Foden FH70 refurb restoration

[Motleyholt]

You know when you think at the end of the day I'll do a quick job on the truck and it gets way out of hand???

Well I thought I'll quickly remove the hydraulic leg locks on the crane so there's no chance of the legs dropping whilst driving. The legs hadn't fully retracted in the past and the pistons on the locks had been left extended and open to the elements. The elements did there thing and seized the pistons with corrosion.

First job was to see if the bolts and pipe would undo....the bolts turned and the fitting did too. Next secure the leg so it doesn't fall to the floor. I thought I'll unbolt the lock cylinder, swing it out of the way, then raise the leg so the spring loaded lock engages. Then lower leg to release the pressure. That's when it went wrong. The leg won't lift far enough to engage the lock....

Piston dangling at the back.

I also realise the main leg ram is turning the pin in its mounts rather than turning on the pin. This has snapped the pin securing bolt on one side and snapped the bracket on the other. This explains the stiff movement. So I think I'll put a strap across and pull the legs in the last inch, the N/S leg pulls up and starts to lock but I haven't removed the cylinder on that side.

  

The other side is solid and won't budge. B#@*$r.

Time to give up for the day! There is an adjuster on the ram but that's probably going to involve removing the pin so as not to mark the chrome trying to turn it.

Also the seized pins require the removal of the rear body as the designers didn't think it was practical to face them foward where there is plenty of space! I was planning to take the body off in the future to fit the gun tractor winch. Hoping I can get the legs locked without doing that yet so I can get down the road for the spare Mot I have in a couple of weeks. Wish me luck.

[Motleyholt]

Did fit some marker boards yesterday, much simpler😂

Thinking I will make a removable rear under run bar that can mount additional fog, reverse and slow moving board. Would plug it into the trailer socket. Safer on the road and can be dropped for shows and events so it looks the part.

[robin craig]

I love the idea of making yourself more visible to others and also safer but the best part is you are working out how to do it without brutalising the original vehicle. That is a fine standard to have and hold.

Enjoying watching this from afar, keep up the posts its real interesting

[Motleyholt]

Thanks Robin, its not quite in the desirable range of Scammells and Militants yet but I'm sure they will get there. I remember when Militant mk3 were cheap and no one wanted them. I really should have purchased one when I had the chance of a recovery for a few thousand.

When I get as far as making the rear bar I'll move the chevron marker boards too. Should be able to use the lifting/towing/tie down rings with a couple of spring loaded pins.

Had a go a working the crane leg free enough to lock today. Went another step backwards when I realised the top ram pin was seized and turning in the wrong place too. So adjusting the ram might be off the cards for now. Also whist working the leg up and down with lots of penetrating oil I had the feeling I could hear an air leak. Shortly followed by the confirmation of the cab warning buzzer. A quick search found the clutch air cylinder that operates the range change/overdrive was now leaking from its exhaust port.

Hey ho another part to service.

Stripped it of and split it for a look see.

The O rings are past their best and lubrication zero. Although I remember reading something in the manual about lubricating the seals. Fairly grubby inside too.

But far from the worst I've seen. Will go through it tomorrow and worst case I have two more to either use or strip for parts. Then I may possibly get the heaters reinstalled.

[Motleyholt]

There have been a few productive evenings this week, firstly the clutch pull cylinder was overhauled.

  

Stripped

Cleaned

New O rings selected

Reassembled

The manual says to avoid any oil contamination of the bonded seal which is the tapered seal in the centre. So this was left dry and the bore of the cylinder lightly lubricated with rubber grease. This way it will lubricate the O ring and keep the seal dry.

Lastly made a new gasket.

Next day went back to the crane leg and persuaded it back to its fully stowed position.

  

Chain pullers are very handy things.

Finally on day 3 and 4 I've refitted the heaters. Applied the foam seals which are two different thicknesses as the heaters are not quite flat. Not an error that's just how they are!

And refitted to the cab with new air hoses.

  

Re connected the wiring and all the control cables. Then cut some new coolant hoses.

Next job is to drain the coolant again and reconnect them.

Also hay has been made on the farm which means big open spaces....

