Brake fluid
Turbo Mini Forums

I've been servicing one of the mini's and decided to bleed some fresh fluid into the brakes.

It's only been bled through once since we got the car in 1998, and the foul mucky coloured stuff that came out made me realise I should make the effort to this more often.

So, if your car is overdue a brake fluid change think about doing it as soon as you can. You may be surprised at the state of the fluid that comes out.

Cheers

Neil

thats true neil

best if your purse strings allow it!

is to use silicone

job sorted no more corrosion U/S cylinders etc

its in there for the life of the car

but the brake fluid companys dont want us all to know this!

It's kind to paint as well, but I heard it can react with the seals if your braking system is quite old. Is this true? Is it better to use silicone fluid when the whole brake system is new or has been restored with new parts?

silicone is not good at high temps thou...

not much use on track!

alex

AlexF

Had very very nasty experiences with silicone in my old MGB (had it in when I got it). As the old Lockeed warning says:- "Can cause spontaneous and complete loss of breaking efficiency"

Slowing down to avoid an accident on the M1, peddle just went like a sponge and couldnt put any more brake pressure down. Had to make some very very rapid manuvres to dodge the problem. Stopped immediately on the hard shoulder and waited to call the RAC to pick me up - i thought the master cylinder had let go or i'd blown a pipe.

Turns out that 2 things had happened -it had eaten the seals on the rear drums (not completely), and the front disks had overheated the fluid.... (according to the MG Motorsport chap I asked for a second opinion when i tried to bleed the brakes down and got bggr all)

May or may not have been the fluid, but there are dire, dire warnings against it in many haynes manuals..

Just 2p's worth - anyone had any other experiences with it?

for got to mention when systems NEW or been fully restored

neTgen did you replace the old fluid for silicone ?

whats a good fluid for cars that are used for track days and road blasts? i was gonna use silicone, but ive kinda gone off the idea after reading the above..... dot5?

And on the 7th day........... God created turbochargers!

The higher the "DOT" number the higher the boiling point of the fluid. So for track use the higher the better. I use DOT5.1 in my track car.

Brakes on the MGB were completely restored (and clean as a whistle) - i knew the previous owner well and had done some of the work with him. Like I said, its only my experience and there are a number of factors in play.
I was in a couple of other nasty situations later on, and they held up then on std fluid.

Anyone else got any experience? I'd love to know as it is a damn sight cheaper and I've heard it can preserve your breaking system (thats why it was in the system in the MGB).

I used silicone brake fluid in my 8 port estate. All components were new when I used it.

That car did trackdays at Goodwood, Cadwell Park, Thruxston, Mallory, Binbrook airfield, Castle Combe, and all the road miles between with no brake problems at all.

Maybe I don't use my brakes enough.... :)

I have made many cautionary comments about silicone brake in the past and appear still to have been ignored.

PLEASE READ THIS AND TAKE NOTICE.

http://www.apracing.com/car/brakefluid/inf...conebrakefluids

I have first hand experience under race conditions of the problems with this type of fluid, including two occasions where I have spun and flown backwards through the air at 100 mph as a direct result of using silicone brake fluid.

Dave.

All of the components in my braking system were AP, and in 1998 when I put the car together I did check with reputable sources (admittedly not AP) if silicone fluid was ok to use.

I'm not saying people should use it or shouldn't use it, I'm just stating I've used it on the road and under trackday conditions and had no problems.

People should, as I did in 1998, make their own decisions based on the information available at the time :)

Cheers

Neil

well the information available at the time is right there on that link neil, I'm not being nasty about it but if you choose to ignore facts that are clearly stated by a major manufacturer then you do so at your own peril.

I know that people have used the stuff and got away with it, I didn't have any luck at all with it. At the time I was having the problems I spoke to two miglia racers who were having similar episodes of irregular braking. They both changed back to glycol fluid and both cars showed an immediate improvement in braking efficiency and stability. Basically every time I pressed the brake pedal hard, I didn't know if the car was gonna shoot off left, right, in a straight line, lock the rears or indeed not pull up at all.

I have studied this problem at great length and expense, having replaced every single component in my braking system before I heard about the possibility of the problem being down to the silicone fluid. As soon as I replaced the fluid it was perfect.

In my opinion, which is shared by many racers, the stuff is feckin dangerous.

