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7740 oil leak

wdah/him

Member
Location
tyrone
I have an oil leak on the right hand side of the 7740 in behind the diesel tank it seems, I thought it was from around the area where the loom goes into the housing but it only leaks when the tractor is running, so surely not it, and when I replaced that loom I sealed the rubber in with silicone.

It seems to be more form the rear housing and running down the back of the fuel tank bracket. the tractor is used everyday nd I would like a rough idea if there is any common things on that side that could be loose or gaskets etc before taking the tank off. for a look and it being out of service for a few days.
 

wdah/him

Member
Location
tyrone
no that side is the left below the gearstick, this is the otherside leaks, tractor is sle and 1997. it is the side u get in at most often and seems to have very little on it, possibly leaking from the top?
 

Nearly

Member
Location
North of York
Is it the rubber grommet that the pto wires go into the back end through? The rubber goes hard and cracks then oil leaks out as it sloshes around inside.
New pair of wires and grommet are about £30. You need to remove tank and round plate in side of back end to disconnect little multi plug.
s-l500.jpg

Need new gasket and sealant to refit.
Just an idea.
 
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agrimax

Member
Location
Co Down
Think there's a left and right confusion here......
Sitting in the seat looking forward, isn't the bottom fuel tank on the left and the hydraulic pump and 3 filters on the right,also on the gear lever side?
There's a good chance the oil is leaking between the top hydraulic lid and diff housing or from o rings below the lift solenoids.
 

wdah/him

Member
Location
tyrone
Sounds like it could be the pto oil feed pipes to me.


is that the steel pipe running behind the tank?

yes tractor has to be going for oil to leak.

it had a habit of the lefthand half axle coming loose but sorted with nordlock washers.


@agrimax where are these located seem to be a possibility, leaks if tractor setting ticking over so not sure on sloshing around. would the cab floor out help for a look
 

agrimax

Member
Location
Co Down
Been a while since having a 40 series,but isn't that steel pipe for the dipstick?
Depending on the model,whether you have electric hyds(EDC) and/or an open or closed centre system,the solenoids can either be in front of the cross shaft,mounted directly onto the lift cover or else to the right hand side of the cover,above the trailer brake valve.(If to the right,obviously not them if your leak is on the left!) If they aren't on the top,there will be an unloader valve block there instead which will still have o rings below it.This is directly below the seat.You may need to raise the rear of the cab if you do find there is a leak there.
I'd suggest taking the left wheel off and the tank straps.You should then be able to pull the tank out enough to see in from behind,without actually removing it.
My 8240 had oil leaking behind the tank also.It was from the lift cover gasket. Cab had to be raised 2 inches to get the cover up and out.If you do need to go there,watch the windscreen as you tilt the cab.
IIRC,if you take the floor rubber out,there is a small cover comes off that should let you see in to the front of the lift cover.At the back of the floor to the front of the seat,iykwim!
 
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agrimax

Member
Location
Co Down
Don't think it's any benefit with the floor out on the 40 series,but you need the rubber out anyway to get the smaller inspection panel off.Unless the leak is further forward and coming from the gearbox top lid?Don't think it would be behind the fuel tank then though.......
 

wdah/him

Member
Location
tyrone
had that panel out before joining the shuttle up again, and as u say I think it mostly is gearbox only. will lift it out and look for any wet bits, there
 

wdah/him

Member
Location
tyrone
have the side washed and floor pan out only thing I see is the grommit for the pto but seems clean when i feel below it, is there anything else about there.

if I remove the tank and join the two pipes up will the tractor still be fit to run and be used, want the leak fixed and see one of the tank straps has rotted away.
 

agrimax

Member
Location
Co Down
A lot of hassle joining the big inlet pipe to the smaller inlet pipe and don't forget about the return line that would need linked to the front tank. Would be handier tying a 20l drum on to the bonnet and gravity feed the sediment bowl.Don't forget the return line needs to run into a drum as well. All only temporary to run the engine to see if you can pinpoint the leak.Would gave thought with the wheel off and the tank slid out a bit from the rear,you should be able see enough?
 

wdah/him

Member
Location
tyrone
sounds like a lot of hassle, might just do with the leak for another while to cattle is out and less for it to do. time is short here.

thanks
 

Jato

Member
Take tank off, bung off the top pipe as this is only the vent pipe letting air from out of bottom tank when filling.
Put pick up pipe in a drum and then run it.
That way you can see everything on LH side.

Try engaging and disengaging PTO as there was an issue where when PTO disengaged oil squirts out of the PTO pack directly at the grommet where wires feed causing the leak.

There was a modification to stop the oil squirting at the grommet, but can't remember exactly what it was.
 

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