hi all,

The day after rm60 with my bus parked outside the front my house, I went to start her and got nothing batteries dead, with the isolator off I knew I didn't leave the lights on by mistake (brand new batteries fitted too)
Turns out I had corroded connections on the back of the alternator, so I cleaned them up, soldered the crimps on to wires and the problem was solved with the batteries charging!

As a result I decided to hard wire a voltmeter into the fuse panel where the pull starter is. It has worked well until today were it brought to my attention when idling I am getting no charge at all from the alternator.
I did notice yesterday it wasnt registering a increase in voltage after the engine first started, till I reved it, then worked fine. It did the same again after a day of working on her when I put her away. I thought nothing of it at first.

Today started the bus, no increased voltage. Reved it again no change, kept reving it and it started to charge but after about 2 seconds it dropped out. Then it Charged again and dropped out a few times as I was moving it out of the barn.

Turned the engine on at the end of the day and in all of the 5 mins it was turned on to put it away, it charged once for 2 seconds only when reving a lot.

I was in a rush to get home for the roast dinner , so forgot to check the voltage on alternator directly, but all the wires at a quick look, were in place.

Can anyone offer advise, as I am planning to look at this next Saturday and possibly have it off to check the condition of the brushes as it has been suggest by the ex (car) mechanic who was round for dinner they may have worn out.

Not sure what type alternator it is, but I'm sure I will find out next weekend.

My bus number (if any): RMF2771 (RCN701)

What control board / regulator is fitted and what is it current state modification wise (in the big box nearest the cab door)

mark

My bus number (if any): RM1414 sort of

Hi Mark,

I can't say for sure but i will make sure i check properly on Saturday when i go back to my bus, but i think it is a Cav one.

My bus number (if any): RMF2771 (RCN 701)

Northern Routemasters Had Leyland Engines, Simms electrical equipment ad Monocontrol gearbox , worm drive differential as running gear. At least they did when new.

As Northern had a very good maintenance and overhaul regime for much of the working life of the NGRMs changes and upgrades may have taken place, presumably this has all been documented somewhere and may even be in an archive held by Go-Ahead, Northern General's successor.

What is the spec of your vehicle? Has it been changed? What are the engine, electrical and drive train now?

The Simms electrical units were deemed obsolete and were often the sole reason for condemning a perfectly good Routemaster over another far from good one. As were Leyland engines.
I recall while on a short course at Chiswick seeing some 40 fully overhauled Leyland engines being loaded onto trucks having been disposed off as surplus.
Outside were another few dozen Leylands awaiting overhaul that never made it. Some were from Garages but most had been reclaimed from scrappers

I understand that they are mainly still in use in fishing boats in Tunisia, and the North African coast along with a few hundred AEC engines also sold via breakers.


The electrician I knew then thought the Simms gear was very good and rarely needed attention although the alternator charging equipment was always a problem for spares. Alternators on AEC and Leyland RMs were a problem in the early to mid 70s.

All the connections need to be clean and well protected, but the biggest problem is failing resistance on cables caused by condensation, insulation failure and general damp and corrosion. This is now a problem that is also age related and problematic for vehicles in irregular use.

I've come across a couple of buses still running with the 3 phase alternators and "toast rack" rectifier wired in! the last one was an RM in Germany. the rectifier had gone defective and burnt out the control board. I replaced the alternator with a later type and fitted a "fag packet" transistorised 441 type control box. Problem solved.

Were any of the 3-phase unit made by Simms?

My bus number (if any): RML2532

Right not through lack of trying, but I have been unable get any service history for my bus from previous owners but where in resent history someone made a pig of her electrics and bodged a lot probably when made a party bus.
I have removed all of these i have found and wired them correctly

She has original Diff and i think the gearbox is original but looks exactly the same as all the other routemaster ones i've see. I isn't automatic, just goes in gear as soon as you select the gear.

she has a more modern alternator with circuit board on the alternator.
There is no rectifier under the bus near the hydraulic pressure switches

and she was given a AEC av590 by LT in 1980/1 from memory
this engine was changed a year ago to a AEC AV760 because a previous owner was running her on a damaged crank shaft and bearing. the 760 is what as available at the time!

I am now taking a half day at work friday so i can get the alternator off friday to look at the brushes and for any other obvious issues. I will also take some photos of the plates on the control box on Friday,

Then i can spend the whole weekend fixing the issue
If it is the alternator bust i will taking it to a special repair place local to me monday.

My bus number (if any): RMF2771 (RCN 701)

i have worked out using the RM maintenance manual, i have CAV control panel.

i have a high and low regulated voltage switch and a main fuse on it, the manual says the Simms doesn't have them

My bus number (if any): RMF2771 (RCN701)

They were obsolete Jack.Could no longer be bought and spares were not obtainable any more. We have Simms starters and have been told to bin them as cannot be repaired.
In the 70s LT spent £000s on a programme of replacement CAV equipment for the Simms gear on a large number of RMs which also threw up spares for the Leyland engined ones that were not converted.

Not sure about RM engines in boats, the Gardner DMS engines ended up as such in Hong Kong, but the DMS engine was a marine engine anyway.

