How do you virtically raise the steering wheel in hino rainbow bus

a Huge bus./
no country told
and the manuals are there only
ask HINO yet?

ask them

https://en.wikipedia.org/wiki/Hino_Motors

indicates that the problem is in the master cylinder with a blocked compensating port not allowing fluid return from the slave cylinder

hino schematics are found in the hino workshop manual for the vehicle
as the schematics is vehicle specific, you most likely will have to either get the manual or see if the service dealer will give you a copy from the manual

There should be a small lever, usually on the left of the steering column, under the steering wheel. If you pull or lift on the lever, it allows the steering wheel to be tilted up or down. When you release the lever or push it down, it will lock the steering wheel at that height.
Cheers.

I am sorry that I can not help you, I do not know what a Rainbow Bus is but make sure you have a clean passages to allow the Automatic Lubrication to work.

STEERING WHEEL TILT LEVER ON LOWER LEFT OF THE STEERING WHEEL NEXT TO THE TURN SIGNAL SWITCH JUST LOOK FOR ANOTHER LEVER BELOW TURN SIGNAL SWITCH THATS YOUR STEERING WHEEL TILT LEVER. YOU CANT MISS IT UNLESS IT BROKEN OFF.

REMOVAL
WARNING: To avoid serious or fatal injury on vehicles equipped with airbags, disable the Supplemental Restraint System (SRS) before attempting any steering wheel, steering column, airbag, seat belt tensioner, impact sensor, or instrument panel component diagnosis or service. Disconnect and isolate the battery negative (ground) cable, then wait two minutes for the system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the SRS. Failure to take the proper precautions could result in accidental airbag deployment.

1. Disconnect and isolate the battery negative cable.
2. Remove the screw (2) that secures the tilt steering column knob (1) and remove it from the tilt actuator (3) on the left side of the column.
3. From below the steering column, remove the two outboard screws that secure the upper column shroud (1) to the lower shroud (3).
4. Using hand pressure, press inward on both sides of the upper shroud above the parting line of the lower shroud to release the snap features that secure the two shroud halves to each other.
5. Remove the upper shroud from the lower shroud and the steering column.
6. Remove the one center screw that secures the lower shroud to the steering column (4).
7. Remove the lower shroud from the steering column.
8. Disconnect the wire harness connector (2) from the back of the multi-function switch housing (1).
9. Rotate the steering wheel far enough to access and remove the two screws (4) that secure the switch to the multi-function switch mounting housing (3).
10. Grasp the switch control stalk and pull it toward the left side of the vehicle to remove the switch from the mounting housing.

INSTALLATION
1. Slide the multi-function switch (1) into the multi-function switch mounting housing (3) from the left side. Be certain that the alignment pins on the top and bottom of the switch are properly engaged in the channels of the mounting housing.
2. Rotate the steering wheel far enough to install and tighten the two screws (4) that secure the switch to the mounting housing. Tighten the screws to 2 N·m (20 in. lbs.).
3. Reconnect the wire harness connector (2) to the back of the switch housing.
4. Position the lower shroud (3) onto the steering column (4).
5. From below the steering column, install and tighten the one center screw that secures the lower shroud to the steering column. Tighten the screw to 2 N·m (20 in. lbs.).
6. Position the upper shroud (1) onto the steering column over the lower shroud. On vehicles equipped with an automatic transmission, be certain to engage the gearshift lever gap hider into the opening in the right side of both shroud halves.
7. Align the snap features on the upper shroud with the receptacles in the lower shroud and apply hand pressure to snap them together.
8. Install and tighten the two outboard screws that secure the upper shroud to the lower shroud. Tighten the screws to 2 N·m (20 in. lbs.).
9. Position the tilt steering column knob (1) onto the tilt adjuster actuator (3) on the left side of the steering column, then install and tighten the screw (2) to secure the knob to the actuator. Tighten the screw to 2 N·m (20 in. lbs.).
10. Reconnect the battery negative cable.

There is no secret button. It sounds like the linkage between the tilt lever and the tilt mechanism inside the steering column has come loose, or the mechanism is jammed. If that's the case, it's a complicated job to repair it, and because of the air bag in the wheel housing, should only be done by a qualified shop.

Remove horn pad . After removing the large nut SCRIBE A LINE ON THE CENTER SHAFT and the STEERING WHEEL, Using a steering wheel puller, remove steering wheel. Now comes the tricky part. Remove signal stalk ( just pull out a couple of inches ),and 4-way flasher knob. Disconnect multiple connector of signal switch. Remove 3 screws holing switch down. Gently pull upward on switch to expose lower steering bowl. The large bolts are LOOSE that secure it, so the reason for the wobble. Tighten bolts, and reverse procedure.

you will not alter the steering angle more that what you have
however you can raise the seat
get a piece of RHS x 1/8" thick ( comes is dimension 1x1", 2x2", 2x1" and 3x1") and by drilling new bolt holes for where the seat runners are , you can raise your seat up to 3"
Any body with mechanical experience can do it for you or get an engineering shop to make the bits for you