It's BIG, Yellow and digs holes! JCB 3CX Project 8 is joining the Tractor Shed

[awemawson]

When the dentist had finished poking about in my mouth I was able to start fitting the new (used s/h) slew pots.

First a good clean up of the pistons, remove the old piston seals, backing rings and wear rings, douse with ISO32 hydraulic fluid and fit the replacement seals. Fairly uneventful.

Then a good clean up of the slew pot, again douse it in ISO32 hydraulic fluid and offer it up approximately at the right level using my pump up trolley. Then fitting my patent pot pusher it was pretty easy to pull the pots into place. I did try first doing it manually but that wasn't happening !

Pot mounting face where it joins the slew gearbox is sealed with Blue Hylomar and then those four big bolts need torquing down to 990 Newton Metres  So far they are just 'pretty darn tight' - I can't swing the torque wrench where the machine is at the moment - it needs pulling out of the tractor shed.

Then I replaced the hydraulic hoses feeding the pots. One was well past it's sell by date so I had already made up new ones some weeks ago.

I've just downed tools and come in for supper - I'm pooped ! Tomorrow a grand clear up, oil up the slew gear box which had to be drained for the pot replacement, then see if the new pots work !

[awemawson]

Hopefully this is the end of Slew Pot issues.

Today I added hose protectors to the new slew pot hoses - mainly as the near side one had originally been grouped with the tiny 'boom lock' hose to give it some support, but the sleeve had hardened and cracked off as I fitted the new hose. The same sleeving had been used where the hoses are clamped between the king post and it's cradle so it seemed sensible to carry on to the off side hose. I already had the spiral wrap so it was a no cost choice !

Then I filled the slew gear box - darn silly place for the filler - the only way of getting at it is to stretch to the boom and dipper out on the ground then reach in behind the boom pivot where the (plastic) filler bung sits covered in all the hydraulic hoses ! And to complicate matters the filler incorporates a breather so a deep socket is needed when you can guess what size it is (1-1/8" AF for future reference)

Squeezy oil bottle is about the only way of getting the oil (4 litres of 75W90 GL4/5 Universal gear oil) in as the spout is needed for its reach.

Having done all that I brought the machine out into the yard where I could try full left and right slew and check no hoses were stretched.

Glad to say all  seems to work 

The only thing to work out now is how to torque those bolts to 990 Newton Metres - my big torque wrench runs out of steam at 550 NM ! (But they are blooming tight! )

[vintageandclassicrepairs]

Hi Andrew and All,
The next time you see a "sump draining pump" in Lidl or Aldi buy one!
Pull off the dipstick tube and fit a same size tube as the outlet side
I have found many uses for the pump since I did this.
Filling almost a gallon of gear oil into my MGB gearbox only took a couple of minutes

John

[awemawson]

At long last I've been able to make some progress addressing the weeping rod gland on the front shovel ram. It's only a little weep but annoying. I bought the seal kit some months back but I've been unable to unscrew the rod gland nut. I even made a custom 'flogging spanner' but the flogging got to a pitch where I was reluctant to go further as it threatened to bend the rod itself.

So basically I've given in and enlisted the aid of a local hydraulic company. My previous traveling hydraulic man Martin seems to have disappeared off the face of the earth so hunting for another I came across a promising sounding chap and gave him a call. He was refreshingly honest saying yes he was happy to do the job but he actually would remove the rod and take it to Ella which I could do myself. Imagining Ella to be another specialist company I asked for details. Oh NO Ella is a young lady who rebuilds hydraulic rams ! Apparently her father was running a small company out of the family farm and when he passed on she took over the business and is very good.

So today's job was to remove the ram from the machine - I'd already checked that the pins were moveable. Now this ram isn't enormous but it's big enough to be a handful at head height so I enlisted the aid of the Epco engine hoist and I'm glad I did. Disconnecting and blanking off the ports and hoses, and with the ram secured to the Epco with a strop I pulled the pins. The upper end was happy to come away but the lower end fought me fiercely. Turns out that there are steel 'wear sleeves' in the holes in the machine and on one side they were pushed in too far preventing the eye of the ram from disengaging.

Anyway it's now out, sitting on my pump up trolley and waiting for me to take it to Ella - I assume she has well equipped hydraulic benches as this stuck gland business must be fairly common.

Hoping to get it to her on Monday between other duties - more to follow . .

[tom osselton]

I sure miss the like button!

[awemawson]

Thanks Tom 

So off to Ella's place early doors - a very interesting farm yard with a huge American Army howitzer, multiple Land Rovers of all ages in various stages of rebuilds, much farm machinery, and tucked away in a corner Ella working from a small barn.

Concreted into the yard outside she has a steel framework allowing ram eye pins to be tethered, and from her workshop she brought our a humongous Stillson Wrench that was about as big a she was and probably weighed a bit more 

One swing on the recalcitrant nut and it turned 

Should be ready for collection tomorrow morning - guess where I'll be tomorrow.

