Chafer mirage drive issue

[farmer phil]

Got a oldish (1999) Chafer Mirage that has suddenly lost its drive, the brakes wont come off, and the steps don't go up which I assume are linked to the brakes. All other hydraulic functions (steering, drive to sprayer pump, and boom functions) are working. Having spoken to my local sprayer company they suspect it is something to do with the coupling between the engine and the big hydraulic pump, apparently a nylon coupling they think. They can't come for 3 weeks, which is better to know rather than be waiting not knowing, and they've spoken to Chafer who are being a bit non-comittal. We've wound the brakes off manually so that we could retrieve back to the yard.
So my question is, does anyone have any ideas as to whether this diagnosis is correct or could it be something else, and does anyone have any exploded parts diagrams as I've got a guy coming wednesday who is very willing but not too sure what he is tackling. Some diagrams would be useful. I wondered if newer ones might be a similar design. It looks as though the hydraulic tank and/or the electric fuse box may have to come off first.
Many thanks in advance

 

[Mr Happy]

If the main hydrostatic pump has other hyd pumps piggybacked onto it and they operate the hydraulic functions as required. I doubt the problem is the coupling between the engine and the pump. On the other hand if those pumps are driven if another part of the engine engine then the diagnosis could be correct. Yes you do need a hydraulic schematic to under the circuit . You could try contacting Agrikel in Norfolk as they are or were a Chafer dealer.

 

[farmer phil]

yeah there is a pump on the end so that was my thoughts but i'm being led to believe that theres a shaft that goes all the way through. does sound a bit over complicated though to me. I'll try them tomorrow, thanks.

 

[Mr Happy]

Each hyd pump has its own drive shaft. On the rear the drive shaft if it's being used in a piggy back set up will be a spline. This allows you to connect another pump to it by using a spline coupling. I suspect that if all the hyd functions operate the problem is with main hydrostatic pump.

 

[Hjwise]

On the Cummins engine machines the steering, spray pump and booms come off a tandem pump mounted on the other end of the engine. Does it attempt to drive?

 

[farmer phil]

On the Cummins engine machines the steering, spray pump and booms come off a tandem pump mounted on the other end of the engine. Does it attempt to drive?

No it makes no attempt to move at all.

 

[Oliveau]

Could it be an electrical connection to the controls? Transmission pumps don’t usually just pack up.

 

[farmer phil]

Could it be an electrical connection to the controls? Transmission pumps don’t usually just pack up.

I did think this but we checked and they seem ok

 

[Oliveau]

I’m still thinking electrics. Back along in the last century (1980’s)! I had one of the three Ransomes CTV which was basically similar to the first Chafer SP machine. I never had transmission problems, (pump on the back of the engine) except for oil getting hot on long road journeys. But I did have hydraulic problems (belt driven pump off the front of the engine). Sometimes the boom hydraulics would play up which an auto electrician eventually traced to a bad earth.

Do your brakes come on automatically when the engine stops - ie no hydraulic pressure - with a switch to apply the brakes when the engine is still running? I assume that the steps go down when the brake is on and vice-versa? Can you get at the transmission pump to slacken off a pipe to see if it’s actually pumping?

 

[farmer phil]

I’m still thinking electrics. Back along in the last century (1980’s)! I had one of the three Ransomes CTV which was basically similar to the Chafer machine. I never had transmission problems, (pump on the back of the engine) except for oil getting hot on long road journeys. But I did have hydraulic problems (belt driven pump off the front of the engine). Sometimes the boom hydraulics would play up which an auto electrician eventually traced to a bad earth.

Do your brakes come on automatically when the engine stops - ie no hydraulic pressure - with a switch to apply the brakes when the engine is still running? I assume that the steps go down when the brake is on and vice-versa? Can you get at the transmission pump to slacken off a pipe to see if it’s actually pumping?

We’ve managed to get the charge pump off having checked umpteen other things first and have discovered the small drive shaft driving it from the transmission pump is sheared, probably caused by the bearing going in the end plate of the charge pump. Thanks to all for your suggestions

 

[Oliveau]

If the main hydrostatic pump has other hyd pumps piggybacked onto it and they operate the hydraulic functions as required. I doubt the problem is the coupling between the engine and the pump. On the other hand if those pumps are driven if another part of the engine engine then the diagnosis could be correct. Yes you do need a hydraulic schematic to under the circuit . You could try contacting Agrikel in Norfolk as they are or were a Chafer dealer.

 

[Oliveau]

I'm glad youv'e got to the bottom of it. Hopefully the repair will be quick and not TOO expensive. Perhaps a recon pump?

 

[Adeptandy]

Great info, thanks for sharing.

 

[Chae1]

I once thought I saw a mirage in a field near here. I was mistaken.