Elite rear window

Body parts, seats, dash, headlining, windows and stuff!

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richardw
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Elite rear window

Post by richardw »

I've removed my rear window to waterproof the frame and secure the mounting (using custom made eccentric window hinge spacers) to allow it to close without fouling the bodywork.

I have noticed, really for the first time, that the door hinge/gas strut arrangement puts a huge torsional load on the hinge mounting to the body when the window is shut and the struts fully compressed. I have minor cracking along the rear lip of the roof and I now believe this stress may be responsible; I had originally thought that it may be the sudden force of the window opening fully. Essentially the full compression strain of the strut is fed through to the hinge mounting in such a way that it tries to twist the mounting towards the rear of the car - not to mention forcing the window downwards. It is very difficult to compress the struts by hand, so I can only imagine what force is being applied to the hinge mountings.

So, when I reassemble the car it will be without struts. I am looking at a latching strut arrangement for the window to allow it to remain open - in the short term, as AlanM suggested - I will probably use a painted tube with a rubber buffer at each end to prop it open. I also need to fit some sprung buffers to allow the window to pop open sufficiently to lift it when it is unlatched.

Richard
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Pete Boole
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Re: Elite rear window

Post by Pete Boole »

My current plan - (which may be superseded by plan 97b) - is to bond something to the "vertical" section of the rear aperture to take the strain of the strut, relieving the hinge of that duty. I may use an old-fashioned latch type strut - the sort of thing you used to get on old Leyland car bonnets. Of course it would look more "intrusive", and might get in the way slightly more when loading the boot, but that's a small price to pay.

Pete

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MetBlue
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Re: Elite rear window

Post by MetBlue »

These gas struts usually are supplied at full pressure, but there is a small hex head grub screw that can be used to bleed some pressure out and reduce the load induced on mounting points.

Possible they have been replaced and not 'tuned' to best load. I've not done this stage yet, but I would think they can be set to pop the latch out when cable released, but not necessarily raise the glass. There would hopefully be enough pressure to then hold the glass fully open when helped up manually.

Caution though, because there is no way back if too much pressure is released.

Tony
What goes together.... Must come apart.

richardw
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Re: Elite rear window

Post by richardw »

Pete Boole wrote:
Fri Jun 19, 2020 21:25
My current plan - (which may be superseded by plan 97b) - is to bond something to the "vertical" section of the rear aperture to take the strain of the strut, relieving the hinge of that duty. I may use an old-fashioned latch type strut - the sort of thing you used to get on old Leyland car bonnets. Of course it would look more "intrusive", and might get in the way slightly more when loading the boot, but that's a small price to pay.

Pete
Exactly my plan Pete - I haven't been able to find any old bonnet struts yet but am looking at some supports used on cabinets. As there will only be stress when the window is raised, I'm happy to use the existing strut mountings if I can. There is no stress 99.9% of the time when the window is closed.

Cheers, Richard
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richardw
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Re: Elite rear window

Post by richardw »

MetBlue wrote:
Fri Jun 19, 2020 21:39
These gas struts usually are supplied at full pressure, but there is a small hex head grub screw that can be used to bleed some pressure out and reduce the load induced on mounting points.

Possible they have been replaced and not 'tuned' to best load. I've not done this stage yet, but I would think they can be set to pop the latch out when cable released, but not necessarily raise the glass. There would hopefully be enough pressure to then hold the glass fully open when helped up manually.

Caution though, because there is no way back if too much pressure is released.

Tony
Good point Tony - the struts are those suplled by Lotusbits. However I think they need to be very strong in order to raise the window at quite an extreme mechanical disadvantage from closed - the struts are nearly parallel to the glass.

Cheers, Richard
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MetBlue
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Re: Elite rear window

Post by MetBlue »

Do they actually need to raise the window?
Pretty sure the lower edge of my window is slightly convex, hence when the catch is released, this shape alone can pop the catch. If you're happy to raise by hand, the gas pressure only needs to support the weight of the open window (and there are 2 of them).

