Here's the run-down.

4.9L

My girl was driving it one day. Right front brake hose separates. She drives it like that to get it home, all fluid lost.

I replace brake hose and bleed just the front brakes if I remember right, attempt to drive it. Front brakes grab late, and pull when they do. To get them to engage I have to pump pedal up in semi-rapid sucession.

Proceeded to bleed all four brakes (with one man bleeder and with helper). No more pulling but front brakes still way late to engage and soft pedal.

Replace Master (remand) and Proportion Valve (new). Bleed all 4 again. Same issue.

Basically as soon as I start the van I get air in the front. I just bled the front brakes 10 times in a row, soft pedal as soon as I start it. Even bled it with the van running. Pedal never felt normal.

Van doesn't leak brake fluid at all. All bleeders are closed completely.

Van was fine until that line broke.

A brake booster causing it doesn't make sense.

 

Did you bench bleed the replacement master first??

Are you bleeding the ABS unit??

Do you have RABS or 4ABS?? = different bleeding procedures.

Bone drying the master could have gotten the ABS unit air locked, which will take you forever to get corrected, unless you have the correct tools.

Might be better and cheaper in the long run to take it to a shop or dealer??

 

Rear ABS only. Yes I bench bled the master before installing.

And yes I bled the ABS module.

I am more than capable of doing any of the necessary repairs to the van. So it will not be going to any shop or dealer. I get one track minded sometimes though so I was hoping someone could help me out. It seems as though I have a massive amount of air the likes of which I have never seen.

If it was constant air being sucked in I would have visible leaks somewhere.

If need be I can remove the rear ABS unit and bypass it for now to try that out.

that just does not seem necessary to me because the front and rear systems on this man are completely separate except for at the master cylinder.

 

Sorry if I offended you on your capability for this repair.

So, for further information on this matter, rgnprof posted this link that you might want to read thru, Link

Another thought would be the condition of the soft lines you did not replace, and the age of the vehicle, soft/rubber lines do deteriorate internally, and can act like a check valve, allowing fluid only in one direction.

Bleeding the ABS unit first, and then do the RR/LR/ABS/RF/LF might get some results for you.

I don't get your statement - "
If it was constant air being sucked in I would have visible leaks somewhere."

If the lines are not leaking, how would the air get sucked in??

When you dried out the original MC, you would have siphon fluid from the rear lines/ABS unit, causing major air lock.

 

I'm not offended, since I don't really expect you to know my capabilities, and appreciate your help, since you're the only one responding.

A major air lock is definitely possible, and I can look into that (if it wasn't raining right now I'd do it now).

I'll bleed the hell out of the brakes in the order you specified, spending a good deal of time at each of the 5 points. I'll probably bleed the system with the van running.

And as far as the question you've put forth, an air lock is the only thing that I can propose that would cause me to get air everytime I start the van. The van has NO leaks anywhere.