MF 7495 Parkbrake stuck

[OrkAhaN]

Hello!

As the text above reads, I have a problem with my handbrake. When the tractor has been running for a while and the oil has become hot, if you then switch off the tractor or apply the parking brake then it locks and you have to wait until the tractor has cooled down to be able to move it. We have changed parts for several 100 Euros at our MF workshop but without success.

As you can see in the picture below, we have a magnet that "tricks" the tractor so that it does not think the handbrake is on, this sometimes works and sometimes does not. This is above the rear right.

I now turn to you as we completely lack ideas on how to solve this.

Found this forum and could then get help with why it leaks oil as in a jet under the brake pedals when the tractor is running and you brake (see picture below). There were threads that the main brake cylinder usually cracks. So we'll look into it when the time comes. Or if there is any other sugestion what it can be?

As you will probably notice, English is not my mother tongue but I really hope to be able to get help with this.
/Swedish farmer

 

[davedb]

The oil leak will be the master cylinders caused by the accumulator under the cab going flat replace that along with the master cylinders

not come across your other problem but @Spud @davidroberts30 May have

 

[davidroberts30]

The oil leak will be the master cylinders caused by the accumulator under the cab going flat replace that along with the master cylinders

not come across your other problem but @Spud @davidroberts30 May have

I've got the manual lever

 

[davidroberts30]

And yes you need a new master cylinder

 

[davidroberts30]

Check your emergency power loss Breaks by being in a safe area and switch the engine off and see if you have brake pedal to stop the tractor
The nine bar accumulator under the cab has probably gone causing the master cylinder to crack

 

[OrkAhaN]

Thanks for the reply. We're gonna change the master cylinder and accumulator after the work on the fields are done, new master cost 1200€ at our MF workshop so we are looking around if there is anyway else to get one.

But it's the parkingbrake that is the big problem right now, if you start the tractor you cant turn it off until it's time to end the day. So that's alot of time just standing still running unfortunely. But it dosent seem to be a regular problem, our deeler had not done any job like this before.

 

[cows sh#t me to tears]

And yes you need a new master cylinder

And a new accumulator.

 

[Spud]

The little arm with the red magnet on is adjustable - makes sure all is clean in that area, and there is nothing stopping the handbrake cable fully retracting, or stopping the arm moving. it wont need adjusting far. That will allow the handbrake light to go off and progress to continue.

Don't be long changing the brake accumulator

 

[davidroberts30]

Thanks for the reply. We're gonna change the master cylinder and accumulator after the work on the fields are done, new master cost 1200€ at our MF workshop so we are looking around if there is anyway else to get one.

But it's the parkingbrake that is the big problem right now, if you start the tractor you cant turn it off until it's time to end the day. So that's alot of time just standing still running unfortunely. But it dosent seem to be a regular problem, our deeler had not done any job like this before.

Just a thought, have you ever adjusted the rear brakes ?

 

[Southmec32]

Can you grab the arm with the magnet and pull it back. If the actuator is siezed it will not let handbrake light off.

 

[OrkAhaN]

Now we are done with the field work and have now changed the main brake cylinder and also the accumulator (our local workshop did not think it was needed but we went on the forum experience instead).
No leakage and the brake works better than before, so THANK you!


I have tried to move the arm by the magnet but it is stuck, probably because we have had it like this for a few years. But the lamp goes out because of our magnet, so I guess there is something else that keeps it from releasing the parking brake. The strange thing is that it is only when the tractor is hot and it is hot outside (about 20+ degrees). Otherwise it releases as it should as long as we have the magnet there.

No one has fallen over any case of this or heard any solution?

 

[OrkAhaN]

Here is an update and maybe a way forward, we have now had time to look at it a little more and disassembled a little more parts. We have now made it work like this:

When we apply the parking brake and then push both brake pedals to the bottom, it goes out, and seems to work even when it is hot. (however, have not had time to test in the field after heavy load on the gearbox)
But here comes the strange thing, if we press a foot pedal then everything locks, the handbrake does not go out, even if we return to doing it in the way that works. The only solution when this happens is to turn off the tractor and then start again, then it works again as before.

 

[John.mcnally]

I have a MF7618 dyna vt that’s keeping the handbrake light on. I tried adjusting the magnet to no avail and I cleaned as best I could around the linkages but still no joy. Would it be the handbrake sensor in this case like my magnet and sensor aren’t lining up fully even at full adjustment but I’ve a vicegrips on the linkage moving it back and forth and it only goes so far in either position. I was drawing in bales with her she was grand all day till I got out and pulled the handbrake now it won’t go out.
appreciate if anyone has any ideas

 

[John.mcnally]

I have a MF7618 dyna vt that’s keeping the handbrake light on. I tried adjusting the magnet to no avail and I cleaned as best I could around the linkages but still no joy. Would it be the handbrake sensor in this case like my magnet and sensor aren’t lining up fully even at full adjustment but I’ve a vicegrips on the linkage moving it back and forth and it only goes so far in either position. I was drawing in bales with her she was grand all day till I got out and pulled the handbrake now it won’t go out.
appreciate if anyone has any idea

Also she’s not really holding air pressure either but I can’t see faulty airlines there is an air sound from under her but I think it’s coming from the shaft driving the gearbox from the engine

 

[Spud]

Give it a proper wash if you can. Is there anything stopping the hand brake mechanism releasing on either side? They're a bit vulnerable to collecting crud, if the magnet won't line up at max adjustment it sounds like the brake isn't releasing fully. Don't get run over!

 

[davidroberts30]

Have u ever manually adjusted the brakes?
What hours is it on?

 

[John.mcnally]

She’s on 11k hours was fine until I pulled the handbrake then just wouldn’t release I tried to power wash out the area each side it’s still going to the same point

 

[davidroberts30]

Also she’s not really holding air pressure either but I can’t see faulty airlines there is an air sound from under her but I think it’s coming from the shaft driving the gearbox from the engine

the air lines wont be in that area

 

[John.mcnally]

It was the parking brake sensor on end plugged out the old one plugged in the new one no problems

 

[davidroberts30]

It was the parking brake sensor on end plugged out the old one plugged in the new one no problems

Tidy, have you ever adjusted the rear brakes?