Brake Bleed Troubles Rear 2010 Caravan

[tinkering]

2010 Grand Caravan. Rear caliper bleeding problem.

I finally got around to doing the rear bearings and brakes both sides. Installing the bearing and hub went fine but I am having trouble with bleeding the new brakes.
I've never seen nor heard of this problem before and I have done lots of brakes.
When I bleed the air out of the caliper the pedal comes up the way it should but no more fluid will come out of the bleeder even when pressing hard on the pedal.
When I take the hose off at the banjo bolt, fluid will pump out of the hose fitting. It will drain out as in gravity bleeding too but I can't get anymore fluid to come out of the bleeder. The bleeder fitting is clear, the banjo bolt is not plugged...
When I open the bleeder valve the pedal will not go down any further!

Is there a metering valve or a proportioning valve in the system that can act like that? What the heck? I am stumped.

[tinkering]

Looks like proportioning valves are no longer used since around 2000? There is nowadays 'dynamic rear proportioning' that is controlled by the ABS system.
So this leaves me in the dark again. Why am I having this bleeding problem? There must be an answer to this.

[tinkering]

It looks like a malfunction in the dynamic rear proportioning in the ABS system should trip a 1248 trouble code. There are no dash indicator lights illuminated but I will put the scanner on it anyway.

Maybe I need to drive it a ways so the ABS can calculate the wheel sensor data and stuff... The pedal is up high so there is no danger. I'll just go around the block, and then finish the hub bearing and brake job on the passenger rear, and then try bleeding everything.

Anybody out there ever had a bleeding problem similar to this?
Maybe there is something really weird going on inside that new rebuilt caliper?

[Stealthee]

It sounds like there is something stuck in the caliper itself. If it was a proportioning valve then you wouldn't even get fluid when you took the hose off.

[tinkering]

Originally Posted by Stealthee

It sounds like there is something stuck in the caliper itself. If it was a proportioning valve then you wouldn't even get fluid when you took the hose off.

Thanks for that!
It did turn out to be a blocked up replacement caliper. I've never had that happen so it was almost the last thing on my list. I did a mock up using the old caliper, pads, and rotor on top of a five gallon pail. Sure as heck I had free flow through the bleed nipple!
Thanks a ton for your reply.

[tinkering]

Well I'm back to a bleed nightmare. It's not the same problem again but it's got me reeling again.
I bled the wheels in sequence. DR PF PR but whoa on the PR. I just installed all new brake parts on the PR wheel, and I am having trouble.

I'm doing the two man bleed. I'm using a clear hose over the bleed nipple (it is sealing well). Sometimes when the nipple is closed after a pump and bleed, air and lots of it bubbles up. It's like the bleed valve is leaking or the hose is letting air in around the nipple. It doesn't leak air like that on any of the other wheels. I tried another bleed valve in there, same air bubbles.

I had the pedal up near the top and when we start the engine, the pedal goes down close to the floor.
I don't have enough mind left to lose.
I am done for the day. Tomorrow I will try a full bleed again.

Does it sound like I have air in the ABS pump?
...or does it sound like I have another bum caliper (like the seal in the caliper is leaking at the bleed screw!!! I'm done. All the suggestions you can come up with the better

Can this kind of thing happen if you don't follow the correct bleeding sequence. I've been using the sequence I got from an IN search. What does the factory shop manual say?
I bled with the master cylinder cap tightened on. Should it be just sitting in place? Can that cause bleed problems?
Damn I've never had this much trouble with a brake job.

[Stealthee]

I've always bled furthest from the master/reservoir to closest. PR, DR, PF, DF

You could check to make sure the caliper doesn't have some kind of leak around the seal or nipple with soapy water. Anything is possible.

There could potentially be air in the ABS pump. A scan tool is the "easiest" way to get that air out but I have seen, and done bleeding the abs pump itself.

Basically you crack the line loose at the pump just enough to push fluid/air out. It's not clean, but it's worth a last ditch effort at times.

[tinkering]

Originally Posted by Stealthee

I've always bled furthest from the master/reservoir to closest. PR, DR, PF, DF

You could check to make sure the caliper doesn't have some kind of leak around the seal or nipple with soapy water. Anything is possible.

There could potentially be air in the ABS pump. A scan tool is the "easiest" way to get that air out but I have seen, and done bleeding the abs pump itself.

Basically you crack the line loose at the pump just enough to push fluid/air out. It's not clean, but it's worth a last ditch effort at times.

The teflon tape trick seemed to stop that phantom air getting into the hose when the bleed screw was tight. The fluid in the tube might have been syphoning a vacuum into the tube.

The bleed sequence is determined by the length of line to each wheel. They put the ABS units in different locations sometimes and that changes the sequence. We finally found the sequence in a factory shop manual. It is indeed DR PF PR DF, a diagonal pattern.

I will keep that last ditch effort bleed of the ABS hydraulic unit in mind. That is three of four non scan tool ways I've heard of now.
Apparently vacuum bleeding can 'pull' air from the valve body where standard bleeding can't 'push' it out.
I've ordered a new pneumatic vacuum bleeder and a mid range scan tool that says it is cabable of doing ABS bleeding. I am waiting for it to arrive from amazin.
Gravity bleeding is supposed to be another solution. I have to work up some more patience for that
Activating the ABS on a gravel road is supposed to move air out of the pumps but the pedal is so low I don't want to gamble driving it.