Few things;
1) does the pedal travel get progressively higher with each stroke?
2) does the pedal get hard?
3) does the pedal remain hard when you hold it for say 30 seconds?
As to no 1
multiple strokes can mean a couple of things;
1) This proves the compensating ports are working
2) the mc does not have enough capacity to energize all calipers, or
3) Air trapped in the system,probably right in the MC, or
4) the pads are retracting too far. This could be for any of several reasons;
A)the steel pad backings are acting like springs and kicking the pads back, or B) the pads are not sitting flat on the rotors and retracting non-parallel, or C) the wheel bearings are not properly adjusted and the turning motion is knocking the pistons back too far, or D) the piston seals are retracting too aggressively.
As to no 2
A hard pedal sorta proves that the system is air-free, that the hoses are in good shape, and that the pads are sitting flat on the rotors.
As to no 3
If yes, then this proves the mc is not leaking internally
If all of the above are found to be properly set up, then the pushrod may be too short, or the pedal ratio is off.
Half the battle is believing you got all the air out,and the following procedure will prove it. The most reliable test I have found is to pop all the calipers off and C-clamp them into the bores so they cannot move; then test the pedal.
A spongy pedal, well, you know what to do; start with a bench bleed. Multiple strokes I cannot imagine. A low or long stroke would be a pushrod adjustment; maybe it's not properly seated in the MC. A high hard pedal means the hydraulics are A-Ok, everything is normal; move on.
So now just make sure the wheel bearings are adjusted right, then
Prove the pads are flat to eachother, not worn at an angle,and move freely on their guideways, don't get stuck in hammered out stops, and sit parallel to the rotors, then
start reinstalling calipers, one atta time, starting with the front ones, and test the pedal after each one. You will find the problem.
Unless the lines are reversed, and you have a braided hose on the back. The reservoir closest to the firewall is usually plumbed to the front brakes. A braided hose on the back may not balloon enough to allow the front calipers to work; the MC will hydraulically lock, and the pedal may remain hard with the caliper only sorta functioning to the extent that the braided hose will allow it to. If you find this happening, loosen one of the rear clamps and pump the pedal hard, then tighten that rear clamp again and pedal test one more time.
Tip
If you have plumbed as described above; when you step on the pedal the first portion of the pedal-travel slides the MC piston assembly forward until the rear brakes are energizing.... this stops the forward sliding of the piston assembly and begins the front energizing. Think about that for a bit.
This means if the rear pistons have excessive travel, front braking will be delayed, and the pedal may seem to have excessive travel. Sound familiar?
Furthermore, the MC has a dual operating system. There are actually two pistons inside it; one for the rear brakes and one for the fronts. Normally they are hydraulically coupled during bench-bleeding., so they operate in lock step with eachother. However, if either end suffers a hydraulic leak, then the rearmost pistons inside the MC slides forward and the two become mechanically locked together, and the remaining brake will still work.Of course, you will know this because the pedal travel will be really excessive now. Also, the factory plumbed and wired a safety switch between the two systems, to turn a warning light on.
Excessive travel... Sound familiar?
It is possible to trap a lil pocket of air in the chamber between the two pistons. Air of course is compressible, so if you just cannot get the system working properly you might want to revisit the bench-bleed. However, air trapped in here, will not cause multiple pumps to bring up the pedal. And because the air-pocket would be so small,you might not actually feel it. Nor will it cause a geyser in the reservoir.
To get it out, the front of the MC has to be lower than the firewall end, then I just tickle the pushrod while watching the little bubbles pop up thru the C-port in the rearmost reservoir. I have done this on the car, no big thing.
Keep in mind brake fluid attacks paint, please don't demand a repaint from me if you spill.Here is an image I snagged to show the ports. Not a Mopar but you get the idea.That's all I got
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