mweir2
New member
A good discussion. I have some experience with my old TC48DA to report, which uses that same SBA... valve pictured earlier. For your consideration:
Not using the lock nut does/did help some with the coolant weep.
The hex is 27mm or 1 1/16 inch; wrenches of both sizes will work.
The thread pitch appears to be 14 TPI, matching NPT or BSP.
The valve will thread a short distance into a 3/4 NPT fitting.
Removing the original one is HARD. I had cut a slot in a deep socket to clear the drain nipple, but broke off the side branch of the tee when the socket slipped off the fitting. That turned out to be a Good Thing, as the torque required to loosen and remove the fitting would probably have spread the modified socket beyond usability, or broken it. I suggest breaking off the side branch to start so you can get a socket on. It required all the force I could apply at the end of an 18" breaker bar to loosen the fitting, and to continue turning it for several turns. It would be a good idea to buy a flank drive (was a Snap-On patent, I think, but now seems available from Kobalt and others) type socket if you need to buy one, as the corners are well distorted with a plain 6-point deep socket - but it did work. I was quite afraid it would round off.
There's a lot of ...stuff... in the threads. I doubt it's corrosion, but suspect Shibaura's original thread sealant.
I did use the modified socket to install the new fitting, without cleaning out the block threads as I didn't have a suitable tap, but using several turns of teflon tape.
It seems leak free.
In view of the cost, I think if there's a "next time" I'll use NPT pipe fittings and a conventional block/radiator drain as others have posted.
Not using the lock nut does/did help some with the coolant weep.
The hex is 27mm or 1 1/16 inch; wrenches of both sizes will work.
The thread pitch appears to be 14 TPI, matching NPT or BSP.
The valve will thread a short distance into a 3/4 NPT fitting.
Removing the original one is HARD. I had cut a slot in a deep socket to clear the drain nipple, but broke off the side branch of the tee when the socket slipped off the fitting. That turned out to be a Good Thing, as the torque required to loosen and remove the fitting would probably have spread the modified socket beyond usability, or broken it. I suggest breaking off the side branch to start so you can get a socket on. It required all the force I could apply at the end of an 18" breaker bar to loosen the fitting, and to continue turning it for several turns. It would be a good idea to buy a flank drive (was a Snap-On patent, I think, but now seems available from Kobalt and others) type socket if you need to buy one, as the corners are well distorted with a plain 6-point deep socket - but it did work. I was quite afraid it would round off.
There's a lot of ...stuff... in the threads. I doubt it's corrosion, but suspect Shibaura's original thread sealant.
I did use the modified socket to install the new fitting, without cleaning out the block threads as I didn't have a suitable tap, but using several turns of teflon tape.
It seems leak free.
In view of the cost, I think if there's a "next time" I'll use NPT pipe fittings and a conventional block/radiator drain as others have posted.