Screwing Items To Metal Bodywork

[MrT]

What is the best way to screw items to external metal bodywork whilst preventing that area from rusting? The typical way would be to drill a pilot hole and use a self tapping screw, but I am concerned that this would create a potential future for rust. The areas I am thinking of doing this in are all external folded over edges with access to both sides similar to the wheel arch where you would attach mudflaps.

[Richmond]

You need to avoid metal/metal contact if possible, even if one or both are sealed (by paint or sealant). The only way I can think of is to drill a hole, seal the bare metal and attach whatever it is with 'soft' (such as nylon) bolts and washers. Depending on what and where it is, you might be able to use clips of the type sometime used to attach mud flaps to the flange inside the wheel arch, using rubber pads if necessary to avoid metal/metal contact.

 

I'd be very reluctant indeed to drill into a panel, although I bolted a luggage rack to the boot lid of my MGB; no rust problems, but new panels for Bs are very cheap so the risk was small (I never once used the luggage rack). The rack sat on rubber strips above and below the boot lid, which were drawn very tight onto the lid in the region of the holes by the (steel) mounting bolts, presumably providing an effective water seal. You might be able to do something similar. What are you going to attach, as a matter of interest?

[Ivor_E_Tower]

..and where? Will dirt/moisture get to the exposed threaded end of the screw?

[MrT]

It is the plastic chrome strip trim to the leading edge of the bonnet as on the 2004 Galaxy. The idea is to cover some nasty stone chips that I have touched up, but are still noticeable. When held in place, it does not look like an add on.

 

The trim is a V profile which sticks with tape to the upper surface at the edge of the bonnet and has screw holes for the lower surface which would screw to the lower inside folded back edge of the bonnet.

 

I would have thought that the new Galaxy bonnet (on the underside) either has holes with plastic inserts or uses "U" clips, like mudflap clips but "threaded" on the inside.

 

In the attached picture the red on the lower edge is the reflection of the backing on the sticky tape on the upper inside.

[Richmond]

For a lightweight (I assume) item like this there are two possibilities which might do the trick.

 

1. Drill and seal holes in the flange and attach with plastic studs if you can find the right size (I mean studs with 2 legs which go through the hole in the trim and the hole in the flange and are resiliently biased outwards to retain them in place). Plastic washers will take up a certain amount of slack if you cannot find the exact length needed.

 

2. Glue the trim onto the flange. Half the trim on cars is glued on these days anyway. Will the bonnet slam on the trim as it is shut?

 

Bear in mind that Sod's law states clearly that the first time you take it out after fitting the trim:

a. you'll get a huge great stone chip on the bonnet about 1 cm away from the trim strip; or

b. a stone will hit the trim strip and bounce off and crack the windscreen; or

c. both.

Why not fit the trim just before you sell the car (and then it won't matter if it does rust around the screws!)?

[seatkid]

I think he means plastic rivets.

 

Dome headed stainless allen key bolt and nut - far nicer than nasty self tappers :rolleyes:

[MrT]

Thanks all.

 

I just stuck it on with the sticky part ready to drill for the lower part and it is so solid, I am not going to bother drilling or fitting the lower part. If it does come off it is less than

[Ivor_E_Tower]

Wise move - if the drill slips you could add a nasty bump to the bonnet. Best to leave it as it is now. Have you bought the chromed grille to go with it? If so, how much? I was thinking of upgrading my Gal, but somehow the chrome doesn't really show up against a silver body colour. It looks good against black, though.

[Richmond]

I think he means plastic rivets.

Well, yes, but I think plastic rivets usually include some arrangement to spread the legs wide (ooo-er) once the shaft is in the hole (sorry, I'm feeling a bit faint) and are usually intended to be more or less permanent. These would be fine for Mr T, I imagine, but what I had in mind are thingies which are just a push fit (or a light-tap-with-a-hammer fit) and rely on the resilience of the plastic to return the legs to a sufficient spread to keep the stud/rivet and the trim in place.

 

Mr T, maybe a bit of foamed adhesive between the trim and the bonnet flange would help.

[MrT]

The chrome grill was about

[Ivor_E_Tower]

Thanks for the info.