Still find gear changing akin to juggling. I'm used to double declutching but the clutch brake takes more concentration. You have to really think not to push the pedal all the way down. I'm still not happy with the range change yet. Changes from low to high fine but makes a meal of changing down, with a fair bit of grinding. Not sure if this is operator error, wear from when the selector wasn't fuctioning pre rebuild or an air pressure fault. There does seem to be residual air pressure which in my mind should be exhausted from the clutch pull cylinder. Unfortunately the air system diagrams only cover the brakes so I'm going to have to do some pipe tracing to see what's connected to what. But according to the words only the range change and clutch air assist should be connected to the pull cylinder.

Five days to an Mot slot if I can get it all together in time. The count down begins.

[Motleyholt]

Have now nearly refitted the front wings, firstly sand blasted and galvanised sprayed the U clips. Tried to buy some new ones but they are a bit unusual. All the clips I could find with the correct screw size were too big to fit the wing supports.

Whilst the paint dried I got the wax oil gun out to do some rust protection/prevention. Sprayed inside all the hollow bits and a coat over the outside of the heater boxes. I like this stuff as it works well and when you need to you can just steam clean it off and re-apply. Dries to a slightly tacky surface and probably horrible if you get it on matt paint!

Applied a strip of electrical tape to the mating surfaces to avoid scraping the paint whilst fitting. Some of the joins had sealer in but as I  will be taking a lot of the mating panels off in due course they were left dry with tape.

The captive nut threads were all cleaned out with a tap. Then with much jiggling they were on. 

The front panel is a fibre glass replacement. The originals were pressed steel and rotted away but if anyone knows of one in any condition I would be interested. It took a fair bit of tweaking to get it to close and I'm still not quite happy with it yet. But some of the hinge bolts have seized so final adjustment will have to wait until I reconstruct the scuttle panel. Also, as these weren't designed for FH70, there is a bar and piece of sheet that hits the heater boxes. The sheet had been cut and bent to almost miss but it only took one screw to remove the bar completely giving lots of clearance. 

New old stock lights

I could only find the side light version so two of the lenses will be swapped for amber. Made a tool for inserting the wires out of a piece of copper pipe. It's pushed through, the wire inserted and then pulled back through. Works a treat. 

Doesn't look any different on the outside which is a little disheartening considering the hours invested already!! Still fuctionality and reliability should be vastly improved. The pretty bits will come later. 

 

[Motleyholt]

Had a mad day on the Foden today. Finished reassembling the front end and reconnecting the lights. Had to re rivit one of the rivinuts on the front vent as it was spinning.

Cleaned up the indicator lenses which had been partially camouflaged. 

Used the remnants of a headlight restorer kit with good results.

Spent far longer than anticipated getting the washer jets operating. Crud in the reservoir and pipes kept blocking the washer jets. Took a good hour to get the system cleaned out and functioning. I think a filter may be a worthwhile addition. 

The additional reflectors were fitted. More loose bits were restrained.

Decided to strip and service the gear lever range change valve.

As the gaiter needed replacing it seemed like a good idea. I somehow forgot to take any pictures though!  Suffice to say it's quite simple inside just a close fitting disc with slots to align with the various ports. They operate in pairs so I assume both cylinders on the gearbox operate together. It was all a bit dry inside but easily serviced. Polishe'd the mating surfaces, lightly lubricated everything and reassembled.

New gaiter installed.

And the old one.

Hopefully a bit of test driving tomorrow.

 

[Motleyholt]

Evening all, short one tonight, 

Ahead of mot'd day, see what I did there, I thought I really should give it a run on tarmac to check the brakes behave properly and it will make it to the test centre. After a warm up around the farm, as much for me as the Foden!, I hit the road. Imediately fumbled a gear change and had to pull up and start again. After that I operated perfectly and the Foden did too. The brakes were a bit savage to start with but soon cleaned the last 20 years of inactivity and worked excellently.  The range change played nicely too. After a while my confidence was up and I took it up to the giddy speed of 45mph. When nearly back I risked engaging the overdrive. Not so pleasant, very slow to engage and disengage. Hopefully this will free up too. Will avoid using that tomorrow. 

All in all a success and a good workout for me. Big day tomorrow, off to test after lunch where we will load on about 8t of concrete blocks and see what happens. 

