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

A lot of sense there George!
It would be interesting to know from those who have long pedal travel, whether that shortens if the brakes are pumped repeatedly. If so, I would look to re - bleed. Just because it’s been done during recent factory recall, doesn’t guarantee it was done successfully. (due to time pressures etc)?

The following is just my opinion.

A soft brake pedal often pointed to air in the system, sometimes this gives a feel of longer travel.
In the days prior to ABS and servo assist you could check this by rapidly pumping the brake pedal, if the pedal went hard and travel reduced and then when left for 5 to 10 minutes went back to a soft pedal again it pointed to air in the system. Even a very small amount of air can make quite a difference on a brake system.The ABS pump itself can be difficult to completely bleed depending on its type and its position in the brake circuits. I do not know what make/type of ABS pump Morgan have used in the Plus 6 ( no parts scematic available to owners ). My experience with motorcycle early ABS pumps was that it took quite a few goes to get the air out of the pump, some even had bleed nipples on the pump itself. There was also a set sequence to bleed the early ABS systems.
In my previous post I mentioned that after our Plus Six M/Cylinder replacement I was not happy with the pedal travel/feel and asked the dealer to look at it again. I am fairly certain they re-bled the system. After their second intervention the brakes on the Plus Six are acceptable and better than pre M/Cylinder change.

Lastly, ref poor handbrake.. Our Plus Six initially had an excellent handbrake, but was noisy from cold in the area of the NSR wheel. The noise sounded like rubbing but gradually stopped after 1 to 2 miles as everything warmed up. The dealer looked at it and reported that the brake pads needed cleaning and light greasing in their retaining area. After this work the brake noise from the NSR wheel area was gone, but the handbrake was lousy, would not hold on a 5 deg incline, so it went back to the dealer and they adjusted it.. Its now back to working well and its not producing noise. So from this I am inclined to think that adjustment on the Plus Six handbrake is borderline and does not take much to either work well or not at all.

Deejay, thanks for commenting. Had I that degree of sense in my yoof, I would have saved a lot of cash spent on modifications that demanded further modifications and ultimately threw many a practical machine out of balance and made it a pig to ride/drive except when operating the very narrow window of performance I had created.... and that I did so man more times than once....

Dave, in my limited experience air in the system is usually associated with leakage, or may be found when the system requires bleeding after having work carried out on it and not being properly bled.... For sure some machines can be far more ackward to bleed than others..

The soft pedal that can be realy scary, is the one where as an example... After lay-up, where a caliper may have partially seized and is holding a pad or pads against the disc to the extent it is no more than rubbing, perhaps not in any way first noticed when one fires up the Mog to head out for that first run in the sun, brake pedal feel s fine, brakes seem to be working well, then after a few miles, the pedal hits the carpet under braking.... The rubbing pad has heated the caliper and disk and in the process boiled the fluid, which can manage in a shorter period of time if the fluid has not been changed as recommended, and as a result has a high water content, the water boiling at a lower temperature than good condition brake fluidwould ever do so...?

As always just thinking in type..

Ref the air, yes totally agree. But its quite possible that A: The factory did not get all the air out at time of manufacture and B: The dealers could have had the same issue when the M/Cylinder recall happened. Bleeding some ABS systems can be tricky. This may account for a small % of cars reporting poor feeling brakes and longer travel. I am not saying this is the total reason, as there seems to be quite a lot of reported variation in brake quality. But it could be one of the reasons for some cars. Also the CX cars are relatively new, most will not have done high milage, so the hardware should be in good to fair condition...

That's a bit low spec, ok for a Ford Fiesta, Is the P Six a better spec ?

Agreed. I thought they only used single piston floating calipers on the rear of modern cars as they better support cable operated handbrake action as well.

I think we are boxing round the question that the thread posed "Are the brakes on the M23CX cars better?"

Somebody needs to test drive a Plus Six that the dealer claims is up to the specs re braking performance, then test drive a 2023 Plus Six demonstrator. Original reviewers of the Plus Six commented on the soft pedal and the long brake pedal so it was a known. What we don't know is an accurate comparison between the models. If there is a difference then we need to find out what has been changed.

Presently my dealer is in contact with MMC as to what to change on our car to get maximum brake performance. Watch this space!
Kerry

Looking forward to the answer...

RAMBLE ALERT..!
As I typed a while back it is so easy to get confused with all this chat, and I am perhaps more guilty than most when it comes to rambling on...(-:

On the other hand the chat has caused my old brain cells to become more active than they might otherwise be, which at my age might be considered worthwhile.. (-:

I suspect we have all learned by now that mistakes abound in discussions, I know I have typed a few myself and been grateful for them to have been corrected by more knowledgable folk.

Back to fundamentals on brakes... or at least trying to brake (no pun intended) down the complexities of operation into a form of more basic understanding..?

As suggested best to stick to manufacturers spec on much, especially brake fluid. No harm in seeking better understanding and if so motivated this link has had some work put into simplifying things, even if the presentation is less than professional..?

https://youtu.be/SdnSlBG71G4

As no one has yet asked, I think DOT as in brake fluid and much else equates to Department Of Transport..?

Bleeding ABS.... I have only ever bled two ABS systems and managed to do so without causing issues which may just have been down to luck..? Both NON-MORGAN.

