JD 5210 Hydraulics Hot

[jgbanshee]

I was flail mowing a few acres (2 hrs) of field yesterday with my 5210 sync reverse trans. and was temp outside was about 80 degrees. When I was done mowing I took a short road trip back home. I noticed I had no brakes. The pedal would just push in with no brake whatsoever. Was not like this earlier and today after everything has cooled down. I assume this is due to excessive heat on the hydraulic fluid. Hydraulics work yesterday/today. What should I be looking into, hyd. pump and relief valve??

 

[workinonit]

If everything else was working as it should then I would say it's may not be heated fluid but something actually wrong with your brakes. You call it a sync reverser which I've never heard of. I had a 5310 with a sync shuttle and they offered a power reverser. You need to do a bit more troubleshooting and determine if other hyderaulic functions are working when this happens.

 

[Tx Jim]

1st thing I'd suggest checking is how clean is hyd oil cooler. Is scv control valve centered in neutral?

 

[jgbanshee]

Sorry, it is sync shuttle trans. My 4300 has the sync reverser. 3pth seems to work fine, loader and p/s definitely have a noticeable difference in performance almost sluggish and jerky when hot. Hyd. fluid level looks good when cool but seems to drop when hot. All hyd. levers do return to center/neutral position.

 

[M59]

I was flail mowing a few acres (2 hrs) of field yesterday with my 5210 sync reverse trans. and was temp outside was about 80 degrees. When I was done mowing I took a short road trip back home. I noticed I had no brakes. The pedal would just push in with no brake whatsoever. Was not like this earlier and today after everything has cooled down. I assume this is due to excessive heat on the hydraulic fluid. Hydraulics work yesterday/today. What should I be looking into, hyd. pump and relief valve??

Time to dig out the workshop manual and determine if the braking system uses the same hydraulic fluid as the rest of the hydraulically driven items and then adjust your investigation as appropriate. I would expect, but don't truly know, the braking system's hydraulic fluid would be separate from general use hydraulic fluid since brakes are a life safety critical item.

 

[Tx Jim]

5210 uses hyd oil for brake fluid. Hyd pump keeps brake valve reservoir replenished with hyd oil

 

[M59]

5210 uses hyd oil for brake fluid. Trans pump keeps brake valve reservoir replenished with hyd oil

OK, so the trans pump keeps the brake fluid reservoir filled with the general use hydraulic oil but when you step on the brake, I expect, that pressure is transmitted directly to a braking disk and thus the two systems are essentially separate vs actuating the brake tells some other valve to correspondingly open and transmit hydraulic pump pressure to the brakes. A mechanical system vs brake by wire.

 

[Tx Jim]

No hyd pump pressure is applied to brakes. Pressure is created by piston in brake housing being pushed by brake pedal sending oil into brake line to wheel piston.

 

[jgbanshee]

No hyd pump pressure is applied to brakes. Pressure is created by piston in brake housing being pushed by brake pedal sending oil into brake line to wheel piston.

Correct, but it does use the same oil as the hyd. system.

 

[M59]

Based upon your responses, jgbanshee should be focusing his attention on the braking system as it is separate from the general hydraulic system except the trans pump keeps the brake fluid reservoir filled.

If no brakes means no reduction in speed or very little reduction when brakes applied then I would be looking at routing of brake lines near heat sources and whether he boiled the hydraulic fluid in brake circuit OR his hydraulic fluid has some water contamination in general hydraulic circuit or specifically in brake circuit and the heat boiled the water. Liquids are substantially in-compressible at temperatures tractors experience but vapor ( boiled water or hydraulic fluid boiled ) is very compressible.

Boiling would explain why brake returned after tractor cooled down.

Brake fade and loss come from 40 years of racing cars.

 

[coosa]

I am pretty sure that my 2012 5075e is designed in a similar manner to yours. I actually traded a 5210 for this one. I had an experience a lot like you have described a couple of years after I bought it.

I had not used the tractor for a couple of weeks and ran it for a couple of hours pulling a 7' disc. It was a hot day and I was aware that the surface of the tractor was hot, but the temp gauge was reading normal. I went to turn at the end of a row and had no brakes at all. I brought it in and used a laser thermometer on it and found the temp at the PTO output was 301. I shut it down and let it sit for an hour and it ran normally when I started back up.

I talked to some folks about it and decided it would be best to change the hydraulic fluid and filter. The tractor had 200 hours when that happened, and it has gone 600 since without it happening again. The best guess as to what happened seems to be that a hydraulic valve somewhere didn't open properly, probably because it had been sitting without cranking for a while. That may not be right, but I am thankful that it hasn't happened again. I hope this helps in figuring out your issue.

I remember that I was using my 5210 in the woods one day and a stump punched a hole in the hydraulic filter. I immediately lost steering and brakes, so it would make sense that overheated hydraulic fluid could cause you to lose brakes like the 5075 did.

 

[Harry in Ky]

I have a few questions on this problem myself. I'm not quite sure on the supply of brake fluid on these tractors. I suspect it's part of the steering return flow but I can't confirm that. With a gear drive transmission, there are no clutch packs to supply, so other than transmission lube what need is there for a transmission pump? I'm not aware there is one.

As for brake lines, They originate in the engine compartment, so heat is present, but why would that suddenly make a difference?

I'd be leaning toward the brakes themselves. Fluid pressure present when applied, possible mechanical problems inside, that sort of thing. Wet brake issues can be the source of hydraulic oil heat, not just a result.

 

[Tx Jim]

Harry
You're correct & thank you for bringing my mistake to my attention. I incorrectly stated trans pump supplies oil to brake valve. I was thinking about older model JD utility tractor's hyd systems when I made that incorrect statement.

I'm not sure which hyd pump(PS or 3pt/scv) supplies oil to brake valve reservoir on 5210