OK lets see if we can clarify a bit more, here is the layout as per Nulines catalogue:
So the 253 is the smooth idler bearing/pulley and is available.
The 250 is the ribbed tensioner pulley but is apparently not available. It is the pulley only not the whole tensioner assembly.
The OAP007 is the alternator overrun bearing/pulley and is available.
These are all the Nuline part numbers.
Other part numbers for the alternator pulley are:
Klarius QH available through Rock Auto 1010101
INA through IAT is IAT391014. I found it throough that ebay link of Pipers but a search for IAT for me did not pick them up yet.
This is the page from the Nuline catalogue that shows the 250 pulley and the ones close to it if you want to source them.
The 262 and 046 look worth investigating and Piper has used the 026.
It is also possible that if the bearings can be pressed out of the pulleys then that will be a cheap fix as most of those bearings should be cheap and available from your local bearing shop. Bodgie has replaced the bearing only in the tensioner pulley under bearing number 6203ATN-RSVC3.
The bearing inside the heater clutch is also a standard style bearing similar to most A/C compressors and a number for that is 35BD5222DUM18A (OD=52mm, ID= 35mm, Depth=22mm),
I would suggest if you have original steel or Nuline steel pulleys then it would be worth seeing if you can replace the bearings only assuming the pulley is in sound condition. If you have plastic pulleys already and they are in need of fixing then it would be better to replace the whole pulley as a unit.
I also think I noticed Rock Auto had the whole tensioner assembly under their Sprinter listing if you need the whole thing.
If I'm wrong please speak up and clarify and hopefully Drover can put this info into the sticky topic where it will be easier to follow. If someone else has used a replacement for the 250 please clarify likewise if you have replaced the bearings in a 253 and have a number please clarify.
