4x4 Toyota Coaster-Cummins-F250 conversion

Whether it's your first tourer or a hardcore playtruck, show us your vehicle or what you're building inside, and keep us up to date on your mods as they happen!
4x4Coaster
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Re: 4x4 Toyota Coaster-Cummins-F250 conversion

Unread post by 4x4Coaster » October 13th, 2011, 6:09 pm

Doowrag wrote:Looks like a 60 series Cap ???

Spot On Doowrag!

4x4Coaster
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Re: 4x4 Toyota Coaster-Cummins-F250 conversion

Unread post by 4x4Coaster » October 17th, 2011, 9:05 pm

I was having trouble finding the right tool to fold the metal skin over to suit the filler panel, pliers & multigrips were too long, so I cut a 1mm slot at 45deg in this piece of 10mm flat and used it to bend the edge.

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here are the original panel & filler section once separated-

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The original fit only had the 4 spot welds, I used the 4 tabs and plug welded them but also put a little spot weld every inch or so around the perimeter. so here it is all welded in and the door back on.

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Here's a pic from inside- I also welded in some pipe section to put back the strength in the lower section that the filler neck cuts right through, also the internal frame is welded back in place-

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Now that I have to do some painting I figured I might as well finish off this side of the bus. I've painted the other side and the front and rear. First some rust repair just in front of the rear right wheel.

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mark hopkins
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Re: 4x4 Toyota Coaster-Cummins-F250 conversion

Unread post by mark hopkins » October 19th, 2011, 12:29 pm

Great bus mate. You shore do have a way with the tools. Its taken two days on and of to read all the threads.
Fantastic job on the bus., the most interesting build up i have seen. Keep the posts coming.

HOPPY

4x4Coaster
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Re: 4x4 Toyota Coaster-Cummins-F250 conversion

Unread post by 4x4Coaster » November 4th, 2011, 11:37 pm

Thanks Hoppy! glad you enjoyed the thread.

Well I have finished painting the driver side, what a marathon, lots of sanding and wet rubbing fiddly bits 'n pieces. I took the driver door off the body and stripped it completely, including removing the glass & frame, so that I could paint it properly. So the next step is off to Brown Davis to get a tank made. I did weld nuts in the chassis for the tank to bolt to as well as finishing the filler & breather hoses. I also got the lock barrel on the filler door altered to match my ignition key for $25.

Here is the first layer of body filler around the new filler neck;

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Bus outside for wet rubbing;
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Bus all primed;
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Door primed;
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Bus all painted & back together;
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smokescreen
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Re: 4x4 Toyota Coaster-Cummins-F250 conversion

Unread post by smokescreen » November 4th, 2011, 11:51 pm

Great build thread mate this things going to look awesome cruising up the road you will have to post a video of the maiden voyage.

Great work.
2000 GU Patrol TD4.2T ute
2013 GXL 200 Series TTD Diesel Landcruiser
2012 Can Am XMR 800


stretch4x4
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Re: 4x4 Toyota Coaster-Cummins-F250 conversion

Unread post by stretch4x4 » November 5th, 2011, 8:07 am

You mean like the ones in this post: viewtopic.php?p=1173565#p1173565
Doing the border track in SA.
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Gojeep
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Re: 4x4 Toyota Coaster-Cummins-F250 conversion

Unread post by Gojeep » November 5th, 2011, 4:54 pm

Came up well mate. Looks factory.

4x4Coaster
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Re: 4x4 Toyota Coaster-Cummins-F250 conversion

Unread post by 4x4Coaster » November 19th, 2011, 5:11 pm

Update on the tank install - all finished!

Filled the tank today & it took 187 litres. Original tank is around 85 litres so all up around 272 litres.
At my average consumption of 17.5 L/100k I'll get about 1550 k's range.

heres a couple of pics-

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stretch4x4
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Re: 4x4 Toyota Coaster-Cummins-F250 conversion

Unread post by stretch4x4 » November 19th, 2011, 8:41 pm

I like! Surely is an impressive rig.
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4x4Coaster
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Re: 4x4 Toyota Coaster-Cummins-F250 conversion

Unread post by 4x4Coaster » January 29th, 2012, 4:33 pm

Here goes another round of improvements / fixes on the bus;

Still having issues with belt tension which virtually makes the airconditioning unable to be used – horrendous belt squeal due to tensioner in wrong place.

