JCB 3C11 Power Steering Problem, Please HELP!

[valvebounce]

Hi, I have recently replaced all the seals in the power steering ram due to it leaking, when I started the digger up, the steering wheel went round and round and the wheels weren't turning both ways . I lifted the wheels off the ground and it would vaguely go left and right, the steering wheel feels like it is slipping /juddering, I have bled the power steering pipes a lot where they join on to the ram, now it intermittently moves to the left but still won't work to the right. I thought it was air in the system, but now I hear there is a relief valve (which I know nothing about) could this be the cause of it? The annoying thing is before I did the work on the system it was working perfectly although the ram was leaking. I have replaced the hydraulic filter and there is the right amount of fluid in the system, Any advice would be really appreciated. It is a 3C11 1976 leyland engine with manual gearbox and it has got the Plessey power steering pump if that helps

[agrimax]

Have you checked out the PS filter in the rectangular box in front of the radiator (or perhaps that's the one you did replace)?

[valvebounce]

Have you checked out the PS filter in the rectangular box in front of the radiator (or perhaps that's the one you did replace)?

Hi thanks for you reply
All I can see at the front is the main hydraulic pump, the feed pipe for the steering pump comes of 1 of the main pipes coming from the main pump. All so it has got the plessey power steering pump.

[essexpete]

It does sound like air in the system. Would it be possible to damage the pump if run with air for a brief while. Most of the systems I have fiddle with bled out by working the steering one way then the other a few times. I remember our old MK11 orbitrol did not pressure up when the engine was not running so there was not any manual steering.

[TullyveeryClassicJCB]

Definitely the first thing I'd be doing is cleaning the power steering pump strainer as agrimax says. The symptoms you say point directly to a blocked strainer.

[valvebounce]

Definitely the first thing I'd be doing is cleaning the power steering pump strainer as agrimax says. The symptoms you say point directly to a blocked strainer.

Hi, Thanks for you reply I will have a look for it

[valvebounce]

I have cleaned the power steering pump strainer, it wasn't that bad really but at least it is done now But it still hasn't fixed the problem Please help I have run out of ideas

[agrimax]

Perhaps time you had pressure guages on the steering ram hoses to see what the pump or relief valve is like. Seems strange that it was working fine before you had the ram resealed. Are you absolutely sure the new seals haven't been damaged( or are the wrong size) on refitting the piston? If oil was passing the seals/ram piston enough,it would give rise to your symptoms too.

[essexpete]

If you have not a press guage to hand you could take off a steering pipe and put the open end into a clean container and see if it pumps oil out.

[essexpete]

If you have not a press guage to hand you could take off a steering pipe and put the open end into a clean container and see if it pumps oil out. 2 Handed with care?