Purple/yellow Dot 5 mixing?

[vtach]

Okay, so the truck is stenciled "use silicone brake fluid only". I pulled some of the yellowish fluid from the MC and put it in a jar of water and it did not mix. I think this confirms that I have silicone dot 5. I bought some Napa dot 5 silicone brake fluid but it is purple. Can I mix the purple stuff with the yellow that is already in the truck?

Also, my brakes feel mushy but they work. The fluid in the MC is bearly low, any ideas? Bleed them?

 

[atilathehun]

dot 5 will compress more than 3 i have been told it is not a good idea to mix 3 and 5 if they are both 5 i would say go for it wont hurt to flush out the yellow 5 there is no telling how long it has been in there

 

[sermis]

Bleed the air and adjust the shoes.
I have mixed both colors of DOT 5 and not had any problems.
Check the classifieds here and buy you a gallon of DOT 5 which is mil spec.

 

[randyscycle]

Purple DOT 5 will turn yellow after a long time. Not sure why, but I have had a few containers of it that were half used, and sat on my shelf for a long time (4-5 years) and they turned yellow.

 

[wdbtchr]

I don't know if it's the same for brake fluid, but the purple dye we put in synthetic fire resistant aircraft hydraulic fluid was designed to fade to indicate the exposure of the fluid in service. If it got to hot, oxidized, or absorbed moisture it would fade out to indicate the need to replace. Maybe they do the same for brake fluid?

 

[littlebob]

While replacing the brake parts on my Deuce, I have noticed the fluid seems more purple when I first open the container but is more yellow when i open it up later to top it off.

 

[ctmustang]

I checked with a NAPA rep. about some dot 5 being purple and some yellow when new and after he checked he told me it was ok to mix and the color diff. was because it was from 2 different manufacturers. I mixed the two and have had no problems.

 

[CARNAC]

There was a very informative post about a year or 18 months ago by David Doyle about mixing DOT 3 and 5 and the testing the military did. Bottom line, it wasn't dangerous to do. Now as far as age...I'm changing out all my fluids this week in prep for the big trip.

 

[Brock Steel]

Same stuff different color. Bleed out the old and replace with the Barnie Purple your peddle with feel much better.

 

[vtdeucedriver]

Interesting thread as I have added the purple to my M151 and it had the yellow in it previously. My current issue is that with each brake application, I am building pressure and eventually I will get a rock hard pedal and I will start to drag the brakes..............Think the master is shot, what you guys think?

 

[Jake0147]

How are the brakes boosted on those? Or are they boosted?. My first thought is a master cylinder push rod adjustment or a sticky brake pedal not quite releasing all the way.

 

[DREAD KT]

Bleed the air and adjust the shoes.
I have mixed both colors of DOT 5 and not had any problems.
Check the classifieds here and buy you a gallon of DOT 5 which is mil spec.

All good advice from the contributors on this subject. Just checked the brake fluid in the clutch reservoir that had turned yellow and mixed some with water to confirm it is DOT 5. Need to top up now but will eventually have to flush it. Thanks to all!

 

[ihavea65]

wait........bells in my head ringing! I have a new, old, 1968 5 ton, I think it is a M39? Anyway, I was driving it home and the brakes AND the clutch both stopped working in my driveway. You mentioned CLUTCH RESERVOIR? DO the brakes and clutch both share a master cylinder? This would make sense that they both went out. Yes, the master IS leaking and empty, AND adjusting the clutch linkage didn't help the clutch engage. This must be the answer! I saw a master and I saw a rebuild kit, half price. Would you recommend the new master cylinder from Boyce or the kit?