Brake questions

[7mmTCU]

Starting to go thru my new truck checking fluids and learning its sounds.

I expected to see purple brake fluid but I found yellow (see picture of a sample I pulled from the MC)! I am assuming that DOT5 only comes in purple, correct? The fluid is nice and clear, just yellow!

If so, assuming DOT 5 only comes in purple. I guess this truck has had the DOT5 replaced by DOT3 and I'll stick with it. From what I read here DOT 5 to DOT 3 is OK for the seals and has some advantage of absorbing moisture instead of rejecting it and letting it settle to the low spots. Just need to remember to flush periodically.

Wanted to make sure which fluid before I flushed the lines.

On to the next thing. I have good pedal and the truck stops good but I noticed two things. First, with air in the tanks and the engine off I press on the brake and I hear a continual sound of air escaping. Pressing harder seems to increase the amount of escaping air. Is this correct?

Somewhere on here I read that there should be a short burst of escaping air when you let off the brake. Mine does not do that as far as I can tell.

Also, when I press really hard I feel like the pedal may be coming to a mechanical limit and I press the pedal no further. If everything is like it ought to be should I be able to get to a mechanical limit in the pedal travel?

Reading about lubing the air pac mine does not have the plug to remove(picture attached). I believe I read on here that I should remove the hose and add the oil thru the fitting. Correct?

Any help or advice is certainly appreciated.

Dean

 

[WillWagner]

When BFS gets old it turns amber. If the truck came out of service from Uncle Sugar, it has old BFS. BFS...dot5 is not the same as civi dot3 or dot5. You can flush the system out with what ever flavor brake fluid you choose to use...I did mine with plain 'ol Prestone dot3 and have had no issues for 5 years +. Just make sure you flush it thoroughly. As for the air pac, you have the newer short style, there is no lube point on it. When the air is up and you depress the brake pedal..engine off..you should hear a hiss. If not, the air pac might not be working.

HTH, welcome to SteelSoldiers from So. Cal!!

 

[998Junkie]

When BFS gets old it turns amber.


HTH, welcome to SteelSoldiers from So. Cal!!

 

[hndrsonj]

Yep old DOT 5 is yellow. Don't mix with DOT 3.

 

[7mmTCU]

Thanks guys. Sounds like my air pac is working correctly.

Until I can get some real stuff is it ok to use consumer DOT 5?

Dean

 

[WillWagner]

The two don't mix. The BFS and dot 5 you get at Kragan are not the same.

 

[Recovry4x4]

You can remove the steel "J" tube and put air tool oil in the can of the airpack for lube. As far as the escaping air, are you noticing a quick loss of air? Double check to make sure the drivers side glad hand valve is closed.

 

[MrAugust]

my brand new dot 5 is yellow in the ltr can and purple in the 500 ml can... it mixes ok...

 

[WOLFMAN1]

i have a few questions. where is the air pack? my vent tube is missing and shoots fluid out of the master cylinder brass fitting for vent tube. is there an easier way to cvap the system w/o poping a seal. someone suggested that i run a line from the cap to inside the cab for air to vent. if so what kind of hose or line should i use. don't rubber lines breakdown from brake fluid? help is needed here. i want the brakes to work withoput losing the fluid in the process.

 

[stumps]

The two don't mix. The BFS and dot 5 you get at Kragan are not the same.

I don't know what Kragan is, but the Silicone DOT5 that NAPA sells is the same as the MIL BFS.

-Chuck

 

[doghead]

Yup, Auto Zone or Advance Auto had DOT 5 and it is indead, the same as BFS.

 

[7mmTCU]

You can remove the steel "J" tube and put air tool oil in the can of the airpack for lube. As far as the escaping air, are you noticing a quick loss of air? Double check to make sure the drivers side glad hand valve is closed.

Thanks for the advice on the J tube. I guess I'll go ahead and lube it as a required maintenence activity. Although I am always leary of "don't broke it if it aint fixed" since I don't have any issues with stopping. Also, I'll check the glad hand. I was back there pressure washing and may have bumped it.



Any thoughts on my question about seemly being able to press hard enough on the pedal to get to what feels like a mechanical stop?

Thanks to all,
Dean

 

[7mmTCU]

Found the source of the air leak. Turned out to be the pressure switch on the air pac plumbing.
Dean

 

[wreckerman893]

my brand new dot 5 is yellow in the ltr can and purple in the 500 ml can... it mixes ok...

The last gallon of Milspec DOT 5 I got was yellow also.

 

[SoldierwithaM109A3]

I agree with Stumps Napa sells dot 5 and its purple the same stuff as Mil

 

[gimpyrobb]

I agree with Stumps Napa sells dot 5 and its purple the same stuff as Mil

Yeah, have you priced it at Napa? WOW

 

[3rdmdqm]

I priced it at NAPA, and yes WOW. $26 a quart. I just replaced all of my brakes and wheel cylinders. The fluid that came out was yellow like yours. The fluid I put back in was purple. I mixed some of the two together in a jar just to be safe and they mix, do not separate and are the same/compatible. I flushed and bled the whole system doing a complete fluid change.

 

[stumps]

The NAPA price is indeed high, but compared having to use DOT3 in an emergency, and then having to tear the entire system down and clean out the unwanted DOT3 later, I'll pay the extra cost for the NAPA... in a pinch.

...though I much prefer to buy it ahead from just about any of the surplus guys.

-Chuck

 

[gimpyrobb]

Yeah, after buying surplus gallons for $30, the price I was given at Napa, I had to sit down for a minute.

 

[Valence]

Old thread, but I'm getting ready to rebuild an airpack and replace my master cylinder. I have some older DOT 5 brake fluid in a jug that is already amber (the container was opened a couple years ago). Is it okay to use? (What's in my truck is already amber, ie: old DOT 5).

I honed out and rebuilt all 6 wheel cylinders 1 year ago. I'm tempted to just flush out the old and buy some new purple DOT 5.