Are there vacuum hose on the brakes hydraulic system?

Your better off going by the feel of the pedal rather than measurements. Try this. With the engine off and the brake system cold remove the key from the ignition and pump the brake pedal. it should get progressively harder and your foot travels a shorter and shorter distance until its too hard to press.
Press and hold the brake pedal hard down then start the engine. You should feel the pedal soften, that's the vacuum inside the brake booster kicking in.
Release the pedal and again press it hard down, holding it there. The pedal should feel firm and not change. Release and repeat to make sure.
If the pedal has no resistance check your work as there is no pressure in the system. If the pedal is soft or spongey re-bleed the system starting with the calliper furthest away from the reservoir.

You describe a brake problem of a master cylinder leak.
But the vacuum booster could interfere with the application of brake pressure on the master cylinder.
For a firm brake pedal and holding a leak inside the brake booster.
and rotor, front pad, drums, and brake band have to be in very good condition.

Hope it helps.

The most obvious cause for a hard pedal is simply not enough vacuum. Check the brake power booster by pumping on the brake pedal while the car isn't running. Continue pumping until you've "bled off" the vacuum from the booster. Hold the pedal down while you start the car. The pedal should go down a bit more beneath your foot. If it doesn't, then you should examine the connection between the vacuum hose of the brake power and the engine's vacuum.
Replace the brake power booster if the connection's fine, which would fix the hard brake pedal problem.

It may be your calipers need replaced. Check them for signs of wear. Look at the metal spring where the brake pads sit.
Apply tension to the pad and see whether you hear a pop. If you do, the brake pad is moving too much on the bracket. Replace the caliper. This could help the hard brake pedal.

1: inspect all brake linings first.
no pulling left or right braking?
the car has 100% full manual brakes. if the brake booster fails.
(its only and assist !!! for 50lb small folks)
so does it? it takes more pedal pressure but has 100% full braking.
this is no accident its by design.
make sure none of the brake shoes/pads are soaked in DoT3/4 fluid
or grease or gear oil.
and no brake fluid leaks end to end, this is really #1 on all cars.
look, then look again. even behind and in front of the master cylinder.
look at tires (inside for fluid leaks>)
2: do the booster test. did the vacuum hose to it fall off?
or got pinched, or ?

google brake booster test
if ABS system. get it all checked,
if ABS get the ABS scanned.

if you cant stop correctly,,,,???? , dont drive.
get it fixed.

The following steps will help you to replace a Toyota Camry brake booster :
1 With the engine off, step on the brake pedal several times to relieve the brake booster of vacuum.
2 Press the brake pedal down and start the engine. Verify that the brake pedal sinks slightly. Turn off engine.
3 Remove the vacuum hose from the brake booster.
4 Remove the brake lines from the master cylinder. Remove the master cylinder from the brake booster. Plug the fittings to prevent brake fluid seepage.
5 Disconnect the brake pedal from the push rod.
6 Have an assistant hold the brake booster from inside the engine compartment. Remove the nuts that hold the brake booster to the firewall. These nuts are usually located under the dash on the interior of the firewall.
7 Remove the brake booster.
8 Install the new brake booster to the firewall. Tighten the mounting nuts.
9 Connect the push rod to the brake pedal.
10 Connect the vacuum hose to the brake booster.
11 Attach the master cylinder to the new brake booster and reconnect the brake lines.
.12 Bleed the brakes at the master cylinder.

12 specific steps will help you :
1 With the engine off, step on the brake pedal several times to relieve the brake booster of vacuum.
2 Press the brake pedal down and start the engine. Verify that the brake pedal sinks slightly. Turn off engine.
3 Remove the vacuum hose from the brake booster.
4 Remove the brake lines from the master cylinder. Remove the master cylinder from the brake booster. Plug the fittings to prevent brake fluid seepage.
5 Disconnect the brake pedal from the push rod.
6 Have an assistant hold the brake booster from inside the engine compartment. Remove the nuts that hold the brake booster to the firewall. These nuts are usually located under the dash on the interior of the firewall.
7 Remove the brake booster.
8 Install the new brake booster to the firewall. Tighten the mounting nuts.
9 Connect the push rod to the brake pedal.
10 Connect the vacuum hose to the vacuum brake booster.
11 Attach the master cylinder to the new brake booster and reconnect the brake lines.
.12 Bleed the brakes at the master cylinder.

The power brakes vacuum booster... may have a vacuum leak. you can check it with an engine vacuum meter, or remove the rubber hose from the booster and plug it.. and see if the engine changes pase, idle smooths out, revs a bit higher, etc. noticeable change in engine idle would confirm a leak.

if something goes wrong with abs the brake system it reverts back to standard system!! If you can pump brake pedal up and hold it and start engine and it drops thats normal.You say low pedal if you go 15mph on road and check where pedal is when brakes apply.Power brakes will push aLMost to floor while stopped but while moveing you`ll almost go to slide or will go into slide if pedal is pushed to floor.Get on some gravel at 10 mph and hit brakes to a complete stop get out and check to see if all 4 tires slid or 2 front or only 2 rear. this will get you closer to problem good luck.

I assume you bled the rest of the system. If so check your rear adjustment. Adjust the parking brake at the same time. If no fix, then open up your rear brakes and inspect the hardware, cylinder/caliper, and adjuster. Only after all that would I suspect the proportioning valve. Ways to test that vary vehicle to vehicle. Good luck!

sounds like brake booster not working
check vacuum hose that goes to booster is ok and not leaking
engine off
pump up brake pedal several times
hold brake pedal down
start engine
pedal should sink down approx half to 3/4 way down indicating booster is working
if pedal doesnt go down when engine is running booster has leak or no vacuum supply from engine which requires great pedal effort to try and get vehicle to stop.