MF6840 Error Code T151 - one for the MF experts!

[jd6820]

Hi,

I'm usually repairing the green brand of tractors so my experience of these Masseys is limited. I was helping a mate out this weekend who has an MF6840 Dyna-6 with a perkins engine. I noticed whilst driving the tractor it was flashing the brake pressure symbol and error code T151 was present. I questioned him to see if he'd seen the code before, he said that mechanics from an MF dealership had been out to the tractor and tried to solve the problem and had been unsucessful and spent plenty on parts! So my aim is to solve it once and for all. I've a tech manual for the tractor and have read up on how the system operates and cannot really understand why they replaced the following if the fault isn't with these components, especially as it is stuff they could test!

New pressure sensor, could have done a resistance check rather than replace?

HP brake block itself, unsure whether this would include the relief valve or accumulator or internal suction screen

New brake switches - if they checked continuity they could have isolated these parts.

The code relates to: Sudden drop in HP braking pressure (pressure measured by sensor less than 78bar) with no braking.

This to me suggests either a bad connection between sensor signal pin and Transmission control unit 1 (pin 35) or more likely a dodgy accumulator not storing charge and therefore pressure is dropped quickly after being initialised?

Could anyone advise me as to whether I'm on the right tracks or any past experiences of the same problem would be great!

Thanks in advance,
jd6820

 

[davedb]

take it the pressure switch has be T into and a gauge put on it? to see if its up to spec

 

[jd6820]

Yeah, that was my plan so I can monitor pressure and eliminate mechanical faults, I suppose then just leaving the electrical side to discover, I must admit the wiring diagrams I have show all but the HP braking system, so I can't see which wires on the sensor reach which controller and what connectors they pass through, I don't suppose anyone has this much needed information. Thank you for the input so far.

jd6820

 

[Roy Stokes]

Best of luck, our local Massey dealership also cannot get rid of error codes on the tractors he sells, in 2 cases he has offered exceptional deals, took away offending tractors and replaced with something that is working correctly and lost the ones he cannot fix to the trade, what a state to be in when you cannot fix the brand you sell

 

[davedb]

im by no meens an expert but owning a 3000 series MF gets you some electrical fault finding experience haha, wouldnt know where to start on a 6480 tho id say your on the right track, sort the easy bits first the mechanics then its wire testing time, every 6480 ive been on has a fault code or another no one seems to be able to sort them, as @Roy Stokes says its a bit bad when all the dealer does it swap bits and hasent a clue how to find the real fault

 

[jack6480]

Mine does this using a square baler, pto cuts out trying to start the baler up first time which gives you t151 and brake pressure light comes in the afternoon I think when it gets warm, but only when using hydraulic brakes. Dealer said keep going.

 

[Roy Stokes]

I actually think the 64/74 series Massey have good basic reliability, however they let themselves right down with cab suspension that is knackered within 3000 hours, poor design of drawbar storage, crap battery box siting, crap linkage stabilisers, poor pickup hitch visibility, vunerable valve chest siting on front axle, incompatable spool QR couplings, I could go on all night, but the electronics are terrible, we recently had a 7626 for a couple of weeks and the set up for headland/engine management was still a mix of lefthand dot matrix and data 3 screen, has no one at Massey thought to put it all in one place, and as for adding oil to the rear end................................................. FFS

 

[James]

I actually think the 64/74 series Massey have good basic reliability, however they let themselves right down with cab suspension that is knackered within 3000 hours, poor design of drawbar storage, crap battery box siting, crap linkage stabilisers, poor pickup hitch visibility, vunerable valve chest siting on front axle, incompatable spool QR couplings, I could go on all night, but the electronics are terrible, we recently had a 7626 for a couple of weeks and the set up for headland/engine management was still a mix of lefthand dot matrix and data 3 screen, has no one at Massey thought to put it all in one place, and as for adding oil to the rear end................................................. FFS

have a 6480 here and pretty much on the nose every 1200hrs the front cab mounts need replacing, the linkage stabilisers I like cause at least you can get them tight unlike auto ones, can see puh fine only had one issue with front axle valve chest but that was my own fault
don't get me wrong I like the tractor

 

[Roy Stokes]

have a 6480 here and pretty much on the nose every 1200hrs the front cab mounts need replacing, the linkage stabilisers I like cause at least you can get them tight unlike auto ones, can see puh fine only had one issue with front axle valve chest but that was my own fault
don't get me wrong I like the tractor

