no brakes on JD 300 industrial

[jd110]

The water contamination is not good, but that by itself will not cause the brakes to have no pedal. I am guessing, like Tx Jim, that your master cylinder(brake valve) needs attention. However, since you are from the north, water contamination in freezing weather, can cause the axle housings and/or brake valve housing to crack internally and lose braking ability. If you can remove the brake lines from the master cylinder and cap off the fittings coming out of the housing, the pedal should become very firm. If not, then you definitely need attention in brake valve. If the pedals do get firm, then you have leakage in axle housings. Either piston packings are worn, or axle housings are cracked.

 

[Tx Jim]

I am guessing, like Tx Jim, that your master cylinder(brake valve) needs attention.

JD110
You're correct on the guessing. I never was fond of the brake master cylinder design on JD utility tractors. The valves in them can give a tech grey hairs.

 

[lowufo]

Hello All
well I isolated the brake master cylinder (where the lines enter the axle ) no braking action at all. I am assuming it needs at least a master rebuild . I will keep you posted on the progress. Thanks everyone for all the input and advise !

 

[DannyWyatt]

I too am having the same issue, My tractor is a late model JD300 with a reverser. I have no brakes and the pedal for the right brake is all the way down as if there is a spring collapsed on the piston for that side. Along with that issue I have no reverse, the lever seems to be stuck at the reverser.
I made a previous post on another thread and TX Jim advised me to drain the fluid and check the relief valve above the transmission filter. I did drop both filters and drained the transmission to find very milky fluid. I have not been able to pull the relief valve out of the hole above the transmission filter. TX Jim also advised me to check the sump screen, but I cannot find one.
I have drained the aux reservoir and the oil cooler of the contaminated fluid and I am getting ready to reassemble, and fill with clean fluid. I am new to hydraulics (other than automotive brakes and steering). I assume I need too bleed the system.
Also the tractor does have a front loaded and a model 92 backhoe. The backhoe is disconnected from the hydraulics and the lines are capped with pipe caps. I don't know it this is causing an issue.
I bought this tractor in this condition. All forward gears work well.
Suggestions????

 

[Tx Jim]

I'll advise you to locate orifice that sump screen goes into & check screen(key 30) or install screen if AWOL. I'll also suggest to check revers pressure which should be 155-165 psi.

 

[DannyWyatt]

TX Jim, I have the plug out but I can't seem to remove the relief valve. I can stick my finger in it and move it, but it won't pull out. advise?

 

[DannyWyatt]

I see now, Sorry, I was confusing the relief valve for the location of the screen. my apologies

 

[jd110]

The plug you show in the picture is the filter relief valve plug. Just to the rear of that plug, there is an elbow with a line attached. Then to the rear of that and down lower is where the oil filter housing is attached to the transmission with a short length of hose and hose clamps. That is where the screen is. You have to drain the oil, remove the entire filter housing, and then remove the hose nipple where it screws in the transmission. Behind that hose nipple you will find the screen.

 

[DannyWyatt]

I have dropped both filters, and located the correct plug. I was a little confused at first as the picture posted above did not have the nipple for the return filter. I had to order a 2" wrench, that will be here tomorrow, in order to remove it.

 

[DannyWyatt]

I was able to find a gauge at my local Southern Farm Supply, in order to test the pressure at the reverser.
I have to work all weekend and I will try to get it back together on Monday.
Thanks for the input