Brake Bleeding

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Al_Cam
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Joined: Tue Mar 01, 2005 3:37 pm
Location: Melbourne Australia

Re: Brake Bleeding

Post by Al_Cam » Mon Aug 03, 2009 7:03 pm

I had no luck until I made up a pressure bleeder (retail are way too expensive here in Australia). I put a brass nipple on top of a spare master reservoir cap and a tube to a tyre valve connector. I used a bicycle tyre at 12-15 psi. I found I had to use a bit of wood to keep the brake pedal half depressed, or otherwise I drained one half of the master while there was fluid still in the back half! I then started at the rear, one side at a time. I started with the Australian drivers side (right-hand) that has the longer brake line. Open the bleed nipple wide enough to get a good flow of fluid, ½ a turn or more. Had to open the nipples so far that they leak a fair bit from the threads as well.

My theory is that I needed a quick flow of fluid to prevent the air bubbles from floating back up the lines.

What I will do next time is put Teflon on the bleed nipple threads to stop the fluid leaking out there as I was worried I’d get fluid on the disc rotors. Same for the fronts as they had been painted when re-built.

I found that 10psi didn’t work. I seemed to get all the bubbles out, i.e. good clear fluid flow, but still had a soft pedal. Hence 15psi or more and cracking the nipples more than half a turn to get a good rush of fluid! I have read of the 105 guys causing problems with the seals in masters at pressure above that though.

Top up the master and I could probably bleed all four several times without trouble, but I’d check the level before starting on the fronts as I did drain it once.

AL.
Al Campbell
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