JCB 3C MK11 ,slow moving hydraulics

[engineeringblue]

Hi all , I really hope you can help. So I picked up a 3C mark 2 for the remainder of this project that I am on as i was sick of paying for hire costs.
This is what I know
Engine turns and starts on the button
Drives in all gears fine
brakes could do with an overhaul but will be ok for now
front bucket moves but takes an age to function
rear hydraulics pretty much the same
topped the oil up via the large nut with the 'O' ring on which is situated on top of the cylinder .
small leak on one of the pipes in the area
looking at this forum I see a lot of folk getting help from you guys , so i was wondering if you can help me too please.

So i can see a large nut running horizontal through the top of the cylinder ?? is this a filter ??
Where is the pump on these beasts ? is it likely to be the pump at fault ??
what shall i try first
Tomorrow i have to fix the manifold and exhaust as they are blowing and reweld the bonnet , a few other things to sort out too but really want to get this working ASAP lots of work to be done as iam looking at 60tonnes of sub base and 80tonnes of top soil as we speak .
Best wishes
Darren

[agrimax]

Hi Darren,could still be low on hydraulic oil or could have blocked filters as well.The pump is right at the front,ahead of the radiator,driven by a shaft from the engine crankshaft pulley.There should be a sight tube in the cab on the rhs in front of the brake pedals but it's likely hard to see through with age.If I remember right,you fill the oil where you did but it's a very slow process (or maybe that was on my MK 3).It can be speeded up by removing that horizontal plug on the side that you mentioned. It's under spring pressure. Remove plug,big spring and plunger(valve).Refit plug and you can pour oil in freely through the top plug on the rubber hose. Replace plunger and spring of course.The cylinder you mention contains the return filter. Need to undo the U bolt and then the long bolt that goes up through from the bottom, and then the outer cylinder will come off. Be prepared to catch the oil.Also,and it may be best to check this out first,there is a suction strainer that can be washed,if it's not destroyed. It's above a rectangular plate up below the bottom step on the lhs of the machine.Should be a drain bung in that plate and the majority of oil will need drained first before removing the plate to get at the filter.
It's knowing how much oil is in there to begin with and then how much to put back in again to get to the right level. Really needs the sight tube to be usable.

[engineeringblue]

Hey mate , cool , i have been trawling through the downloads aswell as other info on the net. your help is very much appreciated as i will go in tomorrow and smash it out lol . I saw the hose in the corner which i now know its a level indicator lol . I looked at the horizontal plug and i actually thought that the top up oil would have to pass through it so i may slide it out of the way tomorrow after i have seen how much reads on the level tube . i may renew it if needed. i will check the strainer out first though .
I will message back tomorrow with an update
cheers matey

[engineeringblue]

One more thing , all the remedies that you suggested would this sort it , do the pumps fail and if so can i repair the pump if needed ?
Is it common for the pumps to fail on these ?
Cheers

[agrimax]

The pumps are very robust generally but who knows the history of the machine.If maintenance has been lacking any pump will fail... Unless it's really knackered,it would normally work ok for a while until the oil gets hot and thinner and then the power and speed reduces. Does sound like oil starvation moreso but even if the filters are ok,at least you can rule that out. Another place may need looking at,is the rubber suction hose from the tank into the pump. They can delaminate inside and block the oil flow.
It would be more common to replace the pump than look at repairing it.If it's that bad,it'll be scored inside.The likes of Vicary Plant would probably be able to supply a good used pump if needed but hopefully it's just the filters needing sorted in your case.

[engineeringblue]

many thanks mate , i will get back to you later after ive given it a shot
Darren

[essexpete]

I think Agrimax is right, a lot of the older gear or vane pumps are fairly forgiving when I think what we have had and done in the past with dirty oil/low oil/blocked filters. If the oil is anything less than fairly clear it need changing along with the strainer cleaned and a new filter.

[engineeringblue]

Hi mate , so here is what i completed today
Drained down the strainer unit area under the step on the left hand side of the truck, very messy and a lot of sludge and shitty oil
Took the strainer out and cleaned it dried it and refitted it
Refitted the cover plate and new gasket fitted
stripped out the the oil filter from the cylinder on the other side of the machine behind the door tightened all weeping clamps and unions
the oil level indicator tube in the cab was so dirty i couldn't see where the oil level was so i have cut out the old and replaced with new
two breathers on top of the tank ( just under the front window sill ) weren't functioning so i replace these with similar
fitted new exhaust and now its slightly less noisy including new / second hand manifold
refilled the hydraulic oil and used 65litres WOW
this has only just shown up up on my nice new clear tube indicator so i will top it up a little later on

IN SUMMARY
the machine is absolutely bang on now its so responsive and very powerful.
I will keep my eye on the little leaks on it now and will probably fix each one over the next few months as well as repairing a few other minor issues but many thanks for the heads up on this mate
kind regards
Darren

[agrimax]

Well done that man...You're obviously handy with the spanners and weren't scared to get stuck in anyway!

[engineeringblue]

yes mate iam a mech/engineer , but have only worked on prototype cars . but i guess engineering is engineering eh .
seriously though thanks for your help dude