So, who's had the master cylinder reservoir crack while

[Huw Powell]

> No, the reservoir cracked...with 123K+ on the clock, the plastic wore out. I
> don't know the pressure that COULD force the crack to grow, but I've had
> other plastic fluid containers crack for no reason. And this thing had a
> stress crack already...so it could have failed while driving.

But not only would it be incredibly unlikely, it also wouldn't be a 
catastrophe.

The reservoir is not under pressure, it just sits there and holds 
"excess" brake fluid, and its level drops and rises a little each time 
you use the brakes/clutch.

If that crack did finally start to leak "on the road," that's all it 
would be, a tiny leak, giving you time to catch it, keep topping it up, 
and get it replaced.

Under 25 or so psi while bleeding, it is being submitted to conditions 
that never occur at any other time.

Unlike, say, a coolant overflow tank which runs up to 15 psi during use 
and could very well fail catastrophically in normal use.

>>John said, oddly:  "So, all in all, it sucked that it happened, but it could
>>easily have
>>happened in an emergency situation and I'd have been screwed."
>>
>>It's difficult for me to picture a brake master cylinder failing under
>>pressure in an emergency situation, as the ONLY time it is under pressure is
>>when you induce that pressure during an attempt to bleed the system.
>>Sitting in your garage, shop, or driveway is unlikely to become an emergency
>>situation, IME ............................  John

-- 
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/