MGB GT Rubber Bumper Limited Edition Restoration and Maintenance: MGB GT splash panel replacement; fitting a motorised automatic aerial

My splash panels have rusted through at the bottom. This is a real shame as the rest of the panels are in first class condition. A little more preventative attention here would have seen them last in tip top condition and mean that I wouldnt need to do this job. As its a small problem I could repair with GRP matting, but the splash panels themselves are cheap enough and as I have to remove one at least to swap the radio aerial, I may as well replace them at the same time.

The splash panels are a bolt-in fit on their inside edge with a silicone rubber seal down the external sides to bridge against the wing. In my case the panel was held on by 3 hex headed bolts up the side and a large cross-head screw at the base. This is a daft system; if anywhere is guaranteed to corrode its the bottom bolt and this proved to be the case. I bought a new fitting kit for each side and note that this now supplies 4 hex headed bolts!

The three side bolts unscrewed easily with a 7/16Ww socket, the bottom screw head wouldn't shift and as expected stripped the head. The usual approach here would be to use an impact hammer but obviously body components are far too delicate for this. I tried cutting a new groove with a Dremell but that stripped out too and so in the end I had to drill the head off and remove the shaft of the bolt as best I could- this turned out to be not very well!

Bottom cross headed bolt RHS splash panel tight up against wing edge, rust damage to panel visible above

One of the panel mounting bolts (hex headed) RHS splash panel. Clean it off and it came out easily enough

I found I couldn't remove the bottom bolt, but when the top three were removed the top of the panel came away anyway! This left the rusty stump of the panel still attached to the mounting flange by the bolt. In the end I had to drill this out- not a pretty job!

Remnants of RHS splash panel still bolted to body flange.

Base of other side panel (LHS), bolt no 1 visible, cross headed bolt is tucked in under, rust holing visible this side also.

End of Castle rail LHS seen from below the car- bottom cross headed bolt visible in recess of front wing on centre left.

The RHS splash panel came off easily with its body seal. Note bottom section has detached through rust.

Looking inside the RHS wing there was a lot of dirt and debris that will need raking out before the area can be cleaned and stabilized before fitting the new panel. The aerial is visible inside the wing. The mast clamp has failed and it just drops through the mounting now. I want to replace this and will fit a new automatic aerial. These require an under hang of around 28cms but there seems to be plenty of room here so I will go ahead and order the new aerial.

Old aerial in place- the black tube (top) is the original container for the telescopic aerial but this has now lost its grip and the aerial now drops right through- chrome mast visible beneath. Note the narrow channel gap at the bottom formed by the outer wing and the forward projection of the sill.

Fitting an automatic aerial

I bought the Autoleads RMA 1001 compact automatic aerial- it was a good price at around £30 and came with a variety of grommets to suit virtually any shape of panel. If it has a problem, its that it comes fitted with the thinnest wires imaginable- I guess this is the minimum amount of wire for the current- but its so thin it doesn't really work in the even the red sized crimp connectors unless doubled-up. Even then its not the most secure connection so I had to make soldered connections to a thicker wire if I wanted to fit a bullet say to preserve options for disconnection.

Removing the old aerial was simple enough

Unscrew top bolt

Aerial drops into wing beneath

The old aerial was cut out leaving the coaxial lead in place to act as a guide for the cable routing.

I traced the route of the old coax from the console

around the back

across and above the steering column and then taped to a cross beam

before finally diving beneath the footwell side trim right at the top. The cable exits to the wing cavity through a grommet hidden below the trim. It was necessary to loosen the trim to allow the cable to move. I unscrewed the three self tapping screws down the door pillar edge. There is a fourth right up next to the windscreen wiper motor that's virtually impossible to get to but needs to come out to provide leeway to move the cables. My thumb and finger here are pointing at two of the screws.

In an ideal world I would probably have preferred the blue switching lead to follow the coax into the cabin, whilst the red and black power and earth leads went into the bonnet space to connect at the fusebox. However it wasn't possible to get a drill into the wing space to drill through and so I had to route all cables through the grommet and into the cab.

It wasn't as bad as it sounds but its tricky to refit the grommet with so many leads passing through it.

The antenna will be held by the chrome nut at the mast base above the wing and also by a metal strap inside the wing cavity. This latter wasn't going to fit in a useful position so I had to grind the edges down until it would fit over the mounting stud and hang vertically.

I could then offer up the antenna and hold it loosely in place with the chrome nut.

Holding the antenna in place and adjusting the angled lower mounting for the best match with the body profile

Fit the rubber cushion, and lugged profile before adding the chrome cover plate. Make sure that the cover plat covers as much of the hole as possible and then tighten the nut- but not fully at this stage

Once the antenna was held I could fit the metal strap below.

|Loose fitting- antenna dangling from mast base nut above wing.

I bent the strap into a "Z" shape and them drilled a small hole through the strap and end bulkhead allowing me to fit the strapping with a self tapping screw.

Metal strap bent to Z" profile and screwed to bulkhead.

...before I neatened up the wiring as best I could. Its very easy to get this tangled! I pulled most of the excess above into the car and connected the blue antenna signal lead to that I had already prepared from the ISO connector.

