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switching out brake fluid from silicone to Castrol

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bighealeysource

bighealeysource

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Hey y'all,
Going to a local Healey club tech session on Saturday and
a couple of the guys have suggested I will get a firmer
brake pedal if I switch back to Castrol brake fluid from the
current silicone I have been using. Also, per them should be
no issue with flushing the system of the silicone and or damage
to the system when making this switch. When brakes were completely
redone and all new parts put in only silicone has been used.
If I can get better braking or a firmer pedal I am okay with
doing this - thought I would see what y'all think. This is on
my 58 BN6.
Thanks,
Mike
 
Hi Mike,

after using both types of fluid I'd say you won't see any difference, all other things being equal. I prefer silicone fluid because it doesn't eat paint nor draw in atmospheric moisture and so is more suited to classic car use.

I know several people who have gone the other way, conventional > silicone and spent a fair amount of time blowing meths/air down the master cylinder to flush out all the old fluid. Didn't hear any bad results, although I'd be surprised if every last drop of old fluid was expelled.

You will most likely get a bigger improvement by changing the rubber hoses for stainless steel if they aren't already (check safety standard compliance for your region).


Cheers,
Andy.
 
Been there done that. I did not do a flush of the silicone before putting the Castrol in. I had lots of trouble, more with the clutch than the brakes. I would say it is too late to switch if all you want is a better pedal.
 
do you compete with the car? If not then my recommendation is to keep the silicone. Better by far for classic cars than Dot 3/4.

If you want a firmer pedal:1 make sure the brakes are adjusted(rears), 2, if you haven't replaced your rubber hoses with braided, do so.3, bleed properly. A good two man bleed; one at each wheel, starting right rear, and one inside working the pedal...

fill the reservoir. wait 30-60 seconds after a slow pour in. then the pedal pusher push the pedal to the floor three times,not pumping it rapidly, but nice leisurely full pedal depression. On the third pedal depression, while the pedal is being held applied, the wheel worker will open the bleed screw until the pedal drops to the floor. Repeat each wheel three times... Checking the master cylinder between switching to each wheel. Your pedal firmness will not get any better after this type bleed(which is the best way, in my mind) no matter which fluid you install.
 
Thanks y'all ! I kinda of thought it would not make a big difference despite what one person told me but certainly was worth looking into. I was concerned how you would get all of the silicone out. I'm participating in a Tech session on brakes with my local LBC club and my car is the one we are going to work on so figured I would get some good advice.
Thanks,
Mike
 
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