Try this, I hope it helps.
Set account as primary.
Example request:
curl https://api.coinbase.com/v2/accounts/82de7fcd-db72-5085-8ceb-bee19303080b/primary
-X POST
-H 'Authorization: Bearer abd90df5f27a7b170cd775abf89d632b350b7c1c9d53e08b340cd9832ce52c2c'
Response (200)
{
"data":
{
"id": "82de7fcd-db72-5085-8ceb-bee19303080b",
"name": "New hot wallet",
"primary": true,
"type": "wallet",
"currency": "BTC",
"balance":
{
"amount": "0.00000000",
"currency": "BTC"
},
"native_balance":
{
"amount": "0.00",
"currency": "USD"
},
"created_at": "2015-03-31T15:21:58-07:00",
"updated_at": "2015-03-31T15:21:58-07:00",
"resource": "account",
"resource_path": "/v2/accounts/82de7fcd-db72-5085-8ceb-bee19303080b"
}
}