M/C with a screw cap in this vintage. I don't recommend this UNLESS you find a stepped bore M/C the same size you have. Hint- Look at repair kit Diameters.

There's probably a cheaper way but I came across this and thought I'd put it here
https://www.littleshopmfg.com/gm-ck1500-master-cylinder-upgrade/

 

[96-2D-Hoe]

Fed Ex suck and just delivered my RA order.

The Delco MC reservoir is night and day to the Duralast from AZ. The plastic is stronger, the lip around the top is completely level and flat and it fits to the body much more securely than any I got from AZ.

Hopefully this saga will be over soon.

 

[96-2D-Hoe]

Sadly my pedal still sucks, but the brakes do work, and now I need a brake booster. It has been hissing inside for a while, but now it's hissing under the hood too. Still works though.

RA has an new SKP with no core exchange for $75. The rest are remans and there is no Delco option.
Any recommendations?

 

[exp500]

Put a vacuumn pump on it and check leakdown time. Or the brakeclean spray trick while idleing, though I don't recommend that. If your brakes are soft you have AIR in the master or elsewhere.
Maybe its technique, pumping brakes too fast while bleeding maybe? I know firsthand about brake part issues with these- hoping you aren't caught in 5 bad ina row- I buy brake fluid by the gallon.
Again- are the rears adjusted tight? that brings pedal up 3/4-1 inch. Constant battle with the self adjusters about once a month to bring them back up. Rear brakes still last 2 years.

 

[George B]

Put a vacuumn pump on it and check leakdown time. Or the brakeclean spray trick while idleing, though I don't recommend that. If your brakes are soft you have AIR in the master or elsewhere.
Maybe its technique, pumping brakes too fast while bleeding maybe? I know firsthand about brake part issues with these- hoping you aren't caught in 5 bad ina row- I buy brake fluid by the gallon.
Again- are the rears adjusted tight? that brings pedal up 3/4-1 inch. Constant battle with the self adjusters about once a month to bring them back up. Rear brakes still last 2 years.

Good advice about self adjusters. Brake adjustments were part of a tire rotation for me when I had Drums. However I believe the OP has done this already.
One thing I didn't see and would like to confirm is have the rear wheel cylinders been replaced. If so, are they the right bore diameter? There can only be a couple things wrong here:

1. Air in the system
2. Bad master cylinder
3. Mismatched parts
4. leaks