Talk Morgan Forums Morgan Sports Cars Morgan Plus Four, Supersport & Plus Six (CX & CXV Generation Vehicles) My23 brakes

NO, The brake pedal drops about 2” on startup even after the master cylinder upgrade, thank god it’s an auto as the handbrake is a joke. But I can’t justify spending 30 grand plus on exchanging it for a MK23 model. Someone somewhere must be able to come up with a suitable alternative.

I did a small experiment, I put a small scratch on the inner and outer of the rotor, it took over 2000 miles to remove the mark on the outer and over 3000 on the inner.
The trouble is in my opinion is , the pads are to hard and the sliding mechanism isn’t covered it’s open to the elements and if left standing for a while will seize.

All this chat on brake issues caused me to try to update my limited knowledge on brake systems.... Jeez the extra degree of complexity and no doubt cost to make it safer for the brain dead to pilot vehicles on the road is somewhat astounding... For sure the days of DIY are all but done and dusted for owners of modern vehicles, except for those with a real determination and ability to get in amongst their machinery...

I have no idea of the master cylinder type fitted to the Mogs with issues, but it seems some units have an electric motor driving a hydraulic pump which pressurises a ECU controlled multi valve unit dependant on read back from wheel speed sensors.... Seems the KISS principal has long since been binned..!

https://youtu.be/RfAzB_IcWuk

p8mog, on the assumption that you have your foot on the brake pedal, it is interesting the distance that your pedal drops on engine startup, though not unusual on old style servo assisted systems which multiplied pressure applied to the brake pedal by utilising vacuum derived from the inlet manifold. I guess if there is an electric pump and ABS system it may not be unusual that something similar occurs on your Morgan..?

Also interesting that you suspect one side of a wheel disc receives more pressure from the brake pad than the other and perhaps indicated by a degree of less wear on the disc via your test... My expectation might be that the pad wear generally shows up any such situation..with the pad on one side of the calliper being more worn than the other..? As discussed earlier with a brake design where the pistons are mounted on one side of the caliper only and a rail system of some sort employed to ensure even pressure applied to the pads on both sides, any restriction of movement on the rail system will cause uneven pad wear... and thus affect braking performance.

I am again guessing that when you criticise the handbrake performance and find comfort in that your Mog has an auto box, you are typing of the ability to park safely by using the P selection which can lock up an auto box...? Whereas when driving I ever found comfort in the ability to slow down by dropping down through the gears in a manual gearbox and careful use of the handbrake lever to avoid locking up the rear wheels... All of which has been removed in the case of auto boxes and electrically operated handbrakes..?

Hard pads are generally designed to work when brakes are up to temperature as on a race track or fast road driving, where brakes are regularly and perhaps heavily applied causing the discs and pads to retain heat... The down side is that they do not work too well when cold and require more pedal pressure to create a reasonable retardation effect... The correct choice of pad should be based upon your average usage... Sorry not trying to teach my granny to suck eggs.. just that I do like the KISS principal...

These days with so many hobby vehicles laid up for long periods it would seem there may be more potential for corrosion issues affecting brake systems and electrics.

Given the amount of seals likely to exist in an ABS master cylinder unit, I can only begin to imagine the possible problems caused if ever the wrong type of brake fluid was introduced to the system...?

I repeat, I am NO expert, just thinking in type and could be entirely wrong about anything.

The simple truth is, the factory made a mistake with the braking system, if the brakes had been right in the first place, then three years the on factory wouldn’t have had to replace them.
I do hope that a replacement 4 pot calliper will be available at some point from hopefully Mulfab?

I have been thinking about this over the past. couple of days and as Ludite has said, (Paraphrasing) "Brakes is brakes" The one thing that can throw a spanner in the works of what is a fundamentally simple system, is control interference, in our case, in the form of an ABS system.
I haven't studied the Morgan system, but using only logic, I would guess there is a high chance that the issues being experienced by owners are somehow rooted in the ABS.
No-one seems to be talking about the ABS and it is technically beyond me, but it is surely a suspect in the enquiry?

As I’ve said before, I’ve never felt the ABS working under very heavy braking! Other cars I drive, under heavy braking you can feel it through the brake pedal.

ABS, ANTI LOCK BRAKING, only works when the senors located on the hub detect a wheel locking up, when the wheel locks up the ABS pump kicks in, the effect is like cadence braking in the old days when you would pump the brake pedal so you could still steer your way out of trouble, ABS would not operate under heavy braking if the wheels did not lock up. Under normal braking conditions the ABS will have no effect.

I did not know that the CX cars have ABS...Has anyone ever felt it in action on wet or slippery roads?

Mikemog6, Im with you all the way on ABS being similar to old style cadence braking, however I suspect it may be worth investigating ABS further, as for me ABS works under emergency braking much the same as it does in normal braking... The First car I drove with ABS was a Porsche 944 and I purposley put the nearside wheels on a grass verge with the offside wheels on Tarmac and conducted the equivalent of an emergency stop ... the 944 pulled up straight and true..No drama.. Much to my surprise I must admit...

As ever more than happy to be corrected.

I wonder if Litchfield's upgrades to softer pads and brake fluid involve to easy upgrade to DOT 5.1 fluid ? It has viscosity improvers for 'cold' brake feel and ultimately a higher boiling point (without the hassle of full swop to silicone based fluids)

These are the multiple pipes from the ABS unit located in the Plus Six, gets nice and warm in the engine bay...