REAR BRAKE PIPE DILEMA

PETE BELL

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help :roll: im doing the brakes on the rear of my 90 off road car, i have removed the load sensing valve totally, there are two brake pipes that come from the master cylinder to the LSV i have cut the pipes and when the brake pedal is pressed gently fluid came from one pipe so i used it as supply and left other pipe to the side, when checking pipe work etc for leaks got brake pedal pressed more firmly found fluid came from other supply pipe. Should i blank off 2nd pipe or tee it into system??
i dont know why there are 2 pipes when from the LSV to the axle there is only 1 pipe. Cheers.
 

BobMurphy

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PETE BELL said:
help :roll: im doing the brakes on the rear of my 90 off road car, i have removed the load sensing valve totally, there are two brake pipes that come from the master cylinder to the LSV i have cut the pipes and when the brake pedal is pressed gently fluid came from one pipe so i used it as supply and left other pipe to the side, when checking pipe work etc for leaks got brake pedal pressed more firmly found fluid came from other supply pipe. Should i blank off 2nd pipe or tee it into system??
i dont know why there are 2 pipes when from the LSV to the axle there is only 1 pipe. Cheers.


I asked a similar question when I replaced my LSV and brake pipes - I didn't get a reply.

Looking at the parts diagram it appears that one pipe comes from the master cylinder and the other from the ABS modulator, so presumably the ABS pipe pushes a valve in the LSV to reduce the braking to the rear when there is a danger of the wheels locking.

I meant to take my old LSV apart and see how it worked - but naturally I haven't done that yet :lol:


If you are only using your modified car off-road, I guess you won't be wanting ABS anyway, so if I was you I'd blank-off the pipe from the ABS Modulator and see how you get on.

Is the thing going for an MOT :?: :?: :?:

Please let us know the result as I'm curious :?

Bob.
 

Jon Wildsmith

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Might the extra pipe be part of a dual zone set up with the pipe from the ABS actuator being on the normal circuit and the pipe from (further along?) the master cylinder being the secondary failsafe circuit? Not familiar with 90's but I'd guess they're modern enough for this? normal pedal travel pressurises the ABS circuit but in the case of a leak in that pipework further predal travel pressurizes the secondary circuit? That's my limited understanding of how these types of dual zone systems work so you get a second chance at having brakes when it goes pear shaped.
 

PETE BELL

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MY 90 IS FOR OFF ROAD USE ONLY SO NO MOT AND THIS ONE DONT HAVE ABS SO IL HAVE A RITE GOOD LOOK AT THE PIPES AND TRACE THEM BACK TO THE MASTER CYLINDER TO SEE WHAT SEQUENCE THEY COME OF, CHEERS GUYS. ;)
 
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