Haldex to Wabco Air Dryer Swap Help Needed

[MSGulfCoast]

After neglecting to change the Haldex filter in a timely fashion it ruptured. Seeing as it's 20 years old I picked up a June 2015 manufacture date Meritor Wabco System Saver 1200 Plus dryer as a possible replacement.


I need the help of you fine folks with understanding what additional mods need to be made. The Wabco has a built in governor and I can't figure out if the Haldex system saver plus incorporated an external one that I need to bypass/remove if I make the swap.


It seems the connections are all the same fittings so that isn't an issue but on the existing incoming line from the compressor there is a "T" fitting with a 1/4" line - what is that? It's not the control line as that's a separate line.


Any advice would be much appreciated as I have to get the coach back in service since this is hurricane season. I know I can bypass if worse comes to worse but would prefer not to. TIA.

[Topman]

I replaced our Haldex dryer last year with a Wabco. The Haldex did not fail but I have heard of failures such as you describe.
What I did not like was the location of the Haldex. It was super difficult to reach up to replace the outer and inner filters.

So I moved the dryer to the rear of the coach so it would be accessible and easy to service.

Our Wabco is similar to yours but does not include the governor so it was a simple change over but I did have to extend the output air line due to relocating the dryer. The input line from the compressor was okay for length and the 1/4" line from the governor on the compressor needed to be shortened.

Others can chime in regarding bypassing the governor on the compressor if using the Wabco governor.

If you plan to keep the original position of the dryer, you likely will have to modify the mounting bracket. I believe Walt on this forum has pictures of that bracket.

[MSGulfCoast]

That might be an option since I have to come up with a new mounting plate of some kind anyway. Sure would make it easier to perform the maintenance so I wouldn't be as likely to let it happen again. Thanks for the pics.

[barmcd]

I have the Wabco on hand and have been exploring replacing the Haldex and relocating it to the rear of the coach. The only thing I'll have to do is extend the output line to the front tank. There is one other issue I've been debating. The Wabco does some type of drying/regeneration using air from the wet tank and Wabco says to install a 55 psi check valve to keep air in the tank if the dryer malfunctions. I've talked to a couple people and they didn't install that pressure dependent valve. The Haldex has an integral one way check valve in it to do this very thing. I'm still debating.

[Topman]

I did not install the check valve. Actually I didn't know I needed one. My dryer is the 1200 series but not the "Plus" model, so as you say it uses system air for regeneration. I'm not sure but I think the "plus" model has an integrated tank for air for regeneration.
If my dryer fails, because it is located just inside the engine door, I would be able to easily bypass the dryer temporarily with a fitting. Hopefully that won't happen but who knows.

[MSGulfCoast]

Hadn't seen the check valve thing. More research is warranted.



Any idea about the governor? Think I should have gotten the 1200 model not the Plus as it sounds less complicated.

[barmcd]

Originally Posted by MSGulfCoast

Hadn't seen the check valve thing. More research is warranted.



Any idea about the governor? Think I should have gotten the 1200 model not the Plus as it sounds less complicated.

Yeah, I got the 1200 and it uses an external governor so no changes with the switch out.

[barmcd]

This is how Wabco says the desiccant is regenerated.

"System Saver Series Single-Cartridge Air Dryer - The System Saver Series single-cartridge air dryer dries compressed air during the loaded cycle and regenerates (dries) the desiccant bed during the regeneration phase, which occurs when the compressor unloads."

Here's the how it does it.

"Regeneration valve opens. On 1200 regeneration models, when the regeneration valve opens, dry system air flows back through the dryer, 10 psi (69 kPa) is taken from the supply and secondary tanks for the regeneration. Back flow dries desiccant, preparing it for the next cycle."

That's why they recommend a check valve between the wet tank and drier. You can see them on the diagrams Wabco provides.

[BigLar368]

I am new to air dryer stuff. Just curious why the Wabco is more desirable than the Haldex? Our RV came with Wabco 1200 and it has worked great thus far. I am looking to change out the dryer filter. Anyone have any experience with the cheap ones from Amazon? Thanks.

[MSGulfCoast]

Originally Posted by BigLar368

I am new to air dryer stuff. Just curious why the Wabco is more desirable than the Haldex? Our RV came with Wabco 1200 and it has worked great thus far. I am looking to change out the dryer filter. Anyone have any experience with the cheap ones from Amazon? Thanks.

I'm far from an expert here but I can speak from personal experience when the Haldex filter ruptures it's mess.



I'm reading the Wabco won't fail in this manner but that it will just stop taking the water out of the incoming air. I can't positively say that is a fact however.


Another upside to switching is the cost of the cartridges (filters) being approximately 1/4 to 1/3 the price of the Haldex if that's anything.



Main takeaway is to change that freaking filter every other year and save yourself the PITA not doing it will cause.

[airbeat117]

Hey guys I have a dumb question. I have a new Haldex dryer which I need to replace my old one and the air lines do not have any metal connectors. They have a push fitting I guess but how do I get them out? I need to use the old fittings on the new dryer and if I cut the hose I will still have hose line inside the fitting. I'm sure I'm missing something and it's most likely an easy fix. Just don't know how that works. Thanks for any help.

[barmcd]

Originally Posted by airbeat117

Hey guys I have a dumb question. I have a new Haldex dryer which I need to replace my old one and the air lines do not have any metal connectors. They have a push fitting I guess but how do I get them out? I need to use the old fittings on the new dryer and if I cut the hose I will still have hose line inside the fitting. I'm sure I'm missing something and it's most likely an easy fix. Just don't know how that works. Thanks for any help.

They are push to release fittings. The collar is loose, you push it in to release the plastic hose. Most times, there is dirt packed into the area where you would push the fitting to release it. It needs to be cleaned out to allow the collar to move.

You can see the fitting in the center of this picture. The collar is just below the X in Haldex, it pushes to the left. The collar has to move a significant amount to allow you to pull the hose out to the right.



I use an open end wrench just about the size of the hose to move the colllar.

[CountryB]

I have the P-T-C fittings too. They are are real pain to get apart (great only for assembly line work). They frequently leak (at the swivel part) and that part can't be fixed.

I have been able to disassemble only a few of the larger size tubes (3/4"). Forget getting the smaller ones coming apart. Just cut the tube flush at the fitting with a box cutter and use a compression fitting to reassemble. It wont leak and you can disassemble later if you ever need to.

I use the Parker fittings, the VS68NTA series or the VS68AB series. Available on Amazon or any truck parts place.
I have not had a problem with any tube being too short after cutting (there is only 3/8" to 1/2" of tube left inside old fitting).

[BigLar368]

Originally Posted by MSGulfCoast

I'm far from an expert here but I can speak from personal experience when the Haldex filter ruptures it's mess.



I'm reading the Wabco won't fail in this manner but that it will just stop taking the water out of the incoming air. I can't positively say that is a fact however.


Another upside to switching is the cost of the cartridges (filters) being approximately 1/4 to 1/3 the price of the Haldex if that's anything.



Main takeaway is to change that freaking filter every other year and save yourself the PITA not doing it will cause.

Where do you get your filters from? Are they OEM Wabco filters? The ones on Amazon appear to be made in China. Just curious what you use. Thanks.