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Foden FH70 refurb restoration


Motleyholt

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Hi to those that have not seen my introduction, this will be the blog of my Foden FH70 refurbishment and restoration. I say that as to start with it will be a refurbishment to get it through an mot, road registered and out in to the wild and then it will become more of a rolling restoration job to get it back to a sound condition to last another 40 years.

I got a little carried away and my introduction page has the start of this story so you might want to have a look at that bit....

....and now your up to speed I'll continue.

The exhaust had a bit of a blow

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So a new section has been welded in. Not the final fix as the original is a pressed two piece design like the outer one in the photo. Some of the other pipes are getting thin so eventually I'll return it to original and if I can't buy a bend of the original type I'll make a former and make the halves.

 

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Much quieter now.

Also filled the washer bottle to see if the air powered pump worked....the puddle on the floor soon answered that question. With luck I can make a good one from the two I have.

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This afternoon I decided to attack the screen washer pump, it's operated by compressed air as I haven't encountered one of these before I have some questions.

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The underseal encrusted pump is from my Foden and the other is from the donor cab. The donor has already been rebuilt at some point but is missing a ball bearing non return valve. Both were stripped to sort the best parts.

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As you can see the top housing has suffered from freezing. So it was taken to the adjusting machine...20210214_183627.thumb.jpg.ed641be12e61a0912bf9faac026fe7a3.jpg

Or 50t press as it's otherwise known. A little over kill but allows a controlled pressure to be applied. Once straightened it was dressed with a file to a point where it would seal again. Now for the questions, how do these pumps work? There is a rubber piston or diaphragm and a small piston with a seal which acts to shut off the washer fluid at the top housing. The small piston is fed from the center air pipe which has the ball bearing valve in the air fitting. I assume there is a non return valve in the washer fluid pipe somewhere and possibly just uses air pressure directly on the washer fluid?

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The main rubbers are in a poor state, the better one is from the donor, and although I don't think they should be a tight fit on the outer body as it's just rough cast. I think it has shrunk and should be bigger than it is.

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Does any one have any parts or a pump that could be used for dimensions so I can make a new rubber? I would rather keep the original pump as opposed to fitting a modern electric version

 

Edited by Motleyholt
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After a look at the pipes to the screen wash I realised that I was looking at the pump the wrong way. It's not a pump in the conventional sense more of a pressure pot giving a single squirt to the screen.

Fluid enters via either of the top pipes, it's irrelivent which way round the pipes go as the second is just a breather back to the bottle. The centre pipe at the bottom is the air feed, the ball bearing in the fitting stops fluid running back into the air pipe. When air is applied to the centre pipe the small piston is forced up closing off both the top pipes and air then leaks around the piston filling the chamber and forcing screen wash out of the second of the bottom pipes and onto the screen. So simple really but absolutely essential to fill with screen wash so it doesn't freeze.

I haven't yet worked out what the rubber part is for yet. My guess is either to stop the washer fluid aerating or  reduce the volume to use less per squirt possibly.

I'll post a video of how to extract the broken bolts in the housing soon. If I'm not too horrified by the sound of my own voice 😂

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Committed to resolving the diaphragm issue in the gearbox today which I have been putting off for a few weeks. Drained the oil and got back underneath, spanner in hand, for the tedious job of undoing bolts a fraction of a turn at a time through the letterbox.

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Getting quite swift at it the second time. This time I removed all the bits behind the diaphragm to see what was what.

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Then realised it's the clutch brake. Had been wondering what the diaphragm was for! Cleaned everything again, found nothing amiss, but realised if this is the clutch brake why does it have a prmanant air supply?

So went in search of the valve that controls it and found it.

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It's a little hard to see as it's behind the clutch air cylinder, I had already got it on my list to overhaul as it leaked air. Someone previously had the same idea but instead of repairing it they had just plugged the exhaust port with a bolt. Net result was that the diaphragm was pressurised when you pressed the clutch but on release the pressure couldn't escape. So gearbox turning, clutch brake on trying it's best to stop it turning until everything got hot, smoke came out and the diaphragm melted.

