Do I need a new brake master cylinder?

flatlander · Aug 29, 2016

I found out that the clutch master cylinder was knackered (black fluid). I've replaced this, but now wonder if I should replace the brake master cylinder. They both seem to date from 1985, and of the two the brake MC seems to be the must safety critical. But, how can I get any indication of the condition? Brakes seem to be fine at the moment.

Flossie · Aug 29, 2016

Is the fluid black, a sign of wearing seals but you know that.
Pop the cover off and see if it's getting damp where the pushrod goes in?
Or just replace it and rest easy, they are cheap enough even to a sling ass like me.

Al2O3 · Aug 29, 2016

When mine started to go the fluid ran along the push rod, down through the bulkhead on to the pedal, trickles down and forms a drip on the bend of the pedal bar. My brakes continued to work perfectly well. Obviously, I changed it as soon as I spotted the drip. I heard they can go quicker than mine was. How long have you had the Landy? If it ain't broke..............

flatlander · Aug 30, 2016

Thanks for the replies folks.
No black fluid, no leaks. I suppose what I really want to know is if it fails, do you find out by suddenly having no brakes (I know there is a split braking system), or do failures happen slowly?

zeaphod · Aug 30, 2016

As I discovered lately, one of the common signs of seal failure is the brakes fading as you hold on the brakes at a junction etc. The pedal goes soft after a few seconds and drops a little. I had no leaks or other problems. If they are working fine and the fluid is clean and clear, I'd leave it alone. On an older vehicle, you're more likely to have problems with seized calipers or leaking rear cylinders.

Flossie · Aug 30, 2016

^^^
What he said.

flatlander · Aug 30, 2016

zeaphod said:
As I discovered lately, one of the common signs of seal failure is the brakes fading as you hold on the brakes at a junction etc. The pedal goes soft after a few seconds and drops a little. I had no leaks or other problems. If they are working fine and the fluid is clean and clear, I'd leave it alone. On an older vehicle, you're more likely to have problems with seized calipers or leaking rear cylinders.

Thanks Zephod, all the rest of the brake system is new, and the pressure holds OK. I think I'll leave well enough alone.

Do I need a new brake master cylinder?

flatlander

It's not broken!

Flossie

Well-Known Member

Al2O3

Well-Known Member

flatlander

It's not broken!

zeaphod

Well-Known Member

Flossie

Well-Known Member

flatlander

It's not broken!

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