Any advantage or dis advantages to use or top off with # 5.1 break fluid? I have a ABS car- 1992 . Thanks!
Assuming you already have DOT 3 or DOT 4, DOT 5.1 can have a higher boiling point than the other two fluids, useful if you take your car on the track or tow a heavy trailer on steep hills.
The disadvantage is considerably higher cost. Some high boiling point brake fluids absorb moisture more readily, and thus need to be changed more often to maintain that high boiling point.
DOT 3 and DOT 4 can be topped off with DOT 5.1, but these three fluids should never be mixed with DOT 5.
Dave
5.1 has a lower viscosity which works better with antilock brakes. It also has a lower moisture absorpion rate than Dot 3 & 4. Cost is slightly higher but not that much. It is brakes on a Jaguar after all. Motul 5.1 can be had for around $11 per pint on various vendors. Not much more than conventional Dot 4.
Thanks to both of you. I knew that 5.0 was BAD news for mixing, et cetera! You would think that DOT would pick a new # (not 5.x) for a newer, approved fluid! I’ll buy a pint for routine post blead top off’s. Had 4 of my front 8 break pistons lock up hard to date. Now I’ll try to do better on the maintance.
i stamped dot 4 on the support for master cyl. that way there should be no question what it calls for