JD 5520 brake loss after hard use. Any ideas?

[sixdogs]

My 5520 brake pedal goes to the floor after the tractor really gets used hard and is good and hot. After it cools down a bit, the brakes are back.

It happened twice. Once on a 20 mile road trip and last night after chisel plowing a few acres. I checked the owner's manual but it only tells you to step on the pedal to stop the tractor. No more. The brakes are hydraulic wet disc, whatever that means and I have no idea where to look or what to do.

Any ideas or could someone point me in a direction? Thanks.

 

[Tx Jim]

I've never seen or heard of brakes on a JD act as you describe. Does brake pedal fade occur when both brake pedals are applied together? You could try bleeding the brakes which process is very similar to automobile. Bleeders are on top of axle housings.

 

[Gator6x4]

My 5520 brake pedal goes to the floor after the tractor really gets used hard and is good and hot. After it cools down a bit, the brakes are back.

It happened twice. Once on a 20 mile road trip and last night after chisel plowing a few acres. I checked the owner's manual but it only tells you to step on the pedal to stop the tractor. No more. The brakes are hydraulic wet disc, whatever that means and I have no idea where to look or what to do.

Any ideas or could someone point me in a direction? Thanks.

Twenty mile road trip??? Tire replacement will soon be another discussion topic. All that aside you aren't using the brake pedal for a foot rest are you? That could cause the brakes to heat up. Also where is the brake master cylinder located? is it in a area that is exposed to heat being generated by the engine or driveline when in use? The fluid in the master cylinder could be being heated causing your problem. Find the brake fluid reservoir and check the temperature of the contents when the problems occurs.

 

[Kyle_in_Tex]

wet disk means they are bathed in oil. This seems a strange problem because during 20 mile trip, you shouldn't be having to use the brakes that much.

 

[sixdogs]

I've never seen or heard of brakes on a JD act as you describe. Does brake pedal fade occur when both brake pedals are applied together? You could try bleeding the brakes which process is very similar to automobile. Bleeders are on top of axle housings.

Do they have bleeders if in oil? Brakes locked together and tractor was really hot both times. When cooler, no problem and brakes are back.

wet disk means they are bathed in oil. This seems a strange problem because during 20 mile trip, you shouldn't be having to use the brakes that much.

Haven't used the brakes hardly ever. Only discovered extent of issue when I was loading on trailer last night and almost didn't stop.

 

[sixdogs]

Twenty mile road trip??? Tire replacement will soon be another discussion topic. All that aside you aren't using the brake pedal for a foot rest are you? That could cause the brakes to heat up. Also where is the brake master cylinder located? is it in a area that is exposed to heat being generated by the engine or driveline when in use? The fluid in the master cylinder could be being heated causing your problem. Find the brake fluid reservoir and check the temperature of the contents when the problems occurs.

No on the foot on the pedal. I'm a textbook operator with few bad habits.

The road trip was to pick up a piece of equipment I bought at auction only to learn they did not have a loader tractor available. I have radials so they will wear out a very long time after I do. I have maybe 60 road miles on them and they look 100.00%.

 

[Tx Jim]

Brake bleeder is parts key #4

 

[sixdogs]

Brake bleeder is parts key #4

Impressive that you found that. Thank you.

 

[Tx Jim]

Impressive that you found that. Thank you.

It was easy to locate as the bleeder is in the same location as JD 1020/2020 & later utility tractors plus I was employed by a JD dealer for over 21 years working in parts dept selling parts a portion of the 21 years. FYI radial tires do wear out from traveling on blacktop highways. I've driven my tractors many miles on blacktops since I've been in the custom hay baling business since '87. Different tire tread designs/brands wear better/worse than others. The best wearing tire I've ever owned is a Continental radial long bar/long bar.

 

[sixdogs]

It was easy to locate as the bleeder is in the same location as JD 1020/2020 & later utility tractors plus I was employed by a JD dealer for over 21 years working in parts dept selling parts a portion of the 21 years. FYI radial tires do wear out from traveling on blacktop highways. I've driven my tractors many miles on blacktops since I've been in the custom hay baling business since '87. Different tire tread designs/brands wear better/worse than others. The best wearing tire I've ever owned is a Continental radial long bar/long bar.

