2155 brake bleed problem

[Jim.ME]

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.

It appears to be fed some by the excess flow line. That excess fluid line is where the reservoir plug is in some of the earlier ones.

If it is getting fed from the oil cooler return as some are, I believe it is internal. Without the right flow drawings and info in TM4436 this is speculation.

 

[GR Gold]

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.

View attachment 164093

My first attempt at bleeding I did just as the owners manual suggested. Put a clear tube over the left bleed screw and submerged the other end in the bottom of the rear end down from the fill cap. I then opened the bleed screw about a quarter turn and left it open, and cycled the pedal for what seemed like an hour. I could see occasional spurts of fluid going down into the rear end. After no luck that way, I got my son to cycle the pedal up and down as I opened and closed the bleeder, like how I would do a brake bleed on a car. This was all done with the engine up around 2100 rpm. I feel confident everything is plumbed right as I have another 2155 sitting right next to it to compare to. I thought the same thing that the line from the top of the tranny was a vent, and not a supply source. Unless it is fed from a passage between the brake valves and the trans housing, it would have to come from the reservoir in front of the radiator. I am not getting any fluid from that line. I suspect that the reservoir has not filled yet, but I don’t know why. I replaced all the hosed between oil cooler, reservoir and pump so I know all that drained out. Tractor has one set of remotes, and I rigged up a jumper hose between the two, thinking I could purge any air out of the hydraulic system that way? I had to put up for the night but will get back on it tomorrow. My best idea for getting fluid down the tube into the brake valves is a large syringe, and I will try that tomorrow as well. I will report back, and thank you!

 

[Jim.ME]

As is often the case, many theories come up. My view is the line in question is nothing but a vent line. Both the supply and actual return (or overflow) ports are on the tractor side of the valve and not visible unless the valve is removed.

I do not disagree, the correct manual with the drawings and description would be beneficial. If that line is excess flow from the front reservoir and tee'd into the return line to the transmission cover, it would seem it would have fluid in it most of the time.

 

[Harry in Ky]

It would "seem" so, but my limited experience shows it really doesn't.

 

[Tx Jim]

I do not disagree, the correct manual with the drawings and description would be beneficial. If that line is excess flow from the front reservoir and tee'd into the return line to the transmission cover, it would seem it would have fluid in it most of the time.

IMHO line leading from front reservoir to hyd brake valve will only have hyd oil in it when front hyd pump hyd oil supply has exceeded front pump output. Brake valve on JD utility tractors acquires it normal trans oil pump supply via a galley in transmission case direct from trans pump. I think rubber hose on brake valve is an overflow for trans pump pressure from brake valve to return line that leads to trans shift cover.

 

[Fixingfarmer]

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!

Ok I found the drawing I wanted

There is a reservoir internally in the valve

The line that is flexible is the return

The line on the top of the left brake is the inlet supply should go to hydraulic pump

There is an inlet check valve as well. If you have good supply to the hydraulic pump and other things work I wonder if that inlet valve got stuck? A possibility maybe

 

[Harry in Ky]

It might be the drawing you wanted, but it doesn't match his tractor. My opinion (for what it's worth) is the problem is not lack of supply, it's either a valve related issue or (more likely) brake piston seals. A lack of supply problem can be tested by filling the valve manually as was mentioned in one of the first posts. If the brakes still won't bleed then supply can be ruled out. Maybe at some point when this gets sorted out we'll know what the problem actually is.

 

[Tx Jim]

I think photo that Fixingfarmer posted isn't for a JD 2155 open station tractor. I see no brake valve supply line(D) in 2155 parts catalog. I think photo they posted is for a SGB(cab) model due to shape of brake pedals. Photo below shows shape of 2155 brake pedals

 

[Fixingfarmer]

I think photo that Fixingfarmer posted isn't for a JD 2155 open station tractor. I see no brake valve supply line(D) in 2155 parts catalog. I think photo they posted is for a SGB(cab) model due to shape of brake pedals. Photo below shows shape of 2155 brake pedals

It appears they only show good drawings of the SGB in that service manual

It appears as well that they share the same valve housing and should principally be the same although probably are different with the pedal mounting I know the open station 2555 I just sold (it was the tractor I learned to drive on) had different pedals

L64460 appears to be a casting number on the housing for a non sound guard body one they show the same picture for both valves in the parts diagrams.

