daveo90s4

Hi all,

I'm removing the air pump from my 1990 S4. Can anyone please tell me the thread specs. for the connection between the air pump to exhaust small diameter pipe? I think I need to cap off that small inlet pipe to the exhaust as part of this process.

Thanks in advance

Hilton

Dave, its M22 x 1.5 from memory. I'm at the snow in NZ at the moment, but there's a hydraulic cap thats exactly the right size made by Gates. I'm back in Sydney this weekend so can look up the part number then.

I bought the cap a couple of months ago for my newest '87 - my prior 87 I made a cap by welding some steel onto a nut.

Jadz928

P/N 930 113 153 00 is the real deal if you decide not to use a lug nut.

They ain't cheap but they sure are pretty!

LEADASS

I went to NAPA.

daveo90s4

Thanks Hilton, enjoy the snow and if I don't find one before the weekend I'll be in touch. Now off to the local 'nuts and bolts' shop.

Brian, NAPA? I'm guessing tat'd be "North American..." - I'd have to find a SPPA, that'd be "South Pacific..." :-) :-)

daveo90s4

Thanks all - job done, all for just $8

Cheers

Hilton

Just ran across the cap I was talking about when digging in my "useful fittings" parts bin.

Here's the one which is an exact fit for blocking off the air supply tube on the factory cats - where they get supply from the air pump diverter valve.

Part no: G64793-0015
Description: 15FDL-CAP

the flyin' scotsman

I used pipe threaded caps with sealer........long time ago and its been fine.

GlenL

Use the real part and a real sealing ring. The heads are symmetrical so the parts that fit the holes on the front fit the holes on the back.

I tried making my own and finally wised up and just had 928I ship me the right ones.

Hilton

The part number Jim quoted is for something else entirely. Its for blocking off the exhaust test-port on the manifolds.

The part I'm talking about is one for which there is no factory equivalent.

Its for the opposite side to item 33 in the attached picture - to seal up the air-inlet on the catalytic converter. Not something you need to do unless you happen to have a non-cat RoW S4 which needs to run with factory cats, due to the way the airpump connections are made on a non-cat RoW car. Dave's OP was because he removed his complete airpump assembly and was left with the open pipe in his exhaust.

e.g. I did this on my '87 as the airpump manifold feeds each individual exhaust port on the heads, so the connection on the cats is redundant - I was required to use cats to pass emissions.

GlenL

Obviously my reading comprehension is off this evening. Carry on!