Having recently acquired a hardtop for my MX-5, I thought I'd look into some ways of removing and refitting it single-handedly as well as providing a storage solution. A quick Google revealed quite a number of homemade hoists (mostly in the US) and a few off-the-shelf ones (along with a few rather worrying comments describing incidents where the hardtop had apparently fallen out of the sling). I thought I could do better. A major improvement (IMHO) is to anchor the slings to points on the hardtop - there is therefore less chance of slippage when it's being lifted.
As for storage, I have a very cramped garage (as can be seen) and very little storage area, so conventional boxes and support stands are out of the question.
This is what I came up with. I've been using it for about a year and haven't once needed to ask my partner for assistance ;-)
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Step 1: Tools and Parts
For the hoist, I used the following parts:
- 1 off 300kg universal hoist/pulley - available from Amazon here. Circa £12.40
- 1 off 60mm security staple (eye plate). I got mine from a local store, 'Securit' brand, ref. no S1491 circa £3.95 for two.
- 2 off M12 D shackles - available from Screwfix (they come in a pack of 10 but you'll need 4 more for the storage part of this Instructable). Circa £7.99
- 30m x 8mm stranded polypropylene rope - available from Screwfix here. Circa £5.30
- 6 off 80mm 'S' hooks with ball tips. I got mine from a local store, 'Securit' brand, ref. no S6322 circa £2.99 /2pk
- 1 off 125mm cleat hook - available from Amazon here. Circa £2.70
- 4 off coach bolts & washers (for the security staple) - select length to suit installation. I used 60x6mm types.
- 1 off washing line pulley - I got mine from a local store, 'Securit' brand, ref. no S5205 circa £2.25
For the storage slings:
- 10m x 40mm polypropylene webbing - available from Amazon here. Circa £4.85
- 4 off 8mm marine eye plates (security staples) - I got mine from Screwfix, circa £14.
- 2 off lengths of wood for battens (see text)
- 2 off 35mm claw hooks - I had to buy a pack of 6 via eBay, circa £7.50
- 4 off M12 D shackles (see hoist parts)
- 2 off 24mm lengths of 15mm copper plumbing tube (or similar)
- 16* off crosshead screws - length to suit installation. I used 60x5mm types.
- Black polyester core spun thread (eg) ATB Strong core spun thread (circa 0.22mm dia)
* This depends on how many joists are spanned by each batten - I used three per joist/batten but that was over the top (no pun intended) and two would be fine.
One of the nice things about this sort of project is that (if you're fortunate) you can use whatever you've got in your junk box, and the above is just a guide.
You'll need the following:
- Drill and appropriate masonry/wood boring/countersink bits.
- Stud finder & pipe detector.
- Tape measure.
- Plumb bob.
- Step ladder.
- Socket set (for coach bolts).
Step 2: Safety Considerations
An MX-5 hardtop weighs about 20kg (~45lb) but is bulky with most of its mass at the rear and therefore troublesome to handle on your own. If all goes to plan, you shouldn't need assistance but if you do need to manoeuvre the hardtop don't be silly and risk dropping the thing or even worse, doing your back in. Get help!
It almost goes without saying but I'll say it anyway: when drilling, check for hidden hazards such as wires or pipes. Try not to fall off the ladder. Use eye protection. You get the drift...
Please make sure you fix the load-bearing fittings securely into ceiling joists - at best, a hardtop descending from height is going to cause injury to your pride, at worst I shudder to think.
Step 3: Fitting the Hoist Attachment Eye Plate
The first step is to determine where to place the eye plate on the garage ceiling. It needs to be screwed securely into a ceiling joist, and if you're lucky (as I was) there'll be one in approximately the right place. If not, you'll need to use some wood to span a couple of nearby joists and attach the eye plate to that.
Ensure your car is parked in its normal position and put some cloth protection over the top of the hardtop.
The centre of gravity of the hardtop is very approximately 13cm forward of the front edge of the rear window, so hang a plumb-bob from the ceiling to this point on the approximate centreline of the hardtop and mark the ceiling directly above this point.
Having moved the car out of the way, use the stud finder the mark the positions of the nearest ceiling joists to this point. I would say you've probably got 15cm or so forward or back from the mark to play with. Any more than that I'd suggest using a piece of wood to bridge the joists. I'm not going to suggest what size to use - just remember that it's got to be able to handle a 20kg static load plus some allowing for dynamic loads.
