Silicon Brake Fluid

Quagmire

Active Member
#2
I have silicon in my series 2 Landrover and its been excellent - the car doesn't do many miles at all and the brakes are always perfect (which is saying something for drums) the system has needed literally zero maintenance. I decided to go for it as my dad had a load of it sloshing about at the time and I was rebuilding the system completely so everything was fresh and had no old regular fluid left over in the system. Bonus is that it doesn't attack paintwork!
 

keynsham1

Active Member
#4
Be very careful! I used silicon fluid in an MG Midget I used to own and it was really good so when I got the P6, after fully rebuilding the brake system with new seals, I used it again. It made all the rubber seals swell and the brakes started to drag and the pedal went very strange. The fluid will attack rubber if it is not the right type and cause all sorts of issues. I also read that because it doesn't absorb moisture, that any moisture that may be in your braking system from condensation in the flued reservoir for example, could cause further corrosion. I decided that there was no real good reason to bother with it. normal fluid is cheap and readily available and of your braking system is in good condition, there is little maintenance needed apart from the occasional bleeding and fluid change. It certainly caused me a lot of cost and trouble!
 

sdibbers

Well-Known Member
#5
Do you have the slightly spongy pedal that l've seen reported as the biggest downside?
That’s more just people in pubs making it up. Generally you’ll only feel the sponginess on highly servoed applications during racing. As long as the seals are compatible with DOT5 fluid it’s a great upgrade if everything is replaced.

I also read that because it doesn't absorb moisture, that any moisture that may be in your braking system from condensation in the flued reservoir for example, could cause further corrosion.
That makes no sense. As water is not absorbed it would stay where it is, unlike conventional DOT3/4 where it finds itself everywhere. As a general rule a car with DOT5 that sits a lot is far more usable. And even if it’s used on dailies it’ll hold up just as well. I have a friend with a Healey BT7 that has used silicon for years. And even after 15 month layup the brakes were just as he left them.
 
#6
It's the same elsewhere on the net, conflicting opinions. :LOL:
I've decided to stick with the devil l know, if only because of the trouble that silicon causes in a paint shop. Not that she should be in my brothers place very much. The Oxford's easy to bleed too which aids fluid renewal.
 

keynsham1

Active Member
#7
That makes no sense. As water is not absorbed it would stay where it is, unlike conventional DOT3/4 where it finds itself everywhere. As a general rule a car with DOT5 that sits a lot is far more usable. And even if it’s used on dailies it’ll hold up just as well. I have a friend with a Healey BT7 that has used silicon for years. And even after 15 month layup the brakes were just as he left them.
Any water in the system can pool because it is not absorbed by the fluid. This can then lead to local corrosion issues apparently. Not my words but something I read. TBH I would avoid it completely unless you are using it in a vehicle that was designed for it. There just isn't any need. It's just an opinion though. I loved the stuff when I had it in My MG Midget as it was fine. It was the Rover that had all the problems with seals. Maybe the replacement seals I used on the Midget were silicon fluid proof and the ones I used on the Rover weren't!

Anyway we might all have to struggle with E10 petrol soon so yet another non compatible fluid!!:eek::eek::eek::eek:
 
Top