Bad breaks day.

  rdave13 16:24 11 Nov 2010

On the road to work today my breaks failed. Luckily traveling slowly so managed to stop safely. Had a look at the reservoir and break fluid level still ok. Pumping the peddle brought some breaking ability. Car now in Garage to check.
My question is can break fluid deteriorate that fast, as no leakage is obvious, because the breaks were fine this morning? Or could it be the master cylinder? Not a pleasant experience.

  Diemmess 16:40 11 Nov 2010

O-ring seals can fail at any time, though obviously very rarely.

I don't think it will be caused by fluid deterioration.
That shows more obviously if the brakes fail during hot weather and after heavy use when the fluid temperature reaches boiling point much sooner if contaminated by water absorbtion.

  rdave13 16:58 11 Nov 2010

Thanks Diemmess. Fist time, in many years driving, this has happened. The mechanic had a look at the break fluid and thought it was 'thicker' than usual. Whatever that meant. I always use the garage to topup any fluids so it can't be a mixture of different types. Waiting 'phone call to hear the verdict.

  Fruit Bat /\0/\ 20:02 11 Nov 2010

Servo O ring failure - instead of fluid being pushed from servo master cylinder to cylinders in drums / callipers . Fluid slips back passed the servo seals and so no brakes.

No drop in fluid level as no leaks in system.
Afraid its probably going to cost you a new master cylinder as they do not seem to do replacement seal kits any longer.

  rdave13 20:40 11 Nov 2010

Thanks Fruit Bat /\0/\ . Thought it wasn't going to be cheap. Lost a day's wage already on top of the cost of repair. 'Phoned work and the Manager couldn't understand why the garage hadn't fixed the car there and then.
Tried to explain that there are more customers, with appointments, before myself, and they were pretty good at even taking a look at my car let alone allowing me to leave it there over night (in the bay) so that they can work on it as soon as possible.
Master cylinder is looking to be more and more to be at fault. Will WALK up to the garage tomorrow to see if they've had time to fiddle around and see what timescale they can repair the car. I think another two days lost earnings and an irate Production manager.
Just great before that mass we celibrate on the 25th.........
Still I didn't cause a horrendous crash due to break failure and I'm thanking my lucky stars.

  rdave13 21:09 11 Nov 2010

Sometimes credit cards can come useful when the unexpected happens..

..gulp.. click here

  wiz-king 21:40 11 Nov 2010

Brake fluid specs have changed over the years, that's why it is recommended to change the fluid every two years. Modern fluid tend to absorb water which increases the chance of it boiling under heavy breaking - think of the red-hot brakes on a F1 car! Once the water in the fluid boils it is compressible and the brakes wont work.
Most likely fault is the master cylinder but it could be as simple as the breather hole in the fluid cap being blocked.

  Quickbeam 06:30 12 Nov 2010

I had this symptom about 4 years ago and decided that a seal in the master cylinder had an intermittent blow by fault under pressure. I got a new cylinder fitted and cured it.

There's not much else to go wrong in a hydraulic system if there is no leaks in it. I also got it in for changing within 24 hours, I won't drive with any known fault in that department.

  Quickbeam 06:32 12 Nov 2010

...if no fault is found but it happens again, I would change it for peace of mind anyway.

  morddwyd 08:58 12 Nov 2010

"I always use the garage to topup any fluids so it can't be a mixture of different types."

How trusting, an innocent abroad!

I lost a water pump because the garage, a main agent, used plain water to fill the radiator instead of the proper coolant mix.

  rdave13 11:09 12 Nov 2010

So it was the master brake cylinder. Ordered but won't arrive 'till Mon afternoon. So an unofficial Holiday.
Thank you for your replies, much appreciated.
Now I'll have enough time to remember the different spellings, brake and break!!

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