CASE 580G digger starting problem

(cross-posted to uk.diy, uk.business.agriculture;uk.rec.cars.maintenance.)

Hi all,

Before I start rambling on in great detail, is there anyone reading who knows about CASE diggers starting problems please? In particular the electrical and/or mechanical systems which disengage the hydraulic pump during starting of the engine? Or anyone who happens to have a workshop manual? If so please post and I'll explain a bit more. Email if you prefer, snipped-for-privacy@ANDTHIStiscali.fr TIA

-- Holly, in France Gite to let in Dordogne, now with pool.

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Reply to
Holly, in France
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I am not familliar specifically with the Case 580, but am in general with hydraulic systems.

As a rule you have a solonoid operated dump valve on the high pressure line from the pump (gear pump) OR in the case of a variable displacement pump, the valve is in the sense hose at the pump. Basically so the pump can't pump against a head and consume power. Thus the engine can spin over on its starter motor without too much extra drag.

The dump solonoid ONLY receives power when the key is turned to the crank position- its usually a simple feed daisy chained from the starter motor, possibly through a relay.

What problems are you having?

Tim..

Reply to
Tim (remove obvious)

Tim (remove obvious) wrote:

Hi Tim, thanks for your reply. Well, basically, the problem we were having was that the digger suddenly wouldn't start!! And having eliminated the battery, the starter motor, wiring problems (as far as possible) and the fuel pump and injectors as the causes, we were stuck. However, the engine was turning better with jump leads connected directly to the starter than on to the battery, so we thought there might a switch/solenoid/something similar wrong Also the engine wasn't turning as fast as usual. All this led to the thought that there was something wrong with the hydraulic pump or the control system for it which was putting a load on the engine when it shouldn't, but not having a clue how it worked we couldn't work out what. Sounds to me like the dump valve from what you wrote? Anyway....my husband had a long converstion last night with the man from whom he bought the machine and this chap thought there was something physically jammed in the pump or valve chest, (quite likely the rock-breaker system because apparently that is not uncommon) So this morning he has taken the covers off the pump and whatever it was he has sorted it out - I don;t know exactly since he is there and I am here at home. So the digger is now starting and working properly but it is still starting better with leads directly onto the starter and the lights aren't working! So, he can finish what he is doing, will try to get the lights or at least the gyro-phare (orange turning light on top, dunno what it's called in English!) working and get the digger home. Once it's not stuck on such an inaccessable site 2 hours drive away and with tools etc to hand I expect we can sort it out. If we are stuck I'll post again. Thanks again for your reply.

-- Holly, in France Gite to let in Dordogne, now with pool.

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Reply to
Holly, in France

It's easy to forget the earth-side circuit when you're checking the wiring, battery to chassis to engine-block to starter. And it's easy to bypass most of that when you're using jump leads, without really thinking.

An earth problem would certainly affect the lights, but it may also be a fault in the main switch.

Reply to
David G. Bell

This had occured to me. If a digger has any electronics, engine management unit ?, then there is a real danger of poor earthing damaging it, particularly when cranking and drawing large currents. With poor earthing it is possible to have incoming ground lines negative with respect to local earth, not a good thing. The problem is that what a test meter reads as low resistance connections may not be the same when drawing 200Amps. Cured with emery paper.

Reply to
Hamish

The modern digital meters are good enough to measure the voltage drop across a good earth when the engine is cranking.

12 volts nominal across the battery terminals at 240A is 1/20 Ohm total resistance, starter motor and connections. Because of the internal resistance of the battery, you might only get 6v, meaning starter and connections are down at 1/40 Ohm, and most of that should be in the starter coils.

It's tricky measuring such low resistances directly with a cheap meter, but measuring relative voltages will tell you where a bad contact might be.

Some spark ignition engines feed a 6v coil through a ballast resistor, but the coil gets full voltage from the starter solenoid, bypassing the ballast resistor. The voltage drop due to the current drawn means that it needs that direct connection.

