MAKING LIGHT OF IT

For classics used during the winter, moisture can wreak havoc in many ways, especially in terms of compromising electrical continuity…

Recently I have been called upon to sort out non-operating rear number plate lamps on two separate classics. In both cases it was assumed that the bulb concerned had failed, but on removal of the lamp cover it became clear that the trouble was due to corrosion on both the bulb contacts and the ones in the holder. Lamp units mounted within the top, horizontal surfaces of bumpers are especially prone to water ingress. The sealing arrangements for the lamp cover are not always good, especially when the original seals become old and brittle.

In such cases it is worth buying, or making, a new seal to prevent moisture entering the lamp assembly in the future. Alternatively, a bead of flexible sealant can be applied to the original seal, or directly between the lamp cover and the bumper, to help provide protection. The use of such a sealing product should enable the lamp cover to be removed easily when this is next required, although it will be necessary to re-seal it again on re-assembly.

The corrosion typically found on bulb and bulb holder contacts can sometimes be dissolved by applying a little water-dispellant spray and wiping with a soft cloth, or you may need to gently abrade it away. Go easy as the contacts are always delicate and may be very weak. In cases of severe corrosion you may have no alternative but to obtain a replacement lamp unit.

It is often found that the securing screws for number lamp covers are reluctant to come out, especially if they haven’t been removed for a while. Apply penetrating oil around the screw heads, and allow to soak into the threads and try again. On re-assembly, lightly coat the screw threads with copper-based anti-seize compound (or alternatively ordinary lithium-based grease).

I also find it helpful to regularly release such screws a little (say, half a turn or so) and re-tighten them again. If you do this approximately once a year, the screws are then less likely to offer stubborn resistance when you really do need to take them out (usually on a cold, dark, damp winter’s evening!).

TIP OF THE WEEK PHOTO CAPTIONS

1. Rear number plate lamps are fitted within the bumper assembly on many classics, especially those of the Seventies and Eighties. Over time, moisture can seep into the lamp unit, resulting in corrosion of the bulb contacts; regularly check and clean the bulb.

2. The bulb holder contacts in some number plate lamps can sometimes be cleaned up using abrasive paper, then wiped clean with a soft cloth coated with water dispellant spray. If the seal between the lamp and bumper is defective, renew or seal with silicon.

Cable clamp assemblies used to lock choke and accelerator cables in the correct positions can be difficult to align when attempting to feed the cable through the hole in the clamp. A dab of white paint or typists’ correction fluid can help ensure correct positioning for easier cable threading!Tip 1: 

I have often struggled to thread choke and accelerator cables through the holes provided in the respective cable clamp assemblies (used to secure the cables to the carburettor’s operating arms). This job is made more difficult by inaccessible positioning (almost always behind and/or below the carburettor), and consequent lack of available light in which to see what you are doing.

The use of an inspection lamp helps of course, especially, if available, you use one mounted on a headband. However, it is also helpful if the flat on the hexagon immediately adjacent to the cable aperture is highlighted with a dab of white paint or typists’ correction fluid.

This approach worked just last week when helping to get an urgently required classic back on the road in the minimum amount of time. The owner had struggled for ages to guide the cables into place, but without success. After highlighting the flat on the clamp’s hexagon, the job was complete in under a minute…

The owner of this pre-war classic project vehicle had a big shock when he lifted the ‘temporary’ cover that had been in place for far too long. The condensation trapped beneath the cover had resulted in extensive surface rusting of the car’s roof.Tip 2:

CARE USING COVERS

It’s easy to throw a ‘temporary’ cover over a classic car project and forget about it for a long time. The trouble is that the materials used in many such covers don’t allow ‘breathing’, so any moisture between the vehicle’s bodywork and the cover is likely to remain trapped there. The inevitable result will be rust, and if left in place long enough undisturbed, the cover will conceal a real horror story.

There are several relevant tips to help avoid such trouble… First, when buying a cover, try to obtain a good quality type which does ‘breathe’ to a certain extent, allowing moisture to escape naturally.

