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Adams B4 Regulator


Joined: 1-01-70

Topics: 2

Replies: 0

Posted: Fri 15th Jun 2018, 6:25pm
Adams B4 Regulator

Adams B4 Regulator
Can anyone tell me how to dismantle the regulator on my 7 1/4" gauge Adams B4 ? The regulator is leaking so that the engine is always running even when the regulator is fully closed so I want to remove it for servicing but I can't see how to disconnect the two link arms let alone the steam pipe that must connect to the regulator somewhere underneath it.
The attached photo shows the regulator inside the steam dome with a rather rusty and over compressed spring that may be the cause of the leakage.
Thanks for any help,

Replies To This Post


Joined: 1-01-92

Topics: 25

Replies: 318

Posted: Fri 15th Jun 2018, 8:22pm

Whilst fairly basic engineering, what you ask is quite complicated to explain, especially without recourse to pointing out the parts on the boiler. Your best method would be through your local society, there will be several people there able to help, and another pair of hands will not hurt.

To remove the steam pipe you probably need to remove the steam feed in the smoke-box to get at the other end of the pipe and unscrew it. The regulator shaft will likewise need to be dismantled from the back-head bush.

I do agree that the dodgy spring is the likely culprit.

bruce morgans

Joined: 21-01-05

Topics: 7

Replies: 21

Posted: Tue 19th Jun 2018, 5:32pm

Hi Colin, I suspect this is a fairly standard assembly. Remove the central pivot bolt and spring. Then remove the two bolts attaching the operating arms to the disc. Remove the disc. I suspect you will find this and the main steam pipe body scored and will require lapping in. This will be why you have leakage past the disc even when shut. The spring is only there to hold the disc against the body until there is sufficient steam pressure to do the same.
If the main body is scored then this will require its removal, a much bigger job!
Best of luck Regards Bruce
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