My bus number (if any): RTL 960, RM 1585, RMC 1486 and several RTs

Yes, I somehow completely missed out the demise of Simms and the rapid decline of spares from the obsolescence that occurred almost overnight.

One problem was that parts procurement were rather sluggish in securing parts and it was known that Simms were being run down having been absorbed by CAV in 1968.

Troubles at Lucas/ CAV meant that supplies were patchy through most of the 1970s and coupled with Simms demise was a big part of the NBA problem that put many RMs off the road for protracted periods.

Quite why LT never went to Bosch or Valeo post 1973 when the free trade and open trade was permitted I don't know when both were able to produce almost anything in the 24v bus and truck industry.

The replacement of Simms Equipment was a long slow process and we had many buses off the road awaiting a CAV component. Even headlamps and light fittings could be weeks at one stage. We even used some headlights of an accident damaged Ford Anglia service vehicle at one point which the sparks managed to convert and gave me to fit on RML 2711. One of the first jobs I did on a bus unsupervised!

My bus number (if any): RM1414 sort of

So it turns out the regulator is fine and the problem is infact the alternator,

I'm pretty sure it's just a damaged brush but the alternator itself is pretty old and tired so if I was to decide to just replace it are there any recommendations for what one?

My bus number (if any): RMF2771 (RCN701)

SO had my alternator looked at properly now having changed the brushes with it still not working!

The guy looking at it gave me a list things wrong with it and was surprised it was still working with so much wrong before the regulator went. It is not worth repairing.

I've got my eye on a few alternators at the moment but wondered what AMP rated ones other people have. Mine one was 65amp one

My bus number (if any): RMF2771 (RCN 701)

Matt, you have a problem which probably cannot be answered on an internet forum. I suggest you book the services of an auto electrician to try to solve the problem.

It isn't a case of simply changing the alternator; you may have to change the voltage regulator, get an alternator that matches your battery capacity, one that is compatible with the engine idling speed and the number of belt needed to drive it. Will it fit in the cradle?

As you're taking your bus to the other side of the world it needs to be right, not bodged and likely to break down every few miles. Have you done the usual checks for negative or positive earths to body? The body should be neutral.

My bus number (if any): RML2532,GS67,MLL721,MLL738 and an RT.

Matt,

You might want to have a trawl through this site as quite a bit was entered on electrical issues.

I think it was Jack who made the point about water ingress and condensation corroding and damaging the resistance loads and insulation of wiring. Cabling is the achilles of often the most perfect of preserved buses. Electrical fires are not too common but can be very expensive to remedy and potentially catastrophic.

Fitting a higher output alternator could simply finish off the wiring and other components unless they are all in good working condition and compatible.

It's a problem that does not just affect buses, older cars from the same era, even those in pristine original condition are becoming very vulnerable to electrical failures. It's no co-incidence that the biggest growth market area in classic car spares is now complete wiring looms. The one benefit being that the cost of a new loom is now affordable and obtainable and range & quality increased by using improved quality materials.

Electrics on the bus when old, suffer more than probably any other component. On the Routemaster it is just a small list of areas where corrosion can get a grip and make for costly or difficult repairs but it is, as I say, a short list when compared to almost any other bus or classic vehicle of the era.

It sounds like you need to sit down and catalogue all the ancillaries on your vehicle, Type, make and date. and compare with the buses' original specification, and, as has also been suggested, try and find out if it's service history is documented somewhere ( which is possible but a very long call now) It also helps someone troubleshoot from afar if they know what is connected to what.


Keep that list and update all the repairs and mods that you or someone else makes, complete with part numbers, you may need it when somewhere obscure.

Then each component needs to be tested along with its circuit quality.

This can be a long laborious job and does take a good degree of knowledge and skill. If I were in your shoes, I would weigh up the situation and call in someone like David Colin.

It could save you weeks of fiddling about and reduce the long list of glitches that could prevent the bus getting much past Harwich.

In the long run its the prudent option for what you intend to do.

Good luck

Mark

Thank you all for the input, yesterdays question was just so i had a idea of how far out mine was after a text from the electrician telling me mine was f#@$ed, but yes now see it was like asking how long a piece of string is.

Having been to see the auto electrician yesterday after noon to talk about going forward with this properly he tells me mine was meant for a 7.5t lorry with no extras like tail lift.

Most of the wiring in my bus has been replaced now except the last few feet to the rear lights after a terminal box under the lower saloon rear seat which will be done when i have the rear panel the lights are on removed - soon (with a vast amount a dodgy/bodged wiring ripped out, i was shocked how much) i hate to think of many £££ of new copper has been fitted to run the buses existing ancillaries, and the extras i am fitting!

An auto electrician who knows routemasters and who has been working on the electrics with me has sourced me a new alternator. Just down to me to order the new pulley for it on Monday.

My bus doesn't have regulator in the box next to driver, the regulator was built into the my old knackard alternator so the replacements has same arrangement. The alternator idle speed (calculated from the engine idle and the pulley ratios) fits too

The wiring replaced has been done in mind with our plans for the bus and power needs and the alternator to suit our battery arrangement and engine mounting.

My bus number (if any): RMF2771 (RCN 701)