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So two more diaphragms made, refit everything, service the valve and remove the bolt.

Give it a test and all now works perfectly. Very happy I didn't need to drop the gearbox.

Whilst refilling the gearbox I took the opportunity to modify the dipstick by adding an O ring. 

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The colchester triumph is a little large but it did the job.

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Should stop water getting in.

Also tested the crane out to rearrange the spare parts.

Ben hijacked the controls but that allowed me to take a few pics and the video.

 

Next job is to replace the crispy coolant hoses. 

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It was a good call Richard and definitely saved some time. Half the battle is working out how it should work before you can understand how to fix it. I've spent a fair bit of time on a customers Bedford MW and the much newer Pinzgauer. It's nice to have something of my own to work on. 

I've also noticed there are some extra air pipes fitted which are not connected but tied up along the chassis. I think they are for the winch pto and brake. I don't know if all the Foden fh70 limber's had these fitted or if mine was nearly a gun tractor? I don't remember seeing spare pipes on the last one I looked at and it was only one prior in chassis number.

Also does anyone have any history for these Foden's?  There is remarkably little on the Internet.  Would be nice to know when they were designed, how many were made etc. 

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Just some info I found on the Commercial Motor archive - http://archive.commercialmotor.com/article/1st-november-1974/40/fodens-at-the-front-by-gordon-murra

Note that as far as I know, this vehicle was never designated as an FH70. The FH70 was the actual gun it was designed to tow and service. I have had more luck on the internet looking for Foden 6x6 gun limber or gun tractor.

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Thanks for the info, an interesting read. Always thought it was a shame they never gave them a proper name. Especially after the matador's, militant's and martian's. Makes you wonder what they might have been called?

Was talking to a DVSA inspector today, after an MOT, and I'll need to go to an old fashioned test station for an IVA. This will get it onto the DVSA system and then I can book a regular HGV MOT so it can be registered and taxed. Will confirm this once I have called them.

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I suspect they were wired and piped identically so they could be a tractor or limber on the production line.

I don't think they used the same name twice! The handbook, chassis plate and body plate all use different wording. Should have just given it a simple name

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Also they uprated the front axle from the commercial motor article which stated an 8t front axle where all those I've seen have had 10t axles. Or the commercial motor article got it wrong.

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Does anyone know how many still survive in the UK in original spec? tractors and limbers. They seem to have been quite short lived, in service, compered to the recovery variant. Mine only served from 80 to 93 and only covered 4000 miles.

Edited by Motleyholt
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On 2/25/2021 at 7:44 AM, Citroman said:

For your screen washer pump it looks a bit like the foot pumps used in caravans. Instead of a foot compressed air is used.

Yes it's really simple when you realise how it works. It's beautifully made brass or bronze, I'm not sure if I should paint it or get the brasso out.

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Have made some progress with sorting out the relentless warning buzzer in the cab, No. 4 air warning would not go out even though the gauge was right up and the cab lock warning was on constantly. I bridged each of the pressure switches in turn with a length of wire until I located No. 4 and removed the pressure switch.

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They are good old fashioned things that, unlike modern equivalents, can be dismantled and serviced. I took one of my donor spares apart first just to see what was what. Very simple inside, a rubber seal/piston pushes against a spring to break the circuit. The pressure at which it breaks is set with shims behind the spring. The shims and spring form part of the circuit and get corroded as the switches are not water proof.

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So after cleaning everything it was reassembled with a light coating of rubber grease to prevent corrosion. Tested with a multi meter to make sure there was continuity before refitting.

Next was the cab switch

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It lives just behind and below the air filter and so collects all the muck from the road. Which results in this.

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I'm always the optomist when it comes to making things work again but this switch was only going to the scrap bin.

