jonno666 Posted July 30, 2008 Posted July 30, 2008 hi there ppl am new on here and would be very gratefull if someone could help me shed a little light on a little problem i have when i press my brakes the pedel goes down so far as should and the car stops fine but the peddle doesnt spring back up and takes the brakes a couple of seconds to release again everything else on the car seems ok so any help would be very gratfeully appreciated :lol: Quote
techbod Posted July 30, 2008 Posted July 30, 2008 its air in the system and complicated to explain ( or im past it lol ) the haynes manual only just explains it Quote
kfk Posted July 30, 2008 Posted July 30, 2008 hi there ppl am new on here and would be very gratefull if someone could help me shed a little light on a little problem i have when i press my brakes the pedel goes down so far as should and the car stops fine but the peddle doesnt spring back up and takes the brakes a couple of seconds to release again everything else on the car seems ok so any help would be very gratfeully appreciated :P The brakes on the Xantia dont use a conventional master cylinder, but instead use a component called a brake dozeur. The Dozeur is effectively a valve that allows passage of fluid under high pressure to reach the brakes, and when released allows the pressure you have sent to the brakes to be released and thus allow the vehicle to roll. So to stop the car you press the pedal.....the valve is moved inside its housing untill the oil ways line up....all the while the pedal is pressed the oil ways will remain aligned. When releasing the brakes a large spring inside the dozeur pushes the valve back towards the pedal......this aligns a different set of oil ways and allows the pressure to be released within the brake circuit......if the valve is siezed or the spring is weak it will cause a delay in the return of the valve assy. this document has some nice pictures on page 46 and will help explain the operation. I dont think you will have air in the circuit:If the brakes had air in the system the usual description of the fault on a xantia would be 'I apply the brakes and they respond a second or so after.....or if braking gently the brakes seem to grip - release - grip - release. Quote
jonno666 Posted July 30, 2008 Author Posted July 30, 2008 thx for that kfk thats has explained alot.If i could just ask one more small thing.would you no if this is a repair i could do myself and change the unit as when it comes to cars i am ok with alot of jobs but this being my first french 1 have not had to do any jobs before on one with these complicated systems.or is it gonna be a expensive garage job many thx m8 :P Quote
kfk Posted July 30, 2008 Posted July 30, 2008 anyone can do any job given the required tools, time & knowledge. The system needs to be depressurised first, to do this the engine must be off, suspension in lowest setting & slacken 12mm bolt on regulator body by one full turn......if you dont do this you and anyone near you will get very wet with LHM. Remove the brake dozeur....it unbolts....i wont explain how to do that as it will be self explanitory. replace the brake dozeur, use new rubber seals on the pipes......put the rubber seal on pipe and insert into hole......dont put seal into hole and push pipe in as it will cut the inside of the seal and leak. When tightening the pipes they only need to be nipped up....dont over tighten them as you will damage the pipe end.... the rubber seal works! Having refitted the dozeur and pipes you need to bleed the brakes.....at this stage you have no pressure in the brake circuit....so pumping the brake pedal isnt going to do anything. with 2 people ....one person apply brake pedal.....just press and hold down....no need to pump!open the brake bleed valve on first front brake caliper and connect bleed pipetighten 12 mm bolt on accumulatorstart car........at this point you should see fluid flow from the brake calipertighten bleed nipple when air bubbles dissappear.turn off engine and undo 12mm bolt on accumulator to release any pressure in the system Repeat the above for the other front wheel. When bleeding the rear brakes the suspension will need to be in high and you may need to apply pressure with the use of a jack to the underside of the hub assy......rear brake pressure comes from the rear suspension spheres!......obviously if you jack up the arm with the suspension in high, apply the brake pedal and release the bleed nipple you will get fluid out......so get ready to catch it. Have fun Quote
jonno666 Posted July 31, 2008 Author Posted July 31, 2008 Well kfk your a man of very good knowledge and you have truely helped me out have got new part and seals on order and hopefully they turn up soon.All my other cars in the past have had nice simple brakes by way of being servo assisted and have just changed them lol,anyhow i owe you a big thanks and very much appreciated all your help i shall be on here more often now as there is so much good advice on here and i also might be able to help others out the same way with some of my knowledge on alot of the cars i have had and worked on....big thanks :P :( Quote
techbod Posted July 31, 2008 Posted July 31, 2008 my apollos there its because I do many makes of cars and my mind was elsewhere and not thinking Citroen and hydraulic system :( and thanks to kfk for giving the proper answer, ill be a good boy from now on lol :( ps: when you reach my age the mind can wander :P Quote
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