Sunday, November 15, 2015

Brake and clutch pipes

The brake and clutch master cylinders had been fixed in place and so had the flexible braided hoses that will connect the body to the chassis union. The positions on the chassis connection block are nicely etched on from what I have seen. The silicone hoses that link the reservoirs to the master cylinders were also in place, but as yet not connected. So 'all' that was required was to connect them. Easy ..... or so I thought!

The 'output' braided hoses (pressure) had already been attached to the inner wing using the three 10 mm holes and the 'input' silicone hoses (from the reservoirs) had been fed through the three 15 mm holes I had drilled earlier in the inner wing between the engine bay and the compartment behind the wheel arch. The input and output hoses had been installed in the following sequence (from the front of the car):
  • Front brakes
  • Rear brakes
  • Clutch
I had installed the brake and clutch cylinders in the same order on the bulkhead from left to right (when viewed from within the compartment behind the off-side front wheel).
  • Front brakes - 0.75" cylinder
  • Rear brakes - 0.625" cylinder
  • Clutch
Clutch pipes

The copper clutch pipe was identified in the GD kit (it was the shortest one marked No. 10 on the yellow sleeve). The silicone hose from the clutch reservoir to the clutch master cylinder, was connected to the white plastic hosetail, using a pipe clip to secure it. The plastic union was removed from the master cylinder to make this a bit easier. The copper clutch pressure pipe was bent so that it fit between the front of the clutch master cylinder and the rear braided output hose (see blow).
Clutch master cylinder with connections made
Brake pipes

Now read this carefully and take on board. I hadn't!

I had initially tried to connect the unions pre-fitted to the brake pipes to the front ports, assuming that the input pipe would go to the rear ports, like the clutch cylinder. After a conversation with Andy, who was totally confused with what I was doing, it turned out that I had been trying to fit the Jaguar unions in to the two master cylinders that had been supplied. Andy thought that he had explained what was needed to me, hence the confusion.

The rear ports are actually 3/8 UNF and take the pressure pipes. The front are 7/16 UNF and take the silicone input pipes from the reservoir, via brass hosetails.

I had not appreciated the correct fitting or the changes required. So the brake pipes had been bent before I realised that the fittings on the pipes were wrong and that I was trying to fit them in the wrong holes!

I didn't have any of the unions which should have come with the brake pipes/cylinders. After the conversation and a few photos by emails, Andy at GD put me on the right path and sent me the missing parts.
The brake unions
The unions on the pipes supplied by GD, No. 11 and 12, needed changing to the 3/8 UNF unions (the bottom two in the picture above). My flaring tool kit came in useful for this (the pipes were originally for the Jaguar tandum master cylinder which uses M10 and M12 connectors, my car has two separate brake cylinders connected via a balance bar). Are you still following this?
The bent brake pipes plus the unions that need swapping
So with the correct fittings on the copper pipes and the brass tails for the silicone hose I started again.

Remember that the brake pipes are attached to the rear output holes. This is the reverse of the clutch master cylinder just to make things more interesting. The copper brake pipe was re-bent and attached, so that each pipe linked the cylinders to the appropriate braided hose previously fitted. I found that attaching the pipes to the master cylinder first, then to the braided hose fittings on the inner wings was the easiest method to avoid cross threading (loosen the nuts on the braided hose first).
Copper pressure pipes attached to the rear ports
The silicone hoses were then connected to the new brass hosetails (remember to use the supplied Dowty washers - the ones with rubber around the inside) on the front of each brake cylinder. The hoses were clamped in place with pipe clips.
Silicone hoses from the reservoirs in place
Now, when Andy checks the brakes before the IVA test, he may need to swap the master cylinders around to get the correct pressure at the back and front!

NOTE: This wasn't required, but the balance was corrected as expected.

1 comment:

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