Ade Ray Posted March 20, 2002 Share Posted March 20, 2002 Hello everyone AS you may or may not have read on a previous posting I suffered complete loss of brakes when the master cylinder on my rear left drum brake failed. The brake drum is all repaired and everything seems ok. The question is: Are there separate circuits for front and rear brakes and if so what are the possible reasons for the complete loss of braking (ie foot to the floor sort of nothing)? My car is a 1600 X-Flow ex-scholarship car on an N - plate. Ade Make the world a better place, hug an estate agent Link to comment Share on other sites More sharing options...
mav Posted March 20, 2002 Share Posted March 20, 2002 Most brake systems are split diagonally front to rear. Not sure if it is the same on the 7 though! Link to comment Share on other sites More sharing options...
Paul D Jones Posted March 20, 2002 Share Posted March 20, 2002 My Westfeild is split front to rear with a brake bias bar I belive a lot of race cars are like this. Paul. Link to comment Share on other sites More sharing options...
Ade Ray Posted March 20, 2002 Author Share Posted March 20, 2002 Thanks guys I think some further investigation is required. Ade Make the world a better place, hug an estate agent Link to comment Share on other sites More sharing options...
Paul Ranson Posted March 20, 2002 Share Posted March 20, 2002 The cylinder in the rear drum would be a 'slave cylinder'. AFAIK all Caterhams since quite a long time ago have a dual circuit brake system, split front/rear. When one end of the system fails you should expect the other to continue to mostly work, but the pedal will go pretty much to the floor and be very squashy. It's exactly how it feels when you are bleeding the brakes and work the pedal with one nipple open. I don't know if your experience was 'right' or not, but you are still alive and presumably the car stopped? It would be worth ensuring that the front brakes are working, that there is no air in the system, fresh fluid etc etc. Paul Link to comment Share on other sites More sharing options...
Ade Ray Posted March 21, 2002 Author Share Posted March 21, 2002 Paul Many thanks, I am going to go over the brakes this weekend and possibly take Katie to the local brake specialists for a check over. As per my other post, thats another £10 to NTL Ade teeth.gif Make the world a better place, hug an estate agent Link to comment Share on other sites More sharing options...
tony isherwood Posted March 21, 2002 Share Posted March 21, 2002 FWIW my brake master cylinder has 2 pipes out from it and one goes to the rear and other to the front brakes. 1400SS 1995 If it is a single brake system I would suspect one pipe out and a T joint somewhere to split the flow (1 in 2 out). Seems obvious but may nmot be ;o) Link to comment Share on other sites More sharing options...
Gary Furst Posted March 21, 2002 Share Posted March 21, 2002 Ade, When the rear brake pipe broke on my all disc braked De-dion car a couple of years back I too lost all the braking. I lost all the fluid in the system through the crack in the rear pipe, so I guess that there are not two fully independant circuits. Link to comment Share on other sites More sharing options...
SJL Posted March 21, 2002 Share Posted March 21, 2002 There are two circuits, one for the rear brakes (splits at the dedion tube) and one for the front brakes splits at the front of the chassis. The rear circuit is fed from the rear pipe on the master cylinder, front circuit from the front pipe. The master cylinder fluid reservior feed both circuits but is split into two compartments joined at the top. This should prevent one circuit taking the other one out ! Having said that its possible the fluid could slop over the top of front compartment into the rear and then out of the split pipe eventually causing front brakes to get air in the circuit ? Link to comment Share on other sites More sharing options...
Muttley Posted March 21, 2002 Share Posted March 21, 2002 The fluid reservoirs are closed off from the braking circuits pretty much as soon as you press the brake pedal, the seals move down the bore beyond the fluid entrance hole from the reservoir - if it didn't you'd be pressurising the reservoir! It's been a long while since I've had a master cylinder apart but when you have a single master cylinder with 2 lines out for front and rear you have 2 seals on the same piston running in the same bore (although the bore might narrow slightly for the rear half to provide more braking bias to the fronts). If the circuit at the far end of the cylinder fails I cannot remember if there is anything to stop fluid forcing past the intermediate seal into the leaking circuit which would mean total brake failure, but if it is the first circuit (normally the front) that fails fluid cannot get backwards past the seal so the rear brakes would still work. I'll have a look at a couple of haynes book of clues at home and see if I have a sectional diagram, if so I'll scan it and post a link. On a Mini the 2 pipes from the MC go into and out of a cylinder with a shuttle valve. If a circuit fails, the pressure difference pushs the shuttle across and this effectively seals the blocked circuit allowing the remaining one to work no matter which one it is. Muttley. Link to comment Share on other sites More sharing options...
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