Head lamp Bulb Holders (Adaptors) for XKs
1. The PF770 range for XK120
XK120s destined for the UK (“Home Market”) had the larger PF770 head lamps (7¾” or roughly 200 mm diameter) and used a dedicated LH and RH lamp per car of which one had a double filament and the other a single filament. XK120s for other countries (as far as legally allowed) had these PF770s with two double filaments lamps for both LH and RH.
All double filament lamps used Lucas Bulb Holder 554602 (double contact and 1½” or 38 mm in diameter) with 3 wires of suitable length and a rubber grommet. This assembly may have been initially made for Jaguar only. It had Jaguar part number 3581 and received Lucas part number 858543. The single filament head lamp of the early Home Market XK120s (Jaguar part number 3580) had Lucas assembly 858540 consisting of single contact Bulb Holder 554607 and only 2 wires of suitable length and a rubber grommet.
Bulb holder assy 858543 for the PF770 light unit (left). Note large lamp opening in the reflector (right)
The reflector had a large opening, necessitating the use of a “Back shell assembly” or “Shell adaptor” (Lucas 553480) which in fact is a part of the reflector closing the gap between light unit and bulb holder.
Detail of Bulb holder assy 858543 Shell adaptor 553480 fits in reflector opening
2. The “J 700” lamp range for XK140 and XK150
XKs with “J 700” lamps used Bulb Holder Lucas 554855 for the BPF bulb Lucas 404 (60/36 Watt). This bulb holder has 3 wires with a length of about 36” (90 cm) with a black plastic sleeve over these wires. Bulb holder 554855 fits within the round opening at the back of the reflector and has three “pins” that fit in the corresponding holes (see photo) in only one defined position (the so called lamp base “key”).
Bulb holder 554855 and Shell adaptor 554909 Larger reflector opening in J 700 light unit
The diameter of this Bulb Holder is somewhat larger than the diameter of the other light unit types. Like the PF770 lights, the J-700 uses a “Shell adaptor” (see red arrow below and photo above) to bridge the gap between reflector opening and BPF lamp base. The Jaguar number is 6670 and the Lucas number 554909.
Note: this item is also named “Back shell adaptor” which may lead to confusion. The black dome/bucket in which the light unit is housed is also called a Back Shell. Some sources use part number Jaguar 6670 or Lucas 555909 for this black enamelled back shell or bucket, but this is incorrect.
3. Export to USA and Canada: 3-pin “sealed beam” range for XK120, XK140, XK150
Since standardisation of vehicle lighting in USA and Canada was quite different from the European situation, “empty” head lamps (without a light unit and bulb) were supplied with XKs destined for North America. A special Bulb Holder / Adaptor with Jaguar part number 3454 (Lucas 553724) was used for the wiring harness, suitable for 3-pin US “sealed beam” bulbs. The Lucas adapter was a round construction in which the 3 connectors had been mounted. This version was used until July 1960.
Original bulb holder 553724 for North America Complete backshell & bulb holder for US sealed beam
Later XK150s (from early July 1960 onwards) destined for North America had a different bulb holder with part number Jaguar 7764 and Lucas 553738 for 3-pin “sealed beam” head lamps, due to a change in the “USA Vehicles Lighting Regulations” (see also Jaguar Spares Bulletin Q17 dated November 1960). This is a bulb holder without any wires attached. There are two known versions of Lucas 553738:
· The first version looks identical to the aforementioned bulb holder Lucas 553724 however with wire contacts at the rear, using 3 “Terminal Sleeves” Lucas 188818 for ⅜” stranded wire cores. This seems an “intermediate” solution, awaiting the arrival of a new moulded bulb holder.
· A second version with the wire contacts positioned on the outer rim of the bulb holder base-plate, using 3 “Terminal Sleeves” Lucas 555910 (which is a later version of the 188818 also for ⅜” stranded wire cores). This bulb holder or adaptor was used until the mid-70s for all (British Leyland) cars exported to N.A.
