Reviving Oka Door Catches

Are your Oka doors difficult to open? Do you have to slam the doors several times to close them properly? Do they fly open unexpectedly on rough tracks? We've experienced all of the above so I investigated further.

Dust and grit are the first suspects for making the door catches recalcitrant, followed by wear and tear. Fortunately the door catches are industrial strength and are quite easily fixed.

Dust and Grit

The door is held shut by a 2 position ratchet and pawl system. (See Pic 1 centre). Grit and dust can dry out the grease between moving surfaces increasing frictional forces. This makes closing and opening difficult since the plates won't slide smoothly and the pawl won't always drop into the ratchet, despite the strong spring. A full overhaul requires the removal of the door mechanism from inside the door, see the Power Door Lock blog post for details on how to remove the catches (about half way down).

Pic 1. The Ratchet and Pawl System.

Degreasing and cleaning out all the gritty sludge from the mechanism is the best solution followed by a full re-oiling of rotating components and re-greasing of the sliding plates. Also ensure that the ratchet to pawl spring is not stretched and is correctly fitted. It should be quite difficult to remove as it's quite strong.

Dust can enter via the rectangular cut out in the side of the door through which the catch protrudes, particularly the depressed rivet area, (see pic below), which allows free access for dust into the door cavity. The answer is a layer of thin closed cell foam strip stuck around the opening before the catch is refitted. The foam will compress during assembly and form a good dust barrier.

Pic 2. Dust can enter here

Wear and Tear

The next problem is wear and tear on the barrel which transfers the tension from the external latch to the internal ratchet and pawl system. Normally the ratchet plate is in line with the pawl, but when the barrel shaft or sliding surfaces are worn, under extreme shock (eg from a bump on a rough track or the door being slammed shut), the plate can move out of line. The pawl can then jump out of the ratchet and the door flies open, or won't close securely. (See Pic 3).

Pic 3. A worn barrel allows the ratchet to jump free from the pawl.

Wear on the barrel creates a gap between the door catch and the barrel spacer (see Pic 4). This is more difficult to fix since the plates at either end are sweated on and peened over to prevent movement.

Pic 4. The gap caused by wear on the barrel.

A simple solution is to wind one or 2 turns of fine galvanised fencing wire around the outside of the barrel to take up the wear gap. (See Pic 5) This reduces the inward movement of the internal ratchet plate and prevents the pawl from jumping out of the ratchet.

A large circlip would be a better solution but would be difficult to insert. By contrast, fencing wire is quick and easy to fit.

Pic 5. Wires can fill the gap.

You don't even have to remove the catch to make this fix. It can be done from outside. It might not last for ever but it's cheap, quick and effective, and easy to replace. It can also be done on the rear tailgate catches on the bus model.

The last(?) wear and tear problem is the latch plate which hits the striker. This is often worn and won't hold the striker rod tightly and securely.

Pic 6. This latch plate (from a tailgate) has been heavily repaired and is badly worn.

The only easy solution to this problem is to lay some weld on the worn "C" shape (it should be a nice "U" shape) and file it down so it fits and turns on the striker rod smoothly. It's not a quick job but will make a lot of difference to door closing and retention.

If the striker rod itself is worn, as mine were, you could wrap a layer of steel shim around it to pack out the wear. This worked surprisingly well for several years. Alternatively, weld could be laid on the worn part of the rod and filed/ground round.

Finally, ensure that the striker plates on the door frames are adjusted properly (so that the door closes tightly without slamming and doesn't rattle) and the Allen headed screws done up tight so the plate can't move. BTW, never remove all the Allen screws at the same time. The threaded lock plate inside the door frame can drop down, never to be seen again.

And why not grease the door hinges while you're at it? I'll bet that doesn't get done very often because I've found it's necessary to remove the door stay strut on some doors to allow the door to open far enough to access the grease nipples.

Replacing the Oka Springs

Replacing the springs on an Oka is a straightforward but heavy and time consuming job. Springs are heavy (60-70 kgs each) and unwieldy things to move about and locate with any precision and safety. 

A Simple Spring Trolley

I built a small but sturdy trolley to make it easier to manoeuvre them around the workshop and locate the springs under the Oka. It was constructed out of scrap timber and fitted with some old skateboard wheels recovered from long abandoned children's play equipment (the skateboards, not the children) . The sets of wheels were modified to rotate through 90º so the trolley can be moved sideways when under the vehicle, to locate the spring eye in the mounting bracket. It needs to be a "U" shape to go round the end of the axle and wide enough to avoid the brake callipers (and steering rods on the front). Blocks can be added as necessary to rise or lower the height of the spring as it is being located under the vehicle.

