Topic: PVC hose sucks (shut)

[Murf]

My PCV hose sucks  almost shut when the engine (302 "J" code 68 with stock Ford spec parts) is at idle.  The hose is a reproduction script hose, have no idea who actually made it.  So it seemed a simple matter to purchase an OEM spec replacement, install it and toss one more reproduction part in the trash.  Well, to the best of my knowledge and resources a replacement is not  to be had.  Checked the normal supply houses with no luck, a google search yielded nothing else as well.  The reproduction hose is soft and was soft when purchased.  It has not been oil soaked nor mistreated.  So has anyone found a replacement molded PCV hose for a 68 "J" code that will "work"?  I have no need for the "Ford script, it was just a replacement that was easy to obtain when purchased. Do you have a repo that works?  Did I purchase the only flimsy one made or have others had or noticed this problem.  If you know of a molded replacement your experience would sure be appreciated.  Any suggestions also.  Thanks!

[jwc66k]

I pulled my spare from the shelf. It should be the same as your (per NPD), marked C6AZ-6A664-N, still in the Scott Drake bag. It is not soft hose, actually about the same hardness as an aftermarket one that I have.
My only problem is the marked part number. Would an assembly line part be marked as a service part C3AZ-
Jim

[CharlesTurner]

Another example of repro parts being modeled after Ford service replacement pieces.

[krelboyne]

Have you tested your PCV valve? I wouldn't think that the hose would collapse if the PCV valve was working properly.

[Richard P.]

How much vacuum is your engine pulling? I've just used a reproduction hose and it works okay.

[Murf]

Jim, the hose is marked the same as yours  (  -N).  And is pretty limp rather than stiff.  and as Charles stated, the "script" is of no use since it is incorrect. I purchased the hose about 4 years ago while in Florida and visiting NPD.  It was probably molded during the very early manufacture of this part so possibly they have improved the rubber recipe by now since no one else seems to have this problem.  And yes, the PCV is just fine, but to make sure, this morning I replaced it with one from a 66 that does not suck shut the Ford hose and it immediately sucked this -N nose almost completely shut.  The hose makes a whistle type sound when it is nearly shut and was no different than the original PVC in operation.  And Richard, the engine vacuum is 17 - 17.5" HG at idle, dropping to 16 or 16.5"HG  when the AC compressor kicks on.  I guess it is just time to replace this hose, and since no other seems to be available it will have to be another reproduction.   

[suskeenwiske]

This was a very common issue on late 70's models Chevrolet's. The hose was thin to begin with and the heat did the rest...even to the point that it would create a large hole on underside of the hose where it entered the carburetor. The small piece of tubing under the car for AT Vacuum would do the same thing.

You likely just have a sloppy hose. Even if the PCV Valve were to become completely plugged, the hose should be able to hold up to the vacuum.

Should the correct hose collapse on you, there may be something in the crankcase that is breaking down the rubber. High Ethanol laced Fuels could potentially break down the rubber but that would take quite a bit of blow-by for enough vapor to build up and cause this sort of damage. If you use any fuel additives intended for modern engines, make sure that they are compatible with your engine and its soft parts.

The only other thing I can think of is to avoid anything made in mainland China, they are notorious for using inferior materials, especially metal and rubber parts.

Ray

[J_Speegle]

Just an idea John . Maybe you can find a long spring that can be inserted inside the hose to keep it from collapsing like the lower radiator hoses originally.

That would be one of the fixes I would consider giving a try

[Brian Conway]

In reading this post it reminded me that I had the same experience.  It has been several years at least but I ran another piece of 1/2" copper pipe through the center section.  Maybe a 5" piece long enough to stay away from the beds.  I still have it on the 65 and had forgotton all about it.  Brian

[MattDoscher]

Jeff, Brian those are good ideas.  I never would of thought of that.  Kind of like stints for the car versus a human heart!

[Murf]

Thanks for all of the ideas.  You can probably guess where the hose tends to collapse?  Yes, right at the bends where it is the most difficult to insert a stint.  The spring is a good idea - will be on the lookout for one.  And no fuel additives of any kind, ever.  I ordered a new hose yesterday and will see how long it lasts.  Since I drive these cars more than most the marginal parts probably show a failure sooner than for many who read this.  I think the hose is just a little on the "thin and weak" side for the purpose it serves and will post here again when the new part is installed. 

[Brian Conway]

I got out some of the old hoses and yes really weak.  In one photo the hose has corroded or weakened so that the unevenness can be seen.  As mentioned chemical reaction or maybe the heat but in short order it collapses and the car runs like it has a vacuum leak.  Brian

[suskeenwiske]

A Stainless Steel Spring should work well. To insert, try threading it in and lubricate the inside of the hose with Electricians Wire Lubricant; it'll make it easier to insert and it's water soluble, making cleanup easy.

Good luck.

Ray

[Murf]

The new hose arrived and is on the car.  It is very stiff and hard compared to what was removed so they certainly do degrade with time.  The texture was akin to an original ( I guess alligator skin is the buzz word for this texture).  The script was much neater and more precise than the one removed.  On the bag was printed in rather large font "MADE IN CHINA" as if they were proud of that fact along with the engineering number that was stamped on the hose.  It fits fine and works well, the first one went in the trash.  I am guessing that this too will at some point turn to mush but for now it functions well.  And I did try to poke a spring inside of the first hose, made me laugh and think about the axiom I have heard all of my life about "trying to stick a wet noodle up a wildcats a$$" .  Maybe I could have pulled a spring through the soft mushy hose but there was no way to force it in by pushing.  If you want to use the spring be sure and do it before the hose softens or you will be in for a frustrating job. 

[jwc66k]

John,
  I would be curious as to the marking as you said the hose had the engineering number. If you would, what was the marking,  and where did you get it from?
Jim