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Fredk20716 · 03-12-2018, 07:36 PM

Searched and couldn't find an answer so if it has been answered excuse me.

Doing a brake job on my 2002 P32 8.L. I’ve done a little research and see that there is a specific brake fluid recommended (DOT 3 part# 1052535) for use in this model. I’m guessing this is an old WH part # equal to some GM part #. Does anyone know if this is still valid or has the type been upgraded to a new type (DOT 4 or 5)? Told DOT 5 is petroleum based and should not be used or mixed with DOT 3 or 4.

What do you use for your 1999-2003? Thanks in advance.

BFlinn181 · 03-12-2018, 08:19 PM

If you haven't done a brake fluid flush to get rid of the old, it would be a good time to do it, as you know brake fluid is hygroscopic. DOT 4 is superior to DOT 3, so an upgrade to DOT 4 would be a good move. 3 and 4 can be mixed if needed, but a complete change of fluid is best to get rid of any water in the system periodically.

Dougsee3 · 03-13-2018, 10:56 AM

From reading a few articles over the years. I will stay with a name brand Dot 3
As my system was supplied or specified.
On a quick search this siite provides my reason why. But have read the same technical reason for Dot 3 use over the years.

Brake Fluid

vettenuts · 03-13-2018, 05:42 PM

I went with Castrol DOT 4, which replaced the Castrol LMA. The LMA stands for Low Moisture Absorption. The newer DOT 4 carries in the same LMA properties with higher wet and dry boiling points. I felt that low moisture absorption and higher boiling points were all good attributes to have in the braking system for something this heavy.

tmw188 · 03-22-2018, 02:52 PM

Yes DOT 4 if you are bleeding it all or not.

WeatherTodd · 04-01-2018, 10:52 AM

Quote:

Originally Posted by vettenuts

I went with Castrol DOT 4, which replaced the Castrol LMA. The LMA stands for Low Moisture Absorption. The newer DOT 4 carries in the same LMA properties with higher wet and dry boiling points. I felt that low moisture absorption and higher boiling points were all good attributes to have in the braking system for something this heavy.

eh... not sure thats even possible IF you use the brakes ALOT. On long grades... its better to use the transmission versus the brakes. Another thing I realized from "high performance" experimentation... we were using standard auto parts DOT 4 at events from a fresh bottle properly bled/fluid level. Other teams were using $60/pint fancy fluid... chasing their tails wondering whats wrong with their brakes!