I spent the rest of the morning cleaning up the remarkably hard grease from the pins and bushes and clips and also the mounting points for the ram eyes. It really is surprising how hard grease can cake up - I suppose some of it could be 28 years in the cooking.



 

[modeng200023]

I wonder how long it will be before you have a concreted-in peg 
John

[awemawson]

I've certainly thought about it John !

Ella called me at 08:30 to say that although the ram was finished and ready for collection she was moving cattle so just a slight delay. Anyway I was back home by 11 am complete with resealed ram in the boot.

Now without that EPCO engine hoist, fitting this ram single handed would end it disaster but with it it went pretty smoothly. Once the top pin was inserted things got much easier (and safer!) and it was all back together by 12:00. I had two pin shims left over - they are not illustrated on the parts picture and don't seem to be needed - someone in the past has probably been trying to eliminate slop. If I find that they are needed it's fairly easy to fit them.

A quick test to full travel both way with the bucket in the air to ensure that the rams are bled, and all seems to be OK - time will tell evidenced by absence of  pools of hydraulic oil when I look at it in the morning.

I've still to re-fit the 'return to dig' microswitch assembly - it needs a bit of TLC and a coat of paint but that's for another day.

While I was at Ella's place I had a good 'rubber neck' at the big gun which apparently is called a 'Long Tom' - have some photos.

[tom osselton]

 Would make a great Punt gun!

[Pete W.]

That gun reminds me very much of a toy I received as a Christmas present when I was about ten years old.

It was a nicely detailed model with facilities to rotate the gun in azimuth and elevate it.  You loaded it with a wooden projectile and put a percussion cap on the breech.  The firing hammer detonated the cap and the resulting gasses passed via a hole into the back of the barrel, expelling the projectile.

I awoke early in Christmas morn and discovered and unpacked this gift.  Of course, I just had to try it out.  My bleary-eyed father came into my bedroom as I was shooting playing cards off the picture rail!  'Do you know it's only two o'clock?' quoth he!

[awemawson]

It's certainly quite a beast - acording to Wikapedia it can fire a 45 kg projectile 14 miles 

https://en.wikipedia.org/wiki/155_mm_gun_M1

Today I de-rusted, sand blasted and heavy zinc primered the 'return to dig' attachment that was fitted to the recently re-sealed ram. Essentially as the ram moves, a rod co-axial with a mounting tube operates a heavy duty microswitch that cuts off the rams motion when the bucket is at the correct angle if the operator puts the control lever across into a detent.

Tube and microswitch mount got a coat of red oxide primer, and the rod got sprayed satin black which is how it will stay.

Yellow RAL1007 on the tube & microswitch mount will be applied later this evening with a second coat tomorrow.

[awemawson]

I gave the return to dig parts a coat of JCB yellow with the rod remaining black.

Next job: pull machine out of barn to where there is room to swing the dipper full left  right to give the slew pots a final tighten with a 10 foot scaffold pole. Only problem, drivers seat which should swivel to let you use the rear controls was totally stuck.

Then followed a couple of hours pulling the seat out, finding that the main central shoulder bolt that holds the seat down was too short, so when the seat is turned it tightened the bolt clamping the seat. Five minutes of lathe work produced a captive spacer and another lengthy period of contortions putting the seat back 

After that actually doing what I had intended and torquing the eight slew pot bolts was trivial.

[awemawson]

At long last I've been able to re-mount the 'Shovel Reset' or as it's sometimes called 'Return to Dig' assembly on the shovel ram.

This is a simple but very cunning mechanism that once you have tipped a load from the front bucket, automatically returns the shovel to a horizontal position ready to scoop the next load. The left hand (shovel) control spool has a magnetic detent that holds the spool in the 'I'm coming back up' ie far left, until a microswitch on the mechanism mounted on the hydraulic ram trips dropping the detent and allowing the spool and lever return to the neutral position.

In my case the microswitch wasn't playing fair - always open circuit. Now they come as a plug, cable form (moulded into the microswitch) and Honeywell microswitch with a roller ended lever operating arm and are hugely expensive. Opening the microswitch failed to allow me to resurrect it  and the only 'none JCB Spare' equivalent micro switches were equally stupidly expensive (actually slightly more!)

So I ordered up a genuine spare but when it arrived it was faulty  Replacement arrived overnight and worked fine so that is what I fitted this morning. A bit of nifty lacing of the cable form to avoid it being sliced as the rams move and not only is it fitted - it works 

The mechanism is clamped by jubilee clips round the hydraulic ram and unfortunately I rather scratched up my new paint but it'll touch up when next I have an open paint pot.

The idea is to set the 'detect' position to 'shovel level' so a few iterations with a spirit level got it to an acceptable setting.

Before the switch had arrived I'd tested the circuit to make sure that the wiring was OK and that the magnetic detent solenoid worked (paperclip replacing switch!) In these tests the coil was drawing 1.1 amps which seemed reasonable but the control wasn't being retained fully left. Now the engine was not running so no hydraulic pressure but I'd have expected the shovel spool to be clamped. Now it's back together it works so I can only assume that it uses hydraulic pilot pressure somehow.

 . . but hey . . .it works !