The Classic Machinery Network

I recently bought my 2nd JCB 3 with a 1 meter square hole bucket with teeth. The machine is very strong but digging performance is a bit of a disappointment. Raising the boom with a filled bucket is hard and also getting the bucket in the soil does not go so easy.
Is this normal for these machines? I already checked working pressure witch is ok.

I will try to get some pictures online. This type of excavator is very rare here in the Netherlands by the way.

Welcome to forum.
JCB's are known for good digging performance so sounds like you have a problem , sure someone here can help.
Would be nice to see your pictures .

Craig

Welcome Hans

Jeremy

Here are some pictures. Got the one without the cab for about 2 years now. Saved the other one from the scrapyard and rebuild all backhoe parts to the other one.

The backhoe is strong enough to lift the back of the machine. But when digging, the bucket gets stuck in the hard clay pretty quickly.

You are looking at a machine that is the thick end of 50 years old? Perhaps not to expect too much! When you say it does not have much power digging is the engine labouring hard? Is the relief valve blowing off? Or does it seem like the power is not getting to the ram? I suppose the latter could be an internal leak on the ram piston or a worn spool. Do the hydraulics operate smoothly and reasonably quietly when not under too much load?

I found out the machine is about 10 years older then I expected (JCB timeline topic).

The hydraulics are quiet, when the movement stops the relief valve is blowing off indeed, thats why I checked the workingpressure. I adjusted it to 145 bar witch made it a bit better.
The boom stays in position for a long time, that should indicate the ram seals are not that bad.

Maybe I am expecting too much, I should have a smaller bucket too.

Thats quite a big bucket to be digging into hard clay! I would try the smaller bucket and use that one after to move the spoil and load trailers etc.
Or you could try changing/adapting you digging technique to dig in layers til you get to the dept you want

Hello Hans,

I have a 1963 jcb 3 like yours.
I am missing the handle which opens the rear roof hatch.
Any chance of some photos of yours to help me make one?

thanks

Hi Chris, I'll have a look tomorrow. The 'old' JCB is about to get scrapped. I will remove the handle when its still there.

I've hooked up a pressure gauge to all back actor cylinders. I cant get the dipper cylinder over 100 bar, while all others stop at 140 bar (end of stroke). I'm suspecting a problem with the ARV's but the weird thing is that the MRV seems to blow off pressure (based on the noise). So Im a bit confused... anyone got some ideas?

no idea about your problem. sorry.

are you scrapping the one with the cab?