-But then my window may be convex more than the boot aperture due to Lotus manufacturing tolerances. -

Tony
What goes together.... Must come apart.

richardw
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Re: Elite rear window

Post by richardw »

I had a bit of a brainwave this afternoon. I don't need to find and adapt struts - all I need to do is fully depressurise the ones I have and devise some kind of locking clip to hold them in the fully extended position.

This is true project creep - every step forward introduces a new challenge to be solved!

Richard
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Alan_M
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Re: Elite rear window

Post by Alan_M »

richardw wrote:
Sun Jun 21, 2020 14:59
I had a bit of a brainwave this afternoon. I don't need to find and adapt struts - all I need to do is fully depressurise the ones I have and devise some kind of locking clip to hold them in the fully extended position.

This is true project creep - every step forward introduces a new challenge to be solved!

Richard
I had thought something similar after discussion about adjustable crutches.

I don’t know the diameter of the tube of the gas struts, but would something like this fit inside?

https://www.bpfonline.co.uk/show_produc ... atid=10770

I expect the rod part is solid, so could you dismantle the strut - cut and reweld end? Then weld the apex of the U to the end of the rod and drill a hole in the tube for the locking button to pop into on extension of the strut?

richardw
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Re: Elite rear window

Post by richardw »

Alan_M wrote:
Sun Jun 21, 2020 15:36
richardw wrote:
Sun Jun 21, 2020 14:59
I had a bit of a brainwave this afternoon. I don't need to find and adapt struts - all I need to do is fully depressurise the ones I have and devise some kind of locking clip to hold them in the fully extended position.

This is true project creep - every step forward introduces a new challenge to be solved!

Richard
I had thought something similar after discussion about adjustable crutches.

I don’t know the diameter of the tube of the gas struts, but would something like this fit inside?

https://www.bpfonline.co.uk/show_produc ... atid=10770

I expect the rod part is solid, so could you dismantle the strut - cut and reweld end? Then weld the apex of the U to the end of the rod and drill a hole in the tube for the locking button to pop into on extension of the strut?
That's funny - I was looking at those clips on eBay earlier! However, I checked my struts just now intending to depressurise them but can find no grubscrew. I believe that I can use a 3mm drill with the strut mounted vertically, rod end down and fully extended, 20mm from the upper end of the cylinder - googles, gloves etc! Probably won't try this today.

From what I can see of the construction of the gas spring, once depressurised I should get a slight damping effect as air escapes past the piston - not essential but definitely a nice to have.

I'm not sure that it would be able to be reassembled after welding on one of those springs however, so will continue my search for an alternative. Perhaps something as simple as a pipe clip locating in a groove cut in the rod might work - or maybe one of those spring clips, tack welded in place, pushing through the cylinder wall to prevent the piston moving when fully extended?

Thanks, Richard
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AndyD
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Re: Elite rear window

Post by AndyD »

We use tired gas struts to keep the hopper doors open during the paint process at work (we make road sweepers).

We have a black plastic tube with the correct ID of the main body, cut along its full length so it can be clipped over the plated piston rod. When closed it is slid over the main body, when open the tube is slid up off the main body and sits down on the piston rod, butting between the piston fixing to door (window in your case) and the strut body.

Not elegant but if you source black pipe it looks normal when closed. Only works of course if you have enough clearance for the plastic tube over the strut when closed of course.

Cheers

Andy

richardw
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Re: Elite rear window

Post by richardw »

AndyD wrote:
Sun Jun 21, 2020 17:38
We use tired gas struts to keep the hopper doors open during the paint process at work (we make road sweepers).

We have a black plastic tube with the correct ID of the main body, cut along its full length so it can be clipped over the plated piston rod. When closed it is slid over the main body, when open the tube is slid up off the main body and sits down on the piston rod, butting between the piston fixing to door (window in your case) and the strut body.

Not elegant but if you source black pipe it looks normal when closed. Only works of course if you have enough clearance for the plastic tube over the strut when closed of course.

Cheers

Andy
That's a great suggestion Andy - definitely a good workaround and possibly a permanent solution! Maybe I could fix a spring pipe clip over the end of the tube that slips over the body of the gas spring, then pinching the arms of the clip would open the tube sufficiently to slip over the gas spring body in order to close the tailgate.

