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Freightrain

Compressor feed line replacement

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What are you guys doing for replacing the old copper line on a B model?

Went to move truck and heard a hiss noise after shutting it down.   Found a pin hole in the feed line off the compressor, in the Z bend right off the head.   Seems my flexpipe off the turbo must have sunk a touch and rubbed a tiny hole in the line.  I desperately need the truck this weekend.  I soldered the hole shut for now, will likely wrap with a piece of hose and hose clamp it for extra protection.  

I know most newer trucks use a stainless flex line and hope to leave work after lunch and do some checking around town and see what I can find.

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The new stuff is teflon DOT approved.  Still have one truck on copper.  Others were so banged up and got replaced with the new.

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Will it bend around stuff?  I need the ol zig zag to clear the exhaust.   Typical DOT plastic will not bend very sharp.

 

The majority of the truck(mostly the back) is all plastic, along with anything I added up front beyond original plumbing.

 

 

Edited by Freightrain

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3 hours ago, Freightrain said:

Will it bend around stuff?  I need the ol zig zag to clear the exhaust.   Typical DOT plastic will not bend very sharp.

 

The majority of the truck(mostly the back) is all plastic, along with anything I added up front beyond original plumbing.

 

 

It will bend within reason.

It is special Teflon (PFTE) hose that can take the high temp. that the compressed air comes out of the compressor discharge.  A good truck store will have it on the shelf.

I have a 6 ft or so section between the compressor and air dryer on the B75.

 

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Ya, they have it.  Just not the right fitting for my compressor.  I need to make a block so I can put an AN fitting on it to fit the new style hose.

Looks like I need to maker work for the weekend and tear into it Monday.

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Uugh.  There is always a glitch...

 

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you gotta run at least some heat resistant stuff back 4-5 feet. the compressed air is HOT and it will melt the regular black nylon air line. i think i did run 5/8 copper off the compressor of my B then went to a flex stainless on the transmission then nylon from there. i tried finding 3/4 copper like the original and came ip empty then just went with 5/8 and changed the block on the side of the compressor

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I ran the dot Teflon stuff with the stainless braid from the compressor to the wet tank.  The ends that where on my truck where reusable just had to get new compression rings for in them.   What I ran into was the line was a size bigger then what is common today.    Like said above you can't use regular plastic line off compressor it won't hold up to the heat.   

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I do not know about the discharge line off the compressor but the intake off the air cleaner is the same as heat pump air conditioner copper used for home units . I used the teflon stainless braid from Truck Pro to the copper line to the tank .

 

 

 

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16 hours ago, Maddog13407 said:

you gotta run at least some heat resistant stuff back 4-5 feet. the compressed air is HOT and it will melt the regular black nylon air line. i think i did run 5/8 copper off the compressor of my B then went to a flex stainless on the transmission then nylon from there. i tried finding 3/4 copper like the original and came ip empty then just went with 5/8 and changed the block on the side of the compressor

 I went to a HVAC commercial contractor and they had a couple feet of 3/4 OD soft anneal copper tube in the scrap bin. They use 3/4 SACT in most all commercial AC, Heat Pump installs. Got it for my mixer in swap for a coffee.

Edited by 41chevy
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Well, I got a Volvo braided air line installed.  Works fine, though it was quite the PITA to get it all sorted out.

My only question is the truck seems to loose air pressure quicker lately once you shut it off.  It used to last 1/2 day or so at worst.  Now it drops in a couple hours.  Can the compressor unloader valve leak air back out when the motor is off?  Or maybe the compressor is worn enough that it is leaking past the rings?  I have the rebuilt compressor from my 673 laying there just in case.  I kept it since I knew it was brand new and for what I was selling the motor for, I wasn't giving it away with it.

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On 9/24/2018 at 9:25 AM, Freightrain said:

Well, I got a Volvo braided air line installed.  Works fine, though it was quite the PITA to get it all sorted out.

My only question is the truck seems to loose air pressure quicker lately once you shut it off.  It used to last 1/2 day or so at worst.  Now it drops in a couple hours.  Can the compressor unloader valve leak air back out when the motor is off?  Or maybe the compressor is worn enough that it is leaking past the rings?  I have the rebuilt compressor from my 673 laying there just in case.  I kept it since I knew it was brand new and for what I was selling the motor for, I wasn't giving it away with it.

Sorry you had to put a Volvo part under the hood.

Leakage past the discharge valve can be checked by using shop air back through the discharge port and listen for escaping air.  The unloader can be check by building up air until the governor cuts off.  Shut the engine off and listen for air escaping from the compressor air intake.

Sometimes governors can bleed off a little air off when they are not supposed to.  Used to be kits for a rebuild but now it is just R and R.

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Well, made my trip to Pittsburgh last weekend.   Seems it fixed itself.  It holds air without much fuss and even after like 8 hours the shutters were still closed(which means it was holding air).  Not sure what the deal was when I tested it with shop air and it leaked off kinda fast.  On the road, the compressor didn't have to cycle hardly at all while cruising at 70 mph.  I was watching the gauge to see if it dropped off in 10-15 minutes, and it didn't hardly budge.

I made a new gasket for the adapter plate on the head(for the line to attach).   I sprayed water on it and saw a few bubbles.   I made it new, but remade it and that seemed to help with any bubbles showing.

Life is good again.  Just a few more trips this year and it's back in hibernation til next April.

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Your doing good with your air leaks.  How about you come stop my oil leaks.  

  The other day my shutters opened up in just a few hours for some reason.   They usually stay closed for about a week.  Ever since they have been staying closed like before.  Guess it didn't like the air that was in it that day.   

Edited by Hobert62

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