Dave.

No offence taken. I do appreciate the need for safe, reliable braking, as is hopfully obvious from the very first post in this thread.

I am not choosing to ignore any facts, I am merely stating facts. I cannot comment on your experiences, and I am not inclined to force my own opinion or experiences on anyone else.

It's good that both sides are shown like this, then people can make informed decisions.

Truth be known, when I rebuild the car later in the year, I am planning on totally renewing the brake system, and this time I'll be using dot 5.1 brake fluid to see if I feel it's better than DOT4 or silicone.

Cheers

Neil

Edit to add - I didn't have access to the internet in 1998 :)

Edited by Neil8p on 18th Mar, 2005.

I never realised until I studied the facts hard that the fluid could cause such a problem. As you will probably know, my mini is constructed using very high quality components, all of which are new. The car always has extensive scheduled maintainance as well as running repairs. It was therefore a complete mystery as to why we were having such problems. I even withdrew from a sprint after the first practice run simply because the brakes were so unpredictable that I feared I was gonna seriously hurt myself. I refused to use the car at all until the problem was sorted.

At first nobody could answer my question. Everyone had an opinion, which usually involved replacing a specific component. After replacing the lot I happened to be chatting to a mate in the pub about it and he said, quite innocently as he is not an engineer, "ok you've replaced everything, but what about the fluid?" I thought, oh well I may as well give it a go. So I put 5.1 in there and the problem was immediately solved. I couldn't believe it.

I then emailed a couple of brake manufacturers and asked their respective technical departments if they had any information on problems caused by the use of silicone fluid. AP Racing sent me that link and a very interesting fact sheet outlining specific cases of brake failure caused by the stuff.

Silicone fluid was primarily designed for use in motorcycle braking systems. Because they are only using a very small amount of fluid, have separate front and rear braking reservoirs, and of course they only have a front and rear wheel, not one at each corner, the side to side and front to rear braking imbalance that can effect cars does not effect bikes.

I simply want all of my mini friends to have safe cars. This site deals a lot with extremely fast turbocharged cars which are more likely to need better brakes too. So please take my advice, steer clear of this stuff, brake safely and don't hurt yourselves.

Dave

I could not agree more about safe cars, which was why I posted in the first place.

I've seen your car at the rolling road day, and the build is a credit to you so I don't doubt your findings. If I'd known about this at the time I probably would not have gone with silicone fluild.

I don't think there's much more to say. I guess I was lucky not to experience any problems with my brakes.

Thanks for the info - alway something new to learn :)

Cheers

Neil

Dont use silicone fluid in your brakes. I would say that is is good to use in your clutch.

The higher DOT number dosen't always give you a fluid with the highest boiling point. Just about all serious competition fluids are a DOT 4. I'd go for a lockheed (690 i think) or brembo do some good stuff as well. I use a lockheed equiv product in my race cars, i can supply it if anyone is interested at around ?10 for 0.5 litre.

dont F1 cars use DOT 3?

alex

AlexF

Never been told to change my brake fluid ill do it this weekend! Think mines been in the system since the eighties!

Previous Engine: 1040cc Morespeed engine, 1275 turbo head T2 Turbo Mirage Manifolds Megajolt
Previous engine: STD metro turbo, megajolt
Drives: 399bananahp (flywheel) Honda Civic Vtec b18c4 T28 Turbo 1968 Mini

Megajolt maps to download: http://www.jamesfawcett.co.uk/cms/index.ph...&gid=3&Itemid=3

Give the bleed nipples the good news with some wd40 before you do it otherwise theres a fair chance you will be buying a new pair of rear wheel cylinders as well as new brake fluid!!!

Thanks tvr. I posted to make it clear that I've had problems with it, and that in personal experience I could not put it down solely to the fluid - what was needed was more personal experience, although with brakes this would tend to come the hard way.

Dire warnings are appreciated.
Ed.

Great to see everyone taking notice on this safety issue.

As far as i'm concerned every day is a school day, none of us know it all. But it's great to have a good place like here to share our experiences, good or bad.

Dave.

Good call Dave.

I was bought up on the "The man who never made any mistakes made fuck all" theory.

Certainly sorts the wheat from the chaff - especially when it comes to arrogant twats like RR operators!

could not AGREE more T VR , T dave

same school of thought !