2155 brake bleed problem

[GR Gold]

A little history on this tractor. I purchased from a local municipality that owned it since new. The nose of the tractor had been pushed back some and cracked the fuel tank. Some disassembly happened and then it was abandoned. I removed the nose, fuel tank, radiator, etc., and replaced several hydraulic hoses up there as well as the fan belt and hyd pump drive rubber cushion, and a good fuel tank. I also had to replace the left brake line that runs by the hydraulic filter as it was bent and ran under the filter and the line cracked when I was trying to bend it out of the way. Fast forward to now. I have replaced the hyd filter and several hoses, and refilled the Hyguard. The hydraulic reservoir and oil cooler were drained when I replaced the hoses. Following the owners manual on bleeding the brakes, it says to run the engine at 2100 rpm for 2 minutes “ Thus making sure the brake reservoir is filled with oil”. I have a clear tube on the bleed screw and the other end has about an 18” piece of copper tubing that is stuck down in the oil through the fill cap. I have cycled the 3 point several times and turned the steering back and forth from lock to lock, so I believe the hyd system is functioning ok. Problem is, I cannot get the brakes to bleed. When I open the bleed screw a bit and cycle the brake pedal up and down, I cannot get all the air out. I get spits of fluid through the hose, but mostly air. I have done this for at least an hour. It looks like the supply source for the brakes is the small line coming off the hyd reservoir and running back to the “y” and down to the brake pedal area. I am not sure what the “brake reservoir” is that the manual is referring to. Is there another thing I should attempt to bleed here? I sure am getting frustrated. Thanks in advance for all your replies!

 

[MSD]

Don't know if it has anything to do with the brakes not bleeding but did you clean the screen under the transmission case? They get pretty nasty sometimes.

 

[GR Gold]

Don't know if it has anything to do with the brakes not bleeding but did you clean the screen under the transmission case? They get pretty nasty sometimes.

Yeah, and it was pretty nasty. Did it when I changed the fluid and filter.

 

[Fixingfarmer]

Do they function?

Sometimes they don’t bleed like you would expect on a car they use hydraulic pressure and will self bleed better as you use them.

 

[Jim.ME]

Yeah, and it was pretty nasty. Did it when I changed the fluid and filter.

Did it have flaky friction like material on the screen?

 

[GR Gold]

Did it have flaky friction like material on the screen?

No, just black gunk.

 

[GR Gold]

Do they function?

Sometimes they don’t bleed like you would expect on a car they use hydraulic pressure and will self bleed better as you use them.

I actually drove the tractor on and off the trailer and to where it is parked now under the shed. They worked good BEFORE I messed with it. Now, both pedals go down to the floor with no resistance. I haven’t tried bleeding the right one, only the left one. Maybe I should try the right one.

 

[Fixingfarmer]

I strongly recommend you purchase manual TM4436 it’s the testing and operation manual for 2155-2755 tractors

They are available at John Deere publications

Possibly elsewhere

There’s another service manual but it’s how to repair if you were doing a head gasket or know what the problem is on anything both are 200 plus bucks if you are going to purchase one that is the one for electrical schematics as well

Here’s a diagram of your brake supply

It will be fed from the steering up top

There’s no reservoir specifically for brakes that I’m aware of there is a reservoir above main hydraulic pump E that is a surge

This is fed by transmission oil pump

The diagram shows that supply line from steering should come down to the inside fitting of the brake valve you could take this off and start the tractor see if you have flow. CAREFULLY into a pail.

The picture I took of the tee shows the fitting that should feed both steering and brakes

 

[Fixingfarmer]

You should also be able to bleed one side then the other I might be tempted to take the hose off down below and see what’s actually coming out into a pail as well

 

[Harry in Ky]

What I'm getting from the post so far, this tractor doesn't have an orbitrol type steering valve, so the diagram posted above won't apply. The fluid in the brake valve is supplied internally by fluid from the steering system.

 

[Jim.ME]

There’s no reservoir specifically for brakes that I’m aware of there is a reservoir above main hydraulic pump E that is a surge

The cavity in the brake valve body is the brake reservoir. I don't have a 2155 manual, but I know that is called out as the reservoir on some other JD models using that or a similar brake valve. There should be a plug in the top that can be removed to check for fluid in it.

 

[GR Gold]

I will post some pictures

 

[GR Gold]

I strongly recommend you purchase manual TM4436 it’s the testing and operation manual for 2155-2755 tractors

They are available at John Deere publications

Possibly elsewhere

There’s another service manual but it’s how to repair if you were doing a head gasket or know what the problem is on anything both are 200 plus bucks if you are going to purchase one that is the one for electrical schematics as well

Here’s a diagram of your brake supply

It will be fed from the steering up top

There’s no reservoir specifically for brakes that I’m aware of there is a reservoir above main hydraulic pump E that is a surge

This is fed by transmission oil pump

The diagram shows that supply line from steering should come down to the inside fitting of the brake valve you could take this off and start the tractor see if you have flow. CAREFULLY into a pail.

