Sign in to follow this  
Followers 0
Mack58B42

air line question B85

5 posts in this topic

Hi,

I have a question that I'm hoping someone mechanical can answer.  I've attached a Word doc with a picture of my compressor (at least I THINK that's what it is!) and the main air line that comes off it.  I can't quite tell for sure where it goes, although I assume it's the air tank.  Anyway, if you look at the spot where the arrow is pointing, the copper line and the SS braided line have been rubbing together so long that it has created a leak in the braided line, and if the copper line isn't leaking, it appears to be rubbed almost all the way through.

This leak has been there for quite a while, but recently got a bit worse, so it was time to crawl around and find out where the issue was.  I was hoping it would just be a loose connection.  So much for that theory.  I do hold 100psi, although the compressor does run more to keep it there than it used to.  I can't afford to get it into the shop at the moment, but I do have a couple of places to bring it in the near future that are within 10 miles of home.

First, is it safe to assume that as long as I'm holding 100psi in the tank, that my brakes will work?  Does that SS braided line go right into the main tank?  And is that an original line?  Might anyone have the Mack part number for that so I can get the part on order, or see if I can find an equivalent?

I assume that if the line blows out, I'll know it, because the hiss would become a gush, and it would be obvious that I'd lost pressure.  If that happens, I'm also assuming that the Maxi-brake would kick in.  It would no doubt be an unpleasant stop, but I just want to make sure that that is also a correct assumption.

Just want to make sure that my assumptions aren't off base, and that I'm not completely crazy to keep driving it with the leak as it is....

 

Mike

air leak 071617.docx

Share this post


Link to post
Share on other sites

Don't have a part #.  Even if you had a number, no one would know what to do with it these days.  There is special type of DOT teflon hose now so that it can take the heat of the compressed air.  Take the old one off and a new one can be made at a good quality truck shop.  Take a good look at the copper line also.  It may be a wise decision to replace it while you are there.  Last time I bought the teflon hose it was $9.00/ft.  

If everything is is in good shape, the Maxi's would stop the truck at the loss of air.

Stay in the driveway until it is repaired.  

 

Share this post


Link to post
Share on other sites

Thanks for the advice.

BC- as a former firefighter, I am well versed with doing a pre-trip inspection and walk-around, and I take the time to do it before every trip.  When I first heard the hiss, out of curiosity, I checked the maxi by not engaging it when I parked, and when the air drained to 75psi, it did kick in automatically, so I'm fairly comfortable that that works.  But air systems are not my specialty, and I will peruse the docs you attached to get more up on that.  I certainly don't want any surprises with my brake pedal!

J - was speaking with someone at work this morning who is a mechanic, and he agrees with you that a good high-temp hose should be fine, so he's going to take it off, and we'll have a new hose made up to the right length and pop it back on.  He's worked in fleet maintenance in the past, and it sounds like he thinks it's a pretty straightforward job...

 

Thanks again!

Mike

Share this post


Link to post
Share on other sites

If I remember correctly from when I replaced my Teflon feed line.    Modern trucks use 5/8" line and my B was 3/4".     Everything was available just nobody local had on hand.   Bought the Teflon tubing with stainless braiding sleeve by the foot and reused my ends with new crush sleeves.   It goes together just like compression fittings on plastic airline.    

1 person likes this

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0