Saturday, 29 June 2019

Brake repairs for the DHC part 5


I left you last weekend with the wish to continue this story as soon as possible. Well here is! Last Wednesday I visited local brake specialist C&C Parts to explain the problem and drop of both pairs of callipers. Comparing the two pairs revealed a few differences which were overlooked when I ordered the new calliper set. But that was hardly surprising as I only sent them a picture of the old set. Despite that they adapted the new set free of charge, and almost within 24 hours. That’s what I call customer-friendly!
The two most important differences were the thickness of the callipers’ mounting lugs and the chamfer on the wheel hub side of the calliper. The width of the lugs was easily rectified by two spacers of the correct thickness to go between the outside of the callipers mounting lug and the steering arms.
But while comparing an original Até M16 calliper, which they had in stock, with my old callipers, as supplied by S&S Preparations many moons ago, revealed that these had been chamfered on the outside of the wheel hub side. So that’s what they did too. They also found two slight machining faults on the mounting lugs. Needless to mention that these were taken care of with the milling machine too.
So today, with the weather forecast being absolutely unfit for outdoor spannering (sunny and 35°C), I continued the work where I left it last weekend. But not before I had to do a task that didn't represent much on paper, but still took me more than half an hour to complete. Cutting a gasket to fit between the brake servo and the car’s bulkhead. For this I used 2 mm thick adhesive EPDM (closed-cell-foam) rubber. Looks good enough for a part that will be hidden from view!


After I finished the gasket I switched my attention to the back of the car, emptying the rear brake circuit of the car of its remaining brake fluid. This was in preparation of the removal of the brake master cylinder and servo. Pretty easy too. Put a hose on the rear bleed nipple, put the end in a jar, loosen the bleed nipple and let gravity do the work. With gravity doing its job I started preparations for the removal of the brake master cylinder. Most important of these were loads of old towels to protect the paint work from damage by spilled brake fluid. Did I mention that I hate removing brake pipes …


I shouldn’t have worried. No damage was done to the cars paint. Actually no brake fluid was spilt at all. And the removal of the brake master cylinder and brake servo was rather straight forward. Even the servo’s mounting nuts in the interior of the car underneath the dashboard could be reached fairly easily with the correct tools (a very small ¼” ratchet wrench). Which meant that it didn’t take long until I had created some space for the new parts!


Fitting the reconditioned servo turned out to be easy too. I expected that I would need assistance here, but I needn’t have worried. The Servo remained in position long enough for me to put a nut on one of the mounting studs underneath the dashboard. Only the steering column support tube that is fitted to one of the servo’s mounting points did put up a feeble fight. But that didn’t last long.
Next job was fitting the brake master cylinder. But when I removed it from its package I was greeted by three threaded holes to connect pipes to. Not good when the car has only two outgoing pipes from the brake master cylinder. The difference is clearly visible in the picture below.


But there was no need to panic. As the ’76 FHC won’t be ready for a while I decided to remove the brand new brake master cylinder from that car, so I could finish the DHC as soon as possible. But when I went over to the shed I found that this brake master cylinder had the some threaded connecting hole. But on closer inspection it turned out that this hole had been plugged. At least that will make rectifying the other brake master cylinder pretty easy.


And after moving the tools from the boot of the Defender back to the car port I could finish the under bonnet install of the new brake system.


Only items left were the two brake pipes from the brake master cylinder to the brake proportioning valve. But on closer inspection I decided not the reuse these as they clearly were not fit for purpose any more. So that job was postponed for the time being.


Time to start on the brake callipers, though by now the temperature was well passed 30°C. Time to call it a day really! But as fitting the callipers should be straight forward, and I really wanted to know if they did fit correctly now, I carried on. I needn’t have worried, they do fit properly. And there’s even a few millimetres of clearance between the callipers and the wheel hubs. Result!



Next job, store the tools and give in to the heat! The only remaining jobs are ordering some new brake pipes, bend these in the correct shape, fit them to the car, and bleed the system. To be continued in part 6!

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