Andrew Faulkner blog 14/05/10
The last MOT on our Bond GT4S had a warning about uneven front brake balance, so a full rebuild was called for.
Our shopping list included a new copper brake pipe set, Goodridge braided hoses all round, seal kits for everything and new pads (the shoes were fine). With this level of rebuild, it makes sense to invest in silicone fluid. It doesn't absorb water from the air so never needs changing, it doesn't corrode the cylinders and won't strip the paint in the event of an accidental spillage.
The first job was to strip out the old pipes. Then the front and rear junction blocks were removed and cleaned to ensure there was no residual old fluid anywhere. The new set came coiled up in a box but they were numbered so it was easy to identify them. They were straightened and bent to shape.
A pipe, a socket and a vice made for nice even curves.In the case of the master cylinder pipe, it is necessary to do this partly in situ unless the engine is out. I used a convenient socket and piece of pipe to get a neat and consistent bend radius. It is worth taking time over this as copper work hardens very quickly and if you have to modify a pipe that has already been bent, it is not easy and probably wont look too neat.
I only had to trim one pipe – the master cylinder to first junction block. This was about 3 inches too long and whilst I could have 'lost' the extra length with a concealed 'S' (as we found on the one we took out), I preferred to cut and swage the end with my swaging tool.
Don't forget to put the union nut on before making the swage! When making this pipe, remember to make sure there is clearance for the wheel arch which comes down as part of the Triumph flip-front design.
Now for the cylinders. No problems at the back but one side looked to be a bit corroded so £14 bought me a replacement from Rimmers. The calipers proved to be a bit difficult to dismantle. In hindsight, perhaps it would have been good to remove the pads before disconnecting the hydraulics and use pedal pressure to move the pistons out to their limit first.
Still, after much fiddling, the pistons came out and everything was cleaned with compressed air, kitchen towel and a toothbrush soaked in silicon fluid. They were painted in engine enamel (heat resistant) and reassembled with new seals and pistons.
Getting the pistons past the dust seals was tricky but I found I could use the two wire coat hangers I keep in the garage (some of my most useful tools!) to pull them apart enough to slip the pistons inside (see photo) and the job was done.
The master cylinder looked fine so new seals were installed. A tip for removing the piston which was pretty stubborn on mine: Compressed air – either from a compressor or using the pressure form a tyre via an empty Gunsons Easibleed kit (see photo). Just make sure you are not pointing it at anyone!
The hoses went on fine except that I missed the fact that the fronts are longer than the back. Doh! After the brakes, a quick look at the clutch hydraulics revealed both master and slave cylinders were well past their sell-by dates.
Having been stranded twice with failed clutch slave cylinders in the past I decided not to take any chances. New parts throughout! After a bulkhead repaint and new washer pump, stand back and cross hydraulics off the to-do list.
Next up I need to finish the interior, continue finishing the paintwork and then refit all the brightwork.
Posted: 10:12am, 14 May 2010
Words: Andy Faulkner
Images: Andrew Faulkner
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