Bedford TK

[colnerov]

Hi, You have to remember that commercial vehicles and especially coachbuilt buses and coaches at that time didn't have chassis earth return on the electrics. So everything electrical had to have an earth wire and even a simple oil switch would have had two terminals.

Colin

 

[rtbcomp]

I've just remembered what the 3 pin oil pressure switches were for.

One connection is for the oil light as standard, the other two were used to control the older type alternator which had an external regulator, they operated a 6RA relay which disconnected the alternator *regulator when the engine stopped. I had one on a Perkins 4203 I fitted to my SIIa Landrover.

*Edit

 

[rtbcomp]

^^ As the memory mists of time disperse, I recall the one I used had 2 connectors, one for the relay and one for the warning light. You could omit the relay with a 3 pin switch (assuming the 2 other pins are spst). The relay was called the "field isolation relay" and was in series with the alternator field coil.

There was another component in the circuit, the alternator warning light relay, this looked like the old indicator flasher units.

 

[colnerov]

Hi, Yes that ^^^ all sounds like the Lucas 11AC alternator, 4TR regulator, 6RA relay and the 3AW warning light relay (the mechanical versions are no longer available, but there is an electronic version now, SS3AW) They all come in a choice of voltages 12V and 24V.

Colin

 

[mylesdw]

You guys are brilliant!!

It had an old style alternator with separate regulator so the extra connections were probably for field isolation as you say. That would account for it not being in the 'original' wiring loom as this truck as been re-powered at some time in its life. The new alternator (see above) does not need any of that so I just need to work out which connections to use for a simple oil light. None of the terminals appear to be earthed to the block so I'm guessing I need an earth return on one of them.

 

[colnerov]

Hi, Use the two terminals that are normally closed so the oil light illuminates when the engine is not running, then when the oil pressure comes up it goes out.

Colin

 

[rtbcomp]

It could be your switch is spdt (single pole, double throw, changeover) A test lamp or ohmmeter will soon sort it out.

 

[mylesdw]

Two of the terminals are joined, the others are all O/C. The joined ones behave as if there was some sort of inductor/capacitor - when you put the meter across them the resistance reduces from around 1000Ω to <10Ω over a few seconds

 

[8ob]

Three pole oil light switches have one normally closed switch and one normally open, these will reverse when the engine starts and makes pressure. There are many uses for this type of switch including being part of the daisy chain of other sensors ( low air, charging , low water , low brake fluid etc )that join up to bring on the single buzzer or individual warning lamps on the dash in the cab. The variations in wiring with Bedfords is mind numbing, it may be an idea to track down a diagram for your model.

Bob

 

[8ob]

This sort of thing

 

[mylesdw]

Looks likely but none of the terminals appear to be earthed to the body of the switch as shown in your diagram. I wonder if it is broken?

 

[rtbcomp]

Two of the terminals are joined, the others are all O/C. The joined ones behave as if there was some sort of inductor/capacitor - when you put the meter across them the resistance reduces from around 1000Ω to <10Ω over a few seconds

Have you checked the meter? Just connect the probes together to see if it does the same. You will need to test the switch under pressure too.

 

[mylesdw]

The meter is fine, behaves just as you might expect when the leads are shorted. I'll have to wait until I have it running to check it under pressure which should not be too far away. In the meantime I will hedge my bets and run two wires to it in my new loom for the oil light and an earth.

 

[Jeffo]

Hi
I have been reading your restoration story with quite a bit of excitement! If you have the time, take a nose at my bedford TL. Sadly it did not get completed due to a family dispute and zero funds. I'm very sore about it as my truck meant a lot to me.

Good call on keeping the 466 engine. My dad assures me there is no noticeable difference in performance between it and the 500. The detroit engine has lots of plus points but the fuel economy is horrendous and the amazing noise soon becomes an arduous shriek when going any distance. I changed the 500 turbo civilian spec (175bhp I think) to a 500 high blow from a bedford TM with 210bhp. It flew!

Looking at your work I now realise how superficial my work has really been.

Until last year we had 4 TLs but now just 1.
I had been restoring a TK KM. My dad drove it back from the dealer in 1982. Must be one of the last 16ton tks made as the TL was already on sale

There seems to be a lot of opinions and disinformation regarding the tk and tl. It is impossible to make a blanket statement regarding the truck when most people form their opinion around the model they knew or their mate had and that had probably racked up 10-20 years hard service and with so many weight, engine, axle and gearbox options it's fair to say you struggle to fairly compare a bedford to a bedford!
As our business bought the show truck from the N.E.C stand and my dad put a million on the clock in 12 years, I think I trust his opinion.
They are bloody good!

http://www.bedford-cf.co.uk/mboard/thread.php?id=7903&ver=&rp=&page=1

 

[mylesdw]

Hi Jeffo and welcome aboard. I always enjoy other people's projects more than my own and you look like you have your hands full there. My original cab was pretty bad and that is why I changed it. In this part of the world the climate is fairly dry and they don't salt the roads so finding rust free stuff is not so hard.

