M7040 jerking when braking going downhill

[Varnell1980]

Hey guys, new to the forum and so glad I found y’all. I have a M7040 that I’m having issues with. When braking going downhill in 4x4, the whole tractor starts shaking really bad. It almost feels like antilock brakes do when you apply them super hard. When it’s out of 4x4, and the brakes are applied, the back tires will lock up real easy and it slides. I searched online and found that it could be a hydraulic fluid issue so I checked it and when I pulled the dipstick out the fluid was all the way to the top of the dipstick hole. I ended up draining about 3 gallons of hydraulic fluid out of it last week to get the levels within range. The shaking is still happening as of yesterday but not as bad. Could this have caused the problem, because it never did it before this. Please help! How do I go about fixing it? I’m hoping it’s just an adjustment issue.

Side note, when raking hay yesterday going down hills, it acted just fine. It was just when I had nothing behind it, when it would do it the most.

 

[skeets]

I wonder if maybe you have a low tire and it might be slipping on the rim,, the weight on the tongue might be enough to keep it tight,, dont know just a thought

 

[Captain13]

That’s a wet disk braking system, right? How does the hydraulic fluid look? Could the fluid be contaminated causing the problem? If the fluid is degraded or non spec fluid used, it may cause the brakes to not operate smoothly (grab).

 

[North Idaho Wolfman]

Read the WSM!

 

[Captain13]

Wolfman, I looked at the WSM and didńt see anything addressing this problem. Any insight?

 

[North Idaho Wolfman]

Pages 5-S5 and 5-S6 cover how to test and bleed the brakes.
Note: This brake system is not like a typical tractor, it's more like a automotive system.
The brake reservoir is feed hydraulic fluid from the system so it's important to first check the hydraulic system of the tractor first.

 

[Captain13]

Wolfman, my WSM is the 2009 edition. 5-S5/6 outlines the brake disassembly process. I looked through the entire section and no mention of bleeding. It did mention in the Troubleshooting section that poor braking may the the result of incorrect or contaminated fluid and that was about it other than warped plate, worn out pads. The hydraulic plates must have come out after mine. Thanks for the response to my question though.

 

[dvcochran]

I wonder if it is just gear-chatter when the FWD is engaged, and the rear wheels are trying to slip?
How are the brakes under normal conditions?