marktdi Posted July 13, 2016 Share Posted July 13, 2016 Hi got a strange problem with the brakes on my 200 tdi 90 . Normal day to day breaking is spot on as good as it always has been . Last night though I had to slam on the brakes and the pedal just went solid and the brakes were not good Felt like when being towed with engine off . Ie no servo assistance . After the slam on under normal braking every thing is good . This morning I tried a couple off emergency braking tests and every time it's like no assistance . So I'm thinking servo problem or vac pump problem . Is there anyway to test these and has anyone had a similar problem . Quote Link to comment Share on other sites More sharing options...
stephencdavies Posted July 13, 2016 Share Posted July 13, 2016 Vac pump. easy. run the engine for a minute. pull the vacuum pipe off the servo. you should here the vacuum release from the servo. if you do, thats good. put your thumb over the vacuum line. it should be quite strong. if not you can change the inners. about £16 and is an easy job. the pump is lubricated with engine oil being pumped through. if your oil pressure is normal then starvation shouldnt be an issue. it wont be any bother to take the top off the pump and check the vanes are free and look oily. while your at it . blow through the non return valve. should should be able to blow into the pump, but not suck. Non returns are about £8. if these are ok then you could suspect the servo. these are about £65 ( Bearmark ) you can change these without breaking into the master cylinder lines, just be careful you dont bend the brake pipes too much,take care when lining the master back up with the servo rod. before paying out lots for a brake reirb. get someone to sit in the drivers seat and get them to press the pedal while you observe each brake in turn. might be a caliper problem Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted July 13, 2016 Share Posted July 13, 2016 I had the same problem and it was a duff servo. Mo Quote Link to comment Share on other sites More sharing options...
oneandtwo Posted July 13, 2016 Share Posted July 13, 2016 If you have a split in the servo (very common on 92ish onwards) the servo can flex under heavy braking, the split opens up and the vacuum is lost. Check for hairline cracks on servo on the right hand side of the master cylinder on the bend in the pressing. They always go here, almost every defender I buy / scrap / work on has a split servo. Quote Link to comment Share on other sites More sharing options...
marktdi Posted July 13, 2016 Author Share Posted July 13, 2016 Thanks guys I will check for cracks in servo and test pump at weekend . I did fit a new caliper last August but never gave that a thought . And it did come in a blue box Quote Link to comment Share on other sites More sharing options...
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