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24th February 2020, 19:42 | #11 |
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Engines never been on during whole process. We got pipes off after finding the massive blow out looked like a flared pipe already. Reran new lines attached airtight, tested as airtight during bleeding, no air from calipers but still no peddle. No pressure at all apart from the 2/3rd travel blip. There is a broken bleed nipple on 1st caliper thought so we took it off, expelled fluid and retested same result. I'm not going to have to plus gas, and hammer the old broken bleed nipple am I? I should still just have a spongy but pressured peddle for the minute amount of air that might be left because of this? I thought the ABS was on the 2ndary circuit so it shouldn't affect the actual pad operation or am I over-simplifying?
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24th February 2020, 19:51 | #12 |
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what is creating the vacuum? On a diesel, if the engine is off, and you have filled the system, and it is sealed, then there will be no pedal travel after a couple of pumps, until you either start the engine, or open a nipple. (I thought petrols was the same). Or are you saying that the pedal is solid even with the nipple open?
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24th February 2020, 19:59 | #13 | |
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We cant understand it either. Pedals has no pressure at all. I didn't feel the blip personally as I was under the car bleeding. You know the score, pump, pump, pump, fluid comes with no air bubbles then you shout pedal down and tighten that corner off and move to the next. After all 4 corners done still no pressure.All with engine off, suggests air leak but we checked that at the unions and the pipes are all new copper.
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24th February 2020, 20:01 | #14 | |
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With regards the bleed nipple that you removed - how did you manage to bleed this circuit as if doing it by peddle presses you would have to replace the nipple at the bottom of each pedal stroke otherwise you are just going to suck air back in. Also from what I read, one of the nipples is stuck- so was that circuit not bled? |
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24th February 2020, 20:01 | #15 | |
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Id also have thought vacuum pipes too but that only kicks in when engines running. I haven't checked them though, they were fine the last time I checked last summer after replacing the bracket, but until the initial systems is ok whats the point.
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24th February 2020, 20:06 | #16 | |
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Took caliper off and expelled brake fluid by compressing caliper back to fully open. Filled join to flexi pipe with fluid and then rejoined. Not ideal but the air contained within would be minimal and certainly wouldn't result in no pedal at all. Air always comes out of bleed nipples after a brake line burst, but we bled several times at each corner to expell the air. The point is after all of this the pedal still has no pressure. When bleeding used easi-bleed type bottle to with one way pipe to ensure no air back into system apart form the 1st corner where we had caliper off.
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24th February 2020, 20:19 | #17 | |
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If that is the case, I would be looking at the pedal, and master cylinder. I know you mentioned previously, but it is quite unusual for a cylinder to fail in this way - not impossible obviously, even more unusual for a solid pedal (which is why you are getting all the questions lol).
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24th February 2020, 20:26 | #18 | |
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The pedal does move thats the problem. Theres no pressure. It goes straight to the floor with the blip my mate mentioned. I have no idea if he imagined it or not but slight pressure halfwayish then none suggests flipping seals to me. Be aware I was an IT professional not and engineering professional so my rationality is NOT based on experience only on educated guesswork. But several bleeds and no pressure still suggests air to me the 3 mechanics laughing at us are the ones saying master and seal flip. As we have no access to a T4 I have no way of knowing and even if MarinaBrian was willing thats a 65 mile drive with no brakes. I think I have TOAF somewhere does it have the ABS purge brakes thingy?
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24th February 2020, 20:27 | #19 |
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What happens if you give the pedal a couple of quick pumps? Do you get a little resistance back?
What happens if you release a bleed nipple and push brake pedal down - do you get fluid being pushed out of the bleed nipple? |
24th February 2020, 20:27 | #20 | |
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Never done all 4 at the same time. Always went in sequence rear/near to offside front. Would that help the whole circuit open?
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