615C Not build air past 60 PSI

[Brianr3989]

I can't get this machine to build air past 60 PSI. i have a new compressor and governor. Replace a valve that was leakingbut i can't find anything else that's leaking. Any help would be great at this point.

 

[Nige]

What's the S/N so I can pull up the air system & brakes operation.? There is more than one option.

 

[Brianr3989]

the S/N 9XG00948.

 

[Brianr3989]

I don't hear any leaks

 

[mitch504]

Assuming it is like a truck, disconnect the governor from the compressor, see if it builds

 

[Nige]

Here's the air system. The air pressure gauge #21 taps off the bottom of the brake treadle valve #19.
Is there any way you can tee in a pressure gauge between the compressor and the first check valve located between it and the wet tank and measure the pressure there.?

 

[Brianr3989]

I will see if there is a place to run a tee

 

[Nige]

Another thought. Do you have any confirmation that the gauge that is reading 60psi right now is accurate.? Could it have failed.?

 

[Brianr3989]

The brakes won't release at all

 

[Nige]

The brakes won't release at all

Good point. I suppose it might be worthwhile to check the pressure at the brake chamber at the same time as you're checking at the compressor exit, but TBH I'd suggest looking at the compressor end first.

 

[kshansen]

Any chance you have a source to plumb air to this machine, say from a shop air compressor or even a truck with air brakes you could run a hose from?

Just thinking that if you could easily tie in to the discharge line from the machine's air compressor to eliminated anything on the machine causing the problem.

Is this machine outside in the cold? Could there be ice in the system causing the problem?

Also I guess the first question is why you have a new compressor and governor? Did this problem show up before replacing them or it was the reason you did replace them? Coming in on a job after someone has tried replacing things in an effort to "fix" a problem can be tricky especially at a distance.

I know I'm asking question right and left and you really want answers but to give good answers often requires getting to know what has been done already.

 

[heymccall]

Chased my '69 Brockway with the same issue. Ended up being a carbon filled hose/ tube from the compressor head to the back.

 

[kshansen]

Just one thought this morning. You mentioned it would only build to 60 psi. Does it hold this pressure after shutting down?

Also any chance of posting a couple pictures showing the compressor and air governor as installed? No idea what it might show but never can tell.

 

[Vetech63]

Check the main pressure line from the compressor to the wet tank. I have had holes or ruptures in those that you can't hear when the machine is running, they don't leak air because of the check valve at the wet tank when you turn the machine off because there is no air in the line to leak, and it will build air to the point that the pressure will overcome what the leak is capable of holding in that line.

 

[Truck Shop]

heck the main pressure line from the compressor to the wet tank. I

Correct-That's a special discharge hose stainless braded outer with a teflon inner core. Those do rupture
frequently. If you have air at compressor and little at tank?

 

[kshansen]

Check the main pressure line from the compressor to the wet tank. I have had holes or ruptures in those that you can't hear when the machine is running, they don't leak air because of the check valve at the wet tank when you turn the machine off because there is no air in the line to leak, and it will build air to the point that the pressure will overcome what the leak is capable of holding in that line.

That is one of the ideas I was thinking about in my replies when I suggested hooking an independent source of air to confirm the problem is in the machines compressor or someplace else. Just might not have made it clear what my reasoning was.

 

[mitch504]

I see those braided hoses that just look porous, a thousand tiny holes. I guess it is a hard copper line on a 615c?

 

[Nige]

#2 might look like a tube on this illustration but in actual fact it's a Hose As, and as TS mentioned earlier it's of the high-temperature braided stainless steel variety.

 

[kshansen]

#2 might look like a tube on this illustration but in actual fact it's a Hose As, and as TS mentioned earlier it's of the high-temperature braided stainless steel variety.

View attachment 275790

That #2 line in the drawing is the inlet from the cylinder head right?

The discharge line from compressor would be #3 in the image below:

That would be the line I would be thinking of connecting to an external source of air. And as it appears to have an airdryer, if this drawing is right. then maybe that coould stand a close inspection as well!

 

[Truck Shop]

if this drawing is right

KS is that schematic from a 615? because if it is-that is one really outdated air dryer.
A real early version of a Wabco 1800 style. Those were problematic at best.
And if it does have a dryer, I seriously doubt it's ever been serviced.