Bulkhead Weakness Solution

[xvivalve]

Imagine this:



bolted the other side of the bulkhead on Mark's photo using the existing throttle mount bolts on the lower two holes and a new n & b through the top hole.

View from engine bay:

[Jon Tilson]

I thinks thats an excellent solution.

I'll put my name down for one..my own car has suffered the flexing bukhead syndrome in the past. Think I bodged something up with rivets before Ken
replaced the floorpan about 20 years ago.

Jonners

[DoloWIGHTY]

So does this go under the bulkhead pad or on the top or does the pad not go down that far?

Are these the mounting holes from the other side (taken from Mart's resto topic);

[SprintMWU773V]

Seems like a good idea as the area is pretty flimsy as standard.

[mha447v]

Hello All,
Strengthening that area sounds like a marvelous idea,I've tried for a while now to get a smooth pull on the throttle cable and have just about given up,until now it would seem. Put me down for one so that I can remove the previous owner's attempt of riveting a plate and install the new item. It seems this winter's list of jobs is already growing.
Regards
Jason.

[xvivalve]

Those are the mounting holes Alan, the hole above is the accelerator cable hole so a new hole will have to be drilled.

Interestingly there is no variation in the bulkhead panel for auto' transmission in my '73 parts catalogue, though there is for the bulkhead insulation pad; slight localised trimming of the insulation pad may therefore be required!

[DoloWIGHTY]

Thanks Alun. If the club does go ahead with these then I too will take one.

[Robert 352]

I took the attached photo on the plate which I fitted to my restoration, yesterday. As you can see I have fabricated a plate – the lighter green (undercoat colour) which fits under the accelerator pedal bracket but I have also fabricated a plate which fits on the other side and which sits under the firewall padding.

Can somebody tell me what the hole is for to the left of where the accelerator cable passes through?

If it is a spare hole then I would be inclined to make a bigger plate and use that as a third mounting point, in order if nothing else to transfer the forces further across the firewall.

It would be better though to make the plate larger to the right of the picture in order to transfer the force over the seam – cannot be seen in this view, where the inside wheel arch/guard is attached to this whole pressing. The seam on the engine side would help to absorb some of the forces generated when the pedal is pushed.

This bulkhead is not flat of course as can be better seen in the shot posted by Alan.

I shall pull my pedal off again I think, and make up another cardboard template and then go for a scavenge in the scrap metal bin. I used to make hacksaw blades, great for cutting metal!!!!! Great for making little plates like this

Of course if that is a spare hole (not one in Alan’s picture) then I will need to plug it with yet another grommet if it is not serving some useful purpose.

Robert

[DoloWIGHTY]

Had a close look at the bulkhead around the pedal on my own car, incredibly difficult to see I feel, so what I did was stick my mobile phone down there and take a picture:



Certainly evidence of something occurring - what I am unsure though.

With the aide of an attractive assistant I got her to operated the pedal whilst I carefully watched this area, I saw no flexing whatsoever throughout the entire throttle range.

I just cannot see what is on the other side (inside of the car) as the parcel shelf is obscuring it.

I learnt that the bulkhead pad doesn't need trimming if I was to fit this bracket - which if the club does press ahead in making I shall purchase.

[DoloWIGHTY]

Oh, and Robert my car hasn't got that hole. I reckon it was drilled after as it doesn't look as clean as the factory holes. Maybe a CB antenna or another accessory from the past?

[Robert 352]

Alan

You have done extraordinarily well to get that photo. I have visions of you hanging upside down off the roof off your shed (??) wriggling past everything in the engine bay. Well done. I have fabricated a plate to fit that shape - oh please do not ask me to photograph it in position, that sits on that side of the firewall. An attractive assistant - and you perhaps hanging upside down with a camera? Oh dear, my mind boggles.

But that is the cracking to which this thread refers.

But as I say I think I will fabricate a much larger plate on the other side so that it reaches over the inner wheel guard seen in your photo.

And my spare hole? Hmmm. A grommet I think will be used to fill the hole for as soon as put a bolt through it I am sure I will find something goes through there. The previous owner fitted an oil gauge, maybe he took the pressure pipe through here.

Thanks

Robert

[xvivalve]

Robert, I suspect your car was once automatic, that third hole is about where the nut and bolt pass through the plate.

Alan, you may find your pedal can move side to side. In doing so, if it moves toward the off side it will hit the inner arch before the throttle is fully open.

What gives the auto plate its strength is the side peening.

[Robert 352]

It were never an auto, for like Australia there were very few Sprints imported here, all manuals, and I suspect only one order for almost all here were registered at about the same time. And there is a wee burr on the hole which suggests it was drilled and not punched.

Between us all we resolve this problem of flexing in this area. I was going to say "crack this problem"!!

I will find a use for the hole.

Robert

[Si]

I'd take a plate if its a simple bolt on job
cheers

[Robert 352]

In reading through what has been written on this post I decided to manufacture some more plates in order to make sure that I have fixed the problem on my car.

Here then is my solution.

I considered my Mk 1 plates shown on the left in the bottom photo to be too small. So I have constructed two more plates, my Mk 2 version, which are shown on the right. When you look at the first photo, unfortunately I have uncoated the area which shows where there has been some stress cracking so the cracks are not visible, you will see what I consider to be the stronger areas.

The first is the reinforcing gusset which passes below the where the cable goes through the bulkhead. I would have liked to have carried my plate over this gusset but decided not to do so for it would not then sit flush with the bulkhead itself. The second is over the row of dimples formed by the spot welds of the bulkhead to the wheel arch panel behind and the third is the top edge of the bulkhead where it is bent, just above where the accelerator cable passes through the bulkhead.

So I have fabricated a plate that comes down to and sits on the top edge of that bottom gusset, reaches well out and over the spot weld points and gets as close to the radius of the bend in the in the bulkhead itself. The plate passes around the accelerator cable opening and the back of the plate here has been relieved (ground back) so that it is not trying to press back the dimple formed when that cable hole was punched into the bulkhead.

I have utilized the hole which xvivalve has pointed out is probably spare on my car and extended the plate up to pick up that hole too.

I have fabricated another plate for the other side which will pick up that hole too and which hopefully duplicates the function of the plate shown at the top of page two of this thread. That plate has been shaped so that it sits hard up against the inner wheel arch. I will put a picture up later once the now painted plate, (it is presently out in the sun drying) is installed.

By bolting all this together it will effectively form a laminated mount and which I think will fix the problem.

If I am still around in 40 years I will report on how it performs!!

Robert