1975 Beetle FI, broken cap on air filter case

[doriondo]

I found a round cap on the air filter case that was broken and upon doing a google search I read that there's suppose to be a spring/diaphragm installed inside. I tried looking for a replacement but cannot find any. Can I just replace the cap without a spring/diaphragm?

[Piledriver]

Unfortunately that's part of the air cleaner and not a replaceable item.

Its a vacuum operated PCV valve, and it worked a LOT better than most when it worked.

[doriondo]

Thanks Piledriver. So what do people do once hat breaks, replace the whole air box?

[Marc]

Should be a ~$25 swapmeet part. It's the rubber elbow that's in high demand. I think I may have a good one around here somewhere, what's your Zip code?

[doriondo]

It's 93063

[Marc]

It's 93063

Better'n east coast, anyway. I'll see if I can find one tomorrow and find out what the shipping cost would be from Seattle - but if you can find one locally for under ~$30 just buy it.

[doriondo]

Ok thanks

[Piledriver]

If all else fails, and its not an automatic emissions fail due to being "modified" clean it up and put the cover back on with some black RTV, and put a check valve inline like one of these:

http://www.usplastic.com/catalog/item.a ... &catid=489

Sadly they don't make bigger than 3/8", but the restrictor into the air cleaner isn't much bigger than ~1/4" anyway.
These are fast diaphragm type check valves with the working bit made from Viton, in a kynar case.
They are most everything proof, and are commonly used for PCV by the 1.8T folks to replace all the check valves in their factory case evac setups. These hold up better, and cost 79 cents.

They are far more efficient than any weighted std PCV valve setup.

I have two in my case evac rig (one feeds filtered air into the 3/4 side rocker box via a vacuum break, one pulls from the case breather via a restriction to manifold vacuum) and they are still kicking after a couple hundred K miles.

If you have a sand sealed pulley (or T4 or WBX) they can pull a few inches of vacuum on the crankcase under most conditions.
If you don't, it will still works as well as a std PCV valve at least.

[doriondo]

Thanks again. I will go ahead and order that part. By any chance is there a diagram where I can put a check valve inline? I'm sorry, I'm just new to all this stuff and you are the 1st person in the forums that offered anything helpful.

[Piledriver]

Thanks again. I will go ahead and order that part. By any chance is there a diagram where I can put a check valve inline? I'm sorry, I'm just new to all this stuff and you are the 1st person in the forums that offered anything helpful.

Marc offered to find you a replacement air cleaner...

The check valve would simply go in the existing line.
Would require short bits of 3/8" ID line as spacers as the existing line is ~1/2" ID or so.
You could also simply buy a std inline PCV valve from an auto parts store to stay "legal".
(The disc check valve will work better)