[Motleyholt]

A good day all in all. The modern brake rollers didn't like 1600R20 Michelin's much but the experianced examiner knew how to make it all work. On the first part of each brake test the rollers spin the wheels and look for bind (seized or sticking brakes) but the tyre vibrations confused the rollers as it couldn't get a smooth reading. After the tester assessed the readings a very light brake pressure was applied to smooth out the judder and the computer would move on to the brake test proper.

Compared to a modern truck there is relatively little to test as due to age and type it's exempt from many of the rules and regulations.

One of suppliers delivery drivers used to drive the Foden's and I need to get him in the drivers seat and see if it's me or the gearbox as I'm still not convinced the range change is right. If he gives it the thumbs down I may be taking the box out for an overhaul before it grinds too many of the teeth down.

But at least I can now apply for a registration number.....more forms to fill in....

[radiomike7]

Edit, you answered my question as I was typing!

Edited July 27, 2021 by radiomike7

[Motleyholt]

In an attempt to avoid taking the gearbox apart I've been reading through the manual for enlightenment. Have found a possible issue with the air pipes. 

Manual says green, red, white, yellow

And mine is red, green, white, yellow( the white tag has slipped)

I would be stunned if it was that simple but I'll be checking the pipes end to end to end tomorrow. 

[radiomike7]

Well done with the test, when I last drove one of these at Bruntingthorpe many years ago I seem to  remember the overdrive was epicyclic and quick to engage/disengage.  I also remember it had a good turn of speed.

[Motleyholt]

On 7/29/2021 at 11:16 AM, radiomike7 said:

Well done with the test, when I last drove one of these at Bruntingthorpe many years ago I seem to  remember the overdrive was epicyclic and quick to engage/disengage.  I also remember it had a good turn of speed.

Yes the range change and overdrive are all part of the same unit which is epicyclic and has a synchro so should drop in easily. Sadly the pipe colours are wrong but the pipes seem to be connected correctly. So I'm running out of easy fixes. I dropped the transfer into neutral so I could operate the overdrive whilst stationary. If operated whilst in first gear it would shift but if in fourth it just would not drop in.  I'll check the air pressure at the cylinders but I suspect that when the cylinders and detent were seizing up it may have damaged the internals of the box. Or that may be why it was disposed of in the first place. Still I know where there is another 9 speed box. It looks like there is just enough space to remove the rear gearbox case in situ so that may be an option too. 

And yes it's great fun to drive, quick for its size and age too. Leaves a good grin on ones face. The tyres make everything nice and interesting. Definately no chance of falling asleep at the wheel either 😂

Edited August 1, 2021 by Motleyholt
Typo

[Motleyholt]

Well I've checked the range change air pressure, it's well over 100 psi and all the pipes are clear. Checked the clutch adjustment. I've been on another test drive just to make sure I'm pushing the clutch far enough but not too far and have come to the distressing conclusion that the back end of the box is going to have to come apart!

By my calculations if I remove the x member under the box, the prop to the transfer box, an air valve, the selector again and a few pipes. Then there will be enough space to remove the rear housing to access all the oily bits. I'm suspecting the synchro springs and hopefully nothing totally beyond repair. Otherwise plan B goes into action and another complete box will be aquired if a sensible price can be negotiated.

[jpsmit]

Been watching this with great interest. Don't understand even half of it - but love it none the less. Especially with the muppet gif - I saw this on another forum.

 

 

[Motleyholt]

3 hours ago, jpsmit said:

Been watching this with great interest. Don't understand even half of it - but love it none the less. Especially with the muppet gif - I saw this on another forum.

Thanks for the interest, any thing you don't understand just ask. Happy to expand on anything. I'm sure I quite often take it for granted everyone knows what I'm talking about! 

To be honest the Foden is way out on herky jerky and crunchy grindy 👍

[jpsmit]

8 hours ago, Motleyholt said:

Thanks for the interest, any thing you don't understand just ask. Happy to expand on anything. I'm sure I quite often take it for granted everyone knows what I'm talking about! 

To be honest the Foden is way out on herky jerky and crunchy grindy 👍

Thanks for your kind words - I am just in awe of these projects - as mentioned, a lot washes over me but, it is such a treat just to watch the skills and determination. cheers!

[attleej]

Martin,

Well done with your efforts, they are most impressive.

I have a friend who is a guru on Fodens.  I have asked him if I can give you his e-mail address.

