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Bedford 466 bus
14 years 1 month ago #36907
by bus-ted
Bedford 466 bus was created by bus-ted
Hi all, what a champion forum. I have just purchased a 40ft smithfield built 466 bedford motorhome. The bus seems to go okay just a couple of questions, how long do you normally have to wait to build up air for the brakes on startup? The bus has a 5 speed and the gearing between 2nd and 3rd seems a little too far apart, are there any options for fitting a different gearbox? Appreciate any help forthcoming.
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14 years 1 month ago #36908
by
Replied by on topic Re: Bedford 466 bus
Bus-ted, welcome to the forum. The air should normally be up to 60-70 psi in about 30 seconds, with moderate RPM. At that pressure, if an air handbrake is fitted, it should be able to be released.
If the air is very slow to come up, you need to look at compressor replacement or overhaul. Either that, or you have numerous small leaks. Shut the engine off when the pressure is right up, and it should hold with very little drop for a couple of hours at least. If it sinks below 60 psi within 2 hrs, you need to start looking for where the air is going.
A lot of GM gearboxes have poor gear spacings. ACW Bedford are probably your best bet to have a discussion with, over replacement gearboxes. I understand the Commer 6 speed is a favoured replacement, but a good one could be hard to find.
www.acwbedford.com.au/
Cheers - Ron.
If the air is very slow to come up, you need to look at compressor replacement or overhaul. Either that, or you have numerous small leaks. Shut the engine off when the pressure is right up, and it should hold with very little drop for a couple of hours at least. If it sinks below 60 psi within 2 hrs, you need to start looking for where the air is going.
A lot of GM gearboxes have poor gear spacings. ACW Bedford are probably your best bet to have a discussion with, over replacement gearboxes. I understand the Commer 6 speed is a favoured replacement, but a good one could be hard to find.
www.acwbedford.com.au/
Cheers - Ron.
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14 years 1 month ago #36909
by bigcam
Replied by bigcam on topic Re: Bedford 466 bus
Hi Bus-Ted, the air being slow to build up could also be carbon build up in the pipe out of the compressor, or in the non return valve on the wet tank.
Instead of changing the gearbox, have you considered putting a 2 speed diff in.
Instead of changing the gearbox, have you considered putting a 2 speed diff in.
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14 years 1 month ago #36910
by Aussiehooker
Replied by Aussiehooker on topic Re: Bedford 466 bus
the governor valve could be crook and the best way to find air leaks is real soapy water in a squirty bottle or some truck wash build up air and go squirting a hand full of small leaks can add up to a large air loss all the best don
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14 years 1 month ago #36911
by bus-ted
Replied by bus-ted on topic Re: Bedford 466 bus
Thanks all, the air does seemed to hold okay but i will check it after a few hours. Takes around 7 minutes to build up and the brake warning buzzer??? to go off. How do the two speed diffs work? Cheers.
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14 years 1 month ago #36912
by
Replied by on topic Re: Bedford 466 bus
7 mins is waa-aay too long to build up pressure. You need to give the air system some serious attention. Aussiehooker has brought up an item I forgot to mention .. the air governor.
This device freewheels the compressor when the pressure is right up, and it may be knackered.
They operate on the basis of actuating an unloader port in the compressor, once maximum system pressure is reached. This allows the compressor to just freewheel.
Once pressure falls below about 100 psi, the air governor should close the unloader port.
If the air governor is sticky or worn, it may not be functioning properly and may be keeping the unloader port partly opened.
They are not expensive to purchase, about $25-35 on average. I've bought new ones off eBay for as little as $6.
The suggestion of bigcams to check the outlet port on the pump for carbon buildup is also a wise and simple check.
Replacing an air governor .. www.tpub.com/content/constructiondumptru...-3805-254-34_415.htm
This device freewheels the compressor when the pressure is right up, and it may be knackered.
They operate on the basis of actuating an unloader port in the compressor, once maximum system pressure is reached. This allows the compressor to just freewheel.
Once pressure falls below about 100 psi, the air governor should close the unloader port.
If the air governor is sticky or worn, it may not be functioning properly and may be keeping the unloader port partly opened.
They are not expensive to purchase, about $25-35 on average. I've bought new ones off eBay for as little as $6.
The suggestion of bigcams to check the outlet port on the pump for carbon buildup is also a wise and simple check.
Replacing an air governor .. www.tpub.com/content/constructiondumptru...-3805-254-34_415.htm
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14 years 1 month ago - 14 years 1 month ago #36913
by
Replied by on topic Re: Bedford 466 bus
Bus-ted - Two speed diffs contain a planetary gearset in the diff carrier, that is locked or released by a sliding collar dog clutch. Locking the planetary gearset engages the high range .. unlocking it allows the planetary gearset to spin and give you a lower ratio of gearing. This effectively makes a 5 speed transmission into a 10 speed, as you can use the 2 speed diff in every gear. These diff speed changes are usually referred to, as high range and low range.
Eaton put up these videos, especially for you ..
Eaton 2-speed differential operation (part 1) ..
Eaton 2-speed differential operation (part 2) ..
Eaton 2 speed differential design and operation (in print) ..
Page 1 .. www.tpub.com/content/construction/14273/css/14273_190.htm
Page 2 .. www.tpub.com/content/construction/14273/css/14273_191.htm
Cheers - Ron.
Eaton put up these videos, especially for you ..
Eaton 2-speed differential operation (part 1) ..
Eaton 2-speed differential operation (part 2) ..
Eaton 2 speed differential design and operation (in print) ..
Page 1 .. www.tpub.com/content/construction/14273/css/14273_190.htm
Page 2 .. www.tpub.com/content/construction/14273/css/14273_191.htm
Cheers - Ron.
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14 years 1 month ago - 14 years 1 month ago #36914
by kennymopar2
Replied by kennymopar2 on topic Re: Bedford 466 bus
being a bedford /english based powered chassis ..the air may take a long time to build up . . my old leyland was the same,when they drained the air tanks at the RTA yearly rego inspections the RTA examiners always joked saying it was going to take a long time to build up pressure . . 7 mins sounds about right . . also starting the motor then going inside to have a cuppa sounds about right ... another option to help your truck along would be to fit a turbo then the gap between the gears wouldnt feel so bad . . having said that what highway speed is the bus capable of at the moment ?
Last edit: 14 years 1 month ago by kennymopar2.
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14 years 1 month ago #36915
by bigcam
Replied by bigcam on topic Re: Bedford 466 bus
Kenny's right, what sort of compressor is on it? if it's just a little Clayton Dewander single cylinder thing, and it's got a few air tanks it could take a while. The valves in the compressor's make a big difference if they are worn as well, My Reo had no oil in the system, but used to take ages to pump up with a Tu-Flo 400 on it, turned out to be the valves.
Does the air system have any oil in it?
Does the air system have any oil in it?
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14 years 1 month ago #36916
by kennymopar2
Replied by kennymopar2 on topic Re: Bedford 466 bus
its probably more important that the beddy doesnt have any air leaks.. as it will take a long time to build up . . & of course if your going down a steep grade use your gearbox more than your brakes . . otherways you may not have much air left . . . a bit off topic but a lot of people fit a isuzu diesel . . more power,cheaper on fuel,parts readily avail and the isuzu air compressor works a lot quicker . . my old JCR with the little 6BD1 turbo(5.75litre) litre performs well enough & my tare weight is 8.5 tons . . so its no flyweight . . also the isuzu gearbox the ratios are spaced good
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