MMDC air sensors, replacement (?)

[GCecchetto]

Pretty sure I was reading a thread here on SS about a guy that had found a replacement for the air sensors that go bad in the MMDC's and was replacing them. I seem to remember that he thought they went bad from moisture and had installed some small inline air driers in the air lines that feed the MMDC in hopes of preventing these failures. I've searched and searched and cannot find the thread. Does this sound familiar to anyone, and if so, can you point me to this thread? My truck has no issues with the air pressure gauges and would like to install the inline air dryers to hopefully keep it that way. Thanks

 

[GeneralDisorder]

That was me. It was just a post in a thread not a thread unto itself.

A0, A1, A1R and TM's

Mine is a C7.

www.steelsoldiers.com

When it comes to A1R's there's not many people on here that own them and work on them.

I have since changed out the filters since those had issues with the filter body's not sealing well with the DOT tubing fittings I used. These seem to be working fine though:

Amazon.com

 

[GCecchetto]

That was me. It was just a post in a thread not a thread unto itself.

A0, A1, A1R and TM's

Mine is a C7.

www.steelsoldiers.com

When it comes to A1R's there's not many people on here that own them and work on them.

I have since changed out the filters since those had issues with the filter body's not sealing well with the DOT tubing fittings I used. These seem to be working fine though:

Amazon.com

Thanks. Have you had the filters in place long enough to have figured out the lifespan of the desiccant?

 

[GeneralDisorder]

Thanks. Have you had the filters in place long enough to have figured out the lifespan of the desiccant?

There's not a lot of air movement across them if you get the system perfectly sealed, so they should last quite a while. Mine are still purple - may have lightened a bit but look OK to my eye. Given the manufacturer put nothing at all in the truck to protect them other than the main air dryer I'm not that concerned. It was just an easy and cheap upgrade to try to help them out. I would change them every time the main dryer is serviced. I haven't had a single issue with my transducers since repairing them. As Honeywell makes the replacement sensor I've repaired a few more MMDC's now:

https://www.mouser.com/ProductDetail/Honeywell/NSCSSNN150PDUNV?qs=C%2F0tY%2F%2FqZe9ewEwKCB2V2A%3D%3D

The replacement sensor is the same just runs off a wider voltage range than the original. Direct replacement.

 

[GCecchetto]

Thanks, I know who to talk to if mine fails I also ordered the newer style dryer that MWME sells. Supposedly does a better job of drying the air. They have 10% off on everything on their site currently, so the new dryer was basically the same cost as the parts to service mine.

 

[GeneralDisorder]

Thanks, I new who to talk to if mine fails I also ordered the newer style dryer that MWME sells. Supposedly does a better job of drying the air. They have 10% off on everything on their site currently, so the new dryer was basically the same cost as the parts to service mine.

You should already have the top-of-the-line Haldex PURest dryer...... the MWM "upgrade" appears to be the Haldex/Bendix AD9 which is a very common unit but is NOT better than the PURest dryer. Not according to Haldex anyway. And you don't have the clamps for the AD9 because you don't have the A0/A1 style dryer. I would service what came with your truck.

 

[GCecchetto]

MWME says it's a direct replacement for my new style dryer on the truck. Everything, other than the electrical plug is supposed to be a direct bolt on. Do you have a good source for the parts to rebuild the factory dryer? Anyone offer a kit with everything in it vs sourcing each part?

 

[GCecchetto]

Yep, s usual, you are correct, it isn't going to fit. I was talking with Joe and told him my truck was an 08 A1R with latest Haldex dryer and he recommended this over servicing mine and said it was a direct fit. Just spoke with someone else in parts and they are emailing me a label to send it back.

 

[GeneralDisorder]

I just get the dryer cartridge from my local NAPA. They had the best price.

The major and minor kit if you need them are on Amazon or FindItParts or both.

The "service" is just the cartridge which only takes about 10 minutes. The rest of the stuff is as-needed but you should probably do a major kit on it since it's probably never been done. I pulled mine off the truck but I think it could also be done in place.

The best part about the PURest dryer is how easy it is to service. Much easier than the A0/A1 dryer and the AD9. It's literally 4 bolts, remove cover and change the cartridge, then put it back on. Huge win in terms of service and if service is easier it will be performed more often (hopefully).

 

[GCecchetto]

I just get the dryer cartridge from my local NAPA. They had the best price.

The major and minor kit if you need them are on Amazon or FindItParts or both.

The "service" is just the cartridge which only takes about 10 minutes. The rest of the stuff is as-needed but you should probably do a major kit on it since it's probably never been done. I pulled mine off the truck but I think it could also be done in place.

The best part about the PURest dryer is how easy it is to service. Much easier than the A0/A1 dryer and the AD9. It's literally 4 bolts, remove cover and change the cartridge, then put it back on. Huge win in terms of service and if service is easier it will be performed more often (hopefully).

Thanks. I definitely want to do the full service. Do you know the specific Haldex model #? It appears there are multiple PURest models. Looked for a model # on mine but don't see one.

 

[GeneralDisorder]

Yes. It is a Haldex N50011H

4730-01-524-7892 is the NSN for the entire unit with mounting bracket.

 

[GCecchetto]

Yes. It is a Haldex N50011H

4730-01-524-7892 is the NSN for the entire unit with mounting bracket.

Thanks!

 

[GCecchetto]

FYI, spoke to Haldex tech support. They said the AD9 has less than half the drying capacity the PURest unit on our trucks has.

 

[GeneralDisorder]

FYI, spoke to Haldex tech support. They said the AD9 has less than half the drying capacity the PURest unit on our trucks has.

Yet another example of MWM's turd polishing practices. They don't equip the trucks with the right parts - they equip them with what returns the most money. And the AD9 can be found all over for dirt cheap. It's new and shiny and that's all you need to lure a first time buyer. Acela is the same way - I know customers and former employees of both. Neither one gets a cent of my money. I'll wait a year to find something on ebay or just build it myself.