how can you tell if the manual trans master cylinder is going out
 

How can you tell if the manual trans master cylinder is going out. What kind of problems can it cause. 1982 240D

failing master cylinder
 

My first sign of failure was the brake light came on indicating a loss of fluid from the master cylinder reservoir. Eventually the pedal would fail to come back completely after I pulled my foot off. Feel the hard line that extends distally from the lower part of the master cylinder. It will be wet with fluid. The floor drain in my 190D drained fluid from the accumulation. Both have failed recently on my cars. Replaced the one in the 240D without taking out the seat. Would NOT recommend this technique and will take out the seat in the 190D to replace. Nearly herniated a disc in my neck while working on the 240D.

Kevin
1979 240D manual
1984 190D manual

So it causes the clutch to stay down keeping the gears from engaging. I suppose that can cause a lot of trouble.

No, I could still shift but I'm sure that at the endstage it's going to behave that way.

Kevin
1979 240D manual
1984 190D manual

yup, my experience is....first they start leaking, then they start leaking bad, then they stop functioning, but 'benz builds them tuff, I drove mine for a year and a half while the MC slowly died.

I would think an early sign might be everytime you try to shift gears they clash because the clutch is not totally releasing. Perhaps slowly increasing until you cannot disengage the engine and transmission with the clutch. Another symptom as mentioned earlier is the master cylinder fluid level dropping down to service a leak.

yea, my brake light didnt even go on. I didnt know it at the time but i had a blow brake caliper and i was driving around with basically no front brakes for a while:confused: i could still ****, and drove it like that for months, finally though it would shift into gears without grinding, and even whenii had the clutch all the way in, you could still feel the car moving