Start with the spring inverted.
(It will still need to be manoeuvred over the brake calliper).

Carefully turn the spring (they are unstable things).

We found it was easier (and safer) to locate the spring under the Oka whilst mounted upside down on the trolley so it will clear exhaust pipes, bodywork, spring mounting brackets etc, and then invert it when in approximately the right place. Be very careful not to crush fingers when manoeuvring the spring!

Now it can be turned upright and moved into position.

Obviously the Oka needs to be securely supported before removal of the old springs. In my case I built a set of very strong chassis stands made from steel girders to support the Oka 1 meter off the ground, which is the height you need to remove an unsprung spring. We used High Lift jack (60 inch model) to lift the Oka while manoeuvring the stand under the chassis. In theory you could raise both sides at once to enable removal of both springs simultaneously. However, the vehicle does not feel secure with 2 wheels off the ground and with the axle is no longer constrained, it can move or rotate, so it's much safer to do one side at a time.

Heavy Duty Chassis Stand

Whilst replacing the springs, I also upgraded the suspension bolts to 20mm (up from the standard 16mm size) plus urethane bushes. I got these in a kit from Peter Wright, see http://okaownersgroup.info/tiki-index.php?page_ref_id=416 (you'll need to log-in to the Oka Ownwers Group website).

It does need some serious drilling of existing chassis holes and the holes in the spring shackle plates, plus welding of support plates, but the end result looks very strong and maybe will reduce the number of suspension failures we have had on our 0utback trips (3 spring eyes and 2 bolts broken so far, and it's not fun repairing these on remote tracks).

20mm Bolts. Note the lead-in on the end of the bolts to make alignment easier.

If there is significant lateral wear on the shackles, chassis plates or spring mounts to allow the spring eyes to move sideways, they will clonk when turning. Steel thrust plates can be inserted to take up the gap, usually about 1 to 2 mm thick but not so thick that all movement is prevented. The spring eyes must be able to rotate in their mounts.

A thrust plate located on a hanging shackle

Fitting the hanging shackle plates is not too difficult, but aligning the fixed eye end of the springs requires manoeuvring of the spring. This can be done by putting a piece of timber under it so the centre bolt doesn't drop into any holes on the axle and then levering the spring along the top of the axle. Once the bolts are in, a more difficult job is to get the spring and axle aligned, because with the spring unsprung, its centre bolt will be no way near its axle mounting hole.

In the workshop I placed 2, 25mm round bars under the rails of an axle stand to act as rollers on a concrete floor, and lowered the axle on to it (the axle weight is not sufficient to cause damage to the axle stand). Using levers, I could then move the axle to and fro a small amount until the centre bolt and its mounting hole lined up. 


Compressing the spring with a separate jack may also help with alignment. With the vehicle jacked up on one side, there may be considerable lateral misalignment as well, due to one side of the vehicle being higher than the other. The answer is to lift the other side a bit to level the vehicle, but be careful, 3 wheels on the ground is fairly stable, 2 wheels is not. A lot of levering will still be necessary and a breaker bar is very useful for this.

Even when greased and carefully aligned, the bolts may still be a tight fit in the spring bushes (if you are using urethane bushes) and mounting plates. Hammering is seldom effective because the bolt "bounces" in the bush and it can also damage the threads. A simple pusher can be made by using a large G-clamp and putting a socket over the thread end of the bolt (and removing the grease nipple from the head end or using a socket to protect it) and tightening the clamp until sufficient thread protrudes to allow the nut to be fitted. The nut can then be tightened up to pull the rest of the bolt into position. Peter Wright's 20 mm bolts have a lead-in protrusion with a removable tapered cap to assist with alignment. This works well.

With urethane bushes, it's important not to over-tighten the shackle bolts since the bushes can be crushed and the shackle plates can bind on the spring or chassis. This will put additional strain on the spring eyes and lead to premature failure. Tighten the nuts to seat the bolt heads fully and then back them off until its washer just won't turn. That's tight enough, the nuts are only there to keep the bolts and spring components firmly in place. Being Nyloc nuts they shouldn't work loose, but if you are concerned about that, holes can be drilled in the ends of the bolts and "R" pins fitted to retain the nuts.