The likely more modern and complex system was on a sports car where each calliper had two bleed nipples, one for each side of the calliper which had four pistons in total. Apparently during bi-annual fluid changes it seems possible if not likely that the garage mechanics will seek to save time and reach through the spokes of the wheel and use the outer nipple on the caliper to bleed it leaving the harder to reach nipple untouched...?

OK call me a cynic by all means, but it seems quite often on this marque that the inner and harder to reach brake nipple is often found to sheer off when disturbed for bleeding purposes whereas the outer and easier to reach nipple often loosens without issue...

If I might be in any way correct in my assumptions, it would then seem obvious that only one side of each calliper bled in such a way will have the benefit of it`s brake fluid being replaced and in such circumstances over time and if the same flawed bleeding process is followed then dependant on the passage of time who knows what age the brake fluid might be contained within the inner section of the caliper and just how much quicker it might come to the boil under braking creating some degree of increase in pedal travel...Hmm..?

If you come across seized nipples that seem likely to sheer, or have a caliper with a sheered nipple, there as specialists in removing sheered nipples, though the task is simpler if the nipples is not sheered off, but not impossible.. Even on painted callipers, where I believe some form of ultrasonics is involved in the removal process. Such specialists can also supply original nipples or stainless if preferred...

Bleeding... As has been typed it seems there may well be a variety of processes suggested dependent on which system is in use..?

I used gravity and nothing else... and it has worked out well to date, brake pedal felt fine and vehicles pulled up straight and true.. I had removed two callipers, the front offside and the rear nearside and had closed off both flexible pipes with clamps to save loosing all the fluid with whatever complications that might have created in the ABS system.. After replacement of each calliper, starting with the rearmost one first and with the fluid reservoir topped up first released the clamp on the flexible, followed by opening up one nipple at a time on that calliper, the one closest the flexible hose opened first and left opened watching the fluid begin to appear in spurts until the air bubbles stopped spurting, hopefully indicating that side of the calliper was full of fluid, I then checked and topped up the brake fluid in the reservoir, and then followed the same process on the outer side of the calliper, after which I again checked the reservoir. I then checked the pedal travel which seemed OK, it took a couple of pumps to extend the pistons in the caliper I had just bled to the extent that the brake pads made firm contact with the disc. At which stage I then let the system sit for a couple of minutes and checked the brake pedal action for travel and to check if it would pump up and change the length of travel, which it did not...

Exactly the same process for the replacement and bleeding of other calliper with exactly the same results... After topping up the reservoir and replacing it`s cap, I then fired the engine up and again tested pedal travel, which felt fine, followed by a road test which again seemed to confirm I had created no issues when I bled the brakes..

Using no more than logic... It seems that for the brakes to conform to my expectations of fail safe design, that all circuit ABS control valves would surely be opened, to then allow the master cylinder to create pressure to all circuits were the brake pedal pushed down, with no need for the engine to be running or electricity applied to the ABS control system..? Thus with the cap removed from the reservoir gravity bleeding with a bit of forethought seemed to work well enough for me.. I stress again this was NOT on a Morgan.

As for attempting to find answers on brake efficiency one car against another, even with the same driver on exactly the same road surface and in exactly the same weather conditions tyre type and on and on and on... I suspect the variation in assessment could be considerable..? As suggested in my last I suspect any MOT or garage with brake testing equipment can compare and provide readings for all four wheels independantly of each other or in combination, along with handbrake performance on each wheel.... Thus anyone who cares to can create reasonably accurate comparable readings for brake performance to share with others, the only variable other than the performance of the brake testing machinery, would perhaps be the amount of pedal pressure required to be applied create the readings obtained..?

Pedal travel can be relatively simple to measure reasonably accurately..?

My guess is that UK construction and use, if not EU regs, will contain a number of specifications for brake usage and efficiency figures as a minimim for a variety of vehicles as no doubt will MOT regulations..?


Again using no more than logic with zero professional training....As for what the problem might be with Morgan brakes if any.... I would hope that they were bled as required before they left the factory for anything other than that would be too much to ask me to accept as in any way reasonable from a motor manufacturer.

Simple logic would also seem to dictate ..As the MMC do not manufacture brake components other than perhaps the pedal arrangement and linkages specific to Morgan, that MMC are then dependant on other manufacturers supplying DOT approved parts, it would seem to be incumbent upon the MMC to consider the compatibility of the combination of all the parts used to make up the whole system, including the type of brake fluid that the MMC would then specify for use in the vehicles brake system..?

With ABS in circuit given the many valves and seals in that system let alone all the seals elsewhere in the system, the choice of fluid seems best not to be taken lightly..?

As ever more than happy to be corrected if I have been wrong in any of my assumptions

Let's come back to the detailed question of whether the brakes from MY23, which are supposed to be better, can be converted to MY22 and earlier.
The question for me here is what components are actually installed.

Which brake fluid does MMC specify?
Which brake booster is used?
Which brake master cylinder is used?
Which brake caliper with how many pistons?
Which brake pads are used?
Which ABS is installed? Definitely a four-channel system, as you can see from the photo.

Unfortunately I don't have a picture of the brake disc and caliper.

Are the components on the PusFour and PlusSix the same?

Maybe one or the other member can answer one or the other question.

Once the questions for the different model years up to MY23 have been answered, the question of retrofitting can be answered.