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Discussion Starter #1
Hi All,

Well I successfully replaced the front discs and pads the other day and changed to Black Diamond Drilled & Grooved discs and matching predator pads. When I fitted the new pads, I wound the caliper pistons back in with a large G-clamp, whilst having the brake fluid reservoir cap off and keeping an eye on the fluid level. Everything was OK, but now the brake pedal has gone completely soft, and there is hardly any bite on the brakes.

I understand that they need to be bedded in, but the brakes really are poor and the spongey pedal makes me think that there could be air in the system? Surely this can't be possible as none of the bleed nipples were opened and no air could have got into the system!

Is it worth having a go at bleeding the system do you think?

Many Thanks,
Tony.
 

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Do they feel soft when you first get in or just on the move?

If they get hard after one or so pushes I would say it's just beading in.
 

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Discussion Starter #3
The pedal has felt exactly the same for about 150 miles, and not getting any better!
 

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You said everything was ok, was this before a drive I.e after fitted. ?

If it's hard when you first start it I would say just bedding in.

If not I would say it need bleeding, somone maybe able to confirm.
 

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Discussion Starter #5
OK, after I fitted the new discs and pads before driving for the first time, I pumped the brake pedal (with engine off) and as normal, the pedal went hard.

I took the car for a drive, and the brake pedal has much more travel than what it did with the old discs and pads fitted. The pedal still feels as if it is nearly on the floor 150 miles on! No difference at all!
 

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Hi All,

Well I successfully replaced the front discs and pads the other day and changed to Black Diamond Drilled & Grooved discs and matching predator pads. When I fitted the new pads, I wound the caliper pistons back in with a large G-clamp, whilst having the brake fluid reservoir cap off and keeping an eye on the fluid level. Everything was OK, but now the brake pedal has gone completely soft, and there is hardly any bite on the brakes.

I understand that they need to be bedded in, but the brakes really are poor and the spongey pedal makes me think that there could be air in the system? Surely this can't be possible as none of the bleed nipples were opened and no air could have got into the system!

Is it worth having a go at bleeding the system do you think?

Many Thanks,
Tony.
:wow:
i always crack bleed nipple when pushing pistons back then rebleed,can cause havoc with abs
so definetely bleed brakes:thumbs:brakes always a touch springy after first fit until bed in,and i just give it quick bleed after 500 miles to make sure no air:thumbs:
 

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As far as I can tell you've followed the same procedure that the majority of people would follow when replacing discs and pads. I do as you have done, open the reservoir, push back the pistons, replace disc and pads, pump up brakes to push the pistons out, drive the car and bed in the pads - have done this many times

IMO the pedal will feel a bit poor until the pads bed in but the pedal should not have significantly more travel than before and the pads should bed in quickly. From the fact that the pedal travel increased significantly then it sounds like air has got into the brakes or possibly the pads / calipers have not been refitted correctly.

Bleeding the brakes is a very quick process and even if you take it to a garage it should be done in 1/2hr
 

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The correct way to do it is to crack the nipple, the bodge way ( and the way i have also done it for years with no problems) is to just force them back. The danger is that on one occasion out of 100 pushing fluid backwards through the master cylinder will damage the seals which is what i think might have happened in this case.
 

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As far as I can tell you've followed the same procedure that the majority of people would follow when replacing discs and pads. I do as you have done, open the reservoir, push back the pistons, replace disc and pads, pump up brakes to push the pistons out, drive the car and bed in the pads - have done this many times

IMO the pedal will feel a bit poor until the pads bed in but the pedal should not have significantly more travel than before and the pads should bed in quickly. From the fact that the pedal travel increased significantly then it sounds like air has got into the brakes or possibly the pads / calipers have not been refitted correctly.

Bleeding the brakes is a very quick process and even if you take it to a garage it should be done in 1/2hr
in modern abs systems its not advisable to use this method:thumbs:
 

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As davealfa11 said, best slacken a bleed nipple when bleeding as it has been told that the seals in the ABS system can be adversely affected.:(:

Try a gentle bleed off using a Gunsons Easibleed kit and see what end result you achieve? Used my old Easibleed time and again, with 100% results?:):
 

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10 years of doing this to various 156's doesnt appear to have caused any problem but looks like its time for me to change :)
 

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Tony, I wonder if you've done what I once did and fitted the caliper retaining clip the wrong way round :eek:
This gave me the same symptoms as yours, cured on correct assembly with no need to bleed.
 

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Discussion Starter #13
OK thanks for the help guys. I will check the retaining clip tomorrow - I'm positive this has been fitted correctly though, but worth a check! Failing that, I will bleed the system and see what happens!

Thanks guys.
 

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The same thing happened to my colleague when replacing pads in a focus. Like me he is a mobile mechanic of many years experience. (he does'nt do clutches, hence our connection) He's done this job a thousand times, without a problem. He ended up having to change the master cylinder. (no ABS) Just to show the freakish nature of this car I also changed the clutch, which when I re-connected the hydraulics (similar system to Alfas) could not persuade fluid to flow through to slave cylinder. Yep you've guessed it new CLUTCH master cylinder needed as well! Obviously ABS is a complication here but it seems that forcing pressure back through the system has blown a seal somewhere. 50% of your brakes are not operating, hence the pedal travel.
 

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lets face it come on ffs hydraulic circuits in brake circuits are designed for fluid to go just one way!!!
its so easy to just crack bleed nipple with long hose on into a jar ,and push pistons back ,fit pads and bleed up ,simples:cool:
 

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with the pedal at rest pushing pads back should only push fluid back into the resevoir as the line is open.Where a problem may occur is where the seal on the master cylinder is not clearing the inlet hole from the resevoir. Forcing the pads back with a clamp would then possibly blow a seal. That's my theory anyway feel free to disagree!
 

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with the pedal at rest pushing pads back should only push fluid back into the resevoir as the line is open.Where a problem may occur is where the seal on the master cylinder is not clearing the inlet hole from the resevoir. Forcing the pads back with a clamp would then possibly blow a seal. That's my theory anyway feel free to disagree!
i agree for basic brake system,but virtually all cars now got abs systems with valving etc :thumbs:
 
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