Hey guys, I put onbrake calipers from an 07 Street Glide onto my 96 Road King yesterday , they fit great with the adapter. But, which brake fluid do I use.
HDTech here on the forum says dot 4 is amber in color and dot 5 is purple, when I took the cap off the reservoir I found amber colored fluid but the cap on the reservoir says use dot 5 what do you think.
Thanks

 

My 07 touring manual says dot 4

 

The factory fill for the '07 is DOT4, DOT5 for the '96. The two are not chemically compatible, and I've had DOT5 that was not purple, so I would assume it is DOT5 and purge the calipers thoroughly if you plan on using DOT5. But to be safe, I'd purge the entire front system thoroughly to be sure, rear too if you changed it. There should be no remnants of the old fluid, whichever it is, before the final fill. There's nothing magical about DOT4 except it is more compatible with ABS, and I suspect HD was phasing DOT4 in gradually for that purpose. DOT5 compresses 10% more than DOT4, and that is not a good thing with the way ABS works. DOT4 absorbs water while DOT5 doesn't, and that is a mixed bag in terms of which is preferable. I've had DOT5 in my antique car for 25 years without problems, and haven't changed it but maybe twice in that period. DOT4 should be changed every two years or 30k miles, whichever comes first. DOT4 also can remove paint, so be careful working with it around painted surfaces.

 

I would purge it all with brake cleaner a couple of times and run dot 4, dot 5 is horrible.

 

Shooter, why is DOT 5 horrible? I used it for years on old cars, and liked it with my EVO RK. Just curious.