Hello, I have sewer pipe with a rodding access point that dates from the 1950s. It is a cast iron pipe with a brass plug/cap (see photo). My question is: is there a special tool/spanner for opening this? Many thanks.
Normally I would say a flat bar over the lug on the left and under the lug on the right as per the photo however urge you wait to see what others say and the danger (if any) of opening that pipe up.
I want to get in because there is a partial blockage. Water is backing up a bit, but does drain away after a few hours. (There is a unused toilet waste outlet that I can open and look down.)
Start by wire brushing around the joint then liberal amount of a good penetrating oil for a few weeks then might need heat around the pipe (not the plug!) providing you can use heat there safely of course.
Slowly slowly catchy monkey approach.
I'd also put a strap wrench around the the collar to ensure that when you try to unscrew the cap you don't torque the entire length and break the weakest joint, which Murphy's Law guarantees will be the least accessible.
I'd treat removing that cap as a last resort. I think it'll be difficult to remove without damage and/or mess.
This should do it, more than a tap though, use a 'mash' (club) hammer and give it a whack, that should crack the seal which is all you need. Shouldn't need to worry about rest of the pipe it's cast and very solid.