Has anyone used DOT 5 Brake Fluid in their XJS? 'The Book' recommends DOT 4, what is your experience w/DOT 5?

 

DOT 5 is a show car fluid. If you do a site search here, you will find a lot of disagreements on the fluids. DOT 5 is not a high speed capable fluid and all systems must be completely clean before putting into a system as not compatible with other fluids at all. Do a site search on most car forums and you will see the multitude of conflicting posts. Can cause heated arguments quickly.

 

DOT4 only. 5 is for racing and systems designed for it. Your seals and ABS (if equipped) will perish.

 

Use of DOT 5 requires complete draining and thorough flushing (including disassembly of some components) to remove all traces of DOT 3, 4, super 4 or 5.1

DOT 5 is NOT compatible with any other type of fluid.

Since there is no overall advantage with DOT 5, I wouldn't consider using it. It is not 'better' it's just different.

 

I thought it didn't strip the paint......That's a good advantage.

 

But it (DOT 5) requires extensive preparatory work to use it and is very susceptible to aeration, making bleeding a royal pain. It cannot be used with ABS systems.

That's a huge disadvantage.

 

An issue that is not an issue.


Dot 3/4 does just fine. so, why mess with 5???


I think my Jeep's ABS has gone AWOL? Do I care? Brakes just fine.
Might look when it warms up and dries oput around here and I finnish off this head cold!!





Carl

 

DOT 5 is a Silicone based brake fluid, and while it is more paint friendly and does not absorb water as much as DOT 3,4 and 5.1 it is NOT compatible with ABS!


DOT 5.1 is normal Polyethylene Glycol brake fluid, and is the brake fluid to go for if you have ABS!
DOT 5.1 has the same wet and dry boiling points as DOT 5 but is compatible with DOT 3 and 4


Dry Boiling point Wet Boiling point
DOT 5/5.1 500f (260c) 356f (260c)
DOT 4 446f (230c) 311f (155c)
DOT 3 401f (205c) 284f (140c)


Dry boiling point is for NEW fluid, Wet boiling point is about 3.7% water content, about 12 months OLD, in an average braking system.