Main drain line unpblocking clog

[Casio100]

Have a 4inch cast iron drain. There is a cleanout vent near the street. The drain has been getting clogged at the vent. There is what looks like a trap at the bottom of the cleanout . Approximately 8 feet. Ran auger through and even though auger went through blockage was still there. Used auger from inside the house through a toilet removed. I have tried in the past from cleaning out at vent back towards the house. This seeems to work better at unclogging. However, getting the auger to go into the drain is hit or miss. It is a RIdgid 400 with I think is a 3/8 cable.

Trying to figure out how can getting through the clog do nothing. I guess going through the clog and the clog is till there. I have used an inexpensive jetter with a pressure washer and it worked in the past. This was used near the street. It took some time but it finally removed the clog.

The questions I have :

1) How to get jetter or auger bit to go into the main line. Thought of using a pvs pipe with a 90 degree angle and putting either cable through to go into the pipe.

2) What I am calling a trap may not be but it is lower than the two main lines conneted. Is this causing a problem

Thanks for any suggestions for the above questions.

 

[Reach4]

Consider posting a sketch of a side view of how you think the piping runs. Making a sketch with a paint program, would be best, but you could post a photo or scan of pencil drawing. 200kb max, 900 x900 pixels max.

Also give an idea of distances... 30 ft from the house to the street, or what?