Why does my emergency brake light come on in my diahatsu hijet

Google has diagrams and links to Service Manuals. Or you could take a month subscription to AllData.com. What you are trying is not an easy job.

https://www.google.com/search?q=s82+daihatsu+hijet+wiring+diagram

..

to replace corroded fluid lines

two options
find a diahatsu truck wrecker or junk yard
scavenge all the hard lines you need off.. the same model truck

have the hard lines made up from new pipe and connections
brake shop can do all the brake pipes ..even fuel pipes

anything odd a mobile hydraulic hose repair service

When I had that problem with the emergency light it was the sensor for emergency brake
The abs and brakes sounds like you are loosing pressure in the system

Diahatsu recommends 5W30 SAE or 10W30 either semi-or fully synthetic. Fully synthetic is better oil. Whether you choose 5W30 or 10W/30 depends on your climate. If you have frequent days before zero C, 32 degrees Fahrenheit, you may opt for the 5W30; otherwise, the 10W30 in the one you'll want. Selenia oil tends to be the least expensive of the synthetics and it's a fine oil. (I buy mine at Carefour Suermarket.) FUCHS is also very good and doesn't dent your pocket book. Mobil 1 and Vavoline are quite expensive in Europe, and Motul and ENEOS are outrageous.

Pull up on the emergency brake pedal with your hand to see if the light will go off. If it will. there is a slack adjustment for the cable going back to the rear brakes. If it won't then the switch is bad or out of adjustment. It's located on the emergency brake pedal

1-2-3

i have 1991 diahatsu hi jet van tempr geting hot after 20 mins and water steaming from silencer

http://www.daiclub.com/downloads/(daiclub.com)-Daihatsu-Feroza-HD-E-Engine-Manual.PDF