I will say as well it’s been a whole lot of fun and paper wasted redoing the electrical on mine in the last couple weeks which is what made me purchase the second manual. Deere popping you twice for the manuals does give one a bad taste in your mouth but I do think I should have it all now.

on the bright side we owned the other one for 35 years if that’s how old I am it was the same model year as me without trouble so once you figure this out you should have a great tractor.

 

[Jim.ME]

My first attempt at bleeding I did just as the owners manual suggested. Put a clear tube over the left bleed screw and submerged the other end in the bottom of the rear end down from the fill cap. I then opened the bleed screw about a quarter turn and left it open, and cycled the pedal for what seemed like an hour. I could see occasional spurts of fluid going down into the rear end. After no luck that way, I got my son to cycle the pedal up and down as I opened and closed the bleeder, like how I would do a brake bleed on a car. This was all done with the engine up around 2100 rpm. I feel confident everything is plumbed right as I have another 2155 sitting right next to it to compare to. I thought the same thing that the line from the top of the tranny was a vent, and not a supply source. Unless it is fed from a passage between the brake valves and the trans housing, it would have to come from the reservoir in front of the radiator. I am not getting any fluid from that line. I suspect that the reservoir has not filled yet, but I don’t know why. I replaced all the hosed between oil cooler, reservoir and pump so I know all that drained out. Tractor has one set of remotes, and I rigged up a jumper hose between the two, thinking I could purge any air out of the hydraulic system that way? I had to put up for the night but will get back on it tomorrow. My best idea for getting fluid down the tube into the brake valves is a large syringe, and I will try that tomorrow as well. I will report back, and thank you!

Have you looked in the brake valve reservoir yet to see if it has fluid in it?

 

[GR Gold]

All right guys, this is what I have done. There is no 4th line coming off the brake valve assembly. There is one line for the left brake and one for the right, as well as the tube going forward and up to the Y. Also, there is no removable plug on the top of the brake valve to check if there is fluid in there, so, I removed the Y and used a 2oz syringe full of fluid a few times, and filled all the way to the top of the tube with Hyguard. I then thought I would do the right brake first as that is the one that tube goes into. I connected a clear line to the bleed screw on the right brake and submerged the other end of it in a gallon jug of Hyguard. I ran the tractor at higher rpm as the owners manual says, opened the bleed screw, and began slowly cycling the pedal up and down. Almost immediately I began getting a column of fluid with very little air through the bleeder line. I kept on cycling the pedal trying to get ALL the small, occasional bubbles out, only to start getting a bunch of air again. Well, I emptied the tube of the fluid I had put down it, similar to running a master cylinder out of fluid when bleeding car brakes. So, I kept topping off the tube every 3 or 4 pedal cycles until I got the all the air out of the right brake and the pedal got firm. I then did the same on the left. I did a final top off before putting the tranny line and the line from the front reservoir on the Y and the Y back on the tube. Furthermore, while running the tractor working on the brakes, I had a jumper line between the one set of rear remotes and ran the valve forward thinking maybe this might help purge the system any air out of that reservoir with the 1/4” line that connects to the front of the Y. After several minutes, I began to get a slow drip out of that tube. Hard to believe that it is enough to supply both brake valves, but I guess it is a closed system. Anyway, I drove it around and the brakes seem to work fine. I don’t know what running the rpm at 2100 for two minutes does regarding filling the “brake reservoir” as the owners manual states. I didn’t get any fluid out of tube from the hyd reservoir until it had run for at least 10 minutes or more while purging the hyd system through the rear remotes. I guess time will tell if it is getting enough supply. Thanks again for all the help you guys!