• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Brake fluid flow test at -45 ° F

I have had the brake pedal seem like it was froze right at the top of the stroke, when it was extremely cold.
I always figured it was most likely condensation in the brake booster.
Maybe it was froze solid brake fluid instead. 🤷‍♂️
 
I was also, barely pressed the pedal. then waited a long time for her to return. Leaked, blew and filled with ravenol 5.1. in cold weather -40 the pedal was pressed as in summer
 
i ordered Neste, Castrol, Brembo, Shell. What liquid would you like to see in the test in the cold?
 
Brake fluid is hygroscopic (absorbs moisture from the air) and therefore loses its fluidity at low temperatures. It needs to be changed periodically.

Correct unless you run dot5. It is hydrophobic (repells water) and handles both lower temps and higher temps that normal brake fluid. All US military vehicles runs it for that reason.
Some people make the transition, but in my experience anytime someone goes from one to the the other, the seals all fail fairly soon. So I don’t recommend the swap unless you first change all the seals.
I am not sure about the 5.1- that is one I am not familiar with.
 
DOT5 really does not absorb moisture, used where equipment has been preserved for a long time. military equipment e.g.
Dot 5 cannot be mixed with Dot 4. They are completely different.
DOT5.1 can be mixed with Dot 4. But it is still better to completely clean the system of old fluid.
If add a spoonful of shit to a barrel of honey, there will be a barrel of shit.
 
Dot 5 cannot be mixed with Dot 4. They are completely different.

That's not true. You can mix them. (If they actually mix is not relevant.) Then about a week later you replace everything in the brake system with a seal or rubber part. Master cylinder, ABS unit, wheel cylinders, proportioning valve, calipers... Some DipS%$# did this in a quickie lube place to a lot of vehicles and the reputation loss put them out of business.

And I agree with not being around when F and C scales are the same number for temperature. No, No thank you!
 
Last edited:
Whenever I do a total brake rebuild on any vehicle within My possession, it always gets the DOT 5 conversion. That information gets marked under the hood where it is visible.
If I would sell that vehicle, there is always a verbal warning, the painted on warning pointed out and a bottle of DOT 5 goes with the vehicle.
 
Not sure of the brand, most likely got it from NAPA.
I’ll try to remember and see what the brand is, tomorrow.
Well, I guess this is tomorrow. It iz after midnight. 😹😹😹
 
About an extreme case, you can add antifreeze instead of brake fluid. DOT 4, DOT 5.1 and antifreeze are made on the same basis.
For example: You damaged a pipe or hose break system in a back country, lost fluid. reparied or block part of the system and you need to fill the system. If you have Dot4 or Dot 5.1, you can add antifreeze. but if antifreeze is added to DOT 5, segregation a precipitate , which will paralyze the brake system.
I do not recommend anyone experimenting with brakes. described an unlikely but not fantastic case.
 
Back
Top