I’m going to remove the compressor used for pumping tyres etc and replace it with an electric compressor but retain the air tank setup. The tensioner can then be moved to where the compressor was and I’ll put the fan hub back on the motor as well as altering some idlers & alternator slightly. No pics yet.

Also fixing a problem known as ‘KDP’ or ‘Killer Dowell Pin’. Sometimes, if you are extremely unlucky, this dowell pin slips out of its hole and jams between the aluminium housing and cog causing rather a lot of expensive damage. It is a case of prevention more than fix and while I had the radiator out to work on other things, I thought now is a good time to do it. So pics attached showing the pin location and easy fix to prevent it from happening.

I’ve also got new engine mount insert rubbers, actually polyurethane instead of rubber. The rubber ones go soft with exposure to oil so out with the old & in with the new.

Another annoying item on the list is my new long range tank. It can’t keep up supply of diesel under extreme load. It happens even with a full tank so I think the problem is the supply line is too small, currently 10mm but should be 13mm line from the tank. The original tank is 13mm supply.

The other ongoing problem is the wheel wobble. The truck whisperer didn’ fix it, although he did improve the steering generally. I think my biggest problem is still chassis flex. While this isn’t the cause, it is one of the weak points which allows it to get out of control. I thought I had enough bracing on the chassis but I was proved wrong over Christmas when the lower brace broke through fatigue.
Now I’m re-designing the lower brace as well as adding cross bracing in both directions so it will be fully triangulated.

I’ve also ordered a new water pump as mine has movement, in and out along the shaft, and sounds a bit noisy. Still waiting for that to arrive from the US.


HOT OFF THE PRESS!!

I have been keeping an eye on this website for ages and recently there was exciting news!

This company develops and builds 4x4 conversions for mining and tourism operators and for private enquiries if wanted.
He has just been developing a 4x4 Coaster Bus and has tried a few options and looks like he is going to go ahead with a Dodge Ram donor based conversion using the latest 6.8l Cummins and the Dodge driveline.
There will be 2 versions, one dual rear wheel for up to 20 passengers and a single rear wheel version for camper conversions. He will have a third option using the original Coaster engine and gearbox and just add the transfer case & 4x4 gear.
There is an existing conversion on the Toyota Commuter Bus and another conversion for Transit Vans is on the way.

Check out the following link;

http://bus4x4.com.au/?gclid=CLHgq-D31q0CFQuEpAodTENxnA

Front of 12v Cummins with cover removed;
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There is a bolt just near the dowell pin which is removed and then replaced with the little cover plate that fits over the pin head.

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New vs Old engine mount inserts;
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DJR96
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Re: 4x4 Toyota Coaster-Cummins-F250 conversion

Unread post by DJR96 » January 29th, 2012, 6:02 pm

All in the name of "continued product development" huh Glen?

Those Bus4x4 rigs look pretty tidy. And catering for the mining industry is a smart move. Also shows the original manufacturers what they should be making to start with.

Obviously all way too late for you now, but did you consider using the donor Ford of Dodge chassis under the bus body? Is the wheelbase similar enough? A whole lot of different engineering involved, but it may in hindsight been easy to sort the suspension out with.

Good to see you're out and about and enjoying the fruits of your labour. More than I can say for myself........ :rolleyes:
Cheers, Dave.
RCV Supertourer build:- [url]http://www.4wdaction.com.au/forum/viewtopic.php?f=22&t=36370[/url]

robertbruce
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Re: 4x4 Toyota Coaster-Cummins-F250 conversion

Unread post by robertbruce » January 30th, 2012, 10:13 am

settling down for another mouthful of elephant hey Glen, i sure hope those red engine mounts get a peek though the wheel arches....

4x4Coaster
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Re: 4x4 Toyota Coaster-Cummins-F250 conversion

Unread post by 4x4Coaster » April 19th, 2012, 10:45 pm

Alright, time for another update!

Well, after 3 years of trial and error, it looks like I’ve beaten the ‘Death Wobbles’!

