# DOT 5 and DOT 3 mixed... now what?

**URL:** <https://forums.speedlife.net/t/dot-5-and-dot-3-mixed-now-what/274677>\
**Category:** NYSpeed Automotive\
**Created:** [May 14, 2017, 6:23pm UTC](https://forums.speedlife.net/t/dot-5-and-dot-3-mixed-now-what/274677 "2017-05-14T18:23:14Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![KuntryQuestTSi](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/kuntryquesttsi/32/5010_2.png) [@KuntryQuestTSi](https://forums.speedlife.net/u/KuntryQuestTSi)\
**Post date:** [May 14, 2017, 6:23pm UTC](https://forums.speedlife.net/t/dot-5-and-dot-3-mixed-now-what/274677/1 "2017-05-14T18:23:14Z")

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So I have been having problems with the brakes on my 67 f100 for some time now. Ive replaced the rubber lines on the wheel ends, they where shot, all the shoes hardware and drums. when I did all that 4 years ago I dumped DOT 3 in. Its been Sitting in storage sense. I noticed the fluid was dark, but figured it was old. Last year I replaced the master cylinder as the pedal was getting really weak and going to the floor, This year I replaced all the wheel cylinders.  
I ran into the previous owner and was telling him about the work and he mentioned he used DOT 5 in the truck. Not 5.1, just 5.  
From what I’m reading I should dump everything and flush the system with denatured alcohol. I’m also going to replace the combination valve to be sure.  
Anything else I should be doing?

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**Author:** ![Quattro\_Krant](https://avatars.discourse-cdn.com/v4/letter/q/ac91a4/32.png) [@Quattro\_Krant](https://forums.speedlife.net/u/Quattro_Krant)\
**Post date:** [May 22, 2017, 7:09pm UTC](https://forums.speedlife.net/t/dot-5-and-dot-3-mixed-now-what/274677/2 "2017-05-22T19:09:31Z")

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Stop worrying and let them average out to 4