Reply to
David G. Bell

All true, but it might just be quicker to unbolt all the earth connections involved and clean the mating surfaces with emery cloth.

Reply to
Hamish

The message from "Hamish" contains these words:

And smear Vaseline or similar over the surfaces before reassembly.

Reply to
Guy King

Thanks David, Hamish and Guy for your comments - all passed on.

Reply to
Holly, in France

Guy King writes

Or short a battery across same and weld them.

Reply to
Oz

Maybe that's how I can fix my TV aerial? At the moment, because of poor reception, every few months I have to dismantle it and put Vaseline on all the joints, and there are dozens of joints. It's aluminium and it corrodes in the sea air. The galvanised screws holding it together don't help either, but I have been unable to get aluminium screws. So if I disconnect the balun and connect a car battery across the aerial, that might weld it all together?

Reply to
Nick

Nick writes

More likely melt bits all over the place.

Best would be to get a new aerial, assemble it, and then spray with several coats of a silicon conformal coating, then erect.

NB Best to wire up first and spray all the connections with a conformal coating.

NBB Eg for example search on rswww.com for part numbers 494-714 or 101-6343

Reply to
Oz

Buy a new one, assemble, paint it all in a non-metalic quality paint.

Replace standard aerial wire with a quality satellite receiver cable. Sat cable is rated to 2GHz, rather than around 900MHz and is less lossy. Made of more solid copper. Particullary if your channels are 50 upwards, i.e. at the higher TV frequencies. If you go to CPC you will get 100m for between 10 and 25 pounds according to what offers are on. Ensure there are no joints between Aerial and TV, one at wall socket if you must. No severe bends which kink the cable. Put sealant in the connector entry point at the aerial.

Reply to
Hamish

All good advice in cases of bad reception. But in my case the problem is solely corrosion between the aluminium joints, and I have excellent reception when I clean the joints and put vaseline on them. So I have no need to do all those other ideas. When there's corrosion, if it's raining, reception is OK, and when it's fine, one channel cuts out every few seconds.

I don't think paint would keep out the moisture. It would crack with the movement of the aerial in the wind. The joints are bolted inside plastic covers which leak.

The best solution would be to weld all the joints together, but the aerial is too big to bring down and put up in one piece, and a welder is too difficult to use on a 60 degree roof.

I will consider making some aluminium screws and use them instead of galvanised steel. I don't want to use aluminium rivets in case they don't work and need to be taken apart again.

Reply to
Nick

The message from "Hamish" contains these words:

Is it the right impedance?

Reply to
Guy King

Yes. It's all 75 ohm.

Reply to
Frank Erskine

Nick writes

Silicone conformal coatings are very flexible (if you get the right one).

If its just the connections at the box then you can simply repair (do NOT use vaseline) and spray over with the conformal coating (they are aerosols) in situ.

Note that there is a well-known corrosion problem with aluminium and copper. It may be better to have a short length of alternative material (eg silver or stainless) between copper and aluminium connections.

One could even fill the junction box with silicone sealant but:

1) Use a low modulus (soft) neutral cure (eg screwfix 56548). 2) Note that this WILL liberate moisture initially as part of the cure so you need to protect the connections with a paint until the water vapour dissipates. 3) Note that your problem is probably more to do with salt than water.
Reply to
Oz

The message from Nick contains these words:

Conformal Coating is sort of like paint but much more flexible. Failing that you could just pot the whole assembly in something rubbery.

Reply to
Guy King

The difference between the ordinary stuff and the satellite grades is around 10dB per 100 metres, plus extra losses on old cable. Your cable run isn't that long, but it's likely enough to be worthwhile on an old system.

Reply to
David G. Bell

You could try soldering with Al solder and flux.

I have found it REASONABLE to use. On thin sheet anyway.

If you can get a blowlamp up there it may work for you.

Google for carrs aluminium flux - I got mine from a model train place in Raynes Park..by post!

Reply to
The Natural Philosopher

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