I used a 3mm masonry drill to drill some pilot holes to map the exact width of the target ceiling joist and was a tad surprised by how approximate the stud-finder's results were! This method also allows you to determine with some certainty the centre of the joist, so you can position the eye plate right in the middle.
When orienting the eye plate, line the long edge with the run of the joist to ensure the bolts/screws are fixed in the meat of the wood.
Fit the eye plate using the coach bolts - when using big fixings like these, it's good practice to drill pilot holes into the joist first as it makes it easier to tighten them up and reduces the chances of splitting the wood.
Step 4: Attaching the Hoist
Once fixed in place, simply install the hoist using the D shackles to orientate it such that the pulley rope and the bottom D shackle are parallel to the width of the car (see photo).
You may also want to add a small washing line pulley to one side of the hoist. This has the advantage of reducing the amount of twist on the hoist as it's being used. If you fit the wooden battens for the storage sling, one of these makes an ideal mounting point (see step 7).
Install the lanyard cleat at a convenient point on the wall in line with the hoist rope. See here for how to tie a Halyard Cleat Hitch.
Step 5: Making the Lifting Ropes
Take the 8mm stranded polypropylene rope and cut four lengths - two about 3m long and two about 1.3m long. Melt the ends to stop the strands unravelling.
At one end of each of the long pieces tie a Hangman's noose knot.
At the other ends, tie a Halyard Hitch (or similar) and insert one of the S hooks, such that the total length of each rope and hook is about 2055mm long (see picture).
At each end of the shorter lengths of rope tie a Halyard Hitch and insert an S hook into each, such that the total length of each rope and hook is about 890mm long (see picture).
Bend the S hook at one end of each of the shorter lengths to reduce leverage on the edge of the hardtop (see pictures). You'll also note I filed down the end of each of these S hooks to ensure a better fit into the hardtop rear mounts.
Step 6: Attaching the Lifting Ropes
Loosen the hardtop as you would in preparation for a manual lift and attach & run the lifting ropes as shown in the photos.
That's it - start the first lift slowly and check the integrity of all the components before raising the hardtop further.
When it's in its fully raised position, tie the rope to the cleat hook with a Halyard Cleat Hitch.
As there's nothing to stop the hardtop from rotating once it's lifted, I would recommend either lowering it onto the floor once the car is out of the garage or using the storage slings detailed in the next three steps.
Step 7: Fitting the Storage Sling Battens
Using the diagram above, mark up on the ceiling where the wooden battens are to be fixed.
Use the stud finder the mark the positions of the ceiling joists along the lengths of the wooden battens.
As before, use a 3mm drill to drill some pilot holes to map the exact width of the ceiling joists and determine the centre of each joist. Mark these on the ceiling.
Offer in turn each of the battens and drill and countersink a couple of clearance holes in line with the centre of each joist.
Fix the 8mm eye plates to each end of each batten as shown in the diagram.
Attach each batten to the ceiling using the crosshead screws (see parts list).
Step 8: Construct the Slings
The slings need to be long enough so the hoist can take the weight of the hardtop off the slings, so lower the hardtop from the ceiling by 10cm or so and on one side measure (with a piece of string, for example) the intended path of the sling from the front eye plate, under the hardtop to the rear eye plate (see the photos in the next step for the suggested route).
In my case, this measurement is 2670mm and the required length of each webbing piece is circa 2875mm, allowing for folds at each end.
For each piece, wrap one end around the 15mm tubing, fold the end over on itself and sew it in place with the strong thread (see photo). The tubing is necessary as the D shackle is narrower than the webbing. You won't need it if your shackle width matches your webbing width.
Wrap the other end around a claw hook, fold the end over on itself and sew in place.
You can't see the sewing very clearly in the photos (just as well as it's not at all neat) but I hand-sewed each end with three horizontal runs each connected by a run up the edge. I tried to make the stitches about 0.5mm apart. A pull test is worth doing to confirm robustness.
Step 9: Fit the Slings
Attach the D shackle at one end of the batten as shown in the photo.
Repeat for the other strap
Run each strap under the hardtop as shown.
Attach the claw hook at the other end of the batten.
Slowly lower the hardtop so the slings take the weight. I always leave the hoist in slight tension to share the load.
That's it - have a nice cup of coffee and congratulate yourself!