OTS bonnet hinge rebuild

Anyone have any experience other than Carl Hanson on rebuilding these hinges? I have tried to reach Carl but he hasn’t responded so maybe he’s no longer on the forum. I need to rebuild mine but need some advice on the dimensions of the pin placements since mine have worn into oval shapes.

Hello Bob Miller…Carl Hanson here. I sent you an email with a photo image of my notebook page describing my restoration of the hinges. I believe you have my email address. Let me know if you did not receive it.
FYI, I am on this forum (since 1996!) and more recently the XK8 forum and am a regular donor to keep the list alive.

Good morning and thanks. Yes, I did get the email and info. I am a pilot and travel quite a bit so have not yet been able to read through it and rebuild my hinges. I will be back in the Peoples Republic of California tomorrow and before I tackle the OTS hinges, I am going to re-install the carbs on my DHC and hopefully get it started up for the first time in a loooong time. Then I have to figure out how to get those front brakes adjusted right then I get to the OTS. Thanks very much for the help.

Good morning. I finally got my hinges rebuilt and there is no play at all. BUT, for whatever reason, when I open the hood, if I don’t slightly pull on the front, the rear will slightly scrape the cowling as it opens. The rear seems to dip down before pulling forward. Any suggestions?

It’s a well discussed topic. Recently here:

Later down in the thread I posted what I did to solve the problem, which involved adding a small stop to each hinge to prevent it from dropping slightly part way through actuation.

I’ll try that. Thanks.

Before I rebuilt my hinges, my hood scraped the cowling. Afterwards, no interference. Depending on how much interference exists in your case, you might try some thin shims at the hinge mounting points on the hood or on the firewall. Might have to experiment to determine what works.

When I open the hood, it scrapes just slightly. If I pull slightly on the nose of the hood, you can see it come forward a little, then raise as it should. Taking that thing on and off is a pain.

I too had this problem. Spent days trying to resolve it. Re- built hinges, machined new pins with oversize spigots and they were nice and tight. Hinges still hit bulkhead and bonnet touched scuttle. Concluded it is a fundamental design flaw in the action/geometry of the hinge in its application. As you identified, the first movement is briefly down as you lift - this is worsened by flex in the bonnet mounting points too. I considered strengthening plates/modified tapped plates to reduce this, but in the end welded small tabs onto the hinge arms as a stop at the bonnet closed position. This prevents the hinge from “squatting” when first moved. They are on the inside, barely visible, and easily removed if desired. It is an improvement but must admit it its not completely cured. I think Ill have to resort to some rubber on the bulkhead or some other means on final assembly as I really don’t want to chip the new paint job.

Hmm, Bonnethinge, wasn’t that a little village down in Devon?

It’s not a fundamental design flaw. It’s a very clever four bar linkage.
The factory boys put these things together with the body on a trolley, plenty of room to get inside. They are adjustable up/down and front/rear. Then they never touched them after the body was painted.

Here are a few previous discussions about the bonnet hinges.

I’d say it was Jaguar trying to be a little bit too clever with their designs.
Some bonnets will touch at the trailing edge, some will not. Having spent a very long time investigating this (see the first thread Rob has linked to above), I worked out that if your bonnet touches, you can try new hinges, rebushing the old ones, making spacers, making new tapping plates, whatever - your bonnet will still touch. Maybe not as much, but enough to chip the paint after a bit of use.
This is down entirely to minor differences in the underlying fit of the main structure. By modern standards, these were hand-built cars built down to a price and there will be variations in scuttle alignment etc. Like all panels, a tiny change deep down in the structure has a greater affect further down the line.
The solution I found, and it is still working, is the attachment of two small rectangular plates welded to the bulkhead at exactly the point where the hinge moves backwards to touch it, allowing the back edge of the bonnet to touch the bulkhead. This has stopped the problem, and even if (when?) the hinge pivot pins wear again the problem should not come back, as the bonnet is being physically held away from the bulkhead. For me, the option was two small, hard to spot plates - or a chipped trailing edge to the bonnet.


Don’t know whether this helps, but I replaced my original XK 120 hinges BD.4379 for the XK 140 FHC versions (BD.10201) with the longer mounting plate.
I drilled two extra holes (3½" from the top holes) in the firewall to be able to use the 4 bolts for mounting the longer hinges to the firewall. I also had to use the longer tapping plate of the XK 140 FHC at the inside of the firewall, which is also better to eliminate flexing of this wall. The risk that the rear end of the bonnet touches the edge is rather high in this Jaguar design, so everything helps.
In my case the long tapping plate now has 6 holes and I could have placed 6 bolts.
In fact, the early alloy bodies also used an additional steel “stiffening” bracket under the hinges, fitted with 6 mounting bolts to the firewall. Jaguar then changed to a 4 bolt fixation.
I cannot deny that, in my case, the hinges of the XK 140 FHC had less “play” than the original hinges, but a possible “flexing” of the firewall might also play a roll and that has now been eliminated.

Bob K.