I believe that the Army changed some of the Fodens to have Fuller gear-boxes which are much easier to acquire. I would recommend an RTO 14613.  However, I expect that you would like to keep it original.

When we first had a 22,000 litre wheeler TTF at 240 Sqn at Barnet we were told to drive it in a very odd way.  We were told to single declutch changing up and to use the clutch brake when changing up.  We must have had to double declutch changing down.  I NEVER got good results.

When I went on my driving instructor's course at Leconfield, the instructor first demonstrated driving the vehicle.  I expressed surprise that he was double declutching changing up.  He said "of course, it is a constant mesh gear-box".

At Leconfield we were trained to go up through he gears to the fourth gear position, double D all the time, when in fourth move the paddle to high range and then change up and into the first gear pos.  When in the fourth gear position in high range, move the paddle to overdrive.  To get overdrive it was only necessary to press the clutch momentarily.   We would then generally pre-select high.  When the speed fell away for whatever reason, we would only need to dip the clutch to come out of overdrive. 

The interesting bit is what we were trained to do next.  If the gradient was making us change down we would go down through the gears in the normal way and on a decent hill it is better to change down two gears at a time.  When negotiating a hazard such as a roundabout we were trained to come out of overdrive at an early point, pres-select low, get the speed right right down using the service brakes, when the speed was low enough, dip the clutch.  This would cause the box to range change from 8th gear (4th pos, high range) to 4th gear (4th gear low range).  This was  a really good system of driving as it avoided lots of pointless down shifts and allowed you to concentrate on finding a gap in the traffic and avoid stopping.  Of course, 4th gear was ideal for negotiating the roundabout. 

Note that overdrive has to be pre-selected when going into it and coming out.

John

[Motleyholt]

On 8/2/2021 at 7:06 AM, attleej said:

Martin,

Well done with your efforts, they are most impressive.

I have a friend who is a guru on Fodens.  I have asked him if I can give you his e-mail address.

I believe that the Army changed some of the Fodens to have Fuller gear-boxes which are much easier to acquire. I would recommend an RTO 14613.  However, I expect that you would like to keep it original.

When we first had a 22,000 litre wheeler TTF at 240 Sqn at Barnet we were told to drive it in a very odd way.  We were told to single declutch changing up and to use the clutch brake when changing up.  We must have had to double declutch changing down.  I NEVER got good results.

When I went on my driving instructor's course at Leconfield, the instructor first demonstrated driving the vehicle.  I expressed surprise that he was double declutching changing up.  He said "of course, it is a constant mesh gear-box".

At Leconfield we were trained to go up through he gears to the fourth gear position, double D all the time, when in fourth move the paddle to high range and then change up and into the first gear pos.  When in the fourth gear position in high range, move the paddle to overdrive.  To get overdrive it was only necessary to press the clutch momentarily.   We would then generally pre-select high.  When the speed fell away for whatever reason, we would only need to dip the clutch to come out of overdrive. 

The interesting bit is what we were trained to do next.  If the gradient was making us change down we would go down through the gears in the normal way and on a decent hill it is better to change down two gears at a time.  When negotiating a hazard such as a roundabout we were trained to come out of overdrive at an early point, pres-select low, get the speed right right down using the service brakes, when the speed was low enough, dip the clutch.  This would cause the box to range change from 8th gear (4th pos, high range) to 4th gear (4th gear low range).  This was  a really good system of driving as it avoided lots of pointless down shifts and allowed you to concentrate on finding a gap in the traffic and avoid stopping.  Of course, 4th gear was ideal for negotiating the roundabout. 

Note that overdrive has to be pre-selected when going into it and coming out.

John

Thanks for the info John, fourth to fourth low sounds like a good idea if the revs are low enough as finding the right revs from first high to fourth low can be fun. I find the clutch brake works well as long as you just give it a dab. Any more and you stop the input shaft completely. Then the scrabble for a gear commences.  My rev counter is a bit intermittent so I'm largely working by instinct and feel. Most of the changes are good and getting better.

I feel that I should be able to skip a few gears in low as I would with a modern 8 speed ie 2, 4, shift to high 1,2,3,4. But I've yet to experiment to see if I can get the revs right. You use half the gears just to get to 5 mph!

As my range change is so slow to engage you loose any hope of a smooth change as the revs are all wrong by that time. 

How smooth was the range change and overdrive when you drove them? 

