Re: Defender 110 brakes, the whole story

I am sorry to hear of your problem. Assuming that the brakes are up to spec to start with, the required pressure could be reduced by either fitting a larger brake booster or increasing the available vacuum by fitting a larger vacuum pump. The second would be the easiest, and I would suggest that you try to find a local brake specialist or a garage that is experienced in performance modifications to vehicles. There are other modifications that could be made to the brakes such as fitting ventilated discs and special pads, but these are all aimed at increasing braking effectiveness rather than reducing the required pedal pressure. However, in the hands of a knowlegeable expert such as I suggest above, they could possibly be targeted at reducing pedal pressure. JD

Two things spring to mind that may (or may not!) be relevant. The first is that I'd suggest that as you found the brakes on your Disco to ok, if all things are equal, you shouldn't have any problem with the brakes on a 110. The second is that I'm wondering if the issue may not be the brakes themselves, but the driving position, as in a Defender you are sitting rather more upright than in a Disco thus the brake is rather more of a "push down" thing rather than "push forward" thing, if you see what I mean. Perhaps some sort to mod to the pedal may help? Just a thought....

Richard

On or around Fri, 14 Nov 2003 12:51:34 +1300, "Rich" enlightened us thusly:

more info, more possible solutions...

OK; your age defender should have a pretty much identical braking system to the disco. But as someone else said, the seating position is not quite the same. The other thing that crosses my mind to check is whether the pedal has extra or stronger return springs compared to a disco. Some of the defenders have double return springs on the pedals, and you'd be fighting the return spring, so removing one if there are 2 or fitting lighter springs might be a point. The pedal needs to return, but only just IYSWIM.

larger servo is a possibility. There's not that much scope for more vacuum, since it's difficult to achieve.

The other thing you can consider if your resources run to it is a power operated brake system such as is fitted to citroen and some other cars, where the brakes are operated by a high-pressure circuit, and the brake pedal simply operates a regulating valve. An adaption of the citroen system would probably work - would mean a certain amount of fabrication and the fitment of the hydraulic pump and a reservoir, but I'm sure it could be done. My Ford has an electrically pumped power braking system, similar design and ABS (when it's not broken) except that the pressure is achieved by an electric pump, not an engine-driven one. This has the advantage that the system is available with the engine stalled.

I suspect that some Range Rovers use this system too, anyone confirm?

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(snip) Good idea - didn't think of that. A minor correction - the Citroen system includes a hydraulic accumulator so that it operates if the engine is stopped. Some variants use the weight of the vehicle as the accumulator. The Citroen system may be difficult to adapt to a Landrover as it uses much higher pressures than conventional brakes. However, the solution may lie in the adaptation of a Landrover ABS system - which is available on the Defender - to provide a powered as opposed to a power assisted system. JD

The classic Range Rovers with ABS certainly used this and it is not beyond the bounds of possibility that you could fit one of these to a

110, the electric pump and regulator is a self contained unit. The problem is going to be regulating the pressure. It is feasible that you could use the ABS master cylinder/block from a Range Rover as well as that will give you the use of the built in Servo Cylinders. These use pressure from a direct "hydrostatic" circuit (basically the traditional hydraulic power from a master cylinder) to progressively operate the power circuits and provide some feel for the pedal.

With no ECU, no wheel sensors etc... you will get the benefit of the power assistance. If you want to add an ECU and sensors you will then get ABS too.

The RR uses a combined master cylinder and ABS block which may be difficult to fit into a 110 so it would be worth looking at similar setups that use a remote ABS block (Discovery for example)

I'm heading over to Maddison 4x4 this afternoon - I'll have a word as I'm sure they've done similar mods before to a 90.

cheers

Dave W.

I spoke to Patrick at Maddison 4x4 this afternoon and he confirmed that a Series 1 Discovery ABS block and pump could be fitted to your 110 to boost the brake pressure. Without an ECU or wheel sensors, the pump would simply be wired to the ignition and use the built in pressure regulator switches to turn the pump off/on as required. The ECU block will then allow your existing master cylinder to control the power assisted circuits to the wheels.

Obviously you could fit the ECU and sensors as well to give you ABS but that would put the cost up...

HTH

Dave W.

On or around Fri, 14 Nov 2003 21:30:09 +1100, JD enlightened us thusly:

this is more likely. The Ford electrically pumped thing has a pressure accumulator as well, smaller than a citroen sphere though. I takes quite a lot of braking with the pump off to depressurise it, and takes about a minute to charge up again once you turn the power back on, ISTR.

it's also standard rover parts, which makes life easier.