Silicone fluid?

[taupe]

Hi

Im going to be replacing the complete braking system including pipes and cylinders on the traveller.

I have read previous threads and am considering using Automec silicone fluid.

Does anyone have good/bad experience of this?

[alex_holden]

It worked fine in the two vehicles I've used it in.

[MarkyB]

I'm a fan, fit and forget.
No more water getting drawn into the system and rusting thing up, result!
It can be more difficult to get a very hard pedal but well worth it in my opinion.
There will be people along soon to say the manufacturers of brake systems don't recommend it, but then turkeys never vote for Christmas either

[charlie_morris_minor]

i have used silicon and it gets my vote everytime provided that you are replacing all pipes etc as you are. you should never mix the two types of fluid.

[bmcecosse]

If it's such great stuff - how come modern cars don't use ?
Can only be used if the complete braking system is being renewed - as is stated in the original thread. Personall - I don't see the need, and ordinary fluid is fine - just bleed some through each year. Saves the bleed nipples seizing up.

[Alec]

Hello Taupe,

I have never used anything else since the mid seventies, and not found any drawbacks, cost excepted. Doesn't strip paint either.
Automec say that it can be mixed with conventional brake fluid however.
Certainly car manufacturers don't use it, it would cost them more and they are not concerned about the fact you need to replace the fluid they use on a regular basis.

Alec

[alanworland]

Great stuff, no probs with it at all! If the manufacturers used it nobody would buy any new cylinders!

[Innovator]

There are some disadvantages to silicon, the primary one for me is that it is slightly compressable which results in a less hard pedal. I prefer a rock solid pedal in my cars because it is easier to modulate pressure than movement. This probably isnt an issue on a standard Minor with drums.

Modern cars dont use silicon because of the cost and I have read that it isnt compatable with the valving used in ABS.

I also heard that because silicon fluid doesnt absorb moisture if any does get into the system it will puddle causing localised corrosion. Quite how it can get in I dont know.

I also read that silicon fluid is harder to seal. It tends to weep past or through seals.

[rayofleamington]

If it's such great stuff - how come modern cars don't use ?

1) It costs more than standard brake fluid
2) Dealers make money from servicing so why pay more for a fluid that doesn't need changing? It won't make the car easier to sell.
3) usually #1 and #2 is enough for the car industry... however the risk of getting airborne silicon fluid in a car plant does not bear thinking about. At one end of a car plant is the paint area, and airborne silicon (with the wind blowing the right way) could scrap a million quids worth of cars far too easily.
[silicon contamination on a bare vehicle shell will wreck the paint finish)


As for Silicon in a Minor - I would never mix fuids with old seals. Working in automotive hydraulics was a real eye opener. A brake fluid seal is almost a living thing and it's properties + composition will change depending on which fluid it's used in. Using one fluid then another is 'bad practise'. Many perople get away with it, but not everyone - taking risks with brakes is not recommended!
I've used silicon on a Minor with a complete new system. It was absolutely fine. I did take a lot of care but managed to get a good pedal just as easily as with normal fluid.
Silicon does not disperse trtapped air quite as well, so if you get a problem to bleed the system, it can be worse with silicon.

[taupe]

Thanks for all the responses

I think I will go with the Automec silicone as Im putting in a complete new set of lines and cylinders.

I can understand that it might not mix with old seals and fluid but otherwise Im not hearing any big negatives and not having to bleed annually, dispose of old fluid etc is a big plus for me.

Im staying with a completely standard set up.

I had trouble with my old MG magnette (very similar brakes to the minor) with water corrosion in the cyls - though probably my own fault due to being too lazy to change the fluid.

Regards

Taupe

[bmcecosse]

" complete new set of lines and cylinders. " Hopefully including a new master cylinder if changing the fluid - otherwise - there may be trouble ahead!

[taupe]

Yep

Got a new old stock master cyl this week - now have a complete set

[bmcecosse]

And new flexis !

[taupe]

Yep

Already have them

[d_harris]

with a NOS m/c - being a minimum of 35 years old now, I'd crack it open and check that everything is ok in there before fitting....

[taupe]

Ive already unclipped the circlip and popped out the seals springs and shuttle thingy.

Seals all look and feel as new and the bore is perfect. I had brought a new replacement seal set just in case but will keep as a spare.

Thanks

[d_harris]

Good news then!

[bmcecosse]

Well done - you've thought of everything! Good luck with it.