The chassis modification of July 1952 included the addition of a Bracket welded on top of each of the Bracket Assemblies for the Front Bumper (C.5790 and C.5791 for RH and LH). Cannot find any part number for the extra Bracket.
This additional Bracket now had 2 holes for the Bumper Bolts: the lower for the OTS and the upper for the FHC/DHC as the latter had the extra 1" spacer to obtain a higher position for the body. The position of the “cow horn” is defined by the position of these Bumper Bolts.
At the moment I’m fitting the Horn Brackets C.2947 but the Horns are touching the top of the later Extension Bracket. The Horn Bracket is held by 2 setscrews, bolted to the “cow horn”. For the FHC and DHC the “cow horn” is in a higher position in relation to the chassis (top holes of the Extension Bracket) but for the (later) OTS the lower bolt hole is used and the position of the Horn is therefor 1 inch lower and will (or may) touch the chassis there.
By moving the Horn Brackets in the slotted holes and putting them in a “non-vertical” position, I can avoid touching the chassis but is this really the solution?
I checked my Brackets against the dimensions Rob Reilly presented in his excellent contribution of October 2010. [xk] 120 horn bracket dimensions?
Have other members experienced the same problem with their OTS? Should the height of the Horn Bracket not have increased by 1 inch? But the Horn Bracket remained the same over the full lifespan of the XK 120.
I removed my early (god that’s a confusing term seemingly depending on what component we’re talking about) XK horn brackets and connected irons from the main cross iron in the last few days. I did notice the set up was handed left and right. Is it possible that’s your problem?
The SPC refers to only one type C.2947 “Bracket for mounting Horns” which is used for both Horns. Your 1951 XK probably has the same parts as Rob Reilly’s XK 120 : see his Bracket here
The only other possibility I see is that the Horn Bracket was changed by June 1952 in order to fit on the OTS versions as well, but the Jaguar part number remained the same (as it could replace the old version).
Rob measured that the L shaped bracket has one leg of about 4" and the other about 3 11/16".
Anybody with a post June 1952 XK 120 OTS that has a higher Bracket (or another solution)?
My earlier remark (see below) is apparently correct for the OTS versions after the chassis modification of mid 1952.
I found these pics in the photo files of Tadek, clearly showing that the Horn Bracket is no longer vertical but has to be turned in the slots so the Horn avoids touching the chassis, This due to the extra inch added for a higher body position of the FHC/DHC versions, meaning the Horn on the OTS versions is now 1 inch lower.
That’s one solution. As my brackets are far from “nice” I’m considering to do what Jaguar should have done in 1952 and make the longer leg of the L bracket an inch longer. It’s not the most complicated bracket to make.
As an update, please find here the “lengthened” version of Horn Bracket C.2947 which has one leg that is now 1 inch longer than the original Bracket. As it is a special bracket for the post July 1952 XK 120 OTS cars, I coded it C.2947/1 …
Below are photos of the horn on the steering box side of my November 1953 OTS. It’s possible the horn has never been removed since the car left the factory.
Yes, I could get mine in without touching the chassis extension, but only under an angle. Yours fit apparently better. Don’t know whether your brackets had to be adjusted in the slots as well (but that’s what slots are for. after all…).
I’m a typical stubborn Dutch “kaaskop” (cheasehead) and I think Jaguar should have modified Bracket C.2947 when the “Cow Horn” position was raised for the FHC and DHC by 1 inch, but the OTS remained unchanged. This created a bigger risk for the horn touching the (newly added) chassis extension on top of the old chassis.
I have a 120 dhc and 120fhc and helped rebuild 30 or so other cars I have never seen a revised bracket ie same bracket all 3 models
will note exception not seen alloy car
Of course you’re correct that Jaguar only had one Horn Bracket C.2947 over the entire production period of the XK 120.
But when Jaguar introduced the 1" higher spacers for the chassis of the FHC and DHC and had to introduce the Chassis Extensions with the second hole for the now higher located Front Bumper Bolts, the available space between Horn and top of the Chassis Extension became critical. Before that there was ample space on the OTS between top of the chassis front and the Horn.
My intention was to obtain the original space between Horn and Chassis as it was prior to the introduction of the FHC/DHC (no matter what Jaguar decided).
The first picture shows the position of the new bracket in relation to the Chassis Extension (meant for for the FHC/DHC). You can clearly see that the bumper bolt for the OTS is in the lower hole and the upper hole (for the FHC/DHC) is unused. The 1" higher Horn Bracket just reached over the top of the Chassis Extension for the bumper bolts.
The second picture shows the Horn in position with sufficient space between Horn and Chassis Extension.
It’s better to first install the Horn Bracket, then wire the Horn and finally place the horn on the Horn Bracket. The front wiring loom that I used (184 PB and available from several suppliers both in the US and UK) has an “extra” piece of length that allows you to make the electrical connection in the wheel opening. When the cables are placed the rubber grommet (put over the 2 wires before the “bullet” connection was made) can be placed in the opening of the cover and finally the screw on top of the cover holds everything together. Then the complete Horn is placed on the Horn Bracket with two setscrews and the cable eye on the earth wire is placed under one of the setscrews. Not too difficult.
Hi Bob,
I have a fixed head coupe so had no clearance problem with my horns, and installed them in the same orientation as you have, with the trumpet closest to the front of the wing. The trumpets looked like they would fill up with water flying off the wheels when running in rain, so I looked at other original disassembly pix online (thanks once again Tadek) and found I had them reversed. I swapped left and right and have them as seen in Tadek’s and Mike Balch’s pix above. I think you may have them reversed as well? When swapped the trumpets actually aim forward slightly, shown in Mike’s first picture.
You are absolutely correct: I’ll have to switch the horns.
I didn’t realize that the High Note and Low Note are “handed”. I knew that the L and H housing were different w.r.t. the length of the “labyrinth” for the sound waves, but didn’t notice that they also changed the position of the horn itself.
