Latest info on Kierans gearbag ... hope he reads this lot ... all direct from Queensbridge .......... beat that for speed of info on here !!

It has been fully rebuilt by midday today Wednesday 19th Dec .. and is now waiting return to Doc's place for reinstallation ....

Failure problems found inside are as follows ......

2nd gear band adjuster ... SPLIT

3rd gear band ... SPLIT , almost fully across the bands width --- on underside so difficult to see via inspection plate removal ....

4th gear band & clutch plates ...'' mash potato '' ... it all fell out as a lump of mush OR as Q/B chap said ...'' it were mooosh mate ''

Cost of rebuild ....... approx £1100 ........ for g / bag alone

some xmas prezzie then ..... next year its a !!!!!!!!!! rebuild

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Scania engineers at Purfleet who did the installations say do not uprate this engine beyond 2000 RPM as the G / bag won't take it ..... It didn't like 1980 RPM EITHER did it .. !!!

Welcome to the ''' ooop's ' club , Kieran ..... ho ho ho

Having read again all posts relating to Kierans G'Bag situation perhaps the following may help ...

The Scania engines thus fitted are all b-stardised ' Marine diesels ' , likewise the Iveco and the Cummins ' C ' is a UK version of an AMERICAN GENERATOR engine also altered out there for use in their bus & coach type vehicles . They are all ' constant ' revving engines capable of hours of work so long as they are fed and watered regularly ....

Simple research reveals .........

' Blue Stripe ' became more involved with RM GB 32 ' repair ' because it would seem they were chosen to repair rather than go for an expensive rebuild at Q/B ... and also turn around might have been better , but thats not proven , its purely cost based ... Certainly at least ONE London Arriva Garage did their own GB rebuilds and only used the others when they needed to due to various work schedules or having too much work anyway so they shipped em' out for ' repair ' . quite straight forward really .. It would also seem that Arriva South Londons Scania RM buses were downrated even more than London Central ones because RM 6 when out on the open road did nowt more than 32 MPH on a trip when I was on it North Bound on the A1 , a long slow journey but as it was RM 6 thats fine ..

Don't forget also that the Arriva buses have the pumps all engine driven [ creating drag ] and the London Central ones still had the pumps on the Gearbag so the engines would be a bit more free running ... Anyone remember the 36's as they flew around Marble Arch !!!!

When Stagecoach London , as they were , went ahead and had Scania lumps installed in their RML fleet [ to get shot of the underpowered IVECOS ] they listened to the Scania folks and decided to get the Gear bags overhauled at QUEENSBRIDGE to be able take on the additional power and torque these new engines were capable of giving . Most of the S/coach RML buses did not have speeds better than around 35 MPH anyway because that how they were set up when delivered ...

As a result of various discussions QB rebuilt every RML GB32 for Stagecoach [ as the engines were exchanged ] using LEYLAND TITAN GEARBANDS . The reason is simple ...... these bands are much thicker & stronger so can take the additional power being put to them ......... seldom in service after this was done did any S/Coach GB32 fail for any reason other than normal usage wear & tear ....

BLUE STRIPE never did use the Titan gearbands because as I said they were mainly repairers NOT Rebuilders .... time will tell & the good news is - I have a Blue Stripe bag in my RML

All this goes to show tht you really cannot beat the original mechanical spec with AEC engine power outputs. Everything was carefully matched at the design stage with a gearbox which coped adequately with the power. Nowhere near as much research went into the refurbing and re-engineing programmes that followed from the 1990s onwards with the possible exception of the Marshall rebuilds where the Cummins engines and Allison gearboxes seem to be well paired. Sadly, of course, it is now extremely difficult to recreate a true original as spares become ever more scarce.

Anyone would think that I had nailed my poor old bus mercilessly in every gear for months and that I fully deserve this current misfortune!

I, too, have spoken to Queensbridge and have a rather fuller picture of the gearbox problems. The innards of the 'box simply fell apart when dismantled, with the main driveshaft also falling apart. I asked Craig @ Queensbridge if increasing the ability of the engine to rev would have caused this problem; he said categorically not. The possible consequence of too many revs would be the burning out of 4th. gear ( which is a lock-up clutch as John Keohane stated and not the gear band I mistakenly reported.) There was no sign of the clutch burning out, just a little wear as would be expected. Craig believes that a 50 year old mechanical unit has finally succumbed to decades of constant use, rather than less than 200 miles of driving to London by motorway.

My diesel mechanic told me that although max revs were set at 1980rpm this was not under load and in driving conditions revs would not reach this figure even under full throttle.

Changing down a gear, with too hign a road speed, could, I agree, induce excessive engine revs (I once did this in a Ford Capri 3.0 Ghia automatic on the motorway, changing down from 3rd (top) to 2nd at 80mph for a fraction of a second and watching the tacho. needle fly clockwise for half a second until I changed up again) but I never use the engine to brake the bus.

My gearbox has now been rebuilt to the highest spec. & standard possible and will, I hope, not let me down again.

Some of you have clearly made your minds up as to the cause of this failure. I would suggest that the views of those who know best should be respected rather than wild opinion be listened to. It is by establishing facts and having these interpreted by experts that we will all learn more.

