Ferret Fluid Flywheel rebuild

[Robin Craig]

So, I thought I would try to take a few minutes and put something back into this forum for a change instead of being an information vacuum. I hope that others over time will find this interesting and helpful.

Let me say right from the start I am not a mechanic by trade and I am assisted in our mechanical work by a very smart gentleman Gerry Foster with whom I have a great admiration and patience for. He assists me in the maintenance and repair of my own vehicles and also the fleet I look after at work.

I am an enthusiastic amateur with some knowledge. There are many here who have much more experience than myself.

Slowly Gerry is teaching me and I am learning for myself by that experience.

My passion is Ferrets and it is what a number of you associate me with. I am over time becoming fairly well versed in their operation and maintenance.

I thought that I would try to take the mystery and fear out of the fluid flywheel for those embarking down the road of Ferret ownership.

Let it be said clearly that the Ferret is a great vehicle and much misunderstood by many. It is quite simple and quite maintainable by the enthusiast if they have some basic knowledge and can follow along in manuals.

Get the manuals and read them. Especially the field repair manuals as they list the order and tools needed for the tasks. If you can enlist a buddy or friend and work as a team, if not it just takes longer.

I am a big guy and Gerry is the more average sized, so he goes inside and I work outside. Plus he is being paid so he doesn't mind, that always helps.

So, fluid flywheel basics, check it, check it, check it and if in doubt check it.

This tale is what happens when you fail to check the level and other circumstances align and occur.

So, lets start with a dead Ferret and get it into the shop, cue tilting trailer and winch and a nice big shop to work in, yes I am spoiled at work.

So I am not going to dwell on a nut by nut power pack removal, make the lifting jig as per the manual and it makes it easier, or cobble together your own set up as you wish.

Get the assembly out and then we can begin.

[Robin Craig]

So to back up the story this all started a few years ago during our weekly vehicle run up program.

First of all, the fluid flywheel seal was old, beyond best condition for sure, weeping slightly and slowly for a long time we suspect. Checking the level and topping up would have kept it going.

Storage includes having the gearbox in a gear to relieve bus bar spring pressure. Failure to confirm if the gearbox was in neutral was the next problem.

Starting the vehicle from outside, as you can, with the wheels blocked is a short cut that some do. This happened this time I believe but can not prove.

So, to clarify, low fluid level, vehicle in gear, started and then the idle speed raised to bout 800 rpm and let to run unattended for a period of minutes.

The resultant phone call I received was "the Ferret is on fire". A brief exchange followed and the vehicle was shut down and I got on scene. Oil was very visible on the floor under the vehicle and inside the hull. I was fairly sure what had happened.

Let this be a lesson.

[Robin Craig]

Splitting the powerpack into gearbox and engine chunks is very simple, just make sure you block the engine firmly and have the gearbox supported, we use an engine crane. The blocking of the engine on a pallet makes it moveable in the shop and also gets height that allows the engine crane wheels under the gearbox.

Be careful to take the weight on the gearbox before you undo all the nuts and stress the aluminium flange, one could do damage if you do not watch that I think.

Having the engine crane taking the weight makes sliding the gearbox back off the shaft easy. There is some grunting and pry bars needed but no undue force.

Now we have the offending item exposed.

[Robin Craig]

We had ordered the seal and both bearings for the fluid flyheel locally but were short shipped the inner bearing.

We felt that replacing both bearings was the only sensible way to go and would be cheap maintenance, in the end when both were apart we were glad to make the decision because the seal and the front bearing are replaceable in situ as the flange unbolts.

Given the mess that dribbled out we wanted to split the fluid flywheel and clean it and really ensure a proper job. I am not about to get hauled over the coals because we did not perform due diligence.

I seem to have not saved from my phone the two halves split but here is my own unit apart from a few years ago during rebuild.

The old seal was well shot and the new John Deere seal just needs the washer ring flipping and the flange pointing out instead of in to make it all work.

We have bagged it all pending arrival of the other bearing and going back together on January 6th when we are back in the shop.

[Wayne Hingley]

Originally Posted by Robin Craig

...The resultant phone call I received was "the Ferret is on fire"...

Thats a scary phone call to receive Robin! Hows your heart? Was there any fire damage, or did they get it out quickly?

[rob love]

Wayne: Most likely they boiled the oil in the flywheel, causing lots of smoke and mess.

[Robin Craig]

Wayne,

as Rob so rightly says the "smoke" was infact very hot vaporised oil.

It was that very description and a lack of a burning smell upon arrival on scene that led to my avenue of questioning that revealed what had not gone on before start up.

It is a learning curve you have to go through when you don't have enough of the correctly trained people or correctly motivated people.

It has been at least 2 years since the event but maintaining vehicles is just a small part of what we do at work. Winter is our repair time. It is cyclical.

Robin

[Robin Craig]

Apologies for not posting for a bit.

We have surveyed the vehicle and received direction and the scope of the work has widened.

The fluid flywheel is back together and awaiting the threaded plug so we can pressure test it.

We have ordered 4 new flexible brake lines and have started cleaning up other items, one of the most critical is the bevel box breathers. Such a small item but such a massive implication if it doesn't function.

The rear vertical armour was missing some of the cage nuts and some were damaged beyond repair so we have replaced a bunch. I welded them in using a special stainless / mild steel stick electrode that works nicely. Not exactly the same but superior manufacture / function so I am ok with that.

The vehicle will be a good runner once we have gone through all the systems.

