Dot 5 Brake fluid

[Mopar5]

Im about to put on the master cylinder here and considering DOT5 fluid. Brake system is all new including lines. Do you think DOT 5 is a good choice? Thanks in advance

[1970 cuda Joe]

I know some aren't going to agree with me, but I just had to go back through an entire system because of Dot5. I had leaks that wouldn't go away & when I bled the brake, the fluid had a grayish tint. When I pulled it all apart, so of the rubber was deteriorating. Everything was new on the car & most likely offshore. Used over a gallon of denatured alcohol to clean the system. Rebuilt the m/c, calipers, & wheel cyl. Put it back together with all new Dot4 & now no problems. I did some research as to what might've been the problem & my research said it was a combination of new style rubber & reformulated Dot5 fluid. I know lots of people swear by it & maybe it's ok in the older systems.....Joe

[Racer57]

Is there anyway to determined whats in a system ?

[Finoke]

I've gone to Dot 5 several times with no issues. But everything needs to be new and free of fluid.

[b5cuda]

I've run DOT5 in my old cars for almost 20 years, no issues and safe on paint.

[JH27N0B]

I've used DOT 5 in one of my cars.  It was a fresh restoration with all new components.  It was a chore to fully bleed the brakes, DOT 5 is harder to bleed.  It's easy to get it frothy and have trapped air bubbles if you aren't slow and deliberate about filling and bleeding the system.

[torredcuda]

As said the initial bleed takes a little longer but I`ve been running Dot 5 going on 30 years with no issues.

[Jay Bee]

Dot5 all the way. Switched to it 2011, added/bled in 2021, never had a single issue. No fears of the pictured situation again. Click the pic for a closer look.

[Katfish]

I'm with JB, it's not if, it's when does the DOT 4 eat your paint.