Since I have 4 C4s and all of them don't get driven as often,I was going to switch over to the DOT 5 silicone brake fluid to help eliminate moisture. On consulting the shop manual I found a waring against using silicone, but not why. Aybody know why not??????
Puzzled

 

I have read that silicone brake fluid is NOT recommended for cars with ABS, that was in the catalog.(I think it was in Mid America?)

 

silicone brake fluid has an ''off-gassing'' problem....which means that vapor is released from the liquid...since vapor=gas, and gases are compressible, you won't have brakes....at least thats the theory to explain loss of braking by silicone fluid users,especially in mountainous areas

 

1. The rubber seals in the system are not designed for use with silicone brake fluid. This often leads to leaks and poor performance due to either rubber swelling improperly or rubber deteriorating.

2. The seals absorb some of the regular fluid, which then causes even more problems when you have them mixed with silicone. At the least, you are supposed to change all the rubber components in the system when switching.

3. Silicone fluid is more compressible, leading to spongy pedal and less stopping power.

4. Silicone does not absorb water, so any water that gets into the system pools in a few locations, causing corrosion.


All of this could have been found with a web search.

 

DOT 3 standard is good enough for me

 

Vavoline Synpower Brake Fluid. Great stuff!!!

 

DOT 3 is something you'll always find in stores, and if you get a synthetic you should be fine longer than a normal DOT3 fluid.

DOT4 is also out for you, since it generally requires changing a bit more often than DOT3.

 

First time I've ever heard this. A quick google search turned up only links saying the opposite. Can you provide us a reference?

 

http://www.stoptech.com/tech_info/wp...fluid_1a.shtml

"DOT 4 fluids are also glycol ether based, but have a measure of borate esters thrown in for improved properties including increased dry and wet boiling points. A seldom talked about characteristic though is that because of this chemistry, the DOT 4 fluid will have a more stable and higher boiling point during the early portion of its life, but ironically once the fluid does actually begin to absorb water its boiling point will typically fall off more rapidly than a typical DOT 3. By FMVSS116 standards, DOT 4 fluids must have a minimum dry boiling point of 446F and a minimum wet boiling point of 311F.

Does this make DOT 4 fluids better than DOT 3 fluids? Not always. Remember, the boiling points listed are minimums and there are DOT 3 fluids out there with higher boiling points than some DOT 4 fluids. The real differentiating factor should be that if you run a DOT 4 fluid you really should change the fluid more often than if you use a DOT 3, if for no other reason than the rapid fall off in boiling point with time."

 

After some research the bottom line is that ABS sytems don't like it due to the higher viscosity screwing up the pulsing action.
Thanks All

 

The outgassing, or passing vapor (gases) into the fluid results in cavitation in the ABS pump when it operates. This gas wil be in the form of bubbles and is compressible. The gas pressure will cause fluid to flow back into the master cylinder reservoir and effectively results in "air" in the brake lines.

For general street use, a good quality DOT3 fluid is fine and DOT3 is what came in the car originally. Castrol LMA is a excellent fluid as is Valvoline SynPower. Another good choice is the Ford Motorsports HD fluid.

It's a good idea to do a complete fluid flush every few years anyway. Brake fluid doesn't cost a lot of money.

 

This is all i buy anymore. It's relatively cheap and is compatible with traditional DOT3 and DOT4 (or so it says on the package... I've never had a problem).

 

True, DOT4 can be considered to require changing a bit more often, however a bit more often is a very unspecific term. Your post involves an assumption that is not necessarily true.

You got your quote from the StopTech page that you posted
http://www.stoptech.com/tech_info/wp...fluid_1a.shtml.
The reason I believe that Vis Croceus had a different (and correct) understanding with respect to DOT4, is because you failed to also post a quote from another article at the same site that would contradict your assumption. The StopTech article you quote does not specifcally state that DOT4 significantly decreases the period between required fluid changes, and based upon another article from the same site it appears that the difference in DOT3/DOT4 change intervals would be neglible for most drivers.

From: http://www.stoptech.com/tech_info/wp...edbrakes.shtml
1. Under normal operating conditions, and without brake system modifications, typical OEM braking systems have been designed to NOT require bleeding for the life of the vehicle unless the system is opened for repair or replacement. If you're just driving around town or on the highway to work, there is really no need to bleed!

For jan soroka it may actually be an advantage to use DOT4. Based upon the second article from the StopTech site, bleeding the brakes once every several years would be far more frequent than "the life of the vehicle", and more than adequate. Using DOT4 would provide better stopping capability both wet and dry and could still be in the superior range of its life with respect to DOT3 if he bled the brakes every few years.

