What holes to plug in the chassis?

[Cloggie]

Getting on to final assembly and been attacking the various holes in the chassis bottom, underneath the car.

Some are easy, like the series of 8 mm holes underneath the tunnel, each of which needs a little plug to seal it.
Also the holes where the AC lines were fastened are easy to pick out - sealing them for the moment with the appropriate screw, rubber washer and steel washer.

But there are a ton of other holes in the chassis including some in the rocker panels (which I think need to be plugged) and at least 4 on each side underneath which are about 8.9 mm.

Question is, which ones need to be plugged and which ones are drain holes which ought to be left open?

I have been consulting PET, but it just says you need x of this plug without specifying where they go.

Anyone have an "under chassis map" for this?

Thanks!

D.

[76FJ55]

What year/model car are you working on? Can you post a pic an location of the holes in question?

[Cloggie]

Originally Posted by 76FJ55

What year/model car are you working on? Can you post a pic an location of the holes in question?

Good point, chassis is a 1989 Carrera Coupe.

Here are the pictures

This one is drivers side front, near where the seam turns inward around the fender well. I think this one needs to be plugged



This one is the rocker panel just below the door. Almost certain this needs to be plugged and as can be seen from the picture, I found one plug in my spare parts bin which seems to be a perfect fit. Not sure about part number, as PET is a little vague.


This is the rear DS again, but this hole is threaded and for the life of me I can't find any part which belongs there...I presume it's for some other-worldly option I do not have? I would presume this need a suitable bolt and rubber washer.



This is DS, two holes which I assume are to be plugged?




Passenger side is basically identical but with a couple of more threaded holes and of course the holes made to hold the AC hose, which I have already plugged with a screw/rubber washer/metal washer.

Any help and also any part numbers for those plugs is greatly appreciated.

D.

[Cloggie]

Ok, there is a chance I may have solved some of this on my own, but would love confirmation.

I went digging around my box of rubber things I pulled off of the car when I started its reconstruction and found 8 of these - 6 in good shape, two unusable.



They are a Volkswagen part used in the heater tubes of Beetles and are variously called "chassis plugs" or "rubber valves", the latter of which suggests that they are meant to act as a check valve to allow any water/condensation which collects in the structural tubes to drain out while preventing any water or schmutz getting in.

The rubber is actually pretty thin and bendy, consistent with the idea that a bit of water weight on top of them and they would bend and let the water out.

The P/N is 111 801 177 which is in PET in the right place, quantity 8 where they are called "rubber valve".

I tried one in one of the holes, they fit very well, not likely to come out and makes me think these might be the ones.

....confirmation would be lovely.

D.

[Jesse911]

You have 4 threaded holes in the chassis. I believe these were used in the factory to mount the body on a dolly.

I took the rubber valves in your photo out of these holes when restoring my '76.

Other option is to buy 4 hockey pucks and drill a hole in them and mount them on the car so you have some nice jack points. There is a topic here somewhere.

[famoroso]

Which screw/rubber washer/metal washer did you use to plug the AC line holes? I need to do the same.

111 801 177 are installed in the panel just forward of the fuel tank...

[Cloggie]

Originally Posted by famoroso

Which screw/rubber washer/metal washer did you use to plug the AC line holes? I need to do the same.

111 801 177 are installed in the panel just forward of the fuel tank...

Hey great information - and that would mean I need 11 of the 111 801 177's.

I was going to ask about those too....your reply fills in that gap.

As for my AC line plugs, I just got some of the screws (original from when the car used those lines), made up some rubber washers out of some good quality 1/8" rubber material I had lying around and then backed them with a 6 mm flat washer which had the right OD. I think the flat washers were fender washers, but their OD was around 14mm.

Screwed them into the offending holes and voila....no water ingress. I probably ought to have welded them up when the chassis was in bare metal, but oh well...can't remember everything.

Thanks again,

D.

[E Sully]

I don't know if this is what you're referring to, but these were used for quite a few of the drain holes.
https://www.pelicanparts.com/More_Info/91163125902.htm?pn=911-631-259-02-OEM&bc=c&q=chassis%20drain
https://www.pelicanparts.com/More_Info/91102561200.htm?pn=911-025-612-00-OEM&bc=c&SVSVSI=0586

[Cloggie]

Originally Posted by E Sully

I don't know if this is what you're referring to, but these were used for quite a few of the drain holes.
https://www.pelicanparts.com/More_Info/91163125902.htm?pn=911-631-259-02-OEM&bc=c&q=chassis%20drain
https://www.pelicanparts.com/More_Info/91102561200.htm?pn=911-025-612-00-OEM&bc=c&SVSVSI=0586

Thanks for feed back,

The first one is for signal light housings - definitely a requirement if you want to keep your signal lights from corroding.

The second one appears to be a drain in the condenser area in my case not an issue as I welded a panel over that opening as my condenser is now a 993 condenser in the D/S front fender under the headlight.
A lot of fabricating went into that.....but I hated the dual condenser/condenser on the engine lid combo.

I will keep it in mind if I see a suitable hole for it....even though it's $13 for a bit of rubber.

Porsche tax.

D.