Exclude blank column while Joining two SQL server tables

Question

I have set of vehicle parts stored in two tables as per below:

Source Table1:

Vehicle_ID	Part1	Part2	Part3	Part4	Part5
1	10	20	30
2	10	20
3	10

Source Table2:

Vehicle_ID	Part6	Part7	Part8	Part9	Part10
1	40
2	30	50	60
3	30

Required Table like below:

Vehicle_ID	Part1	Part2	Part3	Part4	Part5
1	10	20	30	40
2	10	20	30	50	60
3	10	30

Maximum of the Part column up to 5 only.

I tried Union all statement but that statement is not relevant for excluding blank columns.

Please share your experience to solve my problem .