Extreme IWE confusion

[nipplesNchowder]

Grinding noise coming from front end. I replaced IWEs like 2 months and air lines are nearly new as well (silicone aftermarket).


Quick rundown:



1. Using gauge, determined vacuum system is pulling like 23 inches of pressure on source side of check valve. Doesn't seem to be the issue.

2. Using vacuum tool, can pull and hold over 20 inches of pressure on load side of check valve. Doesn't seem to be the issue.

3. When IWE are under vacuum, both tires spin freely of CV axles. Working normally.

4. The grinding occurs in 2x4 and ALSO in 4x4. Putting truck in 4x4 does not stop grinding.


Now this is the weird part:

The grinding in 2x4 can be stopped if you bypass the check valve, air resevoir tank, and 4x4 relay thingy (see attached photo for better explaination), but doing this only stops 2x4 grinding and NOT in 4x4.
This whole thing makes no sense to me. Am I missing something obvious?

 

[Sozzy12]

Any pinched lines?

 

[Stormtrooper]

Just do the RCV IWE delete.

RCV Ultimate IWE Eliminator Set for Ford Raptor ('10 & Up), F-150 ('04 & Up), Ford Expedition ('03 & Up) & Lincoln Navigator ('03 & Up)

Completely eleminate the OEM IWE and replace it with this ultimate 4340 sleeve. Simply remove the stock IWE and install these sleave in their original place. Once installed, your hubs become fully locked to the axle shafts allowing you to use the transfer case to shift in and out of four wheel...

www.rcvperformance.com

 

[New recaros]

Are your fancy silicone lines collapsing under vacuum? Are the check valves in the correct orientation?

 

[Gen1TillDeath]

How much PSI is supposed to be supplied to the IWE’s? I’m as lost as you but I’m just spit balling here, you said that if you by-pass everything and direct connect to the IWE’s the grinding stops? Well maybe JUST ENOUGH psi is being supplied when you bypass it all and it’s able to engage them but not when everything is hooked back up because of lack of psi ???

Maybe try by-passing one thing at a time and see if it narrows it down at all?

 

[nipplesNchowder]

Update: Purge valve (in picture) was completely plugged with dirt. Took it out and vacuum tested it, it was leaking by badly. Poured alcohol down it (all I had) and now the valve can open and close and it holds vacuum.

Also, the blue ford 2 way check valve was also no good. Replaced with a 7 dollar Dorman piece of trash from Canadian tire.

Truck still grinds in 4x4 but is now silent in 2x4. I think the IWEs are toast again.

Also pictured: my 2mm silicon troubleshooting abomination. Way better then paying Ford 71 dollars for parts.

 

[EricM]

Run copper lines if you want durable vac lines. Another good option would be cupronickle brake lines/tubing.

The rubber vac lines should slide right over if you get the right size.

 

[wjoutlaw]

Are you also chicking the vacuum air resevoir?

 

[nipplesNchowder]

Update: Found out right IWE was completely broken in half. It still held vacuum though, which is why this relatively simple vacuum system has been such a pain in the ****.

Do not use IWEs from Amazon.

 

[nipplesNchowder]

Update: Glued the two pieces back together with the most carcinogenic glue I had, let it sit for an hour, and reinstalled. Been driving for an hour, SHE'S GOOD