Silicon Brake Fuild

[Keith]

Hello
Has anyone expereinced lack of braking effiency/balancing of the brakes when using silicon brake fluid. I have a curious problem that I am trying to solve. My car failed the MOT on the offside front brake being less efficent than the nearside I suspect it maybe the brake fuild. The lining and cylinders are in excellent condition, brakes are adjusted ok, I have replaced the flexible pipe, the drum is ok, no scores, no leaks, I have bleed the system twice, but still have the problem.....any suggestions

thanks

[olonas]

Keith, totally irrelevant and useless reply - but - I have silicon fluid in two Minors, Saloon & Traveller. The Saloon for two and a half years and the Traveller for 8 months without any problems whatsoever and in the case of the saloon no obvious deterioration of seals etc. I've heard of instances of difficulties in removing air from system when using silicon fluid but have never experienced the problem. I think the pedal is a bit "softer" with the silicon. Are all the wheel cylinders the same bore? Are you sure that none of them have seized? Is the lining material on the shoes the same. Has the problem only happened since changing the fluid?

[Keith]

No, the problem hasn't happen since changing the fluid. I did change one of the cylinders recently, as you say it maybe trapped air in the system. I'll rebleed the system again and see what happens. I was just curious if anyone else had experienced problems.
thanks

[olonas]

Keith, my personal preference, when bleeding brakes is to use an "Eezibleed." Unfortunately there isn't a suitable fluid reservoir cap included for the Lockheed master cylinder in the kit. An adaptor can be made up using an old Lockheed Minor reservoir cap by drilling the centre and tapping out to 1/8BSP to accept the pipe end from the fluid container.
However, don't waste your cash if you are not happy about adapting a cap.

[Keith]

thanks for the advice, I'll give the rebleed a go.....

[Chris Morley]

I'm sure the silicon fluid has nothing to do with this. It shouldn't be compressible, and even if it was the Offside would have the advantage as the pipework from the 3-way union is shorter than that to the Nearside.

Compressible air somewhere in the system after the 3-way union is probably to blame, but it could also be:
1) an obstruction within the pipework, thus reducing the fluid pressure (including the small bridge pipe between the cylinders). It shouldn't be the flexible hose as you've just replaced it.
2) one of the cylinders is not as efficient as the other - possibly the old one you didn't replace.
3) The new cylinder isn't up to it (as Olonas described). Did this come from a Minor supplier / is it a Lockheed original? Cheap copies may not be able to do the same job.

[newagetraveller]

Try using emery paper to roughen up the inside of the brake drum.

[tuning72]

Hi
My last effort you will be pleased to hear.(Bought 3 special Mini`s).
I suggest all things are checked on EACH front wheel. Tyres,air pressures,type,suspension,drums,shoes, I also suspect the ONE new cyl. is more effecient than others. When bleeding brakes make sure in right sequence.(All brakes will operate at the same time whatever the length/distance from m/cyl). Use a NON RETURN VALVE on bleeding tube,not expensive. Make sure the tyre tread pattern are similar and same wear depth..............Ivor.........

[olonas]

Keith, just another thought, you mentioned that one of the front wheel cylinders had been renewed, was this because of a fluid leak? If it was, were the linings contaminated with brake fluid? If so, there's your probable loss of efficiency. You are now going to say that the cylinder was renewed in the more efficient drum!

[Keith]

Thanks for all the suggestions, after some swapping of brake shoes left to right, I have discovered that the off side shoes were contaminated from the cylinder leak, so the last suggestion was correct.

many thanks again.... I take back my doubt about Silicone fluid.....well until the next time.....

[olonas]

Keith, sorry about going on again. Maybe you're already aware but it's not worth trying to clean the contaminated shoe(s). Keep safe and replace them. Don't risk it for the sake of a few quid.
You may have noticed that I posted a question re tension springs. During the shoe exchange I renewed a wheel cylinder. Guess what, I' ve introduced some air that I can't get rid of.