boiler man Posted March 20, 2010 Share Posted March 20, 2010 The brakes on my 300tdi disco are very harsh, will BANG on hard , but then the brake pedal sinks very slowly to the floor. ive tried changing master cylinder, no difference, renewed copper pipes and fitted goodridge hoses and i new rear caliper. all other calipers serviced. there are no apparent leaks of fluid. help!!! thanks guys Quote Link to comment Share on other sites More sharing options...
treewhisperer Posted March 20, 2010 Share Posted March 20, 2010 hi boiler man......... as i understand the brake pedal SHOULD sink to the floor slowly if engine is running and servo working correctly.........what do you mean when you say they come on hard? Quote Link to comment Share on other sites More sharing options...
boiler man Posted March 20, 2010 Author Share Posted March 20, 2010 hi boiler man......... as i understand the brake pedal SHOULD sink to the floor slowly if engine is running and servo working correctly.........what do you mean when you say they come on hard? Quote Link to comment Share on other sites More sharing options...
boiler man Posted March 20, 2010 Author Share Posted March 20, 2010 thanks for reply. im concerned because every other vehicle ive driven, when you apply the brakes they will actuate, usually proportionately to the amount of pressure you are applying,and the pedal will sink to a point. with my disco, you start to apply the brakes, and they will almost instantly bite, very fiercely, then the pedal will sink to the floor, literally flat to the deck and touching it. the next brake application will require a pump of pedal first. id like to add that im currently renovating and off road modifying the vehicle, and my brake tests are being done in a farmyard, with no risk of harm to anyone.( unless you happen to be a chicken called minnie!) mark Quote Link to comment Share on other sites More sharing options...
errol209 Posted March 21, 2010 Share Posted March 21, 2010 will almost instantly bite, very fiercely, then the pedal will sink to the floor, literally flat to the deck and touching it. the next brake application will require a pump of pedal first. The first bit means that one or more corners are working perfectly, but the "second try needs a pump" symptom suggests that something at one of the wheel ends is wrong. Check to make sure all the disks are fitted true (if they 'wobble they push the pistons back to far) and the calipers are also good and solid. Are you 100% certain you've bled it all perfectly? A biggish bubble in one line could give you these symptoms too. What did you do to service the 3 calipers? BTW, the pedal should sink if you press the brake and then start the engine, but otherwise you should be able to lock all wheels with the pedal and over an inch from the floor and it should stay there. Last question - the new master cylinder didn't come in a blue box did it? Quote Link to comment Share on other sites More sharing options...
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