I've got Firestones and love them. Great pulling power and they allow me to go over soft areas without much of a mark. I have seen those Continental ties and they do look pretty good--and expensive. While I am rarely on blacktop, guys around here have farmland scattered everywhere and seem to always be on the road. Radials do wear but around here they sure seem last a long time. In fact, it is rare to see a bias tire except on smaller equipment.

On the brake thing, there is also a hydraulic valve that has something to do with it. I called a large Deere dealer around here and he could not find a brake issue like this that had happened before. He was at a loss to explain.

If I were to bleed them would that mean you think air in the line might be an issue?

My plan is to go to a Deere dealer next week and take a look at a shop manual to try to narrow things down and if I can't figure it out let the dealer try. What do you think of that idea?

 

[JD5210]

When was the last time you changed the hydraulic fluid, filter and cleaned the pickup screen. Since it only happens when things are hot, I wonder if the hydraulic fluid is thinning some and getting pass the o-rings or inlet check valve in the brake value. The following is for the 5X10, but I think it would be the same for the 5x20.

When either brake pedal is pressed, the brake piston is moved to the front, thereby closing inlet check valve, which immediately closes brake valve reservoir. As it travel further, the piston opens pressure equalizing valve, trapping the oil in equalizing passage. The increase in pressure causes outlet check valve to open and the oil is forced under pressure to either brake housing. When both brake pedals are pressed, pressure oil flows through both outlet check valves to the brake housings causing the pistons to open both pressure equalizing valves, and the pressure in both brake cylinders is equalized. The outlet check valves ensure a simultaneous braking effect. The pressure equalizing valves and outlet check valves ensure equal braking.

JDparts
John Deere - Parts Catalog

5X20 operator manual
http://manuals.deere.com/omview/OMRE199128_19/?tM=FR

 

[Tx Jim]

Here's the brake valve parts photo. I have a Kubota M7040 that I bought used with very few hrs that has 16.9 X 30 Firestone's that tear up the soil while turning almost as much as a plow.

 

[sixdogs]

The hydraulic fluid and filter has been changed. I'm not aware of cleaning a pickup screen and don't recall it being mentioned in the owner's manual but I'll look into that. Thank you.

The Kubota 7040 is a great tractor and I wouldn't mind owning one.

 

[jd110]

Does it seem as if the hydraulics/transmission is getting extremely hot? I wonder if your brakes may be dragging and overheating. Try jacking up the rear wheels and put transmission in neutral. the rear wheels should turn very freely. Another thing to look at, the bleeder screws TxJim mentioned has a plastic cap on it. Often when the brakes drag, and get hot, the plastic caps will melt.

 

[Tx Jim]

jd110
I noticed that the later 5000 series tractors such as the 5520,5083E,etc have the same brake springs that the earlier 5000 series tractors but do the brakes have the same history of dragging?
Thanks,Jim

 

[sixdogs]

I'll take a look at the bleeder screws today but I can't imagine the brakes dragging. From searching the comments here, it seems like it has to be either air in the system and bleeder screw related or somehow connected to the brake valve.

If it is air in the line related you would think ir would happen all the time so maybe the valve? Brakes work fine when it's not hot. I think I'm going to have to take it to the dealer. Woe is me.

 

[Zebrafive]

I wonder if there is something heating up the hyd fluid, like an internal leak.

 

[Tx Jim]

I wonder if a hyd control lever isn't returning fully to neutral causing pressure to open a relief valve.

 

[Zebrafive]

I wonder if a hyd control lever isn't returning fully to neutral causing pressure to open a relief valve.

It may not open the RV, but could build up a lot of heat.

 

[sixdogs]

I can't take to the dealer for a couple weeks or longer so as soon as I learn the problem I will advise. Tractor doesn't get used hard that often so it may take a while to figure it out. I think it will be trial and error in that you just have to keep replacing things until you get lucky.