I am trying to locate the correct bulbs for the front indicators, the one I am trying to replace shows 28v 26w although the 28v could be 24v as it is a little scratched! Reading through the forum I see that many different types exist,do we have such a thing as a standard bulb, anyway, can anyone suggest a supplier?

My indicators are what I would suggest are the new type and the bus is 24v, hope that helps?

My bus number (if any): RML 2505

Hi Pete,

I think you need a 24V 21W BA15d bulb for your indicator. You could buy it at ttp://www.lampco.co.uk and look for the reference code AUTO346.

Hope this helps!
Cheers
Tonia

My bus number (if any): RML2386

According to my bulb catalogue, your bulbs are Lucas number LLB 344 which is a heavy duty 28 volt 26 watt bulb.

Roy, thanks for your help, I have managed to buy the ones suggested by Tonia, albeit they are 24v, I suppose the original question was not only to do with the correct voltage but to ask if anyone actually knows the correct bulb for the indicators, as the bus is a 24v system, I was wondering why 28v bulbs had been used, or was this another case of using what was available when the bulb last blew!!
I have ordered the wiring diagrams so hopefully they will show the correct bulbs for the indicators.
Again thank you for your help

My bus number (if any): RML 2505

The original ears indicators use 12 volt bulbs in series so that if a bulb fails it does not affect the operation of the other indicators front and/or rear. For reference they are 12 volt 21 watt 25 mm SBC cap

My bus number (if any): RTL 960 RMC 1458 and RM 1585

Wrong. Make a break in a series circuit and the whole circuit ceases to operate.

That should have read "The original ears indicators use 12 volt bulbs wired in PARALLEL so that if a bulb fails it does not affect the operation of the other indicators front and/or rear. For reference they are 12 volt 21 watt 25 mm SBC cap
No wonder my christmas tree lights never work LOL

My bus number (if any): RTL 960 RMC 1458 RM 1585 and several RTs

Sorry I am not surprised that your xmas tree lights won't work!

Wrong on all counts unfortunately. It is a legal requirement in GB for the driver to be made aware of a bulb or circuit failure on one side of his vehicle.If a fault develops then the warning light repeater in the cab will cease to operate when that side is selected. The other bulb on that side will also stop working if it is an AEC or Leyland.

If 24 volts is applied to two 12 volt 21 watt bulbs that are wired in parallel then they will burn out almost immediately.

The AEC/Leyland indicator circuit is connected in series, hence it uses 12 volt bulbs.

Most if not all of the refurb vehicles will have been modified to use 24 volt bulbs wired in parallel. If there is a one-sided fault on one of these, then the in-cab bulb will either remain constantly on, or it will flash very rapidly, depending on the type of flasher unit fitted.

The indicator bulb in both cases has a 15 mm cap.

Which is it Roy? You said in series is wrong then in parallel is wrong.
I thought they are wired in series so as not to affect the opposite side if there was bulb failure but you said that was wrong, so I asked one of my former colleagues at Chiswick and he told me he thought they were wired in parallel but its been a long time now since he touched any. The point of the my post was to give the bulb sizes for interest and information of those with the original indicators. The bulbs size come from the LT bulb chart and are correct for the original fitment for RTs RF GS and RMs. As you don't mention your vehicle perhaps its one of the refurb ones which of course use different wiring and indicator units.

My bus number (if any): RTL 960 RMC 1458 RM 1585 and several RTs

Mr. Watkinson is right - they are 12 volt bulbs (at least they are in the original. spec. Routemasters). Mine has been running quite happily for 20 years on 12 volters. As I'm not an expert electrician I don't know whether they are wired in parallel or series.

My bus number (if any): RM1001

I am sorry Brian, but I can't make the last post any clearer. Please read it again and then hopefully it will become easier to follow.

I think you probably meant to write 24v 21w B22d in your original post, however that is not what has appeared in print. I have never come across an automotive bulb with a 25 mm base cap. Even allowing for a typo, I would be extremely surprised if you are able to fit a 22mm base cap bulb into the 15mm bulb holder in an LT type ear without a hammer. Furthermore, unless the main bodies were at some time modified to a version with a smaller counterbore, I can't see that it has ever been possible to fit a 22mm bulb holder inside one.

I can recall removing a faulty LT style bulb holder from the offside rear indicator of an RT several years ago and replacing it with a modern fitting, but the unit removed was 15mm diameter. Whether this was unusual because it was a Saunders, I don't know and although I looked at another vehicle with the intention of robbing it of its fitting, I cannot remember what size it was.

This afternoon I checked a refurb and an early style rear indicator fitting as well as an RF rear and all three had 15mm bulbs.

Thanks for the reply Roy, I think I may have confused you as the cap size is not the size quoted in the chart. The size quoted is the bulb size not the cap size
From LT chart 0331

SIDE AND REAR FLASHER RMC 0 RM O RT O RLH O RF O GS O

Key Volts Watts Size MM CAP Part No
O 12 21 25 SBC 24615-107
For example the the interior and platform lights on the same chart give the size as 50mm and the destination bulbs as 38mm. I suppose in LT days the part number was the clue to the cap size. Sorry if I have confused anyone else. If anyone wants a copy of this chart please e-mail me

My bus number (if any): RTL 960 RMC 1458 RM 1585 and several RTs