How to Diagnose a Roadside Breakdown

It's perfectly possible to use a classic car as an everyday vehicle. And the more you use it, the more reliable it will get, the more trustworthy they will be. The more confident you'll feel in driving it. But there are occasions, unfortunately when things will cease to function from time to time The good news is these are usually fairly minor. I'm just having an idea of what to look at when the car does stop will soon often have you back on the road and then five or 10 minutes. Now, if your car breaks down, or it looks like it's about to break down. Your first priority, really, is to get it somewhere safe. As far as you possibly can get it off the carriage way. Get it out of the way of following traffic. You've got a warning triangle, set it up behind the car. Some distance away. Put the hazard lights on if it's so provided and do carry carry at all times a fluorescent vest you can suffer a puncture, even if the car is in perfect mechanical order and for a couple of quid it's, it's literally a very cheap lifesaver that. As regards to trying to get the car going again. We at least have the advantage that we knew it was rolling immediately before it stopped. So very often a quick visual check under the bonnet. We can have a look around and see if anything's fallen, off disconnected itself is looking a bit, you know worse for wear. I'm very often put that right And be on our way again in a few minutes. If there's nothing so obvious to see though a very short and logical checklist of the various systems of the car will normally have us going or at least identify the fault in a relatively short amount of time. Now, one of the questions you can ask yourself is, is this something that you were recently fiddling with because perhaps you've not put it back together properly or something like that or was there some symptom immediately before the car broke down and it starts to misfire or hesitate or something like that. Because again, that can be a vital clue, but don't fixate on these things by all means, check them out but don't spend all your time going over and over the same thing again. If your immediate suspicion doesn't bear fruit, then start on the logical checklist, which we'll show you in a moment and just go all around all the systems, and that should quickly identify fault. Now you found it handy to carry a toolkit with you. This is a full role that I carry with a car. It's got far too many spanners in this actually but ignoring the fast constancy of spanners. What you probably need is say two or three spanners of popular sizes, like 10, 12, 13, 17, something like that. Just popular sizes that are present on your car or Imperial equivalents, perhaps an adjustable spanner Spark plug wrench, pair of pliers and three different sizes of screwdriver. So screwdrivers, pliers, small selection of spanners plug wrench. And another handy thing is a little test light which you can make from a side light bulb on a couple of alligator clips, not a little, an hour's little project for you there. Part can come in really handy. And I always carry a little led torch, which are quite good. Make sure it's got decent batteries in it obviously. And that small selection of accoutrements should be enough for most small roadside repairs. Then. Now, the other thing that's handy to carry is a few spares. They don't have to be new but it just needs to be stuff that you know works. So perhaps the last set of contact brokers you took off the car, a condenser that, you know, works perhaps a spare spark plug. If you have one lying around. A distributor rotor is handy to have because they can burn through from time to time. Distributor cap. Yeah. If you've got a spare by all means, carry on. Although they don't go wrong very often. The other thing that's handy to have is a selection of fuses of the various values that fit in the car. Now our break down drill is a quick visual check for anything that might have fallen off or detached itself. Then a check of the ignition side. And then a check of the fuel side Make sure the battery terminals are tightly attached. Make sure that the HT wires are still attached particularly the one from the coil to the distributor cap. Make sure the distributor cap is on firmly and that's not come loose. If there's a fuel filter, just have a look and see if there's actually any fuel in it and have a check to see that none of the fuel hose is anywhere have come unattached. Quick look at the wires to the coil, particularly the one from coil to distributor. And that should complete your visual check then. If there's nothing obvious there, go on and have an investigation of the ignition side. Now, if the whole car is electrically dead. Then check the battery terminals. Check that they're firmly attached, and follow the wires to check they are firmly attached to the other end as well, and that those connections are tight and clean. That should solve that issue. Next of all, move on and have a look at the contact breakers. So turn the ignition on, remove the distributor cap, turn the engine until the points are closed, and give the points of flick by hand. Then you should see some signs of life though. You should see a spark at least generated out the points. If the car's got electronic ignition, you obviously can't do this. What you'll have to do in that case is simply just crank the engine on the unlit for spark being generated. If you've got signs of life at the points, what you can do next is to remove the King lead from the distributor cap. So, connect it to the coil. So it should give us a spark when we flick the points then and you can test this by holding it, preferably in insulated pliers. And don't try this if you have a pacemaker because it will most definitely upset that. If you flick the point, so then you should see quite a decent spark jump between the end of the King lead and the rocker cover or any other convenient earth surface. And that basically proves them that the points are working, that the condenser is doing its job, and that the coil is working. If there appears to be electricity flowing, you can test that with a test lamp put that on the terminal. On the side of the distributor from put one lead to earth. Should light up when the points are open. If that produces electricity flowing but you can't get a spark, then that suggests that perhaps the condenser is faulty. Try swapping the condenser. You