XK 120 special bolt for Heater Valve Bracket

We’re making progress with the restoration of my 1954 XK 120 OTS, but still have the occasional new episode of the “Great Jaguar Mystery Tour”. Viart is not very clear on the subject and I saw a similar discussion on the same subject but now for the Jaguar XK 150 S that didn’t help unfortunately (totally different Bracket and the whole discussion ended explaining the difference between “bolts” and “setscrews”).
This time it’s the way Heater Valve Bracket C.4395 is bolted to the bulkhead. This Bracket has two holes and I understand that one hole is for one of the BSF ¼ “ studs that hold the Heater. The other hole is for a “set screw” BD.1492/1, most probably also a BSF ¼ “ version but otherwise unknown. There is a “cage nut” underneath the bulkhead for set screw BD.1492/1 but unfortunately the “square” nut that should be in there, has disappeared.


  • Are my assumptions correct regarding how Bracket C.4395 is bolted down to the bulkhead?
  • What kind of set screw is BD.1492/1?

Thanks in advance,

Bob K.

From the “no trivia too small” files.
The bolt has a tapered end, a special. That’s why it is a BD number rather than an FS number.
1/4-26 BSF x 3/4" long to the tip

You have it correct that the other hole is the stud coming up from the heater unit.

Thanks Rob, as usual you solved my problem! I found one of these pointed BSF set screws, so I can remove another item from the list.

Bob K.