I thought that readers might appreciate a little insight into some of the day to day challenges of maintaining a historic fleet of buses.  Sunderland Corporation Transport 13 itself dates from 1947 – so is doing rather well on its 77 years of age!  It is the second-oldest of the buses currently forming our working fleet, with the 1933 Leyland Cub, Crosville 716 predating it.  As part of the loan, we are responsible for day to day maintenance and inspection (applied in the same way as any modern bus operator does), whereas larger repairs or breakdowns are managed with the owners, the North East Bus Preservation Trust (NEBPT).  Last year, the failure of the head gasket sidelined 13.  A route to replace this was quickly established with the NEBPT, but as with any such work, there has been the inevitable ‘mission creep’ as a result of dismantling the top end of the engine.

SCT 13 joined us for what was initially going to be a short working loan in 2023, which is now likely to last a number of years.  This is something that I am very pleased about as it adds local variety to the fleet, is beautifully restored and also adds a different note to the sounds of the museum, courtesy of its Crossley engine.  The bus was built in 1947 by Crossley Motors in Manchester, to their DD42/3 specification.  This included manufacture of the engine, chassis and body, though many operators preferred to mix and match these elements according to their specific needs and preferences.  The firm was a major contributor to UK bus fleets, constructing 5500 buses between 1926 and 1958 (alongside extensive motorcar and goods vehicle production).

After 15 years service in Sunderland, SCT 13 became a mobile polling booth, later being rescued for preservation and an extensive restoration.  The bus had been re-engined with the ubiquitous Gardner 5LW diesel engine in 1954, and so the restoration included refitting a Crossley HOE7 8.6 litre engine – restoring 13’s original voice, but depriving it of the readily available parts network that can still be accessed for Gardner diesel engines.  SCT 13 carries the older of the two liveries used on SCT buses in the post-war period.  The later scheme of green and cream is represented on a number of other buses in the NEBPT collection.

Below: The work commenced with a strip-down of the top-end of the engine and the various components of bodywork that obstruct access.  The front nearside wheel was also removed.

Below: In this view, the manifold pipework has been removed.

Below: The paired cylinder heads (this is a six-cylinder engine, and two heads of three form the top end of the engine).

Below: Looking into one of the bores, with the piston visible within.  The work originally identified was to replace the head gaskets that provide the sealed joint between the main engine block and the heads.  These ensure that the vaporised diesel, lubrication and water that all form gas or fluid elements of the engine’s operation don’t meet during operation and also allow for any surface discrepancy of the cast iron components, that might otherwise prevent an perfect seal.  The copper/brass colour visible is part of the gasket material that will be replaced.

Below: One of the additional faults discovered was a broken valve guide, seen in the middle of this view.  To the left of it is its replacement.

Below: Using the broken guide as the basis of the new component, a process of reverse engineering enabled a new one to be machined here at Beamish.  Local suppliers had been unable to assist with finding an example, so the advantages of having our own machining facilities were well displayed, in the creation of a new component.

Below: The new (left) and old (right) are seen side by side for contrast.

Below: Another challenge was locating suitable core plugs as those fitted failed during a pressure test of the heads.  The contractor we were using struggled to find suitable plugs (and to extract the originals) as these turned out to be threaded. Therefore the heads returned to Beamish for extraction and amazingly, a well-known online retailer had suitable replacement core plugs listed; so £6 later we had a new set for the engine.  The heads were then sent back out for machining  of the faces and pressure testing to ensure a true fit on the main engine block (with the new gaskets suitably captured between them).

Below: This view shows the removal of the old plugs at Beamish, with the plugs drilled and then a T60 Torx bit hammered into them to provided purchase to enable the plugs to be unscrewed.

Reassembly awaited new valves, which were procured via the NEBPT, and which then completed the engine overhaul of the bus.  Rather than go straight into service, the NEBPT had arranged for the seats to be re-upholstered by Liverpool Coach Trimmers, and so the bus returned to its NEBPT base for this work to be completed.  With all of this now done, SCT13 has returned to Beamish and re-entered service on the museum’s services – in fitter and healthier shape and

Below: Two views of the re-upholstered seats now fitted into No.13

Below: A view of No.13 after it returned to Beamish, along with the other current NEBPT resident, No.139 (centre) and Sunderland tram 16.  At some point we aim to gather these Sunderland vehicles together in the Town for a group photo, and thoughts sometimes stray to seeing if we can operate all of our passenger transport using SCT vehicles, on a quieter day in the year…

Photos by Phil Doran, Paul Jarman and Ben Wilson and the NEBPT.

References

The two main titles consulted for this post were:

• The Buses of Sunderland Corporation Transport 1929 – 1973 by Mel Kirtley (Self published 1993)
• Sunderland Corporation Buses 1928 – 1973 by David Wayman (Northeast Press Ltd 1997)

The Local Transport History Library has an online history of Crossley Motors Ltd – see link below:

Click to access PDF-202-1.pdf