AdeParko Posted July 16, 2012 Share Posted July 16, 2012 Hi, My brakes had started to feel useless, to the point where you were pressing the brake pedal right to floor just to get a bit braking going on I needed stripped everything down to find the one rear caliper partly seized and the other not moving, so replaced both the rear calipers with new Whilst there, I replaced all the wheel bearings, and also fitted new discs and pads all round Bled the brakes using my ezi-bleed kit, and was a breeze as usual using this Only thing I noticed is that when I connected the ezi-bleed to the master cylinder there is a hiss coming from the brake servo/master sylinder area? Took the car out for a test drive; drives better and stops a bit better, but still not what you would expect. Is there something else wrong? Anyone had any similar problems? I'm thinking it may be servo or master sylinder related Thanks Adwe Quote Link to comment Share on other sites More sharing options...
fozsug Posted July 16, 2012 Share Posted July 16, 2012 Sounds like Master Cylinder seals, are you loosing brake fluid? Quote Link to comment Share on other sites More sharing options...
AdeParko Posted July 16, 2012 Author Share Posted July 16, 2012 No fluid loss Quote Link to comment Share on other sites More sharing options...
mmgemini Posted July 16, 2012 Share Posted July 16, 2012 Take a good look at the brake servo where it's bolted to the mounting brackets. The Defenders crack there so you might find the same thing on yours. The cracks are hard to see. Quote Link to comment Share on other sites More sharing options...
JimDay Posted July 16, 2012 Share Posted July 16, 2012 As mmgemini has already said sounds like a leak in or around the servo have you checked the hose from the servo to the engine I have a problem on the Disco1 300TDi I have just bought but on mine the brake pedal is rock hard like having a brick for a brake pedal on mine the vacuum pump is shot & I'm waiting for a second hand pump to arrive to hopefully cure my problem Jim Day Quote Link to comment Share on other sites More sharing options...
cackshifter Posted July 16, 2012 Share Posted July 16, 2012 I think the hiss may be a symptom - you could do with trying to find where it is coming from as it suggest a vacuum leak (can vacuum leak?), maybe pointing to a new servo needed. If you do need one, get a new non return valve as well (cheap, but they don't come with the servo). It's easy to swap the servo, and you don't lose any fluid. I'd imagine it stops basically Ok but the pedal feels very hard and 'dead' Quote Link to comment Share on other sites More sharing options...
MuddyWinny Posted July 16, 2012 Share Posted July 16, 2012 I noticed a simlar thing on my 90. I struggled to work out what it was until I changed the rear axles (to upgrade fro mdrun to disk brakes). When I looked at the old flexible brake pipe I found it had gone soft near one end and, I guess, was expanding under pressure. Ok, I realise I had changed the whole axle but the drum brakes never used to be that bad and when bending the old flexible pipe in various places you could see it was in poor condition near one end fitting. Regards MW Quote Link to comment Share on other sites More sharing options...
fozsug Posted July 16, 2012 Share Posted July 16, 2012 If the brake pedal is rock hard and not travelling to the floor, check the vacuum pump. Quote Link to comment Share on other sites More sharing options...
AdeParko Posted July 16, 2012 Author Share Posted July 16, 2012 Brake pedal is probably the opposite to feeling hard, it feels soft and spongy, and you have to put your foot right down to get it to brake If you pump the pedal while braking its better Quote Link to comment Share on other sites More sharing options...
fozsug Posted July 16, 2012 Share Posted July 16, 2012 I doubt it is servo, i would try bleeding it again if not i would still say master cylinder Quote Link to comment Share on other sites More sharing options...
AdeParko Posted July 16, 2012 Author Share Posted July 16, 2012 I dont think its a bleeding problem, I've never encountered any problems since using the Ezee Bleed Kit I'm also starting to think master cylinder, I might try overhauling that to see if theres any difference, as thats probaly also the cheaper option as well The way the Ezee Bleed works, by pressuring the top of the reservoir pot with air, if the master cylinder is faulty, could this causing the hissing noise? Quote Link to comment Share on other sites More sharing options...
fozsug Posted July 16, 2012 Share Posted July 16, 2012 I have had this problem with Ezibleed on a clutch circuit. The hissing noise i obviously air escaping , but i would have thought if it was escaping thought the master cylinder in to the servo it would have signs of fluid loss. I still would try bleeding again before stripping things apart. Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted July 18, 2012 Share Posted July 18, 2012 On Defenders the servo tends to crack close to the four bolts that hold the master cylinder. Bogmonster has changed many down in the Falklands. I have only seen one with a crack and that was in a relatively new D110. I reckon the Disco will have the same problem. Quote Link to comment Share on other sites More sharing options...
AdeParko Posted August 7, 2012 Author Share Posted August 7, 2012 I've not really got any further with this as yet I was however reading the Haynes manual and tried to follow the test sequence detailed in there With the engine not running, I pumped the brake pedal and after a few presses the pedal was hard, no movement I then kept my foot on the pedal whilst starting the engine. The pedal then dropped slowly all the way to the floor From reading the haynes it should of dropped but only slightly before holding. Mine didn't do this, so does this indicate a fault? And what to? Thanks Ade Quote Link to comment Share on other sites More sharing options...
Snagger Posted August 8, 2012 Share Posted August 8, 2012 I wouldn't expect the brakes to be great on the first test drive - the pads and discs need to be bedded in by several hard applications to remove the protective coatings. The hiss from the MC could just be a small leak in the cap from the Ezibleed. Quote Link to comment Share on other sites More sharing options...
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