 

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Luckily the manufacturer's name was still present and a quick auction site search found some new old stock at sensible prices. The company still exists and I suspect that they can be purchased brand new so must be a good design to be unchanged over 40 years later.

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Just needs some green paint. Anyone have recommendations for paints? Primers and top coats?

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Lastly for this installment I've started swapping the coolant hoses. Started with the split oil cooler hose.

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The small hose was removed to drain the coolant as all the taps are seized. Will get them all working whilst it's drained. The hose above left of that is the leaky one. It gets flexed as the radiator is tipped foward.

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There is a flexible hose but it still puts a stain on the one that is leaking

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The old and a good used hose. Purists look away now.... I've got some new silicone based hose which is a lot more flexible than the rubber which I'm going to use to avoid the same problem reoccurring. There are only two hose sizes used 2" 50mm and 5/8" 16mm. I have a length of 50mm, a roll of 16mm and some 16mm 90° bends. This should replace almost all the hoses. The top and bottom radiator hoses are a flexible type and appear to be silicone based so will hopefully be able to leave these alone. Will pressure test them once the other hoses are fitted.

 

Edited by Motleyholt
Added missing photos
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Got a quick job out of the way, removed and straightened the headlight guard.

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With a combination of the press and a big hammer it was straightened

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And got it to here

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And with a bit more tweaking in the vice it's almost as good as new

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Just needs stripping in the sand blasting cabinet, a spot of weld where the metal has cracked at one of the bolt holes and a coat of paint.

One more job ticked off the list.

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It's been a quiet week on the Foden front but have continued the coolant hose replacement. To access the heater hoses the front cab corners need to be removed.

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The variety of fasteners used is quite astounding, several types of self taper.

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Metric bolts one side, imperial the other. Some have nylocs and some spring washers and plain nuts.

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It's as if they just had a big box of random nuts and bolts and lucky dip the ones to use. The question is do I put random bolts back in or appease my organised side and put matching bolts in?!

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The hoses run from the heater tap, bottom right, to the left of the heater box,top left. For some strange reason all the hoses have a straight connector to a 6" straight hose to connect to the heater matrix. I have yet to work out why it's not just one length of straight hose.

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So the new hose is just two piece until I discover the reason.

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The heater boxes are just starting to rot through so whilst I have access to them I'll take them out, weld in some new metal and paint them. Have a couple of sheared bolts in captive nuts on the door pillar to deal with too. Unfortunately I'll need to take the door off to get a drill to them. Life is never simple.20210309_173433.thumb.jpg.58ee9fe209a8bc04d7bc3c9f2c6f929a.jpg

Found a bodged repair to the wiring too. I'm pretty certain scotch locks weren't approved by the MOD! Anyone know where I can find the conduit for the wiring? It appears to be a wire and cloth construction.20210309_180645.thumb.jpg.bf387f8eac55149f1aa996fce947af74.jpg

The bodged part is of a different type, is rotten and going in the bin.

That's all for the moment.

 

Edited by Motleyholt
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My personal preference is never to re-use old nuts and bolts unless they are some special entity.  I'd replace them with new ones of the type shown in the ISPL.

On the conduit front, xmod had some a while back, but I've no idea if they still have any.  I'm trying to find a source of the fittings they connect to for my Abbot, such as the T-pieces on the headlamps.

Andy

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9 hours ago, andym said:

My personal preference is never to re-use old nuts and bolts unless they are some special entity.  I'd replace them with new ones of the type shown in the ISPL.

On the conduit front, xmod had some a while back, but I've no idea if they still have any.  I'm trying to find a source of the fittings they connect to for my Abbot, such as the T-pieces on the headlamps.

Andy

Hi Andy, I have quite a few fittings on my donor cab, unfortunately the harness I need has been cut. If there are any fittings of use you are welcome to them. Send a pic of anything you need and I'll have a look through the spares. I keep all the plugs anyway as they are usually the hardest bits to find.

