5400 brake issue

[Brokenheart]

My brother has a JD 5400 with around 4000 hours and the brake pedals goes to the floor. We tried bleeding them and can get good pedal but it doesn稚 last.
Any help would be appreciated

 

[sixdogs]

Do you notice a difference in the pedal from when the tractor is hot compared with cold? I ask because my pedal suddenly went to the floor but only when the tractor was hot. Turned out to be a very slightly stuck remote lever. We solved it by used a laser thermometer on the rear axle and checking the temps. They were getting way hotter than expected and it was the remote lever. I never expected that was the problem.

 

[Brokenheart]

Do you notice a difference in the pedal from when the tractor is hot compared with cold? I ask because my pedal suddenly went to the floor but only when the tractor was hot. Turned out to be a very slightly stuck remote lever. We solved it by used a laser thermometer on the rear axle and checking the temps. They were getting way hotter than expected and it was the remote lever. I never expected that was the problem.

It doesn稚 matter if the tractor is warm or cold. The pedal goes to the floor. While bleeding the brakes you can get good pedal but within a couple of minutes it goes back to the floor.

 

[sixdogs]

I do not know that answer. Maybe call a Deere service shop and ask if they can point you in a direction? That's worked for me over the years.

 

[Zebrafive]

I would start by capping the brake lines. If the pedals still do not hold the brake valve needs to be rebuilt.
If they do hold, then I suspect the O-ring(s) on the brake operating piston(s) (one each side) inside the rear axle have failed.

Try capping each side separately and test, it might be only one side (left/right) bad.

 

[jd110]

Do the pedals go to floor if they are both pushed together or separately? If only separately, the pedal stop screws may need adjustment.

 

[1astronautfarmer]

I agree with jd110. My 2350 was doing the same thing. If I push the pedal down slowly it would always go "to the floor". If I quickly pumped it once or twice it would hold pressure.
My pedal return stops were out of adjustment.