killain

I need to change all four brake calipers and I was wondering if it's worthwhile to drain the system and switch over to silicon brake fluid. What has been your experience doing this?

mrvette

I can't imagine a shark without SS calipers, as by now they allmost all been replaced at least once....so the use of dot5 fluid is highly recommended by me....

do the Master cyl also....parts house 20 bux....
get the VBP O ring pistons and don't use the spring behind them....

GENE

PatG

I agree with everything that Gene said except the master cylinder part. I switched to dot 5 last year and bought a rebuilt MC instead of trying to clean out the old one. I have already had to replace it due to failure. I got a new one online from Rock Auto http://www.rockauto.com/ for about $70. I will never buy another cheapo remanfuctured MC.

killain

Why do I need to remove the springs Gene?


[Modified by killain, 7:44 PM 12/14/2002]

GDaina

spring put a drag on the rotors, too musch resistance w/springs

yellow 72

The stock piston springs won't overcome the o-rings friction, so they are of no use with this type piston :cheers:

74_LS-4

Silicone (DOT 5) used to be the way to go some years ago. Today, most who track their cars use DOT 4. Silicone fluid gives you a mushy pedal. The latest generation of DOT 4 glycol fluids have boiling points and specs that meet or exceed Silicone fluids, with no mushy pedal either.

Go with Castrol SRF or Motul. They are the best. I like SRF. You should also flush it every so often too. That's really the best way to solve the moisture problem. Although Silicone fluid can't absorb water, it can still find it's way into the system.

http://www.centralcoastweb.com/nsxb/pages/m17.html

Rgds,
Jim


[Modified by 74_LS-4, 10:22 PM 12/14/2002]

RJR99SS

If you were to go with silicon, you'd NEED to flush out the entire brake system. Glycol based brake fluid and silicon based dont get along together.

So you'd basically have to open all of the brake lines and flush them out with rubbing alcohol or possibly compressed air.

Now...as others have pointed out. Why bother?

For one...you wont notice any difference at all unless you're autocrossing with this thing. Another reason is that silicon dosnt absorb water like glycol does. So if you ever get water in the lines (which you will) it will just collect right at the caliper (the lowest part of the system) which is the worst place you'd want water.

So, if you're a racer or something it MAY be the way to go, but if you're just driving your vette normally you should just stick to dot 3 or 4.

74_LS-4

Actually, if you're racing you'll definately don't want silicone. Stick with a quality DOT 4 and flush it every year if you race or every other year if don't.

-Jim

mrvette

KIllian, the springs do nothing but encourage pumping from what the factory would call excessive rotor runout...side to side, like it's warped type movement...as the stock pistons follow that with the springs, air is sucked into the system in the calipers....no brakes then....pedal to floor....

mostly seen on rear brakes for some reason...sometimes the hubs need work....

now the factory would have you beleive 4-5 mils is the tolerance for runout....I say pull the springs and runout up to 1/16 inch....that is .0625 or so is tolerable....all it does is push the pads out of the way, much as it would on a floating caliper design and therefore take a slight bit more pedal to activate.....not enough to notice though....

I would rather see maybe as much as 2-3 pin drops of water in the calipers than an entire rusted out system......especially if it sits in the garage or gets lo mileage.....rusted rotted out lines, calipers, M/cyl are not fun either....
all fluids except dot5 are hydroscopic....meaning they actualaly ATTRACT WATER....soak it up like a sponge....apparently right through the rubber brake hoses.....

GENE

GWilliam

The water still gets in the system regardless of the brake fluid.
Because DOT5 doesn't absorb the water (like all the others) guess what,
you have a bigger problem with pure water corroding your brake system!

GDaina

I don't know about that, I've got DOT 5 and the pedal is rock solid.

Guest

Killain,
I've been using Dot 5 in everything for the last 5 years. I just finished up a complete brake job with S.S. calipers and Dot 5. All you need is to bleed the brakes good and you will have a firm pedal. Great stuff, won't take paint off either. You can flush your system with 1 Qt. of Dot 5 (simpliest method) or denatured alcohol with compressed air, then install your components, lines etc., then fill and bleed the system.

hunt4cleanair

Killain

Once you've read through this feedback...you may come up confused but actually you must weight the advantages and disadvantages of the various brake fluids versus your requirements and use of the car.

But I think its safe to state that we would all agree if you plan to change all four calipers and fluid, then pull your master cylinder and check it out as well. Without attention to the M/C, you may compromise whatever good you do by changing fluid and the calipers.

Someone mentioned pulling the springs and I agree unless you plan to install new rotors and true them. My silicone system was plagued with a mushy pedal due to the affinity of silicone to attract air generated by the pistons pumping against the marginal runout of the rotors. You remove the springs and you remove the air induced by excessive or even moderate runout. Once I removed the springs...hard pedal was the norm.

pws69

"Silicone fluid gives you a mushy pedal"

I disagree - my pedal is VERY solid since I went with DOT 5.

ZD75blue

What they mean by a mushy brake pedal is that under extreme conditions, when you slam your foot to the floor, it takes a split second longer because the silicone fluid will actually compress.

Not mushy by any stretch of the imagination, but... not as hard as dot 3 and 4.

PatG

There are obviously many opinions on this issue. In the end you will have to read up and make the choice for yourself. Here is a write up I found with some nice facts and comparisons on the various fluids.

http://www.buckeyetriumphs.org/techn...luid/Fluid.htm