348 rear brake bleeding

Key in "ON" position to run the ABS pump?

 

I'm assuming you can hear the pump prime the system when you turn on the key.
Try disconnecting the line that goes to the caliper and see what happens. WARNING! Could be messy.

 

make sure you have enough fluid in the reservoir. If none of the above work and you are desperate, you may have to prime the rear "pump" but it's really messy and remember brake fluid takes off paint nicely. If you unscrew the rear brake line where it goes into the master cylinder ( uae a brake line wrench.. a regular wrench will often round off the nut), then having already put down lots of plastic rags etc., have an assistant slowly push the pedal down. When it's down, stick your finger over the hole where the brake line was attached. Assistant then let's off the pedal. Then remove finger. Repeat agin until fluid is coming out when pedal is being pushed down. Hook up brake line, then try bleeding it all the way through.

 

Ah, dead-heading it.

 

This... But I build a short steel brake line that loops directly into fluid reservoir.

Best,
Rob

Sent from my ADR6350 using Tapatalk 2

 

I had a similar situation with one of my other cars after restoring the brake system with new lines. I used the old method of the person pumping the brake pedal as well as a vacuum bleeder at the rear and nothing was working. I then bought the largest animal syringe at a feed store (approx. $3) and proceeded to fill it with new fluid and detach the line at the master, opened the right rear bleeder and placed the tip of the syringe into the line next to master and filled the lines with fluid. One full syringe filled the system and I was then able to bleed in the normal manner. It has worked for me several times since then. Hope this helps.

 

So what was the outcome???

 

So when you disconnected the rear brake line and did the finger thing, no fluid or air or anything came out of the port. If you put your finger over the port when the pedal was pushed, you felt no pressure?
Assuming that's the case, did you unplug the big connector to the ABS computer and see if that made any difference? Or instead of un-hooking the ABS computer, you could also try unplugging the connector that just goes to the solenoids. It's the long plug just below the front of the reservoir.

 

Boy, I could be wrong, but it seems if you had a stuck solinoid that was blocking the flow, you would get nothing out the port when the pedal is pushed. If you get fluid, air and suction it seems things are not blocked. You're sure the resevoir is topped up so you're not just pumping air? Of course you're walking a fine line between having a full reservoir, and getting brake fluid everywhere.
Unless someone else chimes in with better advice, here's what I would try. First, double check fluid in reservoir. If that's good, get a brake master cylinder bench bleed kit from a parts store. That should give you a plastic pipe with a threaded connector to screw into the hydraulic unit where the brake line was... a little neater than the finger-over-the-hole. Try bleeding again, this time putting your finger over the end of the pipe. Again, carefull not to spray fluid everywhere! If you have your finger over the end of the pipe when the pedal is gently pressed, you should feel pressure... either air or fluid. Depending on what's in the piston. If you feel pressure, I would try blocking the pipe when the pedal is released just like before to see if you can get fluid into the piston. If you feel no pressure, then try unpluging the connector a few inches below the front of the reservoir that goes to the solinoids. If none of that results in fluid coming out the pipe when the pedal is pushed, you'll need someone smarter than me (that's not asking much) to help.

 

A couple more suggestions, make sure the connection where the rear brake lines attach to the car is solid and doesn't leak. If that connection is not good and tight you may be pulling air back/forth trying to prime the rears. Secondly, have you tried vacuum bleeding from the rear caliper bleed ports? Power bleeding is the way to go, but vacuum might free up whatever might be stuck? Both of these ideas might not hold water, but something else to ponder...

 

How did you guess that to test?

 

Glad you got it figured out. So during all this, when you turned the key on to "aux" and all the dash lights would light up, you were not hearing the wrrrr of the brake booster pump in the front trunk. Good detective work on your part, and now you know that pretty much every time you turn the key to start the car, if you don't hear that pump run, there's a problem....not only will you not have ABS, but there won't be any power brake assistance either.
Get her fixed and have a nice drive!

 

I would also like to add I am in awe of your skills rebuilding you burnt-out car! How you managed to find all those tons of parts is beyond me. She looks great!