Try the long wheel base 6485/90/95/99 for hitch visibility, the cab suspension is also worse on those, compressors are a joke, and the hitch stabilisers do not hold arms in position when hitching up, also as they wear the left one winds it's self loose during operation, ..........................what a pile of crap, take a look at Fendt to see how stabilisers should work

 

[NZ Tech]

Hi,

I'm usually repairing the green brand of tractors so my experience of these Masseys is limited. I was helping a mate out this weekend who has an MF6840 Dyna-6 with a perkins engine. I noticed whilst driving the tractor it was flashing the brake pressure symbol and error code T151 was present. I questioned him to see if he'd seen the code before, he said that mechanics from an MF dealership had been out to the tractor and tried to solve the problem and had been unsucessful and spent plenty on parts! So my aim is to solve it once and for all. I've a tech manual for the tractor and have read up on how the system operates and cannot really understand why they replaced the following if the fault isn't with these components, especially as it is stuff they could test!

New pressure sensor, could have done a resistance check rather than replace?

HP brake block itself, unsure whether this would include the relief valve or accumulator or internal suction screen

New brake switches - if they checked continuity they could have isolated these parts.

The code relates to: Sudden drop in HP braking pressure (pressure measured by sensor less than 78bar) with no braking.

This to me suggests either a bad connection between sensor signal pin and Transmission control unit 1 (pin 35) or more likely a dodgy accumulator not storing charge and therefore pressure is dropped quickly after being initialised?

Could anyone advise me as to whether I'm on the right tracks or any past experiences of the same problem would be great!

Thanks in advance,
jd6820

Hi ya, i have no idea about MF issues... But might be able to help... Ive seen a lot of wiring issues with interference across the harness. The harness gets water down it and it stews over X period and then the interference from a high load wire or two(fuel pump, something that draws a few amps as an example).

With that in mind, Repinning the plug at the sensor and running new high quality wires to the controller will eliminate the interference in the harness and any plug issues.

Also using the wires to power up a light will test the wire integrity, if they are causing an issue they will power the light up... And then the light will soon show any failings. The higher current draw from the light will make the suspect wires fail. Proving the wires are crap.

Maybe this will help.

 

[Will Blackburn]

I had T151 come up temporarily yesterday when bringing a trailer down hill pushing it to 60k, maybe it is detecting overspeed all the time due to a setting or sensor?

 

[NZ Tech]

I had T151 come up temporarily yesterday when bringing a trailer down hill pushing it to 60k, maybe it is detecting overspeed all the time due to a setting or sensor?

It seems to be a pressure sensor not wheel speed sensor.. These are completely different how they work. It maybe be a power surge when braking that is causing it.... guess we'll see how this thread ends.

 

[Will Blackburn]

It seems to be a pressure sensor not wheel speed sensor.. These are completely different how they work. It maybe be a power surge when braking that is causing it.... guess we'll see how this thread ends.

I didn't use the brakes, this is on a later tractor so may have limited relevance.

 

[jd6820]

Some great replies! I'll keep everyone posted on what happens.

 

[NZ Tech]

Some great replies! I'll keep everyone posted on what happens.

Sweet

 

[nickirl]

Some great replies! I'll keep everyone posted on what happens.

This mite be of use to you

If its not clear enough drop me a pm

 

[saly123]

I actually think the 64/74 series Massey have good basic reliability, however they let themselves right down with cab suspension that is knackered within 3000 hours, poor design of drawbar storage, crap battery box siting, crap linkage stabilisers, poor pickup hitch visibility, vunerable valve chest siting on front axle, incompatable spool QR couplings, I could go on all night, but the electronics are terrible, we recently had a 7626 for a couple of weeks and the set up for headland/engine management was still a mix of lefthand dot matrix and data 3 screen, has no one at Massey thought to put it all in one place, and as for adding oil to the rear end................................................. FFS

Any good points then...??

 

[beaconsboy]

Please let us know how you get on. I have the same problem with our 6490. But I have noticed that the hydraulic trailer brakes have gone very sharp. The trailers are locking up all the time. Never had that before.

 

[NZ Tech]

Dam.. I cant make heads or tails of that schematic...

 

[Roy Stokes]

Any good points then...??

Yes, engine and gearbox seem to be reliable, just all the bits Massey add to it seem to be crap