Winter is a time when most tractors on the farm are at rest, making it the perfect time for maintenance and repairs. It was time for my Zetor Crystal roof to get some more TLC.
With a farm museum occupied by several vintage tractors, one thing we know about at St Winnow is fighting rust. Most of the rust on the Zetor Crystal is just starting on the surface, but parts of the roof were starting to get a bit rotten. Acquired only in June 2020, and with a couple months in the shed until ploughing in February, there was time to attack the rust.
Lifting the lid
Removing the upper interior inside the cab is simple enough, exposing the bolts to free the roof. The challenge comes with physically lifting the roof off as it’s pretty heavy. Fortunately the Zetor Crystal roof is has two lifting eyes which make lifting off with a loader the best bet.
Down in the workshop, with the lights and aerial removed, the first phase is to wire-brush and attack the rust patches. An angle grinder with a wire-brush head makes easy work of it. Once we got started on the roof, the extent of the rust became evident. It was worse than we first thought.
The paint and outer tin work was starting to bubble out due to the corrosion inside
The extent of the corrosion was laid bare when we attacked the rust with a wire-brush on an angle grinder
How does a Zetor Crystal roof rust?
For all machinery, being parked outside is the beginning of the end (in damp areas like Cornwall at least). Exposure to the elements can corrode tinwork and leave behind a rusty wreck in just a few years. Just take this David Brown that’s local to us as an example:
Where our Zetor is concerned, the previous owner had the Crystal parked in a large lean-to, but the rear of the tractor was at the open end of the shed, and would be exposed to some of the elements.
We were able to confirm this when we found the Crystal on Google Street View.
The Zetor Crystal roof has an outer and inner sheet of steel, with a cavity on both sides. Based on the corrosion we’ve seen on our roof, moisture builds up in this cavity and corrodes the inner roof steel. This also causes the outer roof steel to bubble out.
Fighting rust with Vactan
Removing rust is a fairly pointless effort if you don’t also attack the rust and try to stop the corrosion. This is a lot easier said than done and it’s not really a battle you can win. When seeing how readily classic and vintage tractors corrode, you can see some positives in so much tractor bodywork being plastic these days.
With the rust wire-brushed and the rest of the paintwork roughed up, a coating of Vactan is applied to treat the remaining rust. The suspicious milky substance is applied with a rough paintbrush and turns blue as it reacts to rust. After some time, the Vactan will cure off and darken to black. It’s important to give the Vactan time to cure off before the next stage.
Patch and paint
With the rust gone, there were some significant holes left behind. A combination of patching with 1mm steel sheets inside and smoothing over with body filler on the outside gets the roof back into shape.
Vactan also doubles up as a primer. The first layer of paint is a Teamac anti-rust black undercoat. The top coat, a matte black.
Finishing touches
The eagle-eyed among you may have spotted the three white stripes running up the sides of the roof. However on the underside of the roof, these were clearly red and the colour had faded to white over time. The previous stripes were decals (i.e. stuck on) but I opted to paint these on.
These proved particularly fiddly. On one side, we’ve managed to recreate the thin-thick-thin lines fairly well. On the other, they look more like three equal width stripes. Fortunately, you can only see one set at a time when you’re looking at the tractor…
The Zetor Crystal now…
Finally, after several weeks of plugging away at it, it was time to put the roof back on. Fortunately the Manitou was on hand to make light work of this. The roof dropped on fairly easily, despite the slim chance that our new steel could have altered how it sat on top of the cab frame. I’d also taken the opportunity to wire-brush, vactan and paint the very top of the cab frame. We’re very much hoping not to have the Zetor Crystal roof off again.
Also this winter, we’ve given some of the electrics an overhaul. Replacing the front and back work lights and bringing the interior console back to life makes the Crystal a lot more accommodating. One of Dad’s major gripes last Autumn was a lack of a radio, so a new stereo was promptly fitted.
In addition, a new rev counter and tacho cable should make field work a little more predicable this year. Having gotten a feel for the sound of the engine, I can confirm I was definitely too low on the revs whilst mowing last year. The previous hour clock had also stopped in the mid-four-thousands. The new rev counter also means the Crystal will count her hours once again.
Now that I can put on both the right number of revs and a good CD, the Zetor Crystal 12045 will be less of a wild ride in 2021.