LDRover Posted June 13, 2013 Share Posted June 13, 2013 Hope someone can point me in the right direction, on the last MOT I only just passed with 51% on brake test. MOT is due and still have not solved the problem. I have poor stopping power but and normal road speed it is not a problem, but if off road on a bank the brakes will not hold the discovery. I have no leaks and have change brake master cylinder for a new one. Had another look last night and it is doing the following. 1 With engine running I can get the pedal all the way to the floor with steady pressure on the pedal. Seam to go down quicker when I rev the engine. 2 engine off I can only get the pedal 3/4 of the way down. 3 Took the small rubber vacuum pipe off that run's through the bulkhead and with engine running i can feel it sucking when I put me finger on where I removed the pipe. Tried brakes with the pipe off and only just stopped from about 10mph. I had a leak from the pressure reducer for the the rear brakes. Replaced this a while back hoping it would sort things out but no joy. Since then i can feel that my front discs are warpped. Has anyone got an idea what i can check next. Thanks. Quote Link to comment Share on other sites More sharing options...
wizard Posted June 13, 2013 Share Posted June 13, 2013 Hi check the pipe that runs from the vacuum pump to the servo, they have a habit if splitting on the T piece. wizard Quote Link to comment Share on other sites More sharing options...
Marten Posted June 14, 2013 Share Posted June 14, 2013 I would focus on the vacuum servo efficiency first. With the engine at fast idle, check you have a good healthy vacuum at the engine vacuum pump connection. Use a vacuum gauge if you have one. Small bore braided fuel hose is a good substitute for the Land Rover original rubber hose to heater. Temporarily bypass the line with the tee piece (sends vacuum to the heater valve actuator) and connect directly from engine vacuum pump to brake servo. Use a new, good pipe or pressure test the one you have. Check servo action by pressing the brake pedal with the engine off. (If the pedal goes to the floor with the engine off, you have a hydraulic system defect). Start the engine and the pedal should go down a bit further without any increase in foot pressure from you. If the pedal doesn't move down, you have a vacuum or servo fault. If it goes down and settles, the servo and brake master cylinder is probably ok. If the pedal goes all the way to the floor the servo is probably ok but you have a brake master cylinder or other hydraulic system fault. Basic checks are:- Fluid in reservoir? System properly bled? No leaks? Pads good? Are you sure that the brake master cylinder piston seals are in good condition? Are the flexible brake pipes in good condition? Do you get any swelling of one or more of these pipes as brake pressure is applied? Check all your brake callipers carefully for signs of leakage. Best of luck! Quote Link to comment Share on other sites More sharing options...
Thon Posted June 14, 2013 Share Posted June 14, 2013 Firstly, if you changed master cylinder and fixed a leak, are you 100% positive that there is no air left in the system? I think this is pointing towards a hydraulic leakage problem, whether internally within the master cylinder or in the pipework / hoses / calipers themselves. The servo (as I understand it) is a method of assisting you in applying pressure to the master cylinder to make it easier to modulate the pressure on the brake pedal but ultimately is not part of the hydraulic circuit. If you can get the pedal to the floor applying steady pressure then the hydraulic system is not holding pressure, either by an internal or external leak. My suggestion is to follow Marten's post above, starting with leak testing. All you need is 2 people, one with a strong leg, to keep pressure on the pedal whilst you carefully inspect the hydraulic system in its entirety. If no leaks / bulging hoses are present, it would make me lean towards a master cylinder internal leak. Are you confident that the replacement master cylinder is good quality? Quote Link to comment Share on other sites More sharing options...
Snagger Posted June 14, 2013 Share Posted June 14, 2013 It sounds to me from the first post that the vacuum system has already been proven. I would remove each pad in turn and have an assistant press the pedal down so that you can check for free movement of the calliper pistons - I suspect they may have seized or partially seized. Check the condition of the pads while you're at it. Also inspect the flexible hoses for any signs of tackiness, perishing or bulging under pressure. Quote Link to comment Share on other sites More sharing options...
LDRover Posted June 14, 2013 Author Share Posted June 14, 2013 All, Thanks for the idea's. I have not checked the hose's, rebuild the calipers about 2 years back so had not thought to check them. I will check the the hoses first as I have never changed them in the last 4 years, then move on to the calipers. Thank. Quote Link to comment Share on other sites More sharing options...
LDRover Posted July 7, 2013 Author Share Posted July 7, 2013 Back again for more advice, After finding a pair of weeping seal on a rear brake caliper and thinking it was sorted, no such joy. I have now got a front caliper covered in brake fluid, found the problem is a leaking brake nipple. Any idea where to buy good ones. Local parts shops only sell ones which are twice as long as the standard ones. Also seem very loss in the thread until done up, have stripped one today. Quote Link to comment Share on other sites More sharing options...
DrRob Posted July 9, 2013 Share Posted July 9, 2013 Call John Craddock Land Rovers in Cannock.......... Quote Link to comment Share on other sites More sharing options...
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