purge troubles

[zpromax777]

Hi all. Have a small, but frustrating problem. The purge plate on my air dryer will stick open. Truck is A2 with ABS and HALDEX N50011F air dryer. I pulled the snap rings and bottom cover off and O rings are ok and clean. Valve will blow/ pulse , especially on narrow road or traffic. A quick bump with a nut driver end and I am back on my way. Does This happen to anybody else

 

[juanprado]

Yes, it is common. the piston will stick. There is a lower rebuild kit. Clean and hone bore plus lube the o ring. Many have also replaced with a more modern design. Plenty of choices out there in the civy world. Ours does have a 24v heater so I don't know the weather in your parts so that could be a consideration to have a 24v compatible heater. Search on here as many threads on rebuild and conversions on the m939 platform.

If you do rebuild, change the cartridge also.

 

[Mullaney]

Hi all. Have a small, but frustrating problem. The purge plate on my air dryer will stick open. Truck is A2 with ABS and HALDEX N50011F air dryer. I pulled the snap rings and bottom cover off and O rings are ok and clean. Valve will blow/ pulse , especially on narrow road or traffic. A quick bump with a nut driver end and I am back on my way. Does This happen to anybody else

.
And often times, your hand (flat palm) on the bottom of the dryer will also do the same thing (fix your leak). Rebuilding and cleaning like @juanprado mentioned should solve the problem. Cleanliness is next to Godliness in your air system!

 

[mikev]

.
And often times, your hand (flat palm) on the bottom of the dryer will also do the same thing (fix your leak). Rebuilding and cleaning like @juanprado mentioned should solve the problem. Cleanliness is next to Godliness in your air system!

I can "vouch" for the flat palm technique...!!!

My dryer was leaking and I could not build up air pressure to release the spring brakes (gauges "stuck" at 30 psi and would not build pressure)...

Searched for leaks and found the dryer leaking. I put my palm over the air leak and after it built up air pressure, the valve closed and pressure built up to 130 psi on the air gauges...!!!

This was "discovered" after testing the air compressor (good to go - was "dreading" replacing that...) and searching for air leaks (so many lines, valves, fittings...)

 

[Mullaney]

I can "vouch" for the flat palm technique...!!!

My dryer was leaking and I could not build up air pressure to release the spring brakes (gauges "stuck" at 30 psi and would not build pressure)...

Searched for leaks and found the dryer leaking. I put my palm over the air leak and after it built up air pressure, the valve closed and pressure built up to 130 psi on the air gauges...!!!

This was "discovered" after testing the air compressor (good to go - was "dreading" replacing that...) and searching for air leaks (so many lines, valves, fittings...)

.
Awlright! Yes sir. It is pretty amazing how well it works. Ultimately, I used that trick several dozen times - culminating in the rebuild of the dryer. Found a rebuild kit and it was done in under an hour for about a hundred bucks...