MF 4255 4 Wheel Drive

dp639

Hi all,

Got an issue with a MF 4255. Can anyone shed any light on the 4WD engagement on braking as I think this is the crux of the issue.

4WD works fine, using the switch, on and off works as you would expect.

Every so often I get a loud banging sound from underneath as if something is just not engaged correctly. It is only in forward - never in reverse. If you go around in a circle the noise does not happen.

Usually happens after leaving the yard, so I'm guessing, I reverse out, brake (and the 4WD doesn't engage fully/correctly), then I put it in forward and take off and there comes the noise.

Doesn't happen all the time and now I try to avoid braking unnecessarily which seems to be helping.

Any ideas or similar experiences?

Thanks

blue5000

I’m not an expert but I suspect wear in the front differential or trunion pin. Can you lift the front end off the ground and see how much play there is in the front axle?

what hours are on it?

Cavanjack

when you brake 4wd engages automatically so you have 4 wheels braking (safety feature). When you drive forward and the wheels are turned the banging noise is the 4wd disengaging. If you drive off with the wheels straight you don’t hear the banging.

I had a Massey mechanic in the yard one day and that is more or less how he explained it. The short version anyway.

He also said you can fit a switch for when you are around the yard to stop 4wd coming on when braking.

dp639

Thanks blue5000 - not sure on hours will check later.

Cavanjack - what you say is how I thought it worked and it makes sense - always better to have wheels straight when switching on/off 4WD but the banging can still happen when continuing to drive in a straight line which indicates something is possibly wrong.

hopeso

https://www.boards.ie/discussion/comment/119520604#Comment_119520604

That switch would be very handy around a yard alright. It would probably be better for the tractor too if 4wd wasn't constantly switching on and off on hard surfaces. I saw it explained how to fit that switch once, but I forget how it's done now.

Gillespy

8340 NH here came with it. Looks factory. Great feature. It's nice to have 4wd braking available when needed. Just need to get into the habit of turning it on and off as required.

dp639

https://www.boards.ie/discussion/comment/119520125#Comment_119520125

just 3113 hours on it.

FintanMcluskey

What levels of grip are left on your tyres?

If your front tyres are further down than the rear tyres that may be an issue.

dar31

check the 4wd shaft running from the from to the rear of the tractor.

the splines on one of the shafts are more than likely wore out, it takes a bit of time but handy enough to drop down the shafts.

this is usually cause when the housing/feral on the main axel housing becomes wore out causing the axel to move ever so slightly.

have done it a few times on our 4245.

satstheway

Check that the handbrake switch is OK. It also makes it engage 4×4 and if it's a bit worn it can cause it to jump in and out (took me a while to figure it out). Our 4370 has quite a bang when disengaging on a hard surface.

dp639

https://www.boards.ie/discussion/comment/119536526#Comment_119536526

Thanks for that!

dp639

https://www.boards.ie/discussion/comment/119536560#Comment_119536560

I'll maybe not use the handbrake (safely) for a while and see does the issue still happen - thanks alot!

somofagun

I have a 4345 and it is doing the same, seems to be alot of play in the front axle where to crown pinion is. I expect its going to be an expensive fix.

dp639

https://www.boards.ie/discussion/comment/119552513#Comment_119552513

Here's an update.

Up until now I was convinced the foot brake was to blame and recently I avoided using the foot brake as much as possible. This made no difference.

When applying the foot brake to slow down say at a junction I hear the bang once and then it doesn't continue when you lift of the brake - so as above there could be play in the front axle but at least it is engaging 4WD and disengaging when it is supposed too.

Then I thought about the handbrake as it also engages the 4WD - yesterday evening I was bringing in the bales (about 3 hours of work) and didn't use the handbrake and the issue did not happen at all. I'm going to investigate the switch on the handbrake - maybe something as simple as a faulty switch or debris getting caught in it - as the switch has a plunger on it.

satstheway

I put a cable tie on the plate the plunger touches so it added a mil to it. That helped alot. If my handbrake was not seated down tight the banging would go on when travelling as the switch contacts opened and closed.

Of course a new switch will be needed soon