john deere 310b break issue

[slade]

hello everyone, i am new to the site, i have a 85 john deere 310b, when i try and use the breaks the peddle goes right to the floor. seems like im looseing pressure? i toped up the break fluid but still nothing.

 

[willie59]

Are you loosing fluid to require refill?

 

[slade]

the fluid was down a little bit, it only took a spounfull, but ive pumped it quit a bit, then checked the fluid and im not looseing any. i checked everywhere for leaks and cant find any.

 

[willie59]

Can't say for sure, but sounds like problem with the master cylinders if it's not losing fluid.

 

[slade]

ok thanks....are the breaks in the rear end or the transmission? this is my first hoe so its a learning curve

 

[willie59]

Service brakes are in left and right rear axles.

 

[slade]

ok thanks....so where the filler cap is for my breaks am i correct in saying that this is the master cylinder? and is it possible that i could have a enturnal leak that is not spilling on the ground or the backhoe?

 

[willie59]

Item 21 is the brake master cylinder. It has two chambers, for left and right brakes. Item 18 is the filler cap, one for each chamber. But I can't recall whether they used brake fluid or hyd oil. I think I'd call Deere dealer and ask them to be sure.

 

[slade]

i cant be sure, but i think mine only has one filler cap? i know it has a break for each side.....im not 100% but i think it takes hyd oil....or thats what i put in it, i done this because thats what was already in it. if there are 2 chambers i know i have only filled one.

 

[willie59]

And you would be correct, I looked at the parts breakdown again and it shows only one filler cap, prolly common chamber for two master cylinders.

 

[slade]

Good, i thought i may have missed something.....im going to have to go through her again tomorrow. if i cant find any leaks, where is a good place to start? can the master cylinder be rebuilt or will i have to search up another one? if thats not the issue is there anything elese i can look for?

 

[willie59]

Well, hard for me to say what your problem is. I can only tell you it's a rather simple system, I don't think it's a power assist system, just simple master cylinders pumping oil to service brakes. Don't hold me to that though as my memory on those units are vague. And I'm not sure how the separate master cylinders interact with each other internally, I only know they can act independent to apply only one brake, left or right. There should be a bleeder screw at top of axle housing on each side to bleed air from brake pistons at axles. If you bleed service brakes, get only fluid and no air, and don't have fluid loss from leakage or failed service brake piston seals, I would wager you have a problem with master cylinder. Not sure what it would take to repair/rebuild master cyl, but likely could only get parts from Deere and not aftermarket. I've never rebuilt one of those master cylinders so I don't know what would be involved.

 

[slade]

im going to bleed the breaks if the weather holds up seems i have to do it outside. if that works i would still be puzzled on how the air got in there to begin with? but its worth a shot seems it wont cost me anything to do. thanks for all the quick replys!

 

[slade]

went out today, to have a quick look. i know my hoe dont have front breaks. but would there be a line coming from the master cylinder to the hyd pump or around that area? because i have a leak there.

 

[Wild Bill]

There is a line that goes from the low pressure return side of the hydraulic system to the master cylinder. Bleed the brakes as follows;

1. raise the front wheels off of the ground with the loader
2. steer to axle stops (over relief) and hold for 30 seconds to fill brake reservoir
3. While holding steering at stops pump brake pedal up and down slowly 12 times
4. Release brake pedal completely and wait a minimum of 10 seconds
5. Repeat steps 2-4 until a firm pedal is obtained within 4.5" of travel

If firm pedal cannot be obtained then you need to adjust the brake stops.

 

[slade]

ok, so what do you mean by steer to axle stops? turn the wheels until there to there limt? and do i unscrew the bleeders on the rear both at once? or do one at a time?

 

[Wild Bill]

Turn the wheel until you cant turn it anymore. You will here the hydraulic relief valve open (whistling fluid flowing sound). The book says nothing about bleeders. I was just under my 210c, I adjusted the brake stops and don't think I saw a bleeder. There are three screws and nuts around the axle flange, those are the brake stop screws, NOT bleeders. DO NOT unscrew them all the way. If I figure out how to post pictures on this forum I will just give you a pic of the manual.

 

[Deon]

Wild Bill, I'm not sure if your information is correct for the 310B, but it may. It is though 100% correct for the 310D as it has a filler line that keeps the reservoir full. I don't see any in the online JD parts manuel of the 310B. This function of turning the steering to stop is to speed up the flow of oil into the reservoir.
Slade, on the 310D (don't know about the B) you do not open any bleeder screws to bleed the brakes. As far as adjusting the brake disk, get under the rear axle housings and find where the brake line is connected to the housing. On that same flange face you will find 3 allen set screws with lock nuts threaded to the screws. I believe one screw is located at 12 o'clock and one at 8 o'clock and the other at 4 o'clock. Hold the allen screw with the allen wrench while you loosen the lock nut. Turn the set screw in until you fell it bottom out. Unscrew it 1/3 of a turn, hold it and tighten the nut. Do that to all 3 screws and on both brakes. If your pedal is still not firm then you could have a damaged check valve in the master cylinder. Also I must tell you that there are no piston seals inside the master cylinder. If oil is not leaking out, all your seals are good. The brake pressure is created by the space the brake plunger is occupying inside the reservoir and not buy a plunger seal like in a car master cylinder. You are telling us there is only one filler plug. I think you should have one removable plug above each brake plunger as that is how you remove the check valves. Try this and let us know if you see any progress. If still no success I try to explain about the check valves.

 

[wncgrown]

Willie59
I have a '83 310B with brake problems,would you have a blow up of the internal view of the brake system on a 310B. I am losing fluid but when I add fluid I can pump up the brakes and they are good for a few days. I am wondering if I may have a leak inside the axle housing.

 

[lantraxco]

There's a piston with a pair of O-ring seals in the main housing where the axle housings bolt to it, if they're leaking the fluid ends up in the transmission case. Later models usually had a small line from the tank or pump housing to the brake valve to make up fluid loss.

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