Author Topic: It's BIG, Yellow and digs holes! JCB 3CX Project 8 is joining the Tractor Shed  (Read 11186 times)

Offline vtsteam

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Sometimes discretion really is the better part of valor.  :dremel:  :beer:
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline awemawson

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With all the faffing about failing to get the steering ram pin out I hadn't finished the tie rod - the off side bush, pin and seals were still sitting on my desk in the workshop nagging me.

So with slight trepidation, not wanting to start another mammoth task I set too. And I'm delighted to say that the pin came out with two bursts of the air hammer and the entire job took about an hour including rebuilding my grease gun :clap:

Quite significant wear on this side (why more here  :scratch:) - the nominal 25 mm pin was down to 24 mm in places and the bush was at 26.5 at the worst place.

Previously, when the front end was up on the bucket you could grasp a wheel and rock it quite a bit - now there is no discernible play  :thumbup:

So just that pesky steering ram bush and pin, but that will have to wait until the season is over. If only it was a 'through pin' and not buried in a blind hole.
Andrew Mawson
East Sussex

Offline vtsteam

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Must feel good to have the steering tight, though.  :clap:
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline awemawson

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I got a call the other day from the chap who I bought the JCB from. He'd found the 'engine covers' which he hadn't thought that he still had.

These were originally optional extras, and a designed to reduce noise as much as keep the engine clean of mud etc. Project 7 ones and Project 21 ones regularly turn up on eBay (at a very silly high price) but I've not seen them for this Project 8/9 machine - available new but again at a silly price and they are by no means essential - but nice to have.

He let me have them for a modest price and they arrived this morning. Rather filthy so they've been pressure washed and will be mounted when the sound proofing has dried - or I may replace it as it's acoustic foam and showing it's age by being rather crumbly.

In other news: Ditching paused as the first lambs arrived this morning, one is not feeding and is on the bottle already, and as the lambing shed is on the other side of the hedge from where I'm ditching the attendant noise isn't wise!

Andrew Mawson
East Sussex

Offline awemawson

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Having had a fan blowing on them overnight the foam sound deadening on both engine panels is now dry, so I've re-fitted them.

The fit isn't brilliant - I suspect that the front nose cone / radiator cowl arrangement has met with a mishap at some time as the angle that it sits at isn't quite right compared to the shape of the panels. I can't see that the panels have altered so the cowl must be bolted on at a slightly jaunty angle.

. . . another winter job to put on the list but again definitely a non-urgent one.


In other news, reluctant ram lamb now feeding off mum, but I still can't resume ditching as we've have modest rain for two days and the ground is no firmer than it was before
Andrew Mawson
East Sussex

Offline awemawson

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When I got this 3CX there was a slight leak from the 'Auxiliary Valve' - this is a foot operated valve that would operate a hydraulic breaker were one fitted, but on my machine operates the 'ExtraDig' dipper extension slide that gives an extra few feet of reach.

As I played with the machine the leak got a bit worse and I decided that it needed sorting.  It was a check valve that was leaking - a simple cylindrical body crossed drilled for one of the bolts that hold the slices of the valve together and thus retained in the valve. This body has an O ring and backing ring to seal to the body of the valve and has a spring and clack valve pressing onto a machined surface for it's check valve function.

Internal spare parts for this valve are 'no longer available' from JCB or the various parts dealers, however I was able to find a good secondhand valve which I got my hydraulic fitter Martin to put in, his flexibility being considerably greater than mine. It only needs a mechanical pedal linkage removing along with four hydraulic hoses and some mounting bolts - technically trivial but physically impeded by loads of other bits of JCB surrounding it!

Needless to say after a few months of operation the replacement started leaking in exactly the same way  :bang: I tolerated it until recently while ditching I burst a hose on the Extradig circuit and when replaced the valve leaked hugely. Probably the extra pressure pulse had destroyed the O ring seal.

Well - this time I still had the original valve so could dismantle it to measure O rings, backing rings etc - slightly odd ball sizes but I am sure that I could have found them from the myriad of hydraulic suppliers that are on line.

In an idle moment one evening I searched for 'Check Valve' on the official JCB parts portal and found all sorts of definitely different valve but one 'spares kit' that looker remarkably close to the one I'd dismantled. Listed as a spare for a totally different machine and NOT for a 3CX I got a spares dealer to measure the bits and guess what - the same size  :ddb:

Armed with the part number I was then able to identify the correct O ring and backing ring and ordered a complete 'spares kit' ie the whole check valve, and also spare O ring and backing washer. These arrived this morning allowing me to replace the complete check valve in situ on the machine and have bits to repair my original auxiliary valve as a 'shelf spare' for the future.