Since I reported this story for the benefit of all private owners to learn from I would have appreciated the opportunity to complete the story myself; I will be able to give a fuller account of the gearbox failure after my visit there later today.

Keep your hair on Kieran! As it was you yourself who reported on this forum that the engine had been fiddled with to gain more power and or speed, then a short while afterwards the gearbox goes bang without warning on a motorway run people are naturally going to raise eyebrows and draw their own conclusions, rightly or wrongly.

All people have said is that such actions COULD have been a contributory factor, based on the facts you have supplied, not that it WAS, or that YOU caused it. The fact that you are involved with "racing" is of no relevance whatsoever......!

I think we all look forward to seeing the bus fully restored in fine fettle and reading all about it in the RMOOA magazine with plenty of oily bits photos to accompony it.

The original AEC engine would probably have it's governor set at 1800 rpm. The figure qouted of 1980 rpm is 1800 + 10%. If the governor is set at 1800 rpm this is the speed at which the fuel will start to be restricted, total cut off will normally occur at 10% higher ie. at 1980 rpm. So this is a normal setting, same as for an RF, the only time the max revs are achieved is with the bus driving the engine on a good down hill run with a following wind, does not happen very often.

Ken

I think we need to look at the wider picture on Kieran's misfortune.
Is his gearbox problem possibly something thats heading towards us all , or perhaps just a bit of bad luck on Kieran's part ? There are a lot of refurbed routemasters about , we more or less rally them in the same sort of way so could possibly end up in the same situation . In the good old days of LT with Chiswick and Aldenham looking after the buses in only the way LT could , was there enough research/testing done when the buses were upgraded after the breakup of LT ? The rm'S were designed , tested and then built with AEC/Leyland units in them , all mods etc were tested by LT as and when needed. Just how much work/testing went into the refurbs ? Its been posted on the forum for example about how the buses have been rewired and doubts have been raised at the quality of the work carried out on many of them . Could the same possibly apply to the way the engines have been changed ? Is a cummins/scania/iveco really suitable to go with a 40-50 year old gearbox ? Perhaps we need expert knowledge/research doing on this . Only time will tell if this is a one off (hopefully it is-sorry Kieran!) but if several more owners suffer this type of failure , this question may need answering.
Mark 2391

Hi All

The moral of the story is that we should all be grateful there are still people around who can repair these exotic pieces of ancient engineering.

Regardless of who/what/why/where/when or how the bag of cogs blew up, it did and in doing so provided another opportunity for those who earn their living from putting these relics back together again to ply their trade for the benefit of all.

Also, all of us lucky boys and girls who own a Routemaster are able to glean very useful vocabulary from such discussions. For example, the fact that a band can be faulty but the fault not immediately be visible through the inspection cover is useful info to file away for future reference.

BTW, RML2603 is definately a boy. I don't know why I think that but it just seems to be the case. I make reference to 'her' and 'the old girl' as that is the accepted way of doing things (although when I lived with George and Margaret, farmers in Lea in Wiltshire for a few months many years ago, George always used to refer to his Morris Marina as 'him' and 'he').

Mad? Probably, but then we all must be for becoming self-appointed custodians of intricate mechanical historic icons.

Cheers!

J

I particularly liked the technical term "moosh" - and a bit of anthropomorphism, if that's what you like, never did anyone any harm.....

...was refitted yesterday by Colin, my son Will & me in 2 hours. A quick test drive proved all gears worked well & changed smoothly. The only problem is the speedo drive, which wouldn't work & was found to be chewed up on removal. Colin is sourcing another and once this is fitted we're back in business.

Working with Colin yesterday was enjoyable & informative. Changing the gearbox is quite straightforward, provided you have good access underneath & adequate lifting gear for the gearbox.

I've not been to Queensbridge yet due to lack of time but plan to go over next Thursday, camera & notebook at the ready!

I would rather not have been through this broken gearbox experience, but have come out of it with a stronger item in the driveline and more knowledge of how a Routemaster works. Every cloud has a silver lining.

Kieran,
Glad to hear job done and 719 back on the road . Fairly quick turn round for the repair and overhaul .
Out of interest have you got a warranty with the rebuilt gearbox and have you been advised to "run in" the gearbox at all , or is just full steam ahead ?
Mark 2391

Kieran,

Its good to hear that you are back on the road. It appears that the problems you have encountered with your Speedo drive and the Gearbox mirror our own.

On RM1872 we have also had total failure of the speed transducer drives (i.e. both the speedo drive and the SG). We changed the speedo shaft with one from London Omnibus
Engineering Services and have fitted the SG with a new gear. Over this winter we intend to return RM1872 to automatic operation to see how she gets on because, if the SG is working,
manual selection is still possible. We can't check the speedo drive lubrication without breaking the Tacho sealing so we'll make do by only checking that the SG is now being lubricated following the reinstatement of the oil pump.
For those interested in the speedo drive please look at:
http://www.southdevonrailway.org/RouteMaster/Restoration.html#Hoppers
For those interested in the SG drive please look at:
http://www.southdevonrailway.org/RouteMaster/Restoration.html#March-2006

Wishing you all the very best for the New Year