| Author | Message | ||
     Patrick Francis Frequent User Username: jackpot Post Number: 294 Registered: 11-2016 |
Hi all I took SRH 17968 for an outing yesterday which involved some hilly terrain in Spain. There were 4 of us in the car and a hot day. As happened to me before in Morocco, half way down the second long hilly section, the pedal went to the floor, ie probably boiling fluid. So: Boiling fluid in the master cylinder system caused me to lose pedal. I did not get brake failure since at the bottom of the travel, the valves were activated on the pressurized systems which probably compressed any air and activated the brakes (I could tell that this was happening since braking became less progressive and more sudden). The brakes started to squeal a bit. When the brakes cooled, everything went back to normal again. On the return journey, I learned my lesson and used engine braking a lot more. No repeat! My comments are: Brake failure seemed to happen relatively soon in my opinion. Has anyone else had experience of this happening often? I recently upgraded to Yak with dot4 mix, maybe dot 5.1 is a better option? Some people have condemned the master cylinder circuit and just put a rubber stopper instead- anybody have experience? I was thinking of maybe having a small fluid container that feeds only the master cylinder and bleeding through with synthetic fluid which never boils? This would not affect the rest of the system and would be relatively simple? Any comments are welcome😁 | ||
| richard george yeaman Prolific User Username: richyrich Post Number: 1122 Registered: 04-2012 |
Hi Patrick, Scary stuff, Your separate feed would be a goer and also a larger capacity master cylinder. Richard. | ||
| Alan Dibley Frequent User Username: alsdibley Post Number: 214 Registered: 10-2009 |
Quote:- Some people have condemned the master cylinder circuit and just put a rubber stopper instead- anybody have experience? RR condemned the master cylinder circuit on later Shadows and replaced with a rubber buffer sort of thingy, so you would be in good company. I did so after two instances like yours of long downhill runs followed by pedal-to-the-floor, in spite of a full fettling of the circuit after the first one. Since then - no problems. For the rubbery feel I used the master cylinder with the guts replaced by a piece of rubber hose around the central rod - I can not remember the details and I took no notes because it was a bit empirical till the right feel was achieved. There are posts about this somewhere??? I recommend it. Alan D. | ||
| ross kowalski Prolific User Username: cdfpw Post Number: 1247 Registered: 11-2015 |
Patrick, The best answer is the one you gave. Engine braking. Even if you had fluid that was up to the task the pads, wheel bearing grease, gaiters, and seals also have heat levels they like. I can't see why dot 5.1 wouldn't help I think it has a higher boiling temp. Scary stuff that. | ||
| Mike Thompson Prolific User Username: vroomrr Post Number: 1001 Registered: 04-2019 |
I feel your pain on that scary event. I was driving a Freightliner 18 wheel truck down a 7 percent grade (think roller coaster straight down almost) when the computer decided it was a good time to turn off the engine. Since they have air brakes, they don't last long. This was only two weeks after I started to drive alone after training. I was ready to pee myself. |
