JCB 3?

[MrF]

As a aside, I went through this a few years ago with my 3c3, took the brakes apart which were seized solid inside, free'd everything up, copper slip on every thing that moved that wasnt a friction surface.
Afterwards, its enough to *just* bring the machine to a gradual stop & hold the machine on a steeper slope, but you have to have a heavy right foot especially with a full front bucket. So I'd describe them as barely adequate at the best of times... If I was going to road it, I'd have old tyres pinched in the front 3-in-1 jaw as a real emergency brake. Off road you can always drop the front bucket teeth down for the same result.

Hats off to the people who routinely used to road these machines between jobsites back in the day.

[essexpete]

Mostly all the dry disc brakes were poor, probably just adequate on a basic tractor when everything was working correctly. The 3Cs were heavy old beasts, probably 3.5 ton plus over the Ag tractor.

[dixie-normous]

I was always told not to grease the actuator balls on dry disc brakes as the dust sticks to the grease and dries it out blocking the ramp. And to change the balls when servicing the brakes as if they wear even slightly out of round the actuator won't spread evenly so the discs don't have even pressure all round. Not sure if this is correct or not but the brakes on my 3c3 have always been ok, although i haven't tried it on the road!

[MrF]

Im with Pete on this debate, my 3c3 weighs in at just under 8t with fuel and fluids, and the leyland 270 tractor JCB used as a base weighed 2.5t. My friends 270 I did the same brake rebuild treatment & has exactly the same braking system can hold ok on a steeper slope where I'd be stood up standing all over the brakes in mine.
They're ok in a better than nothing sort of way and it was worth doing because I had no brakes when I first got my machine, just trying to manage expectations of how good they actually will be after

[essexpete]

Im with Pete on this debate, my 3c3 weighs in at just under 8t with fuel and fluids, and the leyland 270 tractor JCB used as a base weighed 2.5t. My friends 270 I did the same brake rebuild treatment & has exactly the same braking system can hold ok on a steeper slope where I'd be stood up standing all over the brakes in mine.
They're ok in a better than nothing sort of way and it was worth doing because I had no brakes when I first got my machine, just trying to manage expectations of how good they actually will be after

Even bigger gap in weight than I had thought.

[mechman]

Hi all.
Had a go at the 3c2 slewing mechanism again today as I'm still not convinced the splines have gone. What I did find was that there was very little oil pressure in the actuator hoses, in fact there was none when I first cracked them open and very little after that. Tend to think It's the spool block. Any hydraulicists out there had this before? I Looked for the relief valve on that circuit but gave up. Next step swap the hoses on to the stabilizer lever and give that a go.
Norm

[Jeremy Rowland]

Daft question Norm but is there much play in the mechanism that connects the lever to the spool valve? Also have you any spare hydraulic hoses in case one has collapsed inside and is blocking the oil way? Is there a good flow of oil up to the spool valve? Just a few thoughts there; there may be a broken spring in the spool valve assembly that is permitting oil to bypass back through the valve to the tank?
Perhaps somebody else has come across this issue before, perhaps as you say it's not the splines that are the problem.

Jeremy

[essexpete]

You could try putting a stop end on the hoses and dead ending the spool. Should load the engine and blow the RV.

[mechman]

Hi all.
One of the info sheets I've read states there's a relief valve in the slew circuit only. Can't find that either. By the end of todays proceedings it was slewing but very slowly. All the other circuits are working fine. I'll swap the hoses to the stabilizer circuit cos that is a known, at least it will prove the king post assembly etc is working or not.
Norm.

[mechman]

Hi all.
I've admitted defeat with the king post malarky, I think the the carriage is gong to be left on (bit of counter weight) and the rest taken off. it will be used as a fork lift and loader as intended. We will see.
Norm.