The picture I took of the tee shows the fitting that should feed both steering and brakes
View attachment 164052View attachment 164053View attachment 164054

Thank you for the pictures and diagram, but they are different than what I have. I do have the Technical manual TM-4435 that is for the 2155 and 2355N tractors, but it really just says the same thing as the operators manual regarding bleeding the brakes. This is what mine looks like. A small tube comes from the round tank in front of the radiator, and another small tube comes from the top of the tranny under the shift cover and they both Y together into a larger tube that goes down to the brake, what I would call master cylinders. It just seems like something is not feeding the hyguard to the master cylinders. I really don’t understand what supplies this if it is not coming from the round tank in front of the radiator.

 

[GR Gold]

The cavity in the brake valve body is the brake reservoir. I don't have a 2155 manual, but I know that is called out as the reservoir on some other JD models using that or a similar brake valve. There should be a plug in the top that can be removed to check for fluid in it.

Thank you. I will look into that

 

[Jim.ME]

Thank you. I will look into that

You may need to remove the footrest to get to it. If it is empty fill, it with fluid and try bleeding. If it bleeds when you manually add fluid it should be a supply issue. If the reservoir is full the brake valve may need a rebuild.

 

[GR Gold]

This fitting with tube is at the front of where the right shifter is located. Is this the supply source for the brake master cylinders? This tube goes up behind the dash and connects to the back of the green plastic Y. The front fork of the Y with the tube on it, goes up to the reservoir in front of the radiator. The bottom, larger leg pointing down goes to the brake master cylinders under the floor board. Harry in Ky said the fluid for the brake valve is supplied internally by the steering system. So should I have fluid coming out of the tube in the first picture here when the tractor is running? If so, I am not. I thought I was fairly mechanically inclined, but this has me stumped. Thanks in advance for your replies, and patience!

 

[GR Gold]

What I'm getting from the post so far, this tractor doesn't have an orbitrol type steering valve, so the diagram posted above won't apply. The fluid in the brake valve is supplied internally by fluid from the steering system.

Please look at my last post. Thank you!

 

[Fixingfarmer]

I believe that flexible line is a drain back to the transmission case once the reservoir fills and would be the same off the brake valve since it should be fed by the high pressure pump after the steering but I’ll double check that in the morning.

there should be a brake line off each side of the valve that heads to each brake. Then is there a 4th line? Or is that it? It’s possible that it could connect to the case and get fluid from an internal line but I thought it was external.

 

[Jim.ME]

Thank you for the pictures and diagram, but they are different than what I have. I do have the Technical manual TM-4435 that is for the 2155 and 2355N tractors, but it really just says the same thing as the operators manual regarding bleeding the brakes. This is what mine looks like. A small tube comes from the round tank in front of the radiator, and another small tube comes from the top of the tranny under the shift cover and they both Y together into a larger tube that goes down to the brake, what I would call master cylinders. It just seems like something is not feeding the hyguard to the master cylinders. I really don’t understand what supplies this if it is not coming from the round tank in front of the radiator.

As Fixingfarmer posted, TM4436 is the manual you need to get system descriptions, schematics, flow diagrams, specs. and testing. TM4435 is the manual for "wrenching" to make the repairs, not for troubleshooting and diagnosis. TM4435 will only tell you how to rebuild the brake valve and how to bleed the brakes.

Please clarify. In your first post you posted you cracked the brake bleeder a bit and cycled the pedal several times and basically only got spurts of air. Did you actually open the bleeder and cycle the pedal up and down several cycles with the bleeder open (as I read your posting). Or did you push and hold the pedal down, open the bleeder to allow air/fluid to escape, close the bleeder tight and let the pedal up. Repeating those steps each time?

Have you checked for fluid in the brake valve reservoir as I suggested?

I marked up the drawing you posted to show where the oil is supposed to be going in each line. The front reservoir should have something in the bottom between it and the main pump. The fluid can flow both ways in that tube/hose as needed. If the main pump is not getting oil from the transmission pump the oil flows into the pump. When the main pump is receiving more oil than needed the excess flows up to the reservoir with any excess going to the brakes and transmission. If that front reservoir tank is not getting oil enough to send oil back to the brakes and transmission the brake reservoir isn't going to fill.

I wonder if something is plumbed wrong or a small part got lost during the front-end repairs you did.