Over holidays in January we ventured across to Cann River in the east and as far as Eden on the lower NSW coast. The wobbles plagued our trip and in the end couldn’t go over 80k’s on the journey home. Then still about 160klms from home the lower chassis brace broke from fatigue caused by the wobble and chassis flexing. Now I couldn’t go over 60kph and had to drive most of the way home in the emergency lane. Down but not beaten, I had to fix this problem before the bus goes anywhere again and at any price!

First up was to improve the bracing design and add cross bracing from both directions as well. So now I have top and bottom parallel bracing joined by an ‘X’ in the middle so it is fully triangulated in both directions. There is no way that chassis can flex now.

Next step was to get a replacement panhard bar. Straight away I was on the phone to the USA and ordered a replacement Panhard Bar from WC Motorsports. They claim their bar will fix the wobbles so I was ready to give it a go, it didn’t come cheap at $800, but like I said, “at any price”!
It was a long wait for the bar, I think about 6 weeks, so when it arrived I was on to it straight away. Removing the OEM bar was easy enough, unbolt the chassis end and separate the axle housing end from its ball joint. However the ball joint, which is pressed into the housing, also has to be removed as it is replaced with a different type of joint. I made a jig so that my 5ton bottle jack could press the joint out and put it to work. It took so much effort on the jack lever that I thought the jack would burst a seal and then with a sudden bang it let go.
The OEM ball joint hung down towards the ground from its mounting point in the centre line of the housing while the replacement joint can be used to point up or down depending on the lift and geometry of the vehicle. I had room enough for the joint to go upwards which meant that it would be almost perfectly parallel to the steering arm thus eliminating any bump steer. I also replaced the steering arm (thanks DJR96!) as mine had been deliberately bent to follow the old panhard bar. The new one is straight so the steering rod is now a straight one again. The new bar uses Heim joints each end to eliminate movement but the price is noise and vibration transfer when the vehicle is stationary with the engine running and in drive. Once moving there is no noticeable difference between the OEM bar and the Motorsports bar.

With the bar finished it was back to the caster. The recommendation that comes with the bar is 1.7 caster on the passenger side and between 2.0 and 2.2 on the drivers’ side. So once again it was off with the wheels, coils and shocks. Body and axle housing supported at ride height and set up my measuring jig using a level, builders steel square, welding magnets and all kinds of gadgets! After removing the top bolts which hold the housing to the trailling arms, I rotate the housing to the desired position, note where the hole needs to be then remove the arm, weld up the hole, grind it all flat and then drill a new hole to suit. Then the arm is re-fitted and the process repeated on the other side.


After putting it all back together, double checking bolt tensions and that nothing has been forgotten, it’s time for a test drive.
This is the anxious bit; Until I drive it, I must optimistically assume the problem is fixed. What if I drive it and it’s not fixed? I’d rather live in hope than face the possibility it’s not fixed. What a dilemma!

Good news is it behaved perfectly. There are several places within a few k’s of home that I know will trigger a wobble episode. None of them caused a ripple. That was a week before Easter. Over Easter we went across to Hazlewood Pondage in Gippsland, about 240 k’s from home, and both ways it felt good. I think the wobble has been beaten, finally!

Here is the new bracing
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Some shots of the new panhard bar
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In the 3rd shot the new steering arm is fitted, if you look closely at the previous 2 pics you can see the bends.
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Here's a pic of the jig to remove the ball joint
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and the removed ball joint
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DJR96
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Re: 4x4 Toyota Coaster-Cummins-F250 conversion

Unread post by DJR96 » April 19th, 2012, 11:30 pm

Great work Glen. Glad it all worked out for you. :thumb:

I'm still impressed with you being able to use the original Toyota tie-rod and idler to "convert" the steering of the axle to the left hand side. Better than the Aussie delivered F250's double box set-up.
Cheers, Dave.
RCV Supertourer build:- [url]http://www.4wdaction.com.au/forum/viewtopic.php?f=22&t=36370[/url]

Gojeep
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Re: 4x4 Toyota Coaster-Cummins-F250 conversion

Unread post by Gojeep » April 20th, 2012, 11:00 am

Glad it is all solved now. :)
What I don't understand is how you could have changed caster one side differently to the other? Being a solid front axle, you can only do it via cutting the weld that goes all around the housing holding the swivel or knuckle on, then rotate that and fully weld in all back. Just altering the arm attachment points can only effect both sides equally. You can not twist the housing after all. Trying to force it will only mean chewed out arm bushings.

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