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Would any of the following work, in conjunction with cloth covered insulating tape? I’ve had a look at xmod and they seem to be out of stock of the correct conduit.

https://www.autosparks.co.uk/electrical-components/conduit

I know that there is some insulating tape which closely matches the appearance of the original covering, being matt in appearance and can be used to disguise.

Also found this - https://www.ebay.co.uk/itm/Cable-Flexible-Conduit-Sleeving-Split-Unsplit-Loom-Harness-Various-Sizes-/263163209329

or this - https://www.vintagecarparts.co.uk/parts_index/conduit

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19 hours ago, ltwtbarmy said:

Would any of the following work, in conjunction with cloth covered insulating tape? I’ve had a look at xmod and they seem to be out of stock of the correct conduit.

https://www.autosparks.co.uk/electrical-components/conduit

I know that there is some insulating tape which closely matches the appearance of the original covering, being matt in appearance and can be used to disguise.

Also found this - https://www.ebay.co.uk/itm/Cable-Flexible-Conduit-Sleeving-Split-Unsplit-Loom-Harness-Various-Sizes-/263163209329

or this - https://www.vintagecarparts.co.uk/parts_index/conduit

Thank you for the links I had a thorough search of xmod's site and found this

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It's for a drops but looks identical, is plenty long enough and wasn't a million pounds like some of the items. On closer inspection it's looks more like string around the outside. Was just hidden under paint. I'll probably need to cut it up and swap the old fittings over. If can extract them from some of the old cables as the later fittings look to be different in design. Will let you know when it arrives.

Also ordered a battery cover and gear lever gaiter whilst I was there....just when I thought I wasn't going to spend much 😂

Edited by Motleyholt
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That reminds me that at one stage I bought some wiring looms (possibly for a Saracen) from Makano Surplus who unfortunately don't seem to still be in business.  That means I'm pretty well OK for the smaller diameter conduit, but the Abbot also uses a larger diameter and I haven't been able to find a source for those.  This isn't very clear and the vehicle is two hundred miles away, but might help explain.

Andy

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On 3/13/2021 at 10:45 AM, andym said:

That reminds me that at one stage I bought some wiring looms (possibly for a Saracen) from Makano Surplus who unfortunately don't seem to still be in business.  That means I'm pretty well OK for the smaller diameter conduit, but the Abbot also uses a larger diameter and I haven't been able to find a source for those.  This isn't very clear and the vehicle is two hundred miles away, but might help explain.

Andy

 

 

I've got two of these Andy, 2 male 1 female?

The female has been chewed up and has popped off but I think I can fit one of the spare good ones from the cables and swage the end back over.

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Got a few hours on the truck today in between showers. Wrestled some more coolant pipes off to replace the connecting hoses.

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That's after cleaning the ends....this was before...

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Some of the hoses weren't too bad but others had suffered 

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Stripped the seized drain tap whilst I had it on the bench.

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Took some gentle heating, penetrative oil and a spanner on the shaft with some gentle wiggling it broke free and came apart. The spring that maintains pressure on the seal had corroded and stopped everything form moving.

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I thought I had some of the flat spring type washers but I couldn't find one. So I have fitted two turns of a standard spring until I remember where they are. A spot of rubber grease and put it all back together. A small victory but satisfying none the less.

Also found out why the heater hoses were made of so many parts, the heater pipes are slightly larger diameter so the short hose is an adapter. They must have uprated the heaters as my donor cab has smaller pipes and no adapter hoses. So I've ordered some adapter hoses and will fit it back as it was.

Started to free off the heater box bolts, have been soaking them in oil every night for the last week. Have got a couple off but some are spinning the studs. Will need to see if some are nuts and bolts that are somewhere behind the trim in the cab foot wells. 

Anyone know which are the correct cab markers? On my two cabs I don't have two lenses the same.

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I think the second pic is original as the N/S is the one that normally gets ripped off in trees and hedges.

That's all folks for this week.

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