The fuel tank has gone out for cleaning and we are working on the new auxiliary tank and connection.

[Lynn Eades]

Robin, Is that breather what was fitted as original?
They are also an Australian carrier part used to let surplus grease out of the suspension units. I would have thought that they have quite a strong spring and that the Stewart Warner type (look at your Landrover ones) with the loose cap is more suited / sensitive to the bevel box application.
I don't know, just asking.

[Robin Craig]

Lynn they are Original Equipment Manufacture items the breathers. What you cant see in that picture is that I have it held in the open position so the photo is somewhat staged per say.

Robin

[Robin Craig]

Lynn

Here is an underside and topside together

[Phil Waterman]

Hi Robin

Thanks for posting the photo of the new style cage nuts.

A comment that I would offer to anyone going to use these as replacement for the original ones used on CMPs. That being that the lip on the under side needs to be considered when using them as in most cases it will not fit down into the original hole, if you don't the nut will not sit down tight when tightened.

Depending on location I used three different approaches:
1. Grind the lip off
2. Drill out the hole on that side
3. Use a counter sink bit to provide space for the lip

From time to time the old style caged nuts, made from a folded single piece of steel, do show up so people should keep thier eyes out for them and grab them when the can.

Cheers Phil

[Robin Craig]

Perhaps I didn't make it clear but I confirm Phil's comments and in my own usage i ground that lip off.

[Wayne Hingley]

Hi Robin,
Where did you purchase the cage nuts with the weldable tabs?
I need to get a few of various sizes.
Thanks!

Originally Posted by Robin Craig

Lynn

Here is an underside and topside together

[Robin Craig]

Wayne I bought them through Brofasco, a fairly well known company hereabouts.

There was an order minimum and I split that with work, I bought half so did they, I have one to do myself.

The biggest problem you will have in searching for the is the terminology as cage nuts is not how they were described, it was something obtuse.

I took a photo in to the store and spent the time worth the local guys who humour me.

It is still a 3/8" fine nut in the cage.

If you need more help let me know

[Robin Craig]

So, our local whizzo machinist knocked up a plug for us to use in the pressure test of the assembled fluid flywheel so last Wednesday night that was installed and she held 40 Psi for 15 minutes as per the manual and we are delighted.

There will be some frantic cleaning and painting this Tuesday so we can go back in with the pack hopefully.

We do have one other piece of news that I am very excited about and all Ferret owners should be as well as things for all of us are about to improve, but that will have to wait for a few days or maybe a week. Sworn to secrecy.

I have sent off the End User paperwork required for some spares that blindsided me, honestly that system is laughable.

The gearbox and engine are back together now, fluids checked, everyone should pay attention to their gearbox and transfer case dipsticks and the galleries in them, they get gummed up over time and need to be cleaned.

[Sam Assad]

now am intrigued to know the news :-)

[Robin Craig]

The news will delayed by a bit more than a week, maybe even a month, no I am not pregnant, despite rumours. I'm just fat.

You will just have to wait Sam.

[Tim Kelly]

Thanks greatly for the wealth of info you shared on the flywheel!! I need your help though. I purchased two new drain plugs and washers. In replacing one, I failed to notice that the initial threads were molded improperly and I stripped 1/4" of the threads on the flywheel. I retapped the remaining threads and recut the plug so both are good now... except that I am missing first 1/4" of threads on the female side. Question, can I use a slightly longer drain plug (will replace both for balance) so that I can get a full grab of good threads? Is there enough open space in the flywheel to allow for such an idea or do I need to consider drilling out the remaining threads and using a helicoil to give me new ones? THANKS!!

[Tim Kelly]

By the way, for info sharing... the threads on the drain plugs are 1/2" x 14 British Parallel Pipe threads (commonly referenced as BSP and/or BPP). Just thought I would share if anyone is ever in my predicament!

[Robin Craig]

Tim,

I am unable to answer your question as I do not have enough technical knowledge on the subject. I don't have one handy to reference. It will be a while until I do as things are packed away somewhat at the moment.

I would heartily suggest posting this same question on the HMVF that has many technical folks and also speak or email with James Hill at the REME Depot in Texas, he is a good egg and very very technical. He has a day job. If you would like his email then ping my email and I will give it by return.

I look forward to hearing the results.

I would say that like algebra the fluid flywheel should have done to one side what you do to the other for the sake of balance, as upon close inspection these things are very finely balanced.

Robin

[Lynn Eades]

Back to the caged nut. Isn't that lip supposed to go into the hole, to center it for welding?

[maple_leaf_eh]

Originally Posted by Robin Craig

...

We do have one other piece of news that I am very excited about and all Ferret owners should be as well as things for all of us are about to improve, but that will have to wait for a few days or maybe a week. Sworn to secrecy.

I have sent off the End User paperwork required for some spares that blindsided me, honestly that system is laughable.

....

And ...?

I visited Ryan's Mk I at SFRC over the weekend. Don't feel left out Robin; I was tied to things that were happening at Queen's during the day. Apparently there are at least four Ferrets within close range of your locale. Time to set up a minor assembly line to rebuild everyone's fluid flywheels?

[Robin Craig]

Lynn,

to answer your comment, the lips doesnt work well with the OEM holes in a Ferret so I opted for grinding it off flush and using a few other tricks to centre it for welding.

Terry, yes I saw you on the Eastern Ontario security camera so knew you were in the hood but as I was busy it was fine that your breezed in and out!