Although far easier than removing the auxiliary valve for bench repair replacing the check valve while on the machine wasn't the easiest task however it is done and works so far without any leaks ! I've still to repair the spare unit.

« Last Edit: May 30, 2022, 07:53:13 AM by awemawson »
Andrew Mawson
East Sussex

Offline Sea.dog

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I'm surprised that a dealer wasn't aware that the 3CX was used on later models. It used to be common place in the automotive and motorcycle worlds for dealers to know interchangeable parts.

Offline vtsteam

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One of the things we Madmodders do, which is unusual elsewhere, is investigative research beyond the usual authoritative answers. It's always fun to read about one of us succeeding where most people give up: No Longer Available.

Say's who?  :dremel:

We're not friends of planned obsolescence.....
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline awemawson

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Thanks Steve. Yes also 'beyond economic repair'  is another of my red flags.

If I'd have known it was as simple as it is I'd have pulled the original auxiliary valve apart and even if I had to make the backing ring I'm sure the odd size O ring could have been sourced. That way I'd have saved a sizable chunk of hard won cash (the 'good used' item was £250 including VAT and carriage)

I've just rebuilt the original valve as a known good shelf spare - to my surprise I find the backing ring is actually split with a 45 degree overlapping cut making fitting to the valve body very easy. I'd expected to have to warm it in hot water, and indeed was advised to do this by the dealer, but that wasn't necessary.

The split  backing ring shows up on this image from a CAT dealer's parts site !
Andrew Mawson
East Sussex

Offline PekkaNF

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I enjoy much these stories.

....
I've just rebuilt the original valve as a known good shelf spare - to my surprise I find the backing ring is actually split with a 45 degree overlapping cut making fitting to the valve body very easy. I'd expected to have to warm it in hot water, and indeed was advised to do this by the dealer, but that wasn't necessary.

The split  backing ring shows up on this image from a CAT dealer's parts site !
Looong time ago I needed to field fit one of that kind of hard plastic backing ring on a hydraulic valve. There was no professionals, but there was a spare part and me...I got a hand-written instructions from the office (fax). I had to ask machinist to make two cones, one to expand the seal and the other to calibrate (shrink) the expanded backing ring. Third one was just a piece of pipe to push the seal straight. The backing ring needed to be heated in oil to about 70-80 C and then it would be pliable enough to stretch.  That ring was pretty hard, felt like POM hard.

Offline russ57

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. It used to be common place in the automotive and motorcycle worlds for dealers to know interchangeable parts.

I remember a long time ago my brother telling me of a customer who came into the auto parts store he had just started at. Customer asks for set of pistons for an older jag, computer says yes, price $40 each. Storeman looks at part number, says just a minute and looks up piston for  Holden something, the dominant vehicle of the day. Same part number, price $20 each...

-russ


Offline hermetic

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this is why parts  boxes started to show just a number, and even the "Fits Make, make, make etc" was quicly phased out, it enables the manufacturer to sell the same part at a range of higher prices based on the percieved wealth of the customer. If he can afford to buy an XXXXX he will expect the parts to be more expensive. I used to buy Saab disc pads at the Ford price because the car parts shop next to our second hand selling service was a good guy, and knew the con! I did the same in reverse in our shop, but I had to do it on the fly!
Man who says it cannot be done should not disturb man doing it! https://www.youtube.com/user/philhermetic/videos?

Offline pycoed

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Some years ago, I had a Ssanyongg Korando & lost 5th gear. Usually a circlip comes off & 5th floats free, except the circlip is somewhere in the box! There was a chap on the owners forum who was a gearbox specialist, so I took out the transfer box & gearbox & took the gearbox to him in Presteigne. We sat on his terrace in the sun & he rebuilt the cluster for me using bits from the Ford Mustang Driver’s Club.
The gearbox (Tremec T5 wrc IIRC) was used in the “real” Mustang, with different first & second gears. He had a range of spares on the shelf all bought very cheaply through the Mustang club. Same gearbox was also used in the Sierra Cosworth 4X4.

Following this I kept tabs on Ebay for interest (as you do) & saw s/h Korando/Musso gearboxes for around £200-250 whereas the Cosworth boxes went for £750 upwards!! Sometimes a little knowledge can be a very useful thing eh?

