dougstar Posted March 7, 2009 Share Posted March 7, 2009 Have done a quick search but nothing answered my question. Intermittintly my Disco has a brake issue, always when first started up or within a mile (could be first time i press the brake?) but the pedal goes soft and it sounds as if the ABS is kicking in and although the brakes come on they seem to be very poor, After a couple of pumps of the pedal all is well again and back to what i belive to be very good brakes. Any ideas guys?? Servo? Vaccum pump What you thiink TIA Dougie Quote Link to comment Share on other sites More sharing options...
lrfarmer Posted March 7, 2009 Share Posted March 7, 2009 my gess would be pump as servo would do it all the time and pump would get better once the engine has wamed and the oil got to were it is needed Quote Link to comment Share on other sites More sharing options...
dougstar Posted March 7, 2009 Author Share Posted March 7, 2009 my gess would be pump as servo would do it all the timeand pump would get better once the engine has wamed and the oil got to were it is needed http://www.paddockspares.com/pp/DISCOVERY_...p_-_300TDI.html OUCH !!! O well better than the OUCH if i hit a tree i suppose Dougie Quote Link to comment Share on other sites More sharing options...
pinny Posted March 7, 2009 Share Posted March 7, 2009 Have done a quick search but nothing answered my question.Intermittintly my Disco has a brake issue, always when first started up or within a mile (could be first time i press the brake?) but the pedal goes soft and it sounds as if the ABS is kicking in and although the brakes come on they seem to be very poor, After a couple of pumps of the pedal all is well again and back to what i belive to be very good brakes. Any ideas guys?? Servo? Vaccum pump What you thiink TIA Dougie have you checked the wheel bearings as this will push the pads away from the disc Quote Link to comment Share on other sites More sharing options...
dougstar Posted March 7, 2009 Author Share Posted March 7, 2009 have you checked the wheel bearings as this will push the pads away from the disc They are good mate TIMKIN's not that old and regulary checked, I have had that issue when you get back 'on road' some times and the pads have been rattling around and it takes a couple of pumps to re seat them but this is different The ABS kicks in too ? Cheers Dougie Quote Link to comment Share on other sites More sharing options...
steve58 Posted March 8, 2009 Share Posted March 8, 2009 Have done a quick search but nothing answered my question.Intermittintly my Disco has a brake issue, always when first started up or within a mile (could be first time i press the brake?) but the pedal goes soft and it sounds as if the ABS is kicking in and although the brakes come on they seem to be very poor, After a couple of pumps of the pedal all is well again and back to what i belive to be very good brakes. Any ideas guys?? Servo? Vaccum pump What you thiink TIA Dougie It's a bit of fiddling around, but you should be able to read the logged fault codes of the ABS Ecu using information available on this excellent forum. That should point you in the right direction. I noticed you mentioned your wheel bearings have been replaced not long ago? 1 detail easily overlooked regarding the front ABS sensors is the amount of CV joint shaft end float. The very nature of bearing shaft support for that makes it absolutely critical to keep that end float to a minimum. I set mine up to .08 mm (approx .0032"). I was fortunate enough to be able to make my own spacers on a lathe and finish the thickness on my surface grinder. Again on this forum there is details of how to set that end float up properly. Unfortunately in my case that and many other fixes did not rectify my ABS problems, it turned out to be another issue with the Ecu. Quote Link to comment Share on other sites More sharing options...
dooroy Posted March 8, 2009 Share Posted March 8, 2009 I posted on here some time ago as my brother had a few scares with his 96 300 Tdi ES - someone posted to it again and you can see it on pg 2 or 3 . Quote Link to comment Share on other sites More sharing options...
Rolly Posted March 8, 2009 Share Posted March 8, 2009 Wheel speed sensors. One or more is gone but you need that testbook thing to find out which one. Quote Link to comment Share on other sites More sharing options...
stageonesimmo Posted March 9, 2009 Share Posted March 9, 2009 Yeah wheel sensors need tapping back in (I get the same symptoms on mine when it needs doing) which may also point to your bearings being a bit on the slack side, or the sensors weren't tapped back in last time the bearings were done.......... Quote Link to comment Share on other sites More sharing options...
dougstar Posted March 10, 2009 Author Share Posted March 10, 2009 Yeah wheel sensors need tapping back in (I get the same symptoms on mine when it needs doing) which may also point to your bearings being a bit on the slack side, or the sensors weren't tapped back in last time the bearings were done.......... Now this i have not heard of before ?? Will check the bearings again asap but never 'tapped' anything back when i did the bearings?? But then i have done quite a few miles since the bearing change and the brake issue was not apparent from the start, i would presume from what you are saying that it would be straight away after the change?? Thanks again guys its a real help to get a broader range of ideas for me to go at this weekend when i get chance to look at it. Dougie Quote Link to comment Share on other sites More sharing options...
stageonesimmo Posted March 10, 2009 Share Posted March 10, 2009 Play in the bearings can allow the CV joint to run eccentrically in the swivel housing - this can bring it into contact with the sensor pushing it up and increasing the air-gap resulting in the classic symptoms you have. Its not that you HAVE to tap them back in if you do the bearings, but its just a common precaution I use when doing mine as I know the brass inserts dont grip the sensor on mine as well as they should......... Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.