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Repair guides and support for cars produced by the British automotive manufacturing company, founded in 1903.

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My Brakes still very poor

I have a 2015 Vauxhall insignia SRI 2.0 CDti VX line. My brakes suddenly stopped working properly, the brake pedal went really hard and the car was struggling to stop. Tried to get it booked in but everyone saying it could be a couple of weeks before they can look at it. I decided that I will have ago at it, I've done brake pads and discs before. After watching loads of videos and reading up on YouTube I checked the servo first and discovered that this wasn't working, the brake pedal was not dropping slightly when starting the car. I replaced the servo and master cylinder and then bled the brakes but still no difference. The brake pedal is however dropping slightly when I start the car. I decided to then change the ABS Modulator pump and re bleed the brakes but still the brakes are very poor with a hard pedal.

Is there anything else I can try?

Update (04/13/24)

Ok. So I've now replaced my front brake pads and discs and then bled the front brakes. Still have the same problem. I've noticed some oil around the vacuum pump. Also I keep getting an oil pressure fault intermittently displaying. I've ordered a vacuum gauge tested which is coming tomorrow that should tell me if I'm getting enough suction from my Vacuum pump. There is just no brake assist at all.

Update (04/14/24)

Ok, I've just connected a Vacuum gauge tester and my readings are 27 inHP. I've checked what I should be getting and it should be between 16 and 25. So I'm getting more than what is expected the max shouldn't be more than 30. My head is wrecked now. Like I said I've got alot of oil around the pump but if this was a problem then surely my readings would be alot less, take alook at the pics.

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I've tested the vacuum with the hose connected to the pump.

Update (04/14/24)

Is there anything else which could be stopping me from getting the assist for the brakes?

Answer this question I have this problem too

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@peteblun just out of curiosity, have you had a chance to get the OBD_II scanned to see if any of the ABS codes pop up. that is where I would start. This definitely sounds like a very ambitious and involved DIY repair and you have already addressed the common issues. See if this 2008 2017 Insignia ABS System will help you to get your brakes repaired.

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In the US, auto parts shops do not tell you for liability reasons, and some do not use scanners that can check. You need to buy the scanner and do it yourself. Maybe the UK is better about it.

I have a scanner that can do it (LAUNCH CRP129X, the 123X is the same without FCA AutoAuth support, ADBLUE, TPMS, A/F, TPMS, and injector coding), but it wasn't cheap. But still cheaper than an Autel. Both can do the infamous BMW battery BMS reset.

It depends on how badly you want a diesel or BMW if you don't get the 129X on sale.

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Thanks turks for this I will have a look. Everything is pointing towards the front brakes because as you know 70% of the braking is the front wheels. It feels like I've lost the assist for the fronts. But when I bleed the front the fluid is coming out consistently, and if there was air in the system then surely I would have a spongy brake pedal, but I don't it goes hard when I've pumped the brakes after bleeding and stays hard. However the pedal does drop when starting the car.

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I'm thinking it needs resetting in the CPU or whatever you call it. Normally I would send it in to be looked at but I am very practical and have decent technical knowledge.

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Just bought an OB2 scanner now

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@peteblun I think you got all teh mechanical steps covered. This seems to be deeper in the bowels of the ABS electronics. Let us know it your scanner pops a code. I am definitely interested to see what causes these issues.

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Replaced the servo and master cylinder again and now my brakes are working great. The guy sold me a faulty servo and cost me so much time. The only thing now is my pedal feels alittle spongy, I've bled the brakes but I still think there's air somewhere in the system. Is there any other way of bleeding the brakes without doing it from each caliper?

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A good mid level scanners will do it. I'm not sure if you can get these in the UK but lemme check my mid level scanners later.

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Just plugged scanner in now and there is no codes. However it did let me erase the service light. I'm not certain yet if this scanner will show any braking system codes. I only paid £20 for it from Euro car parts

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I will have alook at that link you sent me. Thanks mate

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It is unlikely to support ABS; you need a scanner on the higher end of the spectrum. Innova has the 6100p, but others are also available like the 5410.

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A hard pedal is an indicator of a booster failure. If yours uses the vacuum to boost, you are on the right track.

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Ok, I've attached a video of the noise when you press the brake pedal. After reading more on the problem I have, everything is pointing towards the servo and master cylinder, even though I have replaced it with a used one the used one could also be faulty. Can you test this by disconnecting the brake lines out of the reservoir and then do a pressure test by putting a vacuum gauge on one of the outlets of the reservoir?

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@peteblun I don't see why not. As long as we have some sort of idea about what the pressure is supposed to be. Monitor for pressure leaks while you do so.

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I checked my lesser capable mid-level scanner to see if it can be done at a budget with a scanner (Launch CRP123X) that supports it, and it does. I also have a 129X (Adds FCA Autoauth support and injector coding, AF reset, throttle relearn, TPMS, AFS. On the diesel side, add the Adblue reset option; this isn't on the 123X by default). I can't add Autoauth support to the 123X as it's only on certified scanners. I'm not sure if you can buy these in the UK; if not, look at similar units.

Be warned: The 129X is often much more expensive (usually ~$100 off sale). The 123X hovers at ~$ $178 or less, and the 129X tends to go for ~$ $258-$280. That said, Autel is MUCH more expensive, even at the lower end, even used. Yes, I tried for a used Autel, Autoauth or not; the issue is the discounts aren't deep enough to risk needing to renew the 1-year update subscription so soon.

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Peteblun will be eternally grateful.
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