Regardless of the type of cover you use, whenever possible it’s wise to remove it from the car on dry, breezy days, to allow air to circulate around the vehicle. If possible, hang up the cover inside-out on a washing line, so that it too has a chance to dry out. Make diary notes to regularly check the state of the vehicle’s bodywork.

An urgently-needed horn push assembly like this (and all sorts of other components) can often be sourced rapidly and cost-effectively using internet auction sites. It’s worth a try for the part you need!

INTERNET AUCTION HELP

Many classic car enthusiasts are still unaware of (or dismiss) the various possibilities in sourcing parts for their old vehicles by using the internet. Yet the procedure is relatively straightforward, even for those who are not keen on computers.

By typing into a search engine the name or names of the part(s) required, often a surprisingly long list of available spares will appear. This may be through specialist suppliers, or via internet auction sites. At least it may put you on the right trail to obtain the requisite components.

I have found this useful on a number of occasions recently, not least when a ‘hit and run’ driver broke an ‘obsolete’ lamp unit on one of my regularly-used classics. Within 30 seconds of searching, I had found someone with the correct lamp for sale at a reasonable price, and it was with me the next day. Wow.

A quick check to see if petrol is reaching the carburettor is to slightly slacken the inlet pipe union (or the screw securing the pipe clip) and see if fuel emerges when the ignition is switched on − electric pump, or the engine cranked − mechanical pump. Tip 4:

QUICK CHECK ON FUEL SUPPLY

If your classic should come to a halt at the edge of the road, usually it is essential to diagnose the problem and get the car running again as soon as possible. A full check of the electrical and fuel systems obviously takes time, but if you can ascertain whether the engine is receiving petrol, this quickly narrows your field of search.

To find out whether petrol is being delivered to the carburettor(s), slacken the screw securing the inlet pipe (and carefully pull back the pipe a little way) or release the union nut, and turn on the ignition. If the car has an electrical petrol pump, it should now start pumping fuel. If a mechanical pump is fitted, the engine needs to be cranked to operate the pump.

When carrying out these checks, it is ESSENTIAL to make sure that petrol cannot drip or be sprayed onto hot parts of the engine or exhaust system or into/near electrical components or a fire could start.

If the needle valve in the carburettor is seized shut, petrol might still not reach the engine, despite it being present at the inlet union. However, if fuel is NOT visible at the carburettor union, there’s DEFINITELY a supply problem that needs to be fixed.

I used this ‘quick diagnosis’ approach recently when a friend’s sports car had stopped at the edge of a busy main road in Sussex, and it was possible only to get the left side of the car off the road. Despite the use of hazard lamps and a warning triangle to advise approaching motorists, we were keen to see if we could very quickly get the car running, so that it could be moved to a safer location.

Disconnecting the fuel inlet pipe at the carburettors produced no petrol with the (electric) pump switched on, and within a very short time the contact points in the pump had been accessed and cleaned up enough with abrasive paper to get the engine to run. Further remedial work (more detailed cleaning/points re-facing!) was then carried out in the safety of a car park.

A friend brought this silencer (from a pre-war car) to me, and ‘tongue in cheek’ asked if I could ‘weld it up’. Hmmm. The short answer was ‘no’, but even this rough old silencer yielded pipe and body dimensions, enabling a replacement to be found.Tip 5:

EXHAUSTED…

I am often challenged to repair components that are in pretty dire condition. Sometimes it’s possible, more often not! Still, a recent example that really stands out was an exhaust system silencer, salvaged from a pre-war car and then stored in a friend’s horribly damp shed for many years.

Recently he had made much progress on the car itself, but brought the silencer to me in the hope that I might be able to do something with it. No, really I couldn’t. It was a mess.

All the same, before recycling it I advised him to note the length and diameter of the unit, also the inlet and outlet pipe positions and diameters. He drew diagrams and noted all the relevant details on a sheet of A4 paper, and this information enabled him to find a precise match from an exhaust system specialist.

As I have said before, it’s wise not to dispose of any classic car parts unless/until you are quite sure they cannot be used as patterns, at the very least.