Why not move your project here and include some more pictures? There are a few knowledgeable members who know their Bedfords well.

When I tell people I am doing up an old Bedford the most common reaction is "Why?"!

I have nearly got to the point of lifting the cab back on which will be a milestone: it will look like a truck again. Just trying to do all the things that need access to the front of the engine because the access there is terrible once the cab is in place. I assume your KM has a fixed cab too?

 

[Jeffo]

Yes, fixed cab. A conversion to tilt was apparently available but I don't know who supplied it. I have also heard of someone using TL tilt bits under a TK cab and also several people have put entire TL cabs onto the TK.
As for the loss of turning circle, I can't say I really noticed. The leyland we have is just 1 metre longer but it's a terrible chore to manoeuvre. Yes the steering is light but you have to use it twice as much.

It's only with stopping and thinking about it, my KM restoration started 16 years ago and hasn't been touched in 14 years! It's quite a life it has lead. Virtually written off at just 2 weeks old. Properly written off when parked outside a transport cafe and hit by an artic trailer some 18 years later and then totalled again just as i was about to refit the wings to the cab, all repaired, painted and glossy, when the end wall of our storage unit fell in on it in a storm. It still has the souvenir bricks on the roof. it's just sat like that ever since as a painful reminder. I have very few photos of it. If anyone has a brochure from Sellers Engineering who make skips and the like, this truck, along with its older sibling was used as a product demonstrator in early 80s. Sadly we lost our copy.

 

[Jeffo]

WHY???
The why part is essentially easy, but for me, long winded. Here is just a little part of it....
At 18 years old this truck was thought of as disposable junk and therefore still sent onto landfill daily. 2wd, no diff locks and yet it ploughed axle deep through every type of crap you can imagine. Modern lorries with traction control and all kinds of gadgets would whizz past on the tarmac and then our little bedford would just creep round them whilst they floundered helplessly waiting for a tow.
At the tipping point the 'moderns' have to drop their rear legs for support. Not the bedford, it doesn't even have any! The legs sink into the boggy ground, of course, but if you don't use them the weight of the front of the truck dangling as the wheels lift skyward causes the chassis to twist and bend and it doesn't do the rear suspension and axle any favours either. Haha Bedfords front wheels are now 2 foot off the ground, it's entire 16ton payload rocking on just one axle, no sweat. Now it is empty but bogged down. Stuck some may say but ahh haaaa you hear me cry, many of you won't know about the dogleg box, including those of you who actually drive one with this gearbox layout. 1st and reverse gears are opposite each other like 1st and 2nd on most other boxes. This let's you fire the stick forwards and backwards with violent repetition and little regard for clutch longevity, to create a virtually seamless gradually increasing rocking motion and climb out of that rut. As you sweatily whoop wup whoop wup whoop wup (a glorious noise which I think is the brake compressor heard through the high level safari air intake) past that modern truck you passed on the way in which now has a bent bumper on the front and a bulldozer flattened door mechanism on the rear, you can't tell me honestly you wouldn't swell with pride, joy, and extreme smug.

Down the road by the weighbridge there is a deep wheel wash. 18 inches of filth that is supposed to clean off the collected mud. beyond that is the Renault Magnum that has locked the driver out because dirt got in the door handle and the immobiliser can't read the key. The ERF that the driver is trying to rip that last bit of fibre glass air damn off as it grounded and the ground won! The leyland that cracked it's windscreen from side to side and the Ford cargo which isn't there at all as they had all rusted to buggery years before!

 

[Jeffo]

I decided to go take a few pics today. My camera is pretty poor. It wasn't just the roof as the engine flap was up too. A block hit the bench and by a wonderful chance, managed to rebound into the passenger door. Obviously the windscreen wasn't bullet proof and the dashboard suffered damage. The windscreen pillars have also moved a little.

 

[Jeffo]

Yep. 14 years and I haven't moved a single block. I couldn't bring myself to do it as I knew I would scratch the paint!!!
Sounds daft now.

 

[Jeffo]

I was told by a bedford specialist that the air intake and a couple of other bits, indicated it had come down the production line to fuel tanker specifications. I have my doubts as it doesn't have its silencer across the front under the bumper and it was ordered as a multi lift skip lorry from new.