555e brakes building pressure while using

[Nick350]

About a year ago I installed 2 new master cylinders on my 98 555e. We reused the connecting tube that goes between that master cylinders.

Over the past 6 months the brakes will start to build pressure while using and start grabbing. I park the machine and break free one of the lines on top of them to relieve the pressure.

Then it goes back to working like a charm.

Does anyone know what might be causing this?

 

[Swetz]

Just wondering if item #12 is doing its job?? Using the second image, where are you releasing the pressure to release the brakes...I am thinking possible a clogged hose?

 

[Nick350]

I think the spring is fine as once they are depressurized the travel and action is normal. I typically crack open #4 in the second diagram. My master cylinders also have a bottom hose between them, supposedly a pressure balancer. Sometimes it’s after it’s sat a while and sometimes it builds up pressure when using the machine. We are operating on pretty hilly 4wd ground so we definitely use the brakes .

 

[Swetz]

Do you crack both or do you find that you only need to do one...Do you notice one brake staying on more than the other? Somehow I feel that the brake pedal is not returning to the point that the cylinder (s) are not open to the reservoir. If one of the hoses were blocked, when you release #4 it would not release the brakes.

 

[Nick350]

I typically only need to crack one to release the pressure. I have not tried operating the pedals independently when it was pressurized so I’ll try next time and report back on that part.

 

[Swetz]

And try releasing the opposite #4, and see if that works...You have 2 separate systems, so it is possible one is not happy and the other is, so check that out too.

 

[NH575E]

X2 on clogged flex hoses. I use to see this on older vehicles frequently.