Working with the trunk gasket

[jburning17]

Hey, back again with some pictures of another project. This time, it is a smaller one, but I thought that another dialog might save someone out there some time.

So, let's get on with it already, eh?

My car (750) came with a fairly new trunk gasket, but I was unable to close the trunk enough to get the latch to trip. I was sure that the problem was that I had the incorrect gasket. The gasket looked a little out of place, so I figured that this one just came from Autozone or something.

I ordered a new one from Centerline. When it came, it had the very same cross-section as the gasket on the car. "That doesn't help at all," I thought. BTW, Centerline was very professional, and credited me the cost of the gasket when they received it back in good shape.

Here is a picture of the cross-section of the gasket on my car, which (again) is the same as the gasket sold by Centerline.

[jburning17]

So, I spent some time scratching my head on why the trunk would not close. I didn't dare put more pressure on the trunk than what I was, and that didn't seem like a good long-term solution even if it did work.

I finally came to believe that the gasket had been installed backwards on my car. I think that the fat part of the gasket should hang towards the inside of the trunk rather than in the "gutter" around the edge. To me it looked like that the gasket was sitting poorly, and would require a lot of compression to get the trunk to sit right.

So, I set about switching it around.

To me it looked like the PO had glued the gasket down with the expanding foam stuff that you can get in a can at Home Depot. It wasn't a big deal since it broke away cleanly and didn't damage anything around it.

With the gasket off, and as much goop as I could get removed, I started to experiment with how to mount it and still have the trunk close. This next picture is poor, but what I am trying to show is that the trunk would close like a charm up until I layed the gasket in place along the lower 25% of the lip. If you look close, you can see that the gasket is laying loose at the bottom.

[jburning17]

After struggling for a solution, I finally came to the conclusion that the trunk would never close with the gasket sitting as high as it did.

The only solution that I could find was to use a razor to cut the channel a little deeper. I did this only on the lower 25% of the lip, with the remainder left unchanged.

The picture shows how much the blade was extended on my box cutter when I did this, and is shown in relation to the gasket size.

[jburning17]

With the trench in the gasket deepened, I began gluing.

I used simple black RTV, silicone gasket stuff that I got at the auto parts store to do the trick. I started with the section nearest the hinges, glueing about 1/3 of the total length. I then closed the trunk lid to hold the gasket while the RTV dried over night.

Here is one thing to watch out for:

I was a little too aggressive in stretching the gasket into place. As a result, the gasket pulled away from one of the corners during drying.

To fix this, I had to pull up about an 18" section, pull everything back into place, and reglue. I used several sections of black electrical tape to hold things down, in addition to the trunk being closed. That seemed to do the trick. If I were to do this again, I would have done that from the start.

[jburning17]

The hardest section to put in place is right around the fuel fill cap. It is just a bear to get that gasket to sit still and in the right place.

I ended up using a whole bunch of that electrical tape to get it to sit still. BTW, I don't think that there is anything special about using electrical tape, it is just what I had on hand. I would suppose that the blue masking tape that I see at Home Depot would work well for this, too. I would be a little reluctant to use the tan masking tape for this because, I have seen that stuff pull up the paint, which isn't good at all!

Check it out...

[jburning17]

So, now the gasket sits in place and the trunk closes. I haven't notice any trunk rattles so far, so I think that the gasket is making contact all around.

I would be interested to hear some feedback on whether the gasket is oriented correctly. It is entirely possible that it was right before I got to it, only to have good 'ole me put it the wrong way around.

I will be taking a look at it from time to time to see if the gasket compresses over time.

Cheers!

Jon

[Subtle]

It looks O K to me.

Mine has come loose along the lower portion and I'm told that contaci cement will do the trick.

The job is lower on the list.

[ecdysiast]

Thanks for the interesting post and photos. I have been using Barge Cement, but maybe there's something better. There are lots of Silicone RTV gasket cements out there--which, exactly, did you use?

[tipo101]

I had a similar experience. I set my gasket the way yours was originally, larger part in the trough. It stuck out too much to close the trunk and hit the trunk edge at the bottom, as yours did. I didn't have an old gasket to compare, so just assumed that this was the correct arrangement. I ended up trimming the mating surface back about 3/16" in the area you mention, and all fits fine now. I used the yellow 3M weatherstrip adhesive and won't again (hate that yellow!) as it is impossible to do without some of it showing somewhere. Why announce your sloppiness? I hope someone chimes in with how the original was done. Oh yes... and clean the rubber with alcohol or lacquer thinner where you are going to place the adhesive. There is a mold release agent or something which keeps the stuff from sticking well. Of course this may be an advantage if you are having to place it more than once
Jonathan

1964 Giulia Spider Normale
1988 Spider Veloce
1967 Lancia Fulvia 1.3 Rallye

[cervara]

I have never had to use any glue or adhesive on any trunk or boot as it is called down under. that was on 2 105 coupes and now starting on 750 B guillietta 1957 vintage.

[AlfistiSA]

Hi Cervara

Welcome to the Alfa BB

Check out this thread on our Sprints - Sprinting About

Please post the Chassis and engine number on your '57 750B ?

Please post some pictures as well.

I've got 05262 and 05880

Ciao
Greig

[jburning17]

Quote:

Originally Posted by ecdysiast Thanks for the interesting post and photos. I have been using Barge Cement, but maybe there's something better. There are lots of Silicone RTV gasket cements out there--which, exactly, did you use?

[6alfas]

Does that dry hard or does it stay soft?

[jburning17]

Quote:

Originally Posted by 6alfas Does that dry hard or does it stay soft?