This problem surely can't be as uncommon as it appears from my initial searches, can it? Of course, it could be down to 'posters' not using both Brit and US car English, as I have, but I couldn't find much. Anyway, here goes: No damage to car known; hood / bonnet release has been reliable, until recently, when, on occasion, it would release only on one side. The remedy was to jam the released side back down and try again. Today, that wasn't enough. As I can't pull the lever and lift, the lever pulling was done by my wife, and the DS which always seem to pop, obligingly popped as usual. I had her pull and hold the lever while I raised the PS of the hood. I then set both traps with a screwdriver and had her very slowly pull on the lever. The DS latch snapped open before the DS. That suggests that the latches are not set equally, yet the latches still operated, and the hood / bonnet should have been free to move. It appears as though, if a cable should break, there would be no way to get the hood / bonnet open. Is that the case? If so, this is a troubling fault. At this stage, the fault requires two people (or some device at the latch) to get the hood / bonnet open, but I am concerned that the issue is getting worse. So the next question is: how are these cables adjusted, and where. Assuming that the release springs are doing their job, I have to assume that the latch is not aligned properly on the PS (the latch does seem to operate, but only following the DS, yet the hood / bonnet doesn't release the hood on the PS, although it did with the hood / bonnet up). That suggests that either the weight of the hood / bonnet is a factor on the PS, or that there is some misalignment that is sufficient to overcome the force of the release spring. How is the latch itself positioned (there appear to be no slotted holes for adjustment). With my 57 MGA, it is widely known that getting the pin & spring type center latch misaligned is a complete disaster (there is no way to get the grill off, to get at the latch), I am worried that the same could be the case on the Jag. I hope I have expressed the problem well enough for someone to offer suggestions / guidance, before I get locked out. Many thanks.

 

Attached is a diagram of the bonnet latch system. The cables for release are actually 2 separate cables. If one of them has stretched it may not be actuating the latch.
Try opening the hood and with it up use a screwdriver and latch the mechanism. Observe whether the cable is actually providing a pull on the latch assembly.
You might want to dismount the troubling side and see if the cable end is distorted.
There doesn't appear to be any cable adjustment at the mounting points.

 

Thanks for the drawing: very helpful! I doubt there is much chance to do and 'adjustment' at the lever end, so I may have to 'tweak' the DS cable, where it enters the latch fixing plate. This would be, most likely, by means of a slotted shim, in lieu of the typical bike cable adjuster ferrule. Probably, only a small amount needs to be 'taken out' of the PS cable sheath to make the latch release at the same time as the DS. I must admit to some fear and trembling about messing with hood/bonnet latches when there appears to be no way to get at the latch should it jam closed. Hard to imagine someone creating a design like that, although I haven't researched the subject exhaustively for the XK8. I'll re-post with any worthwhile findings and methods. Thanks.

 

There must be some way to pop a poorly aligned and jammed bonnet latch, or there would have been many cars scrapped at the factory.

 

Logic and reason would suggest that, but I can find no tech note from Jag about the subject which, as another member commented is highly unusual, and I can't even find reference to it in the index of the workshop manual. The closest there refers to replacing the PS hood not latched sensor switch. You can find reference to the setting / replacement of door latches, and the trunk lid, but the hood / bonnet latch is nowhere to be found. There appears no way to trigger the release, except to pull the mechanism toward the front of the car, as the cable does, and that may, or may not, be possible by drilling a hole through the side of the fender, with the splash shields removed, and it would have to be done with surgical precision in exactly the right place and drill depth / size. Were that possible, I imagine a 'rowing-like' motion to move the part that the cable hooks into, and it would have to be done essentially blind. A tech not from Jaguar might give the exact spot or, wait for it, Jag might have provided a removable grommet. Others have written that such a thing doesn't exist.
I can add to the previous post that shimming the end of the cable sheath isn't an option, because the termination is a molded rubber/plastic grooved ittem that is pressed into a slot in the latch bracket (that arrangement bothers me too!). The only other possibility is to bend that part of the latch bracket that carries the cable slot itself; this possibly might be bent slightly toward the front of the car. If that has to be done with the latch bracket off the car, due to the thickness of the steel, it wouldn't be much of a solution but, if a forked tool could be made to do it then it might serve the purpose.

 

From the diagram (Part 4), it looks like the striker parts have oblong holes, so there might be some adjustment there, on the hood side, if deemed necessary. I agree with you that the prospect of messing with this is scary. Maybe attach some strong strings to the latches and let them reach the ground as an override.

Separately, have you checked the driver end (Part 5) if there is anything there to work with? As that area would always be reachable, it seems like a pair of pliers might do in an emergency.

Last, check the "bumpers". Maybe the striker is held too high by one of these bumpers and not allowing the latch to release. I believe these just screw up and down.

Best of luck, keep us posted.

 

Thanks Fmertz, I will take a look at the parts you mention. I don't get the sense that the latch is misaligned, though (nor does there seem to be adjustment for the latch bracket itself - perhaps that's just as well - since that might be a minefield!). It seems just to be that the DS latch operates before the PS unit.
I considered looking at the other end of the cables, but was not immediately successful in getting the kick 'plate' free, More research involved, but I think from the diagram that the mounting bracket captures the cable ends side by side, the same way the latches do. The lever bracket may be blind side out. Also, it may be impossible to bend the bracket so that only one cable length is 'tweaked'.
I have been looking for a route for some fine gauge bare SS 'Bowden' cable I have, and pondering a route for it. There is also going to be some creativity involved in attaching a cable to the release lever at the latches; there's just a hole with the cable-end hook in it. It would seem that down would be better than forward, give all the engine components, so that would mean a sheathed cable and an end stop bracket.