9two8

My gas cap has never had the rubber washer installed, so I bought one from my local OPC.., question is did all 928 caps have this washer fitted, it is a good fit at the bottom where it locates, however, turn it upside down and it can sometimes drop out,( guess this is what happened to the original ).

Is it held in by a spot of glue ? I thought it would be a tight fit and hold itself.., although it is an exact fit.
Any thoughts appreciated.

Ken
80 928 S
5 Speed

UK

Mrmerlin

from the looks of the cap it seems that the sealing area is just next to the top of the threads, fit the rubber to the top of the tank and see where it mates up

9two8

Well I put the sealing ring in some boiling water and then inserted it into the bottom of the cap, then tightened the cap onto the filler neck, in the hope it first shrinks then expands due to cap compression.


Ken
80 928 S
5 Speed

UK

Mrmerlin

see post 2

9two8

..,I,m not sure what you mean when you say QUOTE, ,( fit the rubber to the top of the tank ) do you mean the filler neck, or the actual fuel tank ?
According to the parts list the rubber seal fits in the bottom of the gas cap.

Ken
80 928 S
5 Speed

UK

Mrmerlin

Ken what I was trying to say was that you should remove the ring and see how it compares to the tank inlet. From the picture you posted it doesnt look like the rubber will sesl and the actual sealing area is just inside the cap where the threads end .
I have 3 caps and none of them have a rubber seal in them.
Now that doesnt mean that there might have been a seal at one time as there also looks like a seal could be fitted but then again there dosnt seem to be any way that it would be held in.
But this could be something that has never been noticed before, i have never seen a rubber sealing ring in a USA fuel cap, but i guess that way the cap is it could be one of those things that has fallen out of the cap over time

tomshark

this has explains i hope my problem . have noticed a vapor smell enough that my wife said to get it out of the garage i never had this problem until 2 weeks ago.and the smell came from the gas door when open it got really strong.
removed tank ,checked for leaks, replaced seal, hoses , and went through vent system .
after reading this i understand the problem . mine did have this seal i remember clearly the black on the bottom.but some time two weeks ago it fell of without me noticing. ordered part today.

Mrmerlin

So this might be a new concern for every one with a 928.
Please post pictures of your seal and how its held in

borland

That gasket fits on the end of the filler neck. When the gas cap is installed it seals along the outer rim at the end of the gas cap threads.

If you look closely inside the gas cap, you'll see a sharp edge that mates with the gasket when installed on the car.

So, no gasket inside the gas cap, just put the gasket around the outside of the threaded opening of the gas tank inlet. You'll be fine.

borland

Did you replace the hose from the filter to the hard line inside the wheel well? That hose is long an weeps gas odors. Put your fingers around the hose for a few seconds and then see if you hand smells like gas.

I had a similar odor until I replaced this longer line.

bernard farquart

As Borland stated, the seal actually belongs on the filler neck, not in the cap. I have replaced mine, it is a simple interferance fit there is a groove for it, and if you look, you can see a "v" shaped ring on the flat upper portion inside the cap that mates to the ring when it is installed on the filler neck.

Mrmerlin

I just went out and checked both of my cars and indeed there is a rubber seal around the top portion of the fuel tank. Thanks for pointing this out Borland and Paul

9two8

Old and new seal.., there seems to be a difference, the new seal has a softer sealing lip that fits into the lower threaded portion of the gas cap,
Old seal is "green" and the new one "black", maybe the new design offers a more reliable seal ? when the cap is screwed down.

Ken
80 928 S
5 Speed

UK

The part number for the seal is..., 928. 201. 275. 03

StratfordShark

This is very timely. One of the members of the UK 928 owner list failed his MOT (annual safety inspection) this week because this seal was missing. Must pop out now to see if mine's present!

David L. Lutz

Well another part for the list. Anyone got a part number for this one?