Madcowz Posted November 20, 2018 Share Posted November 20, 2018 Hi, I've recently been driving a new (2010) 130 which is lovely compared to my rattly One Ten but the brakes are odd and I'm looking for advice. The servo works fine and it brakes really well with a firm pedal (not as firm as mine but I have just replaced the brake system very recently except servo and pump) but if you brake to a stop and keep your foot pressing on the pedal, it slowly drops all the way to the floor. It is slow and not a sudden drop but it does sink all the way. Both their same aged vehicles do exactly the same. Their garage have checked it over, checked for leaks, checked brake fluid and checked the master cylinder for leaks (not sure how they did that) and then asked one of their "Ford time serviced mechanics" who said that its a transit engine and components, and that transits do exactly the same and release brake pressure after stopping and "they all do that". As anyone who has seen my previous posts on this forum knows, I'm no expert but this doesn't make sense to me. Quote Link to comment Share on other sites More sharing options...
crwoody Posted November 20, 2018 Share Posted November 20, 2018 I've had two Disco 3's a few years ago that both used to do the same, never really took much notice of it until one had the brake servo recall, then I became a bit more aware of it, probably because of the potential brake fade issue the recall addressed. My 2004 90 does it too, albeit a little more slowly, I can only assume there must be a little bit of by-pass leakage in the master cylinder, or something similar going on with the ABS module. I've got to keep a fair amount of pressure on the pedal for it to occur, probably quite a bit more than I'd use to apply the brakes normally. Quote Link to comment Share on other sites More sharing options...
Ex Member Posted November 20, 2018 Share Posted November 20, 2018 Master cylinder seals. Quote Link to comment Share on other sites More sharing options...
Madcowz Posted November 20, 2018 Author Share Posted November 20, 2018 Cheers. So we’re thinking a MC (or ABS) leak rather than expected behaviour. Quote Link to comment Share on other sites More sharing options...
Ex Member Posted November 20, 2018 Share Posted November 20, 2018 Oh ABS... Sorry never think of that with a Defender. Hopefully not, as that is not cheap. And, no, that should not happen. Quote Link to comment Share on other sites More sharing options...
Madcowz Posted November 20, 2018 Author Share Posted November 20, 2018 20 minutes ago, Red90 said: Oh ABS... Sorry never think of that with a Defender. Hopefully not, as that is not cheap. And, no, that should not happen. I didn’t even know ABS was such a thing on Defenders until recently when I was watching a video on replacing the swivel bearings and it was mentioned. Quote Link to comment Share on other sites More sharing options...
Scotts90 Posted November 20, 2018 Share Posted November 20, 2018 My 2012 Transit does this, has done from new and 180k further in it still does it. Never an issue on braking efficiency and I'm pretty sure it's mentioned in the drivers handbook. Quote Link to comment Share on other sites More sharing options...
JST Posted November 21, 2018 Share Posted November 21, 2018 quite a few newer vehicles do this. if the performance of the servo is not degrading then dont worry. ie if you come off and brake again and it does it sharply in a short space of time then dont worry. Quote Link to comment Share on other sites More sharing options...
Paddy_SP Posted November 21, 2018 Share Posted November 21, 2018 (edited) My 300 Tdi Disco did exactly this until I fixed the oil leak from the vacuum pump - then it stopped altogether! Edited November 21, 2018 by Paddy_SP Quote Link to comment Share on other sites More sharing options...
Madcowz Posted November 22, 2018 Author Share Posted November 22, 2018 Thanks for replies. So some say it's a fault and others say it is normal behaviour and ok. Quote Link to comment Share on other sites More sharing options...
smallfry Posted November 22, 2018 Share Posted November 22, 2018 Never known any braking system to do this and be "OK" Normally the recouperating seal in the master cylinder not sealing properly. It closes off the feed from the reservoir when braking, but if failing, will allow some pressure (and fluid) to leak back into the reservoir. Quote Link to comment Share on other sites More sharing options...
Bigj66 Posted November 22, 2018 Share Posted November 22, 2018 1 hour ago, smallfry said: Never known any braking system to do this and be "OK" Normally the recouperating seal in the master cylinder not sealing properly. It closes off the feed from the reservoir when braking, but if failing, will allow some pressure (and fluid) to leak back into the reservoir. Agreed, I don’t buy it that a hydraulic brake system is designed to ‘relieve’ pressure in this way. It defeats the principle upon which the system is designed. Something’s not quite right with this. I’d investigate further. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted November 23, 2018 Share Posted November 23, 2018 I too had heard a lot of modern stuff does this, and it's normal. In fact I'm fairly sure I've heard D3's do it as standard. Quote Link to comment Share on other sites More sharing options...
muddy Posted November 23, 2018 Share Posted November 23, 2018 Both my 2012 merc sprinters to this as does my D2. never really bothered me as it seems to be an abs thing, if my 90 started doing it then I would be worried. Quote Link to comment Share on other sites More sharing options...
Ex Member Posted November 23, 2018 Share Posted November 23, 2018 Seriously, this means your ABS module or master cylinder is faulty. It is not normal nor acceptable. Sometimes you can fix it by forcing the ABS to activate. The valve cycling sometimes lets the carp out of the valves and they can seat properly again. Quote Link to comment Share on other sites More sharing options...
Farmerfred Posted November 23, 2018 Share Posted November 23, 2018 The short answer here is that they all fade if you keep pressure on the pedal. Don't keep hard pressure on the pedal and it won't fade. Quote Link to comment Share on other sites More sharing options...
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