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Discussion Starter #1
Hi all,

I had my rear brake discs/pads replaced on my Peugeot 307 HDI (117,500 miles) nearly 3 months ago, after getting the car back the brakes felt quite different and this problem has persisted ever since.

The issue is as follows -

When pressing the brake pedal all the way down (most noticeable if I need to break sharply), it feels quite hard and takes me longer to stop due to having to press down a lot harder.
However if I put lighter pressure on the pedal and break more gently, it feels fine and it is only hard when pressed all the way down quickly (there is no hardness when pressing it down gradually).
Ironically, it feels like I am braking a lot more efficiently when putting less pressure on the pedal!
When I do press it down sharply and I come to a stop, there is a very brief period where the pedal feels slightly stuck down before coming back up - the closest thing I can compare it to is when you step on some chewing gum and your foot sticks to it for a second as you lift it back up!

I originally posted a question about this here.

The answers all suggested it was the brakes that needed bedding in, so I left it for a while.

After 2000 further miles without any change, I took it back to the garage and asked them to take a look at it.

They did a brake fluid change but said it made no difference and said they thought it was the brake servo and quoted £438 to repair.

I am however confused, as from everything I have read online, if the servo/booster goes then the pedal is completely hard when not pressed down (like if you try and brake without the engine on), I haven't read anything about it being hard only when pressed all the way down.

If I perform the test of pumping the brake pedal and then turning the engine on, the pedal drops as it should - this is supposed to be the sign of the booster working correctly. Surely if mine has gone, then it would fail this test?

As the garage appeared to only be making an assumption that it was the servo, is there any likelihood that it could be anything else, that is not as expensive to replace?
I'm not an expert with cars, so don't want to spend that amount of money if it is something else that is causing the problem, but naturally need it sorting ASAP.

Extra info - the front brakes/discs were also replaced earlier on in the year (by a different garage).

Any suggestions welcome and thanks in advance!
 

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Vacuum servo unit check valve or vacuum pump itself. First one can be checked by removing it and check it works as a one way valve. The other can be checked using a vacuum gauge. At idle it should show a minimum after one minute idling of approx. 500mmHg. Plumb in the vacuum gauge at the pump after disconnecting the pipe feed.
 

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Discussion Starter #3
Vacuum servo unit check valve or vacuum pump itself. First one can be checked by removing it and check it works as a one way valve. The other can be checked using a vacuum gauge. At idle it should show a minimum after one minute idling of approx. 500mmHg. Plumb in the vacuum gauge at the pump after disconnecting the pipe feed.
Thanks for the tip, sounds like I might have to take it to another garage then as I'm not confident in doing this myself - especially with it being the brakes!

As an additional bit of info, I have noticed that the issue is simply that the pedal is hard when at the bottom (as opposed to it being about how quickly it is pressed - soft braking doesn't usually involve putting foot to the floor, hence not feeling it then), it just feels as though it is hitting something hard when it reaches the bottom.
 

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In reality as long as the pedal is not actually hitting the floor pan the brake pedal will feel harder to push, even solid, after the pads have fully contacted the brake discs and there is no where else for them to move to.
 

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I had a thought that when new pads are first fitted they need bedding in otherwise they can glaze over smooth and so lose their stopping ability. It is best to do a few harsh stop starts to help the pads settle. It might be worth removing the pads all round and give each one a scrape with a file and see if it makes a difference.
 

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Discussion Starter #6
In reality as long as the pedal is not actually hitting the floor pan the brake pedal will feel harder to push, even solid, after the pads have fully contacted the brake discs and there is no where else for them to move to.
Yes it does feel hard right at the bottom, in the same way the clutch pedal does. It is not hard at the top which I know is the main symptom of something being wrong with the booster/vacuum.
If I pump the brake pedal with the engine off, then the pedal goes very hard at the top, as soon as I turn the ignition on then the hardness goes and I can feel the pedal release under my foot - I've read in multiple places that this means the booster is working correctly, so it is confusing.

I had a thought that when new pads are first fitted they need bedding in otherwise they can glaze over smooth and so lose their stopping ability. It is best to do a few harsh stop starts to help the pads settle. It might be worth removing the pads all round and give each one a scrape with a file and see if it makes a difference.
Interesting point, but I have driven 2500 miles since they were fitted, surely they should have bedded in by now and they have felt like this since the day they were fitted - it's got neither better nor worse.

I am having the front brakes and pads replaced next week (they were fitted 6 months ago by a different garage and due to repeated squeaking, they are putting some higher quality pads/discs on).
These aren't the ones that were replaced when the braking problems started (it was the rear ones), but it will be interesting to see how the brakes feel after they've been put on.
 

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Well then it is bottoming out I would say. Sounds like the system needs a good bleeding. You are missing the point on the pads. Once they glaze then they wont unglaze with use. But as the fronts are being replaced you could ask them to perhaps check the rears and if necessary rough the surface of them. You could even ask them to bleed them for you and do a test drive and see what they think.
 

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Discussion Starter #8
Well then it is bottoming out I would say. Sounds like the system needs a good bleeding. You are missing the point on the pads. Once they glaze then they wont unglaze with use. But as the fronts are being replaced you could ask them to perhaps check the rears and if necessary rough the surface of them. You could even ask them to bleed them for you and do a test drive and see what they think.
Sounds like a good plan, can you just confirm what you mean by "bottoming out", so I know what to tell the garage?
 

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Discussion Starter #11
So after a trip to the garage, the problem was identified :

The feed pipe between the servo and the vacuum pump had a hole in it (apparently a common fault on 07 Peugeots!) and as such, the pressure was being lost, which caused the hard pedal.

Apparently Peugeot stopped making this part after the issue was identified to be common on this model, so the part is no longer available to buy from Peugeot. As a temporary measure, the garage patched up the hole and the difference in the braking is huge, I barely have to touch the pedal to stop now. The leak must have gradually got worse over time, as I can't even remember my brakes feeling as good as this before.
The garage offered to fit a replacement pipe if I can get hold of one, so this will be a better long term solution.
 

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So my first suggestion the vacuum system was at fault was correct then. Glad its fixed albeit temporary. Try the scrappies for a replacement pipe. Is it anything special or would a length of hose the correct diameter work?
 

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Discussion Starter #13
So my first suggestion the vacuum system was at fault was correct then. Glad its fixed albeit temporary. Try the scrappies for a replacement pipe. Is it anything special or would a length of hose the correct diameter work?
Yes you were right, I'm just glad it wasn't the servo like the other garage said (clearly they didn't actually check like yesterday's garage did) and they fixed it for free!

I'm not sure re. hose, I think the problem is that the pipe rubs against the engine cover (see below video which appears to potentially be the same issue), in which case a hose pipe would probably get a hole in it again quite easily.

 

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They still have it rubbing against the intake elbow. Unless there is literally no room I would have thought they would have made an effort to avoid the contact. But as they did it for free maybe you can live with it eh! Just keep an eye on it during your weekly level checks under the bonnet I would suggest.
 

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Discussion Starter #17 (Edited)
Looking at it, it's actually the engine cover behind/underneath that it is pressing against more than the intake elbow. I've wrapped an old rag around the repair to provide some cushioning, this should keep it from happening again.
 
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