Thursday, 17 November 2011

Steam Brake Cylinder Completed

On 11th November 2011, I visited our multi-talented subcontractor J R Goold Vintage Steam Restorations Ltd in Camerton to catch up on progress. Grant Goold showed me the end result of his father's superb work on the steam brake cylinder with its brand new piston. Click here to see how it started out.

When the brake cylinder was originally removed from Sentinel 7109, it was not in a good state and needed to be re-bored to a larger diameter. This meant that the piston would no longer be big enough even with new piston rings to work satisfactorily. Thus the old piston was wrapped in tape to make it slightly larger so that it could be used as a pattern for casting a new one. Work was also needed to de-clog a condensate drain valve which had clearly not been operable for some time! 

"As New" Cylinder and Piston
There is still a retaining ring to be bolted to the face using the six bolt holes. This is a useful feature to prevent the piston ejecting every time the brake is applied!
Close-up of the re-bored cylinder
This picture shows where the cylinder is mounted on the near-side frame below the footplate.
The Brake Cylinder is top left
The shaft across the lower part of the picture is rotated by the steam brake pushing on the crank shown below it.

Steam brake crank with cylinder removed
There is a similar mechanism used for the handbrake.
Handbrake crank pulled upwards to apply the brake 
The shaft then has other cranks which pull on the brake gear to apply the brakes.
Brake operating crank
Rear wheel brake shoe and link to the front wheel brake
(Fairly heavy duty mechanism!)
I'm feeling more confident now that not only will we be able to make Sentinel 7109 go but we will also be able to make her stop!


  1. When my mother started learning to drive (1940s), an old family story recounts how she got the car going but immediately panicked on realising she didn't know how to stop the thing! The story has sat in the back of my mind for year or two(ish).


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