kango
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| posted on 13/11/06 at 06:44 PM |
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Brakes - What can it be
I have overhauled master cylinder as well as all the slave cylinders and calipers.
The problem is the pedal keeps fading away.
To bleed the brakes I took a long piece of tubing added an inline one way valve (used on a A1 Golf window spray system) fed it back into the resevoir
and bled the brakes from the furthest point to the closest untill their was no more babbles evedent in the tubing.
Still if I depress the pedal slowly it goes all the way down. If I pump it a couple of times it it fine.
The complete brake system is from a Cortina Mk5.
Any ideas. The master cylinder was honed and tested before I fitted it to the car.
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RazMan
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| posted on 13/11/06 at 06:51 PM |
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So if I understand your method correctly you are recylcling your fluid while you bleed them?
It sounds like fluid getting past the m/c seals.
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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kango
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| posted on 13/11/06 at 07:04 PM |
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My feeling aswell, but the M/Cylinder was tested in front of my eyes and it was solid, no fading.
Any tests one can do.
It is a 2 stage cylinder. The front stage feeds the front brakes and the rear stage the rear brakes.
does it make any sence to block off the rear stage at the M/C and checking the front stage on its own or am I thinking too simplistic?
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timex
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| posted on 13/11/06 at 07:18 PM |
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Have you got the bleed nipple at the top of the calliper when you bleed them?
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flak monkey
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| posted on 13/11/06 at 07:43 PM |
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You shouldnt recycle the fluid you have bled through, its full of tiny air bubbles which wont help your situation.
You arent running a servo are you? If so the behaviour you describe is common of a servo system being operated without the engine running. With the
engine running there shouldnt be any spongyness on the first pedal stroke.
Sera
http://www.motosera.com
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britishtrident
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| posted on 13/11/06 at 08:27 PM |
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Could be a leaking recuperating seal in the master cylinder --- top it right up almost to brim of thefiller neck, put slow steady presure on the pedal
-- the seal is knackered fluid level wll slowly rise as the pedal falls.
Could also be a fluid leak from pipe union.
Could just be bad bleeding --you must hold the pedal hard down after the final bleeding stroke and keep when closing the nipple.
One way valves in the bleed tube can cause problems than they solve when bleeding.
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Peteff
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| posted on 13/11/06 at 08:40 PM |
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I'd just bleed it again the old fashioned way, one man pressing and topping up while the other opens and closes the nipple while the pedal is
still down and shouting on, off keep it down I've dropped the spanner  . Pump a pedal up and wedge it down overnight to see if it forces the
air back into solution, this is a bodge but it does work temporarily.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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rusty nuts
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| posted on 13/11/06 at 09:35 PM |
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Can you get an easibleed kit in S.A. makes bleeding brake a piece of cake . As already suggested do not recycle fluid
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kango
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| posted on 14/11/06 at 04:14 AM |
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1) Do not have a servo.
2) Any sence in taking the calipers off and raising them above the M/C whilst bleeding that particular line?
Thanks
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kango
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| posted on 14/11/06 at 04:16 AM |
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The rear drumms are skimmed and the shoes are new. How important is the adjustment of the drums. I have about 5 clicks before the handbrake is fully
on?
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02GF74
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| posted on 14/11/06 at 08:01 AM |
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you'll have 3 lines out of the master - rear + 2 front?
you may need to go back to step 1 and ttest the master in situ. undo the pipes at caliper and block off - you can do this by putting a small
ballbearing into the caliper and doing up the pipe.
if no change, do another until when you have done all 3 and the symptoms have not gone away, the master is a ba one.
Hopefully the ballbearing ban be extracted wtih a magnet 
(if you have flexi lines, then you can clamp them off).
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kango
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| posted on 15/11/06 at 04:27 AM |
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Thanks to all for the suggestions.
1) I went and bought a new M/C.
2) Bled the brakes as suggested
The brakes still faded
Then common sence took over. My LH caliper is fed from the bottom. Do I have 2 RH calipers on my car? See attached photo.
I unbolted the LH caliper, turned it the other way round (feed from the top and nipple at the top) Spaced the pads to simulate the disc and bled the
line.
Whalla - lots of air out and brakes 100%
 
Rescued attachment LH Caliper 4 web.JPG
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02GF74
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| posted on 15/11/06 at 11:31 AM |
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re feeding in from bottom - well, had you told us that right at the start .....
good you've fixed it 
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