help with air system

I used a reman dryer and it's a AD9. I have a C15 acert in the truck and I know I got the right dryer.

 

I stopped by the dealer yesterday in between loads and had them look at it again. I unhooked the the supply line that goes from the compressor to the dryer and I only got a small amount of air to leak out so I was told that meant the check valve in the dryer was working.

I've talked to 7 different mechanics at 4 different dealers plus you guys on here and everyone says that I've checked everything there is to check. I did talk to a friend of mine who said he had the same problem with one of his trucks and after doing everything I've done he went ahead and replaced the compressor and that solved the problem. I asked my mechanic about that and he said that he did notice that the compressor seemed to pump a little slow and maybe it isn't building enough pressure quick enough to make the system work. So I bought a new compressor and a guy is going to help me put it on this afternoon and see what happens.

I don't know what else to do, I've either checked or replaced everything else in the system. Some things I've even double checked.



ETA: I changed the compressor yesterday(very easy job on the 9900ix/C15 combo)and even though the new compressor pumps alot faster and is quieter it didn't fix the problem. I'm at my wits end with this thing so I called my mechanic up and said I'm bringing it up and do whatever it takes to make it right. I drove the entire 40mile trip to the dealer with the compressor trying to fill the tanks but the air was purging out the bottom of the dryer. I was a couple of miles from the dealer and had to stop at a light and that was enought to get the air down far enough to trigger the low air warning light. I still had four more lights to go through and I thought "this is going to be fun", I got close to the next light and started slowing down to try to keep from stopping and low and behold the system let the compressor fill the tanks.

 

this is what I'm trying to get my dealer to check. But since they already put a new purge valve in the reman and the check valve in the dryer that is behind the hot line from the compressor works they keep saying that there is nothing else that should be wrong with the dryer.

It really ticks me off, I've thrown more parts into this thing trying to figure it out than I needed to and they won't even pull the airdryer off and try a different one. If the new one doesn't make a difference after one or two compressor cycles they could always pull it back off and keep it to put on someone elses truck since it is still basically new.

I talked to a guy that said maybe there is a bad check valve in either the airtanks or between the tanks and the back of the dryer. I'm going to call my mechanic on Mon morning and see what they think about that idea.

 

The purge valve has also stayed open at lower rpm's also. The other day I started the truck up and while it was still at slow idle the compressor tried to fill the tanks and the purge valve just spit the air out. I let the truck run for 4min at speeds ranging from low idle to 1300 rpm's trying to get the system to work right. I then shut the truck off and restarted it about 15min later, at which time the compressor strted filling the tanks right away. I had already made arrangments with my dad to use his truck to finish my load and he would take mine back home and he said on his way home the compressor would start in around 100psi and would spit air out the purge valve until the air tanks would get down to 90 psi then the valve would close and allow the tanks to be filled.

 

The spacer is fine, I looked at it before I installed it to the new compressor. The braided airline to the dryer is something I'll have to check.

I'll call my mechanic in the morning and tell him to check that along with any check valves that might be behind the airdryer.

A friend of mine says it's probably a $10 part that is causing all the trouble. He's probably right.