Marathon brake overhaul completed

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kanga
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Marathon brake overhaul completed

Post by kanga » Sun Jan 10, 2010 2:56 pm

I have finally finished replacing front and rear discs, pads, all 3 brake lines and both rear calipers. what a performance, the biggest headache was the bleeding, after 1 litre of break fluid I still need to bleed the brakes some more.
However, I am at a loss to understand why Alfa recommend bleeding the Front right and rear right together and then the front left and rear left together when the front and rear are separate circuits.
The only way I was able to get the fluid bled at the rear was by doing the 2 rear calipers together ie all 4 bleed nipples at once, especially as the rears are fed by 1 pipe to a T piece going to both rear calipers.. If you only do the rear left and front right together you will continue to get air bubbles at the back because of the single rear pipe feeding both rear calipers via a T piece.
I also tried the bleeding the rears with the rear of the car up and also sitting flat on the ground, I found flat on the ground the best.
I found bleeding the rear brakes together and the front brakes together the best method regardless of the factory recommendation of right front and back then left front and back.
I used Stainless steel brake hoses and Porterfield Street pads and they are really good, even from cold. The discs are front ventilated drilled and slotted , and the rear slotted and drilled. The rear calipers are reconditioned units.
The brakes are much better, but I still have some air to get out .
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MD
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Re: Marathon brake overhaul completed

Post by MD » Mon Jan 11, 2010 2:04 am

What you have stumbled on is the preferred method by me also. You may develop a firmer pedal if you just let it rest overnight and never reuse the fluid that was recovered from the bleed.

Regrettably the factory set up never results in a hard pedal as there is too much flex in the firewall and transfer bar set up for our RHD cars.
Transaxle Alfas Haul More Arse
kanga
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Re: Marathon brake overhaul completed

Post by kanga » Mon Jan 11, 2010 3:12 am

I have purchased more brake fluid and hope to get more air out. \
I didn't realise that the flex was a feature of the braking system, there is at least nearly 20% free play before it becomes hard, it is as if there is a lot of slack in the system.
I will bleed again tomorrow and see if I can improve it. Thanks for your input.
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Re: Marathon brake overhaul completed

Post by Bruce » Mon Jan 11, 2010 9:27 am

"...free play before it becomes hard", oh er misses.

No seriously, I don't use any system of brake bleeding and never had any problems.
kanga
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Re: Marathon brake overhaul completed

Post by kanga » Mon Jan 11, 2010 9:32 pm

Well after a total of 3 litre's of fluid and the purchase of a vacum bleeder that won't work due to the air leaking through the threads of the brake nipples I am not much better off. The fluid flows really well from the front calipers and I can get a complete stroke when i push the fluid through, the rears have a very small flow and only about half the stroke of the fronts when I bleed them.
I am wondering if the rear brake regulator is faulty and restricting flow to the rear brakes? Anyway I will purchase more fluid and put thread tape on the rear bleed nipples as I did on the front and see what happens.
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Re: Marathon brake overhaul completed

Post by Bruce » Tue Jan 12, 2010 1:30 am

I have come across rusted & blocked bleed nipples, and once I have cleaned or replaced them, brake fluid spurts rather then dribbles out.
kanga
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Re: Marathon brake overhaul completed

Post by kanga » Tue Jan 12, 2010 12:53 pm

Hi Bruce, the brake nipples are new as I put on reconditioned rear calipers but I will check to be sure they are not blocked.
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Al_Cam
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Re: Marathon brake overhaul completed

Post by Al_Cam » Wed Jan 13, 2010 6:03 pm

Kanga,

It'll mean bleeding from scratch again, but maybe try pulling the nipples right off and using some Teflon tape on the threads. I had to open the rear nipples nearly a full turn to get a rush of fluid to force out the last few bubbles. If you are using a vacuum bleed, you’ll just be sucking air past the threads with that much opening. I was using a pressure bleeder and fluid does come out past the threads.

Good Luck,
AL.
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kanga
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Re: Marathon brake overhaul completed

Post by kanga » Wed Feb 03, 2010 3:06 pm

Finally, after a total of 6 litres of brake fluid I now have excellent brakes.I also purchased a new rear brake regulator as well just in case the old one was faulty.
The Porterfield brake pads I purchased from Performatek are fantastic, I highly recommend them. Thanks to all who offered advice.
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