JCB 3C2 1978, King post, slew rams

[Proren46]

Good morning everyone,
I'm new to the group, I have a 1978 3C2, which I purchased in 1992 from a farmer who bought it from a public works company, so as you imagine it had been abused most of it's life, being in deepest France it's a case of boggit and make do. I drove it back 50 kms from where I bought it, which was a real seat of the pants experience, driving down the RN20, (one of the main tourist routes to the south),on Good Friday !! Through Souillac a busy tourist destination, virtually no brakes and a back hoe that dropped every 5 minutes.
I was told that gearbox and torque converter had both been rebuilt, within a week gearbox seized up totally, fortunately I have a mechanical history, but not on plant machinery, mostly Jaguars, Porsches, Bmws. Rebuilt the gearbox with as many new parts as I could find and all has been fairly good since, with the exception of the usual hoses bursting, rams leaking, etc,etc.
The back hoe has always had a tendency to swing out when you're not watching, last year it became virtually uncontrollable, king post rams were leaking oil constantly. I managed to order a set of seals for both actuators, however they are not the same, apparently only this upgrade kit is available for the 3C 2, obviously it does several different models, I will suss out the best way to fit them, however when I took it apart clean water (as in a couple of litres) poured out,followed by a fairly small amount of oil, the same when I removed the drain plug from the King post ?
My questions are
A/ how is the water getting in
B/ What oil should be in the king post as it's obviously not hydraulic oil under pressure as it's got a vent tube on the top plate?
C/ There appears to be a removable plate on the extremity of the front right chassis, someone told me there's a filter behind it, but it seems a strange place for a filter, according to my parts picture book there's a filter in the bottom of the chassis tower behind the entry step?
Hopefully someone can give me some pointers, other than that she runs really well, starts 1/4 of a turn every time, no easy start even in the depths of winter. She's virtually retired now but I can't consider getting rid of her, even when I sell my campsite and retire myself I'll take her with me and restore her totally.
Thanks

[Billy26F5]

Glad you like your JCB, what serial number do you have? The last 3CII was 124999, from 125000 they were 3CIII's (1977). Some parts in the slewing actor change between Mk2 and Mk3 ranges. The water will have got in through any leak in the cover plate with the vent pipe, all of that should be tight. Correct oil is SAE 90 EP (JCB specify Mobilube HD90, the same grade), capacity is a gallon. This is the same oil as the gearbox (assuming it's a Brockhouse torque converter). Don't know what plate this is, sounds like a modificartion. A pic would help. The hydraulic filter is on the RH side and requires replacing, the main suction strainer is in the chassis on the LH side and the power steering strainer is in a rectangular box connected to the forward chassis on the LH side, above the main hydraulic pump. The two strainers only require cleaning. There are 43 gallons of hydraulic oil, it should be ISO 46.
Sandy

[mambo]

If its like the 3D from the same era theres a door in front of the right hand rear wheel and the filter is in there, see my post https://www.classicmachinery.net/forum/ ... 47#p117147

[essexpete]

The OP has done well to overhaul the Brockhouse converter. IIRC, the torque con /shuttle takes a Dextron type or JCB SAE 10w that was for the shuttles but also a light weight engine oil. The gear box and axle would be a gear oil.

[Billy26F5]

All contemporary JCB's are very similar. We don't yet know if he wants to replace the return filter or clean the strainers, if the oil is milky I'd do both and renew the oil, possibly flushing out with oil although that would be pretty expensive these days. Don't know for sure if this JCB is what he says but sounds likely to be a Brockhouse unit. The torque converter oil is SAE 10W (JCB specifies Mobil Delvac 1310), the gearbox is SAE 90 EP. It is a good job done, especially with such a big lump as the Nuffield gearbox, compared to the stuff he'd also done.
Sandy

[Proren46]

Hi everyone,
Thanks for all the info, the machine serial n°: 3C 11282573, tractor serial n°384B 206647, Engine n°: 35C44.
Unfortunately the seal kits for the slew rams supplied by JCB are totally wrong, however I have located some seals which measure exactly the same as the old ones, from a hydraulic specialist, at 1/4 the price of JCB. I always use ISO 46 for the hydraulics and dexron for the converter. Just waiting on the seals arriving so I can get her running again.
I'll post pictures of the cover plates (filters/ strainers) and probably take them off to have a look.
I suppose water ingress into the king post is inevitable as she lives outside not in a nice cosy barn. The cabin is solid but is missing most of the glass, so one of the next cosmetic jobs will be to repaint and find new glass, worst way there's a small glass company locally who cut laminated sheet glass to virtually any shape provided it's flat.
Have a good weekend !!

[Billy26F5]

The serial is 112825/3, the suffix indicating a Brockhouse machine. It's a March 76 Mk2 machine, a couple of months older than Mr MacGregor, the tractor number is probably actually 384B/2/206647, the engine number is probably 4/98NT/1792/35044.These last two you'll find on the skid as well (tractor number on top of LH side channel, engine number on top of block under injector no 4), there's also a gearbox number, on the rear flange on the top RH side, starting 10B and ending R, with a number around 149000. Correct seals are 562/11201, 562/11203, 2411/1011 and 2401/0302 from inside out. You'll need two of each of these parts. Dextron (ATF) is not suitable here, it must be SAE 10W. There should be no water in the slewing actor irrespective of whether it lives under cover or not. You're lucky with the cab, the glass could be a bit tricky, especially the sliding window (927/10800). Pics will be great.
Sandy

[essexpete]

If it has a sliding window, I might be tempted to use polycarbonate on that part. I used that for years on our 3C 111. You want proper laminated glass in at least the front screen.

[Proren46]

Hi Billy, great information thank you, so she's 50 years this year!!! New oil & filters as a celebration!!
The seals for the slew rams I managed to get from a company who specialise in bearings, belts, hoses etc, fortunately there was a reference still visible on the ones I took off, so next day delivery and it's now almost back to running again, just the steering filter to check or change, new oil and as good as new!! Maybe not quite that good, but ready to work again
Thanks again
Proren46

[Billy26F5]

Should actually be better. A new engine has issues that only smooth out after running in, some 200 hours or so. The steering strainer only needs cleaning (unless it's damaged, but that is unlikely). Seal factors are great, they can get all kinds of things made up and even in better quality than repro part makers. Indeed, probably already is 50; hoping Mr MacGregor will be able to celebrate nicely too (he's May 18, serial 113341).
Sandy