can't really test it. You can only swap it, but before you do that make sure it's A. Firmly attached so that it's terminal along the side of the distributor B. That it's firmly screwed to the side of the distributor because that's how the condenser gets its earth. It just gets through that attachment skirt. Having proven a spark is being generated. We know that little spark is going into the distributor cap. So the question is, is it coming out again? It goes into the distributor cap, gets sent through the rotor and then sent out of the cap again to the various spark plug leads. And a very common problem is that the rotor arm burns through, the electrical insulation fails, and the spark disappears down into the distributor shaft and never comes out again. Never makes it to the spark plugs. So what you can do now is put the distributor cap back on. We know we're getting a spark. Take a spark plug out and lay it on top of the rocker cover, and just turn the engine over. And try to observe if you've got a spark being generated at the spark plug. Even if you can't see it necessarily you should be able to hear it clicking on the spark plug. Don't forget, for every spark that comes out of the coil, one spark plug will only click, you know a quarter or a sixth as often. Do make sure that you've still got a points gap. The points ride on the cam inside the distributor, which should have either a smear of grease on it or there'll be a little oiling felt inside. Sometimes this is neglected and it just wears away the heel of the point. So the gap that needs to open and close the point slowly gets smaller and smaller and smaller, and eventually the point stop opening altogether. There isn't a gap. Then set a gap. You don't need to feeler a gauge for this. It's not critical, certainly not to get you going up the side of the road. If you've got a business card or something like that in your wallet, the thickness of a business card, will do it. Point four of a millimeter it is. And the other thing, while you're fiddling with the points is just as you flick them by hand just make sure they spring smartly short because I've seen cars that have come to a halt with actually new pairs of points on and the pivots on them has been a bit sticky. It's always been assembled a bit tight. And so it's not been springing smartly short as the engine's turning round. And this obviously means it doesn't generate the right number of sparks or the sparks are at the wrong time or the the thing just sticks out and it doesn't do sparks at all. So that's sort of final check that you can make. I'm going to start my fuel investigations here at this side of the car, because right in front of me is a plastic, a clear plastic fuel filter. I'm going to look and see if there's fuel in it, and then the next job is if you can watch it while you crank the engine. What you shouldn't see is the fuel absolutely washing backwards and forwards in it. You'll see a bit of pulsation in the fuel but if you see the fuel washing backwards and forwards that implies that the valves are stuck in the fuel pump which will either, you're going to have to strip the fuel pump and have look at it, or if it's a sealed one as many are, that's kind of the end of that really. We're going to come around now and take a look at the fuel supply side near the carburetors. The next step would be to remove the pipe that supplies the carburetor with fuel from the pump and see, then, if any fuel is actually being delivered through it. Now you'll need a rag to catch out in a large dish rag if possible, or if you've got one, a container that you can direct the hose into. Either crank the engine, the car's a mechanical pump which lives on the side of the engine, or if the car's an electric pump, simply turn the ignition on. And what you should get then is some strong spurts of fuel out of the end of the hose. And that will confirm then that fuel is being supplied to the carburetors. Therefore, if you've got a spark and you've got fuel being supplied to the carburetors probably the problem is in the Carburetor there. And you'd need to do a bit more investigation. If there's fuel going to the carburetors, then you may have a problem of either fuel starvation or flooding in the carburetors. If it's at all possible. If you can remove the top of the float chamber from the carburetor, which isn't always possible depends on the model of carburetor, how accessible it is, and so on. Have a look at the needle valve which controls the flow of fuel into the carburetor and have a look at the float inside the float chamber as well. The needle valve may be stuck or clogged with dirt, maybe stuck open. So it's just flooding the carburetors. Shake the float bar area, if there's fuel inside it. If you can hear that sloshing about, the float is hold that's that's, it requires a new float. You know, that was kind of the end of that, but just a block or a jump float valve should be very easy to sort by just blowing through it. Now, if the engine is flooded for some reason. Perhaps because of the car Carburetor is flooded, there'll be a lot of fuel vapor inside the cylinders, and just cranking the engine to try and get it going will just wet the spark plugs and you'll run the battery flat eventually. So don't endlessly crank the engine trying to clear a flooded engine. The best thing you can do there is take all the spark plugs out Put them out on the bulkhead or the wing or somewhere just to dry off for a few minutes. And then crank engine over without the plugs with the throttle held wide open. And what this will tend to do is this will tend to push air through the engine. It'll push the fuel vapor out of the spark plug holes and this effectively sort of resets everything inside the engine. So when you put the spark plugs back in, it's starting again from scratch and it should fire up straight away for you. So to summarize. If you're caught by the side of the road with a broken car, you need to do a visual check of everything under the bonnet, check the battery terminals, have a look at the contact breakers, the rotor arm, see the sparks are being produced at the plugs, if the ignition side looks okay from that point of view, have a look at the fuel supply, and the carburetors, but most of all, remember your safety make sure the cars out of the way and that you can be out of the way while you're working on it. And if you can't call somebody, you can take it away.