Offline hermetic

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I have another one! When I was doing classic cars, we bought an early Aston Martinn DBS  V8 rather cheap because its Chrysler Torqflite auto box was dodgy, after some investigation it turns out that exactly the same transmission also fits a Matbro Fork lift truck and there is an auto transmission specialist less than 30 miles away who carries the rebuild kit on the shelf! £90.00 . Box out and stripped, flushed out the cooked fluid, and bits of brake band, and rebuilt! Purrfect!
Phil
Man who says it cannot be done should not disturb man doing it! https://www.youtube.com/user/philhermetic/videos?

Offline awemawson

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The fuel gauge stopped working the other day. Had been fine, then zilch, no deflection at all with a full tank.

Now diagnosis should be pretty simple if access was better. It can only be the gauge itself, a fuse, wiring or the sensor in the tank. Not a fuse as other things on the same feed are working. Access to the gauge is a right pain as it means removing the side console instrument cluster - took two days last time.

So how about the sensor in the tank? On my last 3CX the only way to get at it was to remove the tank, but on this somewhat later model I spotted a trim moulding on the off side cab edge that might just let me get at it.

Sure enough only held on by some M6 bolts and removing it revealed an amazing build up of muck - anyone would think it's been used shifting loads of earth! Digging though the buildup with a scraper, and workshop vacuum cleaner eventually revealed the flange holding the sensor in the tank and it's two pin electrical connector. Carefully puling it apart and squirting it with contact fluid made not a jot of difference. Now these sensors, as far as I can tell, vary from about 24 ohms to 75 ohms empty to full.

I stuffed a 56 ohm resistor into the loom cable socket and lo and behold we have a 2/3rds full indication on the gauge - the fault IS te sensor - no having to dig into the side console again.

When I can get through to the parts place to confirm the part number I'll order one up, but so fr they're always on the phone  :bang:



Andrew Mawson
East Sussex

Offline awemawson

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The replacement diesel level sensor arrived this morning, so first measure it's full and empty values:


Full = 13 ohms
Empty = 285 ohms.

Now to fit it. I had already pumped 20 litres out of the tank last night to avoid it flooding out when I removed the flange, and that black plastic trim bit was already off so it was 'just' a case of unbolting the six flange screws, lifting out the old and inserting the new.

Well of course it wasn't quite like that - as I had feared the long stem on the sensor clashed with the cab floor prevented it tilting enough for the variable resistor bit to come out through the hole. With rather more force than desirable eventually it came out by levering it with a screw driver and bending the case. Obviously the new one couldn't go back like that, and I wasn't going to drop the tank.

I ended up bending the long stem allowing the box of tricks to pass through the hole, then as far as I could bent it back in situ. If I ever have to do this again I will cut the stem and make up a coupler  collar with grub screws to put it back together.

What I've done obviously will change the calibration a bit but not too much I hope.

Then to dismantle the old one and find out what failed. It's resistance element is nichrome wire wrapped round a shaped former, with a springy contact finger rubbing up and down as the float angle changes. End to end the nichrome wire was OK giving sensible readings, but it's end termination had given up the ghost and was broken. Theoretically I could mend it but probably won't !

« Last Edit: June 20, 2022, 07:29:20 AM by awemawson »
Andrew Mawson
East Sussex

Offline awemawson

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So not willing to chuck out a potentially repairable diesel level sensor I pulled it apart.

The break in the nichrome wire was very close to the riveted end connection - so after a bit of a clean up with brake cleaner I drilled out the riveted terminal connector, unravelled a bit of the resistance wire to give enough to wrap round the bolt that I replaced the rivet with, and screwed it all back together.

I bit of tin bashing on the box housing the resistance element to make it back to original shape (damage caused by me levering it out), and it looked almost presentable. Bending the wiper to give a bit better pressure I re-assembled it. bending it's fragile lugs back to retain the halves together.

A quick ohms test shows that it works - so it's been bagged up in the packaging of the replacement one and put on the shelf for next time.

Andrew Mawson
East Sussex

Offline vtsteam

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That is some fine wire!
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline awemawson

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That is some fine wire!

Oh yes Steve - I definitely needed my magnifying glass !
Andrew Mawson
East Sussex

Offline WeldingRod

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And a fun coil to get a complex taper!

BTW, it's probably not nichrome. Probably manganin.

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Offline vtsteam

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I have a burnt out plastic welder I'd like to repair. If you guys could advise on the heating wire (I'll open another thread) and on possibly repairing it, I'd greatly appreciate!
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline WeldingRod

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Worth a try!  Pictures needed, though!

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