With the new larger 20 mm bolts fitted, the top shackle bolt on the rear of the drivers side front spring fouled the exhaust pipe after passing through the chassis, see pic below. In fact I had to remove the front pipe to even fit the bolt. So after it was installed, I lopped off the lead-in end on the bolt with an angle grinder and pressed a 1 cm depression in the pipe around the area of the bolt head to ensure that there would be no contact when the engine rocks under load. Even the previous 16 mm bolts been touching the exhaust pipe and caused a wear mark. I also rotated the muffler (which has off-centre entry and exit flanges) so as to direct the front pipe as as far from the suspension bolt as possible.

The chassis bolt fouls the exhaust pipe.

We got new rear springs made by Industrial Springs in Adelaide and we had an extra 3rd leaf fitted to provide support to the spring eyes. The fronts weren't too bad (Industrial Springs had renovated them a few years ago with new 1st and 2nd leaves) so we just had them beefed up with an additional 3rd leaf fitted and the springs were reset.

History of our Oka Travels

This has now been moved to the right hand sidebar, so it's nearer to hand.

2008 In Review

To all our family and friends.

Once again we've had a full, exciting and occasionally sad year.

In January we had our customary Australia Day BBQ on 26th January. It was hot of course, being mid summer, but we had a garden full of people and we sat out under the stars until very late (ie about 9.30 at our age).

In February we fitted solar panels to our Oka, ready for our next outback trek.

In March we had a severe wind gust which blew our new glass topped outdoor table across the patio and smashed it into a zillion pieces. Fortunately the insurance company paid for a new one.

In April, Scott bought a house about 10 kms away so we were busy fitting stuff to it: a new mail box, replacing window locks, extending his verandah, wiring up his workshop, all the things we didn't have the time for but what parents are expected to do as a matter of course.

In May we overhauled the suspension on our Oka. Fitting new suspension bushes means lifting a 6 tonne vehicle safely to remove the heavy springs and is NOT EASY.

In April we were invited to a former colleague's 60th birthday party in Moonta, a coastal town about 100 kms up the gulf. It was a surprise event which Mike knew almost nothing about and went off very well. His wife Jill arranged everything including renting 2 houses for the weekend for guest to stay at. We had a ball, but also a sore head the next day.

We also had a day trip to Sydney in April courtesy of my QANTAS Frequent Flyer points. We rode the train from the airport across the harbour bridge and did a tour of the Opera House. We hadn't realised it was so complex a structure inside. There were some musical performers rehearsing and the acoustics were quite amazing.

In May we went to a 4WD Weekend arranged by our HF Radio Club in Quorn in the Flinders Ranges. This is a magic part of the country and only about 400 kms north of here. Local land owners have opened up their properties and access tracks to visitors. We did 2 very tough tracks which climbed and wound tortuously through the hills for 20 kms or so. We nearly rolled the Oka over on a few hair rising turns but escaped intact to fight another day.

Endless talk of our experiences around the BBQs took up each evening.

In June we left for another trek across Australia. We met up with some friends in Coober Pedy (1000kms north of here) and drove across the Great Victoria Desert on the Anne Beadell Highway, which is as far removed from being a "highway" as it's possible to imagine, it's just 2 wheel tracks across endless sand dunes and remote, but beautiful desert country. It took us 12 days to cover the 1500 kms and there was only one place to buy fuel and only 3 places where rain water was available. Lucky we are well prepared and fully self sufficient.

In July, continuing our trek, we turned north and trundled across yet more desert tracks to Alice Springs and had a good couple of days at Ormiston Gorge with Tim and Brenda, fellow Oka owners from Byron Bay in NSW.

It's getting warm now as we head further north into the tropics and meet up with Charles and Fred, our friends from the UK who come out here for a few months each year to see a bit more of the country. We waited in Tennant Creek for their triumphant arrival but then I got a text message to say they had already triumphantly arrived some time earlier, and were waiting for us at the caravan park.

We spent the rest of July and part of August travelling with them up to Darwin which is a delightful city but where it was very hot and sticky.

While in Darwin we received a very sad message to say that the son of a very good friend had died after a car accident. We were devastated of course but what can you say or do when you're 3000 kms away? We had known George all his life (26 years) and while we can still remember his Christening, we couldn't attend his funeral, and that left us a bit shell shocked for a few days. 

But then Charles and Fred had to move on to catch flights home and we parted company until next year and we carried on our trek. That took us across the Northern Territory, where had some scary moments with crocodiles, towards the Gulf of Capenteria and to Mount Isa, and from there we headed south across outback Queensland arriving home 2000 kms later at the end of September.

We'd been away for 3 1/2 months, covered 14,000 kms, ticked off several other remote locations and revisited some of our favourites.

We'd had yet another great trek, but the garden had gone completely feral as you can imagine. So October and November seems to have been taken up with garden and house maintenance.

