Background #
If you already know how undertake changing an MGB Headlamp, no need to read this. This may seem obvious to the more experienced MGB Home Maintenance Mechanics. But if you have never done this and the headlight has broken, well, it is probably not that obvious. It certainly wasn’t to me first time around.
Introduction #
Unlike modern cars the MGB headlamp is a sealed beam unit, unless it’s been changed/upgraded by someone. That means there is no bulb to change. The entire lens/glass has to be replaced. You will also quickly find, unlike a modern car, you don’t get access from the rear of the unit. Some wires and a connector are fed through to attach to the rear of the lamp.
Step by Step #
So, for starters then, how do you get the chrome trim ring that surrounds the headlight off? The trim ring is held in place by a tension clip on the lower edge.
Step 1 Trim Ring Removal #
A useful tool to remove this is actually a paint can opener. Yes really. You press downwards on the top of the trim ring and get the paint can opener inserted behind the trim ring and in front of the glass. Move this around carefully making your way to the bottom edge.
Once you get the paint can opener as close to the bottom (6 o’clock position) as possible. Pull firmly towards you and continue to press down on top and the trim ring should come free. Now, it may just come flying off towards you. Or it may come off a quarter inch and then you can work the ring off carefully by pulling and prying around the ring.
Step 2 Headlamp Removal #
Now you have access to start to remove the headlamp itself. There is a retainer ring as well as some other fittings for adjusting the headlamp position. If you look carefully, you will see 3 screws holding the lamp retainer in place distributed around the lamp. On my 77B, which is fairly original, the 3 screws for the lamp retaining ring are Philips/cross head screws. The position adjuster screws are slotted. Remove the lowest screw first as it is the fiddliest. Then remove the other 2. You will want to hold the lamp in place as the final screw is taken out. I suggest to have a rag or towel handy to rest the bulb on to protect your paint. Remove the ring and rest the lamp on your rag.
Step 3 Electrical Disconnection #
Now you can remove the electrical connector. This is a simple push fit and has 3 connectors controlling low beam, high beam and flash. You can find replacement lamps at a local parts store. They are likely to be part number 6024. What I had obtained a long time back was a pair from Victoria British (now part of Moss Motors) that have a number 6014 and that matched the broken one. There are of course plenty of options, I’m not going into that here just dealing with the replace aspect, not what the options might be.
Step 4 Reconnect Wiring – Orient the Headlamp – Retainer Ring #
As Haynes would tell you, reinstall is the reverse of removal. I am not that unhelpful!
Reconnect the wiring to the new lamp and let it sit on the rag or towel. Go and test the lamp by putting on the headlights. Check all 3 positions work as expected, low, high and flash. If good proceed to fit the lamp and the retaining ring paying attention to a couple of things.
Firstly, the lamp has a top and a bottom. The electrical connection probably means you have it the right way up but check the writing on the glass to be sure. Also note there are some locator tabs on the glass. Rotate the retaining ring so that all 3 screw holes line up. The retainer ring requires orientation correctly, so don’t just align 1 position and think you have it right. Put in the upper 2 screws first to hold things in place and deal with the lower one last. Once all are started tighten each one fully.
Step 5 Checking & Testing – Trim Ring Reinstall #
Now all that should be left is to put the trim ring back. But, before you do, go and test all the light positions again to make sure it is still all working. If anything is wrong, you won’t have to do battle with the trim ring twice in one day! Assuming they are working put the trim ring back on starting at the top (12 o’clock) and get it positioned snugly all the way on. Check the bottom edge has gone over the clip and if yes push/pop the ring all the way back and it should hold itself in place. This is why you want to get the top part positioned first and finish at the bottom of the ring. Then test again the 3 headlamp positions all work, and, with luck they do so you can stand back and admire your work and feel accomplished!
Hopefully this has been a useful basic maintenance walk through. Please check for other electrical related items or jump back to the main knowledge base page to find more useful information.
Other Materials #
I’ve built this website and spent time on the knowledge base to bring together a lot of information I have collected from around the internet. The intent is making it easy to find rather than having to know about and have skills with search engine query terms to get what you were looking for. Please make use of the knowledge base.
