C-Spanner would be my first choice.
An old C spanner with the end ground offor knock it round with a punch.
....... There must be the right tool out there.......![]()
They are available ,but I generally modify a c hook spanner......PIN/PEG SPANNER or something like this ? pin/peg spanner.......check around for best prices though....
It's a C-Spanner, but not like anything you've got.
Why not make one?
Normally you'd just engage one hole at a time, there are four holes so you can get the spanner in properly.
I'd use leverage rather than a hammer as the end cap is soft. Warming it slightly might help a bit.
if there is good access,you could make a steel ring to fit over the end cap, then drill and tap holes to line up with the dimples, screw a bolt into each hole for minimum damage to the cap.then figure out the best way of applying torque.I:E nut welded to end of ring or bar welded to the ring.
A piece of round bar that's a tight fit in the hole then knock it round one hole at a time.
Thats what i was going to say. Spin it round like a ships wheel, well for half a turn anyway. Often the simple way is favourite
From the left field how about a chain grip wrench or oil filter remover?