Thanks very much, Richard
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TrevorK
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Re: Elite rear window

Post by TrevorK »

You could try cutting a groove in the piston rod near where it goes into the main body when the tailgate is open (I am presuming that it may be too hard to drill a hole through it with it being chrome plated) and the use an R-clip to hold the strut open and the tailgate up. I am sure there are plenty of struts that have lost their pressure around. Maybe someone on here who is restoring an Elite would be happy for theirs to go to a good home.

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MetBlue
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Re: Elite rear window

Post by MetBlue »

Oh dear. My little brains been doing over time on this. I have a conceptual idea to share.

The chrome rod is 3/8" ( at least on the old one I have). The end cap is held on with two roll pins, so can easily be removed and replaced.
If you drill a very slightly larger hold in a plate, it will slide freely when the centre line of hole is parallel to the centre line of rod - AND LOCK WHEN THEY ARE NOT :D :D :D

As the window is pulled open, a stop of some kind can ensure the plate stays square to the rod. Once in the raised position, gravity pulls the latch plate off square and the "crabbing" will lock the window open. - The latch plate would be pivoted and fixed off a small clamp to the end of the larger dia gas tube. To close, pull the latch with a finger back to the "square " position and down goes the window. Once past horizontal, gravity holds the latch square, so you can fully close.

I spent 10 minutes in the garage earlier as a quick trial. The gas strut I have for some reason whats to return to the "closed position", needing quite a bit of force to pull it open, but an Ali plate, with a 3/8" hole drilled approx 35 mm from one end was able to lock onto the chrome rod and allow me to pull the rod out against quite a force. If the friction is enough to pull the rod from the block, I would think it would work in reverse when the force is the window weight, acting on the rod and into the plate?

Image

Needs some prototyping, but if the hole diameter is tuned to the distance the pivot is away from the rod, I can't see any reason why it wouldn't work. The real challenge could be getting it to work within the space constraints of the window and seal area.

Now -MUST get back to some restoration / repair work.

Tony
What goes together.... Must come apart.

richardw
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Re: Elite rear window

Post by richardw »

Wow - thanks Tony, that's a good idea. Unfortunately it goes a bit beyond the skills and equipment I have to hand. I also need to create a bracket attached to the boot latch onto which I can fix a pair of sprung rubber buffers to pop the window open enough to lift it when it's unlocked.

Having thought about the different solutions here, I think I'm going to try something with pipe clips and a notch cut in the rod that is exposed when it is fully open. Then I have a built-in lever (on the pipe clip) to unlatch the window in order to close it.

My problem is that I spend far too much time thinking rather than doing! I'm also putting the Club Lotus page together... as well as having devised three possible solutions(!) to fix the contacts in my Lucas headlamp lifters, one of which failed today as I need to find a way of drilling a 2mm hole through a narrow strip of spring steel without creasing it. And my younger daughter is moving bedroom which involves parental support...!!

I really appreciate the input you guys have provided and hope by the end of it we'll have a good solution to those dreadful struts that others can easily adopt.

Cheers, Richard
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MetBlue
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Re: Elite rear window

Post by MetBlue »

I take your point Richard that this is impractical for most of us to make in a professional looking way. In my minds eye, I can see a neat little anodised widgetty thingy, about 40mm long and maybe 30mm diameter clamped on the end of the main gas tube, castellated and machines at one end to provide a pivot for a short SS lever plate doing the job of the lock. :D

On the other hand, I can see a piece of wood clamped to the tube, two gash plates screwed to the side and a piece of steel acting as the lock plate via an M3 cap screw as a hinge. :(
It looks something like this :-
Image Image

I can report that this lash up works a treat :lol: :lol: In first pic, gravity is holding the plate square(ish) and rod moves in and out freely. On second, gravity tips it to an angle. You can pull the rod out, but it locks when pushed in.
Problem is, I'm sure there is not around 20 - 25 mm of clearance between the glass and the gas strut on an assembled car :(

If someone with such a rare beast as an assembled Elite can measure the minimum gap available ( not sure if it will be open of closed condition), I will see if I can still make it work within the envelope of the available space.

Tony
What goes together.... Must come apart.

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