Did you double declutch on down shifts with range change? Hand book says double declutch all down shifts.

I've read on another forum there is an air pressure regulator on the range change system which can cause problems but I have full air pressure at the box so I think it's unlikely to be the problem. I'm hoping for a quiet afternoon this week so I can take the box apart and see what's inside.

[john1950]

Changing gear smoothly with a Foden gearbox is an artform in itself and takes practice. It may well just be yours is stiff from lack of use. 

Edited August 6, 2021 by john1950

[Motleyholt]

On the grounds that there was a very slim chance that a pressure regulator may be affecting the range change I decided it should get a strip and service. As every other valve has needed attention it was deemed a good idea regardless. It's just held by the copper pipe work, two unions unscrewed like new and the third wouldn't budge. Luckily the pipe was only short so was unscrewed at the other end and removed with the valve.

nñ

Just four unc screws and it comes apart.

Above the diaphragm all was clean but below the moisture from the air tanks had taken its toll.

Clean up time

  

Smear of rubber grease as a corrosion preventative and back together. Here's where I let the side down as I neglected to take the last pic so I'll edit that in tomorrow! 

Its actually more of a pressure relief valve rather than a regulator. As it stops air circuit five filling until all the tanks are up to minimum working pressure. I assume a safety thing as you can't operate the clutch so can't drive. After the valve opens circuit five will reach the same pressure as all the others. 

So to sum up it needed doing but isn't going to fix the range change. 

[john1950]

There is a picture of 23 GN 73 brand new with its crane minus the bodies in the Foden  factory at Sandbach on FB. With the comment (good truck winch temperamental)

[attleej]

Dear Martin,

Richard Nixon is the spares secretary for the Foden Society, has contacts and is knowledgeable.  His e-mail address is:

Richard Nixon <ricknixon@btinternet.com>

 

John

[Motleyholt]

On 8/9/2021 at 4:42 PM, attleej said:

Dear Martin,

Richard Nixon is the spares secretary for the Foden Society, has contacts and is knowledgeable.  His e-mail address is:

Richard Nixon <ricknixon@btinternet.com>

 

John

Thank you John, much appreciated, this may be invaluable as you will see in the next post......

[Motleyholt]

Gearbox saga continued.....

So I decided that it should be possible to strip the epicyclic range change/overdrive unit in situ. So on Monday the front prop was dropped, the prop from the gearbox to transfer box removed, selector removed (again!) And the air valve above removed.

Front prop

Transfer box prop

It's not essential to mark and refit props in the same place as all the components will be balanced separately,  but it's good practice and there is less chance of things coming loose especially if there is any corrosion. Especially true with wheels.

Dam that short prop is heavy.

Air valve

Selector

The cross member was dropped as it has a mounting that stops the housing being removed. This was harder than anticipated as it's held with close fitting bolts. They look to be custom made and fitted to reamed holes. Took some serious penetrating oil, air gun and a lever to extract them.

There was still quite a lot of moisture in the oil when drained even though it's already been changed. But this may be due to there being a step at the front of the casing that stops complete draining. So there is some surface rust on the inside.

All the casing nuts were removed and the case was ready to simply be slid off the studs.....not.

It was properly stuck and I had to employ the chain puller again, tension was applied and then the copper mallet strategically used and with a bang it came free. A couple of nuts were left on so it didn't drop on my head.

And finally the insides were outside.

Strap was just incase as I wasn't sure how much the rear gearbox mount was supporting, not a lot was the answer.

The selector shaft is on the right, syncro hub in the middle and the epicyclic gears to the left.

The synchro is the part I'm most interested in so that was stripped off with the selector shaft.

  

The syncro ring either has a coating on or its collected metal from the syncro cone. If it's coated it's coming off. Anyone know if it's a coating or all needs cleaning off???

The syncro cone has been working hard and has a lot of surface cracking, which you may just about be able to see.

Everything else seems to be in excellent condition apart from some light surface rust. All the important bits are clean and intact. 

So now I'm looking for syncro parts 

Baulk ring syncro cone Nato No. 2520-99-825-3460 part No. 050-471-03

Cone outer syncromesh Nato No. 2520-99-828-3814 part No. 050-778-00

If that fails I'll go get the local gearbox and hope the bits I need are in good condition.