I have noticed that a lot of RM/Ls have or are being re-panelled, a lot being done just below the waist, not exposing the upper saloon structure to any scrutiny. Now this is not setting out to alarm those that have had a panel job done to their pride and joy, but does your RM crack or click when leaning over going round corners? Is there a clicking or cracking noise particularly near the interior advert or above the cab window? If so, it could be that the pillar feet above the front bulkhead have cracked and the cracking noise is them parting and going back together. There is no need to be alarmed unless you have a PCV for your bus and use it laden.

If you do suspect a problem,and you will hear it if you have, its not a major strip out to check and you do not have to disturb the paint job, you can simply remove the interior (chequer plate) coving panels on the upper saloon, this will expose the pillar feet as the covings rivet on to them. They are triangular in shape and were designed to be weight saving, if they have a large space in the centre of the triangle they are unmodified, the modified ones fitted to most of the RMLs on overhaul and the RCLs under a special programme are more solid with a small hole in the centre, but after 30 years use they may have fractured. If they have fractured the cant (colour band) panels will need to be taken off and the front and upper saloon waist (advert panels) at the front bulkhead join released to remove the bolts holding these in place

Unfortunately I cannot offer a source or supply of replacement items if your pillar feet are cracked, they cannot be welded, but if there is enough demand maybe a replacement part can be manufactured through one of the owner’s associations at a reasonable cost or a trip might be needed to Barnsley…….

My bus number (if any): RTL 960, RML 2667 and an RMC

I mentioned this as well on the other site a couple of times a while back as has another chap.
He also pointed out the other achilles on the body work.
The crack is a good tell tail but the other areas to watch for are the steel spars that are behind the ceiling coving. They rust badly and actually support the upper deck stress loads. again not a serious problem for a preserved bus but crucial for a service bus. Again I have no idea about the part being availible but PAG in Hanwell made some up for RM 408 several years back.
Most open toppers have come to grief because of these not being weatherproofed.

My bus number (if any): Undisclosed but in London

There may be "spars" or inner roof hoopsticks on an RM but they are to the best of my knowledge not made out of steel and neither is any other part of the Routemaster body framework. Having only taken down a few interior ceiling panels in my time, but hundreds of lighting panels, I cannot be 100% certain, but having replaced roofs, the whole of the front and rear of RMs, and most of the Lower saloon floor, I can say that I would be amazed that amongst all that aluminium any form of steel was used in the body. As far as I am aware,and a search of the internet confirms this, the whole body structure is either alumunium alloy sheet in various thicknesses and grades, aluminium alloy top hat sections with sheet riveted top and bottom to form floor sections, although some were later replaced by plywood sections) and in the case of the entire framing an aluminium magnesium alloy which was used to make all the pillars and rails in an H, L or U section. Of course this has corroded over time and surface oxidised, but I can say I have never seen rust in any part of an RM body.

My bus number (if any): RTL 960, RML 2667 and an RMC

I have a picture somewhere from when I had to replace several spars.
I can confirm they are steel and link the upright frames with the saloon roof spars between the window bays.
They are designed to flex & absorb three way stresses. Look a bit like a lower case 'r'
One of the few steel components used. Not easy to notice as they are normally in Chiswick pink.
They will last indefinately if corrosion preventative treated.
One of the signs of corrosion is if the alloy coving that the light fittings are mounted in is bubbling up at the joints, in particular the on that has a flush join rather than a beading overlap.

My bus number (if any): Undisclosed but in London

Ummmm still not convonced they are steel, maybe Colin Curtis can confirm. I can see no reason to have used steel here given that the rest of the framing is aluminium alloy, and after the RT experience why would LT have gone back to using steel?.

Anyway, the "covings" are actually called lighting panels (coving panels are the chequer plated panels between the floor and side) and were originally flush fitted with pop rivets, but due to water incursion from above and movement which caused corrosion and paint bubbling, the 5/32" rivets had to be changed to 3/16", then when they pulled through, those ugly patch plates wewre added to cover the joins, the patch plates were always supposed to be covered by adverts.

My bus number (if any): RTL 960, RML 2667 and an RMC