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Posted: Tue Mar 29, 2005 11:31 am
by dragon
Um, thanks for the replies, Chris and Rich, but you both agree with the site, even though what happened to me and Mart _can't_ happen according to that site - that's the point I was making. I know the fluid boiled, it was obvious, but that site says it just doesn't happen that quickly, which it did.

Anyway, it's a moot point, designed to inspire thought :)

Posted: Wed Mar 30, 2005 10:07 am
by Turnipman
Ok so if you change the front brakes to a vented turbo set up can you leave the back as a solid ES setup?

When changeing pads/disks should you change all four corners?

Other than running with vented or cool running disks what other things can you do prevent Boiling of fluids?




Turnipman Mr question today.

:kill:

Posted: Wed Mar 30, 2005 10:16 am
by martinholmesuk
The rears are not vented on the 480's

I think Bobcat(?) used super bike brake fluid in his 850 t5

Posted: Wed Mar 30, 2005 10:35 am
by atex61
Content removed.

Posted: Wed Mar 30, 2005 7:46 pm
by rpruen
dragon wrote:Um, thanks for the replies, Chris and Rich, but you both agree with the site, even though what happened to me and Mart _can't_ happen according to that site - that's the point I was making. I know the fluid boiled, it was obvious, but that site says it just doesn't happen that quickly, which it did.

Anyway, it's a moot point, designed to inspire thought :)
By happening slowly they mean it takes time for the heat to soak into the fluid (I think). But the brakes will disapear very rapidly once the fluid gets hot, since it is possible to raise the temperature above it's boiling point (while under pressure), then release the pedal allowing the fluid to boil, next time you press the pedal it goes down a long way as you are truing to compress a gas.

Some of it is how you read things I guess.

Richard

Posted: Tue Apr 12, 2005 2:02 pm
by bobcat
Jaytee, if your brakes don't feel amazing, do a full fluid flush first. be warned though - I am reliably informed that the 480 braking systems contain components that are not designed to handle DOT 5.1 fluid - eventually it will go through the caliper and/or master cylinder seals. Use a good quality DOT 4 fluid instead.
chris1roll, you sure you dont mean dot 5?

dot 5.1 will be fine as it is the same as 3,4 and 4+.

however you cant use dot 5! its a silicone brake fluid and as mentioned it will eat away at your seals.

I use ate super blue and it exceeds all the specs even the latest 5.1. its blue in colour so makes bleeding very easy.

but any dot 5.1 will be fine and will have a higher boiling point than the original fluid that the 480's came with.

if you want good brakes then do the following:

steel braided brake lines (goodridge etc)
Dot 5.1 or higher brake fluid
performance pads (ferodo ds series, mintex 1144/1155)
slotted discs (more bite and better cooling)

also making sure your suspension is working well can make a huge diff to stopping!

Posted: Tue Apr 12, 2005 4:56 pm
by SanPhire
I've looked at getting steel-braided lines for my baby but always see them claimiing they are unavailable for ABS models - is there any truth in this or is it just I'm looking at wrong websites?

Posted: Tue Apr 12, 2005 5:08 pm
by chris1roll
yep you are right, DOt 5 is silicone based, whilst 5.1 is ether based like 3 + 4.

However, I am still going to stick with DOT 4:
another website said wrote: As a trailing note on the DOT ratings, if your car was designed for a particular type of fluid (especially prior to the development of DOT 4 fluids), you should make every attempt to stick with that fluid! For example, if your car was delivered with DOT 3 fluid, the internal components of the system (seals, brake hoses, and fittings for example) were specifically designed and tested for compatibility with DOT 3. Because DOT 4 fluids contain a different chemical composition, the system may not necessarily react in a positive fashion to the borate esters floating around in the mix.

In other cases, just the difference in viscosity of the two different fluids may cause the seals to wear at different rates. What starts as an annoying squeak might eventually become a torn seal or worse. The examples could go on and on, but the message here is this: it’s fine to upgrade from DOT 3 fluid A to DOT 3 fluid B, but you should think twice (maybe even three times) before switching from DOT 3 fluid A to DOT 4 fluid of any sort.

That said, when dealing with modern hydraulic braking systems a numerically higher DOT rating is typically considered to be compatible with a lower DOT rating (except for DOT 5, of course). Unfortunately, this same generality just isn’t true for most older hydraulic system materials
I'm not going to use my car to find out if the 480's braking system is sufficiently new to use 5.1!

Posted: Tue Apr 12, 2005 10:34 pm
by rpruen
The answer to the dot 5.1 question is likley to be no.

The seals in the 480 (yours being older) are not compatable with it, and the hoses are also not compatable.

Cars with the later type ABS with the ABS computer in the engine bay should be compatable, but I'm not taking any chances (as if an older caliper has been fitted from a scrap car....).

Richard