Recently I saw the design of a simple slide copier in an electronics magazine so I was fired up with a desire to relive our experiences on our overland trip from the UK to Australia in 1974/5. So I built it and copied all our best slides from the era into digital format. You can see these at http://picasaweb.google.com/jcribbans.

It is kind of scary to see just how young and slim we were then. I made a resolution to go on an immediate hunger strike, right after breakfast.

Today, ironically in the midst of both the global economic crisis and pre-Christmas spending rush, we are both fit and well and looking forward to our next years adventures, whatever they may be.

For some reason we have been thinking and talking of our long distance friends and relatives more this year than in previous years. Maybe the global crisis has made the world a smaller place. Certainly we are all in the same boat this year and, thinking positively, it can only get better from here?

Best wishes to you all for a safe, happy and rewarding Christmas and New Year.

David and Janet

Gary Highway

Because there wasn't one, I wrote a Wikipedia entry for the Gary Highway, which you can see at this Wiki site.

It contains more geographic info than this blog entry and there's also a useful map at the Wild Discovery Guides site.

We came down the top 700 km section of the CSR to Well 33 and Kunawaritji in September 2007, and then 400 kms down the Gary Highway to Everard Junction.

It's then still a further 400 kms down the Gunbarrel/Heather Highways and Great Central Road to the Warburton Community.

Although the Gary Highway almost dead straight (except for a section at the northern end where it winds around some sanddunes), and plenty corrugated, there are some interesting diversions along the way.

1) Veevers Meteorite Crater, 16 kms off the track.

These are the original hand written notes in the visitors book at Veevers Meteorite Crater by Eugene Shoemaker, who confirmed Veevers as a meterorite impact crater.

Eugene Shoemaker was a world renowned meteorite expert from the USA who searched the world for impact craters, and documented most of those in Australia. His biography can be found here and a Wikipedia entry here.

He became a good friend of Len Beadell and visited Australia often. The Shoemakers named an asteroid, discovered by Caroline Shoemaker in 1980, after Len Beadell. It is now known as 3161 Beadell (1980 TB5) and is 12.5 km in diameter.

Len and his family visited the Shoemakers in the US during 1986, and sadly, it was on the Shoemakers next trip to Australia, on 18th July 1997, that Eugene was tragically killed in a car crash in the Tanami Desert. Subsequently, some of his ashes were carried to the Moon by the Lunar Prospector space probe, and to date, he is the only person to have been buried on the moon. The background to this tribute can be seen here.

This is a video of Veevers Meteorite Crater in 2007.

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Signs by the original finders...

2) Tropic of Capricorn

Markers are located at several places around the latitude of the actual Tropic, since it's position has been recomputed and changed as the earth's tilt varies.

The earth's axial tilt varies between 22.1° and 24.5° and is currently 23° 26’ 21.448”. In 1900, it was 23° 27’ 8.26”. See this Wikipedia entry for more details than you'll ever need.

3) Windy Corner, the eastern end of the Talawana track,

Len Beadell spent several days stuck here in a sand storm, hence the name.

4) McDougall Knoll, a good lunch spot overlooking the Gibson Desert.

Look for the tin can (visitors book) lodged in the cairn.

5) Eagle Highway Junction, which looks very overgrown.

6) Gibson Desert Nature Park, which includes:

7) McPhersons Pillar and Milgan Rockhole, both 30 kms off the track to the east,

McPhersons Pillar

The view from the top of McPhersons Pillar. A lonely spot in a big desert. Look for a glass jar (visitors book) hanging from a bush. You can camp in this track loop.

Mulgan Rockhole, dry in 2007

8) Charlies Knob,

A useful lunchspot.

9) Everard Junction with the Gunbarrel Highway at the southern end of the Gary Highway.

It doesn't look it, but it was a stinking hot 40º that day.

From there the track east leads to Mount Beadell, then down the Heather Highway to the Great Central Road.

Mount Beadell. Well worth the climb and there's a good campsite at the base.

One of Len Beadell's few remaining original signs, still there, no doubt, due to the 23 nails holding it to the tree.

There are no buildings or facilities of any kind along the Gary Highway (or Gunbarrel/Heather Highway sections either) and it is very remote from any help. In the 5 days and 800 kms from Kunawaritji to the Great Central Road we saw not a single vehicle or person.

No permits are required for the Gary Highway itself (or the CSR, unless you deviate off it) but they are needed for the connecting roads and tracks (Great Central Road, Gun Barrel Highway and Gary Junction Road). Permits are easily obtainable on-line.

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