Question

what steps were taken by Gandhi to abolish the untouchable

Answer 1

     Mahatma Gandhi wanted to eliminate untouchability and for this he put up a few steps such as;
1. He called the ‘untouchables’ harijan, or the children of God.
2. He organised Satygraha at various places to provide them entry into temples, and access to public wells, tanks, roads and schools.
3.He wanted to tell upper caste people that cleaning work is not an undignified work and for this he cleaned toilets himself to dignify the work of the bhangi /sweepers.
4. He tried to persuade the upper castes to change their heart against the evil of untouchability.

Answer 2

He used "peaceful protest", and "non-cooperation methods", as well as organizing marches, civil disobedience, he even used fasting as a tool of protest.

Edited- 
He helped to raise the standard of untouchables by calling them "Harijans" meaning "God's People". He wanted to spread the feeling of quality and respect among everyone. He had done the same thing in South Africa too. He made an Ashram where he lived with the untouchables and organized public dinner where people of all communities would come and eat together