JCB 3C MKIII /5 picts and questions

[Unknown1875]

Hi everybody,
I'm glad I've found this place !
I've found this machine for 1.5k€ located a few miles away from me.
I only knew it did not run since a year, it had a broken hydraulic cylinder cap and a bad oil leak.
I did not have any urgent need for this type of equipment, I guess it was more of a kid's dream.
In the end I managed to get the machine running and I brought it back (17km!).
The oil leak was coming from a hole in the fuel lift pump (?!)
I topped up the hydraulic fluid and the torque converter oil and now it's moving how it should.
I plan to change the head gasket since i discovered oil in the coolant, none the less engine is starting and running sweet, hard to tell if it's overheating since none of the gauges work.
There it is : JCB 3c mk3 powertrain year 1979 with the extended back hoe.







My first bit of work !





Does anyone know what this follow aluminium knob is for ? I feel stupid.



Do you know if head screws need to be replaced after changing the head gasket ?

Is it worth to drain the hydraulic fluid and change/clean the strainer if the hydraulics works fine ?

Thanks

[Jeremy Rowland]

Hi and welcome I would be in no great hurry to rip the cylinder head off, the oil in the water could be from the engines oil cooler, drain the cooling system and wash it out the best you can, top it up and run the machine, give it some strenuous work to do, if the problem is a blown head gasket it will pressurise the cooling system and blow the water out of the radiator. Stop the engine immediately and let it cool down, you then at least know that the head gasket is the problem, I'm not sure where the oil cooler is on this engine but there are plenty of people who come on this site and can offer you sound advice, good luck with it, looks a nice machine.

Jeremy

[essexpete]

Jeremy is right have a good check before ripping apart. I am not sure if there is an oil cooler. I don't recall one on our v reg. We had overheating problems from the external core of the rad choked up but unseen in the gloom. I think these BMC Leyland engines can suffer from leaks around the bottom of the liners.
You have quite a rare extending dipper there. Not that many were speced with those. Our one had the extender and 4in1.
If shuttle works properly look after it. Check the torque oil on idle or immediately after stopping. Don't over fill either. The oil was originally speced as a 10w transmission oil not ATF. It does not hold much either so worth a couple of changes to help clean it out. Much oil will remain in the system on draining. There is also a strainer in the bottom of the shuttle sump. When using don't push too high a gear as that will result in oil getting hot. Don't shuttle while rolling.
Brilliant bit of kit. Sometimes wish I had kept ours. We found a brand new old stock turbo engine for our one and it was awesome although I suspect it gave the transmission a hiding.
Not sure on the extra alloy lever. Retro fit? Have look underneath through the big filter door perhaps? I wonder if it is a changeover or lock out valve for something.

[Unknown1875]

Hi,
Thank you for the reply, from what I've read I doubt there is an oil cooler on the the 4/98 NT. If I'm not mistaken it's usually located under the oil filter but here's what the manual show :



I've found this piece on the internet, but I couldn't find it in the engine bay nor in the engine service manual.

https://www.asap-supplies.com/engine-sp ... ler-203465

Here is the goo :




PS : I should receive head gasket and a fresh waterpump today, with the 15 days confinement, I'll have plenty of time to work on the machine
Are you guys locked down too ?

I 'd be grateful, If someone can confirm or not the existence of an oil cooler it would save me some time for sure !

Essexpete, Thanks a lot with this details, I remember struggling to find the place to level the converter oil, but apparently on the powertrain it's normal to top it up by the dipstick hole. The oil I've used is called Dynatrans cvt 10w30, sounds good to you ?
There actually is hydraulic piping underneath the lever, perhaps a lock out valve, I'll try it when using the backhoe.



Thanks

[Unknown1875]

I think these BMC Leyland engines can suffer from leaks around the bottom of the liners.
.

Arf I hope it's not that, maybe the liners sealing ring is faulty ?

[Jeremy Rowland]

We are in semi-lockdown with most sensible people isolating themselves; as you have a lot of time on your hands take the trouble to read through the various topics in this section of the forum as I am sure that somebody else had a similar problem, it may just point you in the right direction.

Jeremy

[essexpete]

There are several on here with knowledge of the 4.98 engine and you also try the Leyland uffield tractor forum or one of the farming forums in the classic section.

[philwheelton]

HI if there is an oil cooler on this it will be attached to the oil filter just check if there are coolant hoses going to the area around the oil filter
housing

[agrimax]

No engine oil cooler on these afaik. Just the torque oil cooler in front of the radiator which won't have a link to the cooling system of the engine.I'd guess there's a blown head gasket too.If there was a cracked/porous liner or failed O rings at the bottom, there would also be water in the sump.Likewise,if there was a cracked head or block between the oil and water galleries,the sump would fill with water when the engine is stopped.
Presumably the engine oil is still black? The brown sludge mixed with oil/coolant do suggest exhaust gases are are also present.A good flush out first and see if there are bubbles rising and more oil appearing would be a good start.Going to need flushed anyway.
IIRC,the studs stay in the block and only the nuts come off when removing the head. Can be reused again and retorqued to 110 lbs/ft.(Maybe there are some bolts too,can't remember as it's been a while,but I've never replaced any.
If the hyd oil is clear/clean(a little milkiness at this age won't matter),I'd just change the big filter.

[Unknown1875]

Thanks a lot for these precisions, I've stumbled some other posts related and this was my conclusion for the cooling oil part.
Yep the engine oil is free from water.
I will dismantel the radiator and clean the mess. Parts haven't arrived yet and I realised I will probably need a set of spanner in imperial metric.
I'll let you know what I found.
I take advise for the oil filter and head studs.

Appart from that, do you guys have managed to adapt hydraulic tools to your backhoe ? I've seen the post of someone trynig to plug a wood splitter into his machine. What about rotary cutter ? Most people use a tractor aside, right ? I'm about to by an old farm with 1.5hectare of land. Would it be more interesting to invest in an old tractor or stick with one "multi purpose" backhoe ?

Thanks for your advise,