 

Hardly anybody uses DOT 3 anymore here in Germany. I wouldn't even now where it buy it. Look at the intervals of changing fluids from ATE; DOT 3 every year and DOT 4 every 3 years.
http://www.conti-online.com/generato...f_info_en.html


Arnold

 

Now why would I post something that directly contradicts what I've already posted? If I always did that, then I'd never really be saying anything now would I? I can always find links that contradict anything anyone ever posts here, but I go by what I believe is most correct and thats what I've posted.

Because of its more hydroscopic nature I see nothing in your post that convinces me that DOT4 will end up better for a car that sits most of the time. His original post says he wants to eliminate or reduce moisture problems. If he always does routine maintenance, then it wont matter which he uses for a street car, but I dont believe he's going to do that.

 

A good quality high temp dot 3 is all you ever need. Even in our racing applications some are still using it effectively. I hate to say this but....gulp...the high temp Ford stuff is pretty good.
ok ok......valvoline synpower rocks too lol.

 

As an alternative to changing a less hydroscopic brake fluid, perhaps
installing Speed Bleeders might be a solution?

You would still need to bleed the brakes periodically but the Speed
Bleeders would make the job simpler, faster and a one-person operation.

For my purposes, I bleed a few times per year. This is not necessary
for a vehicle that is not being driven in a manner that builds a lot of
heat in the brakes. If you can tolerate a lower boiling point, then
there are DOT 3 fluids that are less hydroscopic than others and which
will let you effectively extend the interval between bleeding.

In practice, a lot of cars go a long time between brake fluid changes.
As long as someone chose an appropriate fluid and didn't go to the
track or try to make Deadman's Curve at the bottom of Dragon's Breath
Mountain, I think a two year or greater interval could be tolerated
without adverse mild braking or corrosion results.

.

 

I have had great results Valvoline SynPower. I use it in all my vehicles. I change it out every 2 years or when redoing the brake pads.

 

i can't remember the specifics, but the ford brake fluid is supposed to be the best stuff. it's some big name bought in bulk and sold cheap. i think. aren't i helpful and specific?

all right, i looked it up on the web real quick and found this:


DOT Brake Fluid Specs
>- - ---------------------
>
>DOT 3 DOT 4 DOT 5 Ford DOT3HD (these numbers aren't lining up right. just line up DOT3 w/first > ----- ----- -----
>Dry Boiling Point 401F 446F 500F 550F
>Wet Boiling Point 284F 311F 356F ?
>
>Are there other differences? I already know the DOT 5 is silicone
>based and incompatible (another reason to dislike silicone!) with
>glycol based DOT 3 &4.
>
>(Here's some more info on it, the email address for the persons
>posting this back in '96 bounce, so I haven't been able to get any
>info from the horse's mouth.)
>
>>>Just thought I'd add to the thread -- lots'a racers use Ford High
>>>Performance -- doesn't sound as glitsy as Mutul or ATE Super (whatever color
>>>they have now), but it does have a dry boiling point of 550F and is about $4
>>>a pint. Funny thing is that when I bought it, the Ford parts guy asked if I
>>>was putting it in an Acura or a race car when I said it wasn't for a Ford --
>>>'parently it's a big time secret for you NSX'ers out there too..... Rumor
>>>has it that it's made by Castrol -- anybody know fur sure?
>>
>>I learned about this when I was on Fordnatics. Basically, Ford designed
>>one of their full-size trucks with the brake line right next to the
>>exhaust. People had trouble with this heating the brake fluid too much.
>>So rather than redesign their trucks (and so the solution would help the
>>owners of the few million already built), they made high-temp brake fluid
>>available at relatively inexpensive prices. Rumor has it that it is
>>really some godawfully expensive European brand repackaged. Many racers
>>use this. It's come up among the Mustang crowd, on the autox list,
>>somewhere I remember in the context of BMW's... Definitely worth a try.
>>I've used it for two years now and it works just as well as the racing fluid I
>>used previously at 1/3 the cost! Works on the track or the street.
>>Ford Part No. C6AZ-19542-AA
>
>And...
>
>>You have the story right about the Ford Heavy Duty Brake fluid. The
>>Autocross and racing crowd swear by it. I have used it in several cars
>>over the last 4 years. On track I never have got it to go spungy! Very
>>high boiling point as you said.

Ford changed the part number. It is now PM-1/FIR 002092. This is the High Performance DOT 3 brake fluid that has a minimum dry boiling point of 550 degrees F (288 degrees C), which actually exceeds DOT-5 specifications



all right this is me talking now. i looked on the valvoline site and it said their synthetic has a dry boiling point of 500 degrees.