JD TLS Problem

[flyonthewall]

Our farm's 6420s tends to sit high on the front overnight and the cab sits down if a trailer is left on it. Otherwise seems to stay level. We bought our unit secondhand and a former owner/driver decided to let the gas out of the cab accumulators in his wisdom, so we got the jd dealer to recharge these and the TLS ones which were a little low. Including checking the gas pressure in the a/c the bill inc VAT was less than £200 which being used to the rip off merchants that are AGCO via M/F I was very pleased with. Occasionally if you hit a big bump the cab suspension would go into fault mode and turn itself off, since the recharge we haven't had the problem so guessing checking the gas pressure is an annual/1200hr service job. Worth keeping up together as you won't better it for ride comfort!

 

[jd-baz]

What pressure do you recommend @NZ Tech for the accumulators on a 7810?
Suspension has stopped working on mine and a friends 7810 also,both similar symptoms,rams about half way but don't seem to be moving,he was told by dealer that one of his accumulators may be gone,so we were thinking of getting all of them checked,or what would you suggest?

 

[NZ Tech]

7810

At 20 degrees 1 litre size accumulators(printed on the accum) 1160psi

20 degrees 2 litre accumulator 406psi.

 

[SteveO]

One short question, my mechanic told me that he should remove accumulators and then check the pressure. Is that necessary ? I know that I can remove pressure from the system on those valves behind the radiator but he says that he cannot check them if they have small leak on the bladder, the pressure then goes on the other side, in oil housing or wherever.

 

[Lofty]

Just to update this subject. 6420 went to dealers a few weeks ago to have the accumulator pressures checked and calibrated. It all checked out OK and calibrated fine.
Still got the creaping up problem along with another thats been driving me nuts of late. Been hedge cutting for the past couple of days and 90% of the time the suspension is pumping itself up and down repeatedly. It pumps up approx 50mm then 10 seconds latter it lets itself down. 10 seconds latter it goes up again. I can hear the hydraulics pump it up and back down again. Does this mean the level sensor is faulty and if so, is it possible to change it without calibrating it again?

 

[Rusty#1]

Just to update this subject. 6420 went to dealers a few weeks ago to have the accumulator pressures checked and calibrated. It all checked out OK and calibrated fine.
Still got the creaping up problem along with another thats been driving me nuts of late. Been hedge cutting for the past couple of days and 90% of the time the suspension is pumping itself up and down repeatedly. It pumps up approx 50mm then 10 seconds latter it lets itself down. 10 seconds latter it goes up again. I can hear the hydraulics pump it up and back down again. Does this mean the level sensor is faulty and if so, is it possible to change it without calibrating it again?

Id be going for level sensor next, I think you'll need to calibrate it after, I calibrated my 7710 after fitting a new sensor through the dash just stick the cal fuse in and go through the sequence @nztech pointed me in the right direction

 

[manttys]

Just bought a 6920 and tls is not working: once tractor started, it rises slowly and then lowers again to the very bottom. No lights on the dash to gen an error code. Anyone have had a problem like mine?

 

[SteveO]

Try to calibrate it and also replace position sensor fromother tractor.
My 6520 has done the same but it did show TLS light. It was damn TLS block under the radiator, 1200€ excl. VAT.

 

[manttys]

TLS and cab lights do not turn on check-up, so they might just be burnt out. Have few same tractors in the yard and will try to swap sensor. Not fancy the idea to replace whole block

 

[SteveO]

Yes if no bulbs then probably burned. I have searched for used block at like 30 locations in whole Europe, nobody has it. Or they offer it from burned tractor on 1 location for 800€ so I went for new one.

On mine one small steel ball came out and I have opened it and could not locate where did it came from. All other valves are ok.
I'll sell it to you used for 500€

 

[manttys]

hope it is something cheaper Did not think to shut the engine down on the top point and see if it drops. Then all valves should be closed and could leak only mechanically

 

[Tractortech]

hope it is something cheaper Did not think to shut the engine down on the top point and see if it drops. Then all valves should be closed and could leak only mechanically

The logic built into the controller is that at start up the axle will find its centre position then stop there, valves will be closed. You could load it, it will sink under load but not react. It would only react when it detects motion above 1.5 Kmh,,,, ish

 

[manttys]

The logic built into the controller is that at start up the axle will find its centre position then stop there, valves will be closed. You could load it, it will sink under load but not react. It would only react when it detects motion above 1.5 Kmh,,,, ish

I can reach tractor only on weekends right now, so can't test how high it reaches. If stops in the middle, then it makes sense it does see a middle position and stops at it, but due to physical failure it leaks somewhere. However, if it goes up to the full extend and then lowers to fully in, then it could possibly be looking for a middle position but eventually could not get it due to sensor failure. Does it make sense?

 

[Matthew Britton]

Just to update this subject. 6420 went to dealers a few weeks ago to have the accumulator pressures checked and calibrated. It all checked out OK and calibrated fine.
Still got the creaping up problem along with another thats been driving me nuts of late. Been hedge cutting for the past couple of days and 90% of the time the suspension is pumping itself up and down repeatedly. It pumps up approx 50mm then 10 seconds latter it lets itself down. 10 seconds latter it goes up again. I can hear the hydraulics pump it up and back down again. Does this mean the level sensor is faulty and if so, is it possible to change it without calibrating it again?

My 6920s does this and I have been told it’s probably where the brakes went with the previous owner and a bit of crap has damaged the valve. It’s a pita sometimes!

 

[Tractortech]

If it goes right to the top and back down, then possibly the sensor is faulty. They're not fantastic to change so fit a new one rather than swap from another tractor. I assume the sensor link is still attached to the panhard rod??
As mentioned, brake failure can send filings around the system which can cause valves to stick..
Look in the SFA controller for stored error codes, delete, test drive then look again..

 

[manttys]

Seller indicated that brakes changed 500 ago, maybe there was a reason for this.

I will check the rams for internal leakage first. Reviewed one of my videos that I made before and it seems that it is struggling to raise and then goes down again. Don't think it has even reached the middle point.

 

[Tractortech]

If you tried a calibration or bleed procedure from Tech manual / Service Advisor, you would see the full range of travel and hopefully pinpoint any problem.
Take care if you're disconnecting any oil lines, there are 3 accumulators attached to the cylinders. I've never seen them leak internally..
If there's debris inside the TLS valve and the valve is stuck open it will struggle to raise. It will only try to centre for so long before timing out. More revs at start up might help. The TLS valve is very susceptible to brake contamination..
Did you look for error codes??

 

[manttys]

The initial problem was excessive smoke and rough engine work, since new injector it did not help, we went for a replacement pump and it worked a treat. During the procedure, I have cleared all codes and no active light ever came on. But have not checked if there were new codes stored after the that. But usually, you get a yellow light when something is wrong with the suspension. Hopefully, next week a technician is coming for another tractor which is ejecting the reverse lever and will help with the calibration on this one