Suggestions/recommendations?

It seems the mechanic who did my manual CCTs couldn't get it off (so he did them by ear, poorly) and neither can I at the moment.

Would someone confirm the Allen wrench size (10mm)?
Also, any suggestions regarding how to get it free are appreciated. Currently soaking with PB, but looking at schematics I don't think that will help (o-ring).

Mike

 

Check old threads here: most use hammer & chisel. Then buy a new cap.

 

Unfortunately, ^this^.

 

Drill a 3/16 hole at the outer edge about 5mm in from edge and about 3mm deep.
Use a 5/32 punch in that "hole" to turn the cap.

 

I'll have to find a replacement. Anybody got a part number?

 

90087-KT7-000