Split circuit brakes - options and best practice
Discussion
Hi,
when I MoT'd my Bowler last year one of the front braided brake hoses burst leaving the vehicle with no brakes. Fortunately it was on the test roller at the time and not on the highway. The brake circuit is as per a classic Range Rover - dual circuit with a common front rear circuit and a dedicated front secondary circuit. There is a shuttle valve which is intended to change position if either circuit has greater pressure than the other, I guess to reduce fluid loss as well as to trigger a warning lamp.
When the brake hose failed this did not function.
The cause of the failure appeared to be that a stainless strand punctured the teflon inner. All the braided hoses were replaced and the routing improved to eliminate the risk of snagging or rubbing. The shuttle valve was stripped and inspected - the plunger moved freely and the sealing "o" rings were replaced although the originals looked in good condition.
When I fitted new seals to the rear callipers earlier this year I was checking whether the brakes were correctly bled and the "brake fail" light lit.
Should I retain this circuit arrangement or re-plumb for a diagonal split? This would require some work but might save a life.
Thoughts please!
when I MoT'd my Bowler last year one of the front braided brake hoses burst leaving the vehicle with no brakes. Fortunately it was on the test roller at the time and not on the highway. The brake circuit is as per a classic Range Rover - dual circuit with a common front rear circuit and a dedicated front secondary circuit. There is a shuttle valve which is intended to change position if either circuit has greater pressure than the other, I guess to reduce fluid loss as well as to trigger a warning lamp.
When the brake hose failed this did not function.
The cause of the failure appeared to be that a stainless strand punctured the teflon inner. All the braided hoses were replaced and the routing improved to eliminate the risk of snagging or rubbing. The shuttle valve was stripped and inspected - the plunger moved freely and the sealing "o" rings were replaced although the originals looked in good condition.
When I fitted new seals to the rear callipers earlier this year I was checking whether the brakes were correctly bled and the "brake fail" light lit.
Should I retain this circuit arrangement or re-plumb for a diagonal split? This would require some work but might save a life.
Thoughts please!
Iirc, (it's a few years since I worked on a RR Classic) the system was "L" split.
Primary - two fronts and one rear
Secondary - two fronts and other rear.
The front calipers required twin jump hoses.
Replumbing as a diagonal or any other split with existing hardware would be fraught with difficulties.
I suggest you recheck the function of the shuttle and the warning light circuit. This incredibly simple. All you need to do is simulate a fluid leak at a caliper by opening a bleed nipple.
Good luck.
Peter
Primary - two fronts and one rear
Secondary - two fronts and other rear.
The front calipers required twin jump hoses.
Replumbing as a diagonal or any other split with existing hardware would be fraught with difficulties.
I suggest you recheck the function of the shuttle and the warning light circuit. This incredibly simple. All you need to do is simulate a fluid leak at a caliper by opening a bleed nipple.
Good luck.
Peter
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