First 553738 type
Second version of 553738
4. The PF700 and F700 range for Europe for XK140 and XK150
Differentiation is made in two groups of countries:
4.1. Continental Europe: “Le Mans 24” light unit for Switzerland, Holland, Norway, Sweden & Germany
XKs for Switzerland and Holland had special head lamps (Lucas 51565A), as well as those for Norway, Sweden and Germany (Lucas 51564A). These were all based on the so-called “Le Mans 24” light unit (Lucas 554665) and therefore used the same 1½” bulb holder and headlamp wiring loom (Lucas 858543), although the BPF bulbs were different (Lucas 370 with 45/40 Watt for the first group and Lucas 350 with 35/35 Watt for the second group of countries).
Bulb holder Lucas 858543 is an assembly consisting of bulb holder 556402 combined with 3 wires of suitable length for its application and a rubber grommet. It has been widely used for various brands in the 1950’s on PF770, PF700, F700 and other light units. Bulb holder assembly 858543 is intended for light units with a dipped beam and has 3 wires, whereas Bulb holder assembly 858540 is intended for non-dip beams and this loom has therefore one wire less than the aforementioned version
PF700 Le Mans headlights with Adaptor assy 858543 (left) and later replacement Lucas 54933718 (right)
4.2. Continental Europe: other countries with PF700 for XK140 and XK150
Some XK140 and XK150 versions intended for Continental Europe (except France, Switzerland, Holland, Norway, Sweden and Germany) used not a J700 but a PF700 type head lamp (51507A) with light unit Lucas part number 554917.
Lucas PF700 type 51507A with light unit 554917
The corresponding bulb holder is Lucas 554602 for the 45/40 Watt BPF lamps Lucas 370. This adaptor is in fact a bulb holder supplied without wires. For the installation of the earth wire to this bulb holder the “Terminal Sleeves” Lucas 188818 were supplied as well. The light unit of this PF700 is related to the “Le Mans 24” unit and has the same adaptor opening of 1½” or 38 mm .
5. XK120, XK140 and XK150 for France
The French market required different Headlamps (Lucas 51563A) based on a 3-pin bulb BA21d lamp base (no BPF) and therefore also a different Bulb Holder / Adaptor (Lucas 562303). This solution was used over the entire existence of the XK range, although different light units have been applied.
French bulb
The French light unit for the XK140 and 150 is a special version (Lucas 555288) of the standard “Le Mans 24” unit (554665) that we described in chapter 4.1. As Lucas bulb holder 562303 for the P45t bulb has a smaller diameter than the BPF 370 bulb of the standard “Le Mans 24” version, an additional “Shell Adaptor for Bulb” with Jaguar part number 6527 and Lucas 555943 is required.
Special “french” Shell Adaptor Lucas 552943
6. Survey of XK bulb holders, shell adaptors and replacements
The Bulb holder assembly Lucas 858543 has been replaced by Lucas 54933718 which is a generic replacement for various brands.
Can still be found…
7. Bulb holder adaptors
To use BPF lamps on US cars (or European cars with a “non-BPF” headlamp loom) an adaptor exists that fits in the existing Lucas 553724 loom or the later Lucas 553738 bulb holder. This Adaptor has Lucas part number 554691
Front and rear of Lucas Adaptor 554691, converting e.g. US headlights looms to BPF bulbs
In the 1960s Sealed Beam headlamps were introduced in Europe; all sealed beams had the 3 pin connection whereas most British cars still had a BPF bulb holder. To facilitate the conversion to sealed beam lamps special adaptors were made with a 3 pin connection on one side and the BPF connection on the other side, fiting in the standard BPF headlamp harness with bulb holder. Note that these adaptors were also supplied by the (in those days British company) Osram-GEC in an attempt to increase the sales of these sealed beams. This is of course also a fine solution for British car owners in the USA who want to convert an existing BPF harness.
Adaptor for converting BPF harness to Sealed Beam lamps