The bottom of the antenna has a drain hole- it comes with a short length of tubing but this would serve no useful purpose in this position. I attached a longer tube using superglue to keep it in place. This will be routed out of the cavity and below the splash panel.

Wires neatened up and pulled through. I also found that a single screw in the strapping wasn't enough to prevent sideways movement so I fitted a second.

All the wires were now routed into the cab. There was a convenient earth connection in the pedal box below the wiper motor where a hole was already present. I inserted a bolt and fixed an eye connector to the aerial earth to make the connection.

For the live connection I required a permanently live feed. There was a permanent live available under the dash (pink wire entering both multi-plugs) but I was unsure whether inserting a join here would be a problem as there wasn't much spare wire length to play with. To be safer I routed the wire through the loom grommet and into the engine bay. Using a curtain wire to feed through the grommet gave me a lead first time even though its cramped just here behind the servo! I was then able to route the wire alongside and secured to the existing loom towards the fuse box. Here I found the same pink wires were supplying fuse no 4. In order to avoid any potential overloads on this fuse I connected the antenna live wire to the supply side of the fusebox using a piggyback spade connector and fitted its own a 3.5a in-line fuse into the feed.

Antenna feed wire routed alongside loom and fitted with it sown in-line fuse (3.5a). Fitted here the fuse holder lines up with the existing in line fuses fitted to the car.

Piggyback spade on supply side of fuse no 4.(lowest left in this pictire)

Although my radio isn't yet properly installed I connected it temporarily to verify that the antenna extended and retracted when the unit was turned on and off. It did so - so very satisfactory!

Fitting the new Splash panel

Having already removed the bulk of the splash panel, I was left with the rusty fragment and corroded mounting bolt. I drilled out the bolt head releasing the stump of the splash panel. It was tricky but with care I managed to drill through the remnants of the stub and the weld nut on the other side.

Stud of bolt drilled out- not very pretty

I enlarged the hole with a 17/64 drill and then tapped it to 5/8 NC18

At this stage I was obliged to call a temporary halt and as I want to be able to use the car (storms are forecast) I didn't want to have the inside of the wing completely exposed. I refitted the old splash guard temporarily, and fitted a bolt into my newly tapped hole to keep the muck out.

When I got a chance it was easy- if very mucky to clean out the cavity and wire brush the metal edges to remove any loose rust. I treated all the lower areas-especially the lower mounting flange and the ends of the castle rail where the underseal has come off, with rust converter and then applied a coat of Hammerite to the metal. As an aside I will add that this is virtually the last of my original hammered enamel from Finnigan's Speciality Paints in Prudhoe Northumberland- and bought BEFORE the company was bought out. Modern Hammerite is similar in name only in my view and I am really sorry to have run out of the original. The aerosols of the modern stuff are the worst- they seem to have virtually no pigment and little if anything in the way of rust-inhibiting properties.
My view anyway-rant over!

I also painted both sides of the new splash panels in the same paint. The tops of these don't really rust so I clamped them upside down to make sure I got a good coating on the bottom and edges. Turn them round after 24hrs and paint the other ends.

I sprayed inside the wing with Waxoyl from a warmed and well shaken aerosol can

The sill projects forwards into the bottom of this space and this creates a narrow gap with the outer wing towards the bottom. This area is a notorious rust trap. I feel it needs protection, but its important not to clog it with wax as it also needs to drain. I sprayed it and worked the wax down into the gap with a long plastic tie strip, raking the wax forwards so I could tell that it isn't blocking the channel.

Checking that the gap between wing and sill is clear, whilst still protected with waxoyl.

The new splash guards are ready- they will fit either side, but it seems that its best to fit them such that the reinforcing mouldings bulge outwards (ie convex side) towards the wheel so that they don't collect road muck.

The edges are always the most vulnerable because paint tends to be thinner here. I lined the edge of the panel with a bead of grease that will stay inside the sealing strip and hopefully protect.

... and then fitted the sealing strip. I overlapped it at the top

... and only cut it when it was fitted so that the cut edge can follow the line of the panel

I put some corrosion block grease into all the bolt holes and spread it up the mating edge so that it will be between the panel and the wing.

Then I offered up the panel, fitting the top bolt first and working downwards.

Its necessary to bend the bottom of the splash-guard so that it follows the contours of the body and lines up with the bottom bolt hole. I cut the bottom of the sealing strip to fold neatly around the bottom of the guard when its folded, but still permitting some drainage.

Finally I bent the bottom edge into place and fixed the larger bolt I had selected into my re-tapped mounting. Note anti rust treatment on the end of the castle rail.

Splash-guard installed.

I should add that predictably the passenger side lower mount screw was also rusted and degraded. I tried to remove it as before but this time the drill bit broke off inside the bolt and could not be removed. Since the drilling was probably not concentric and straight its likely that the stub of drill is now wedged across the thread, partially in the stud and partially in the weld nut. In this position it would stop me unscrewing the stud (even if I could grab it) and its far too hard to let me drill it out. I'm therefore completely stymied on this and I'm proposing to leave it as it is and fit a rivnut for a new fastening.