They all do that sir - rear brake cylinder

Just a heads up

For a few weeks my handbrake has been sticking. Burning smell when driving.

I took it to the dealer today, and on the way I experienced a rear brake cylinder failure. The brake pedal went almost to the floor and I was left with almost no stopping power. It was a surprise to say the least. Luckily I was almost there, otherwise I think I would have had the car recovered.

The dealer told me that the rear cylinder is the same part number as a 4/4, and those are known to fail over time if the car is not driven enough. So I guess that others with low mileage 2012 cars will start to experience this soon. I have 6,000km and drive it +/- once a week, depending on the weather.

Replacement parts – cylinder and shoes – will be around 250 Euros, plus 2 or 3 hours labour. Annoying. But it’s the safety aspect which scared me! And I guess the problem will be back in another 4 years… they all do that sir..

Oh great! Another thing to look forward to! Sounds like they need to be exercised in order to keep the seals from drying out.

I'm sure the seals are only lovingly manufactured from the finest leather and natural cork.

They haven't been blessed by a Shinto priest, I bet. I participated in a blessing of the cassette decks in L.A. back in the day of HiFi nirvana. That didn't work, either. Damn things still died with regular precision...

Well Vspec/Michael, I've just gotton my 2012 back on the road. The rear wheel cylinder was locked up! A mixture of rust and dirt froze both pistons. The boots were intact. My car has never been driven in the rain, Northern California. I don't understand where this problem came from. I first noticed the car was not rolling (as up to a stoplight). Then I noticed the rear wheel very hard to turn. Checked the E brake and all is well. Finally tore it apart and found the seized cylinder and really worn linings as well. I had to replace the linings, but I found after I disassembled the cylinder all the parts were reusable. The rear wheel is a pain to get out and this is the second time, the firs time was to change the hub. The bottom line: The car should push easily on flat level ground with one hand

If these are the same rear wheel cylinders as the four seaters this is a known problem.

It is best to change the brake fluid every 2 years to avoid ingress of moisture and rusting.

Another permanent solution is to have the cylinder sleeved in stainless steel.

hbatts how many miles do you have on your M3W?

I have 10,000 on mine, so far the brakes are working good, knock on wood!😀

So Morgan have fitted a cylinder with known deficencies! This is bordering on criminal!!!!

All brake cyclinders will rust if not treated as designed (brake fluid changes etc.)

I don't know if this still applies but I had heard that Morgan used the brake master cylinder from an early Mini that had front disks and rear drum brakes. On the Mini they developed a system with a valve that maintained a light pressure on (if I recall correctly) the drum brake cylinders to stop them retracting completely. This was intended to limit corrosion on the exposed cylinder when the piston retracted. On the Morgan they had apparently reversed the connections so that the rear brakes were actuated by the circuit originally intended for the front brakes on the Mini.

As I said I have no idea if this still applies to the 4 wheeler let alone the 3 wheeler.

The valves your referring to are called residual valves.

They are usually used in applications where the master cylinders are about on the same plane as the wheel cylinders.

As you said, they keep the pressure from bleeding off at the wheel cylinders. This keeps both the disc pads and drum shoes in closer proximity to the rotors/drums so a double pedal pump is not needed.

For disc fronts, they use a 2# residual valve and on rear drums they use a 10# residual valve.

In my street Willys street rod, I had Wilwood 4-piston calipers all around and I had to use 2# valves in both front and rear lines.

Timothy, Abt 4,500, not a lot or enough to get rust and gook to freeze pistons.

Really.
My first car was a 1958 Morris Minor and had been in the family for years. Doubt if it ever had more than a couple of fluid changes in its whole life. I really dont recall many problems with drum brake cylinders back in the day.

I haven't used my m3w much in over a year but it was stored without the hand brake being engaged & moved every month a few inches forward & back.this past November i drained some of the brake fluid & topped it off with some new oil. Just now I noticed its heavy to push around, I did bleed out all the old oil & all is fine now.

Q8, I hope you're just using the word "oil" as a generic term for the correct DOT spec'd brake fluid. OIL of course would be a BIG no no...

If you have to get into the brake system, any reason not to flush and replace with DOT 5 silicone-based brake fluid? Unlike glycol-based fluids, Dot 5 doesn't absorb moisture (it's hydrophobic).

I run DOT 5 in my collector cars and no longer worry about corrosion and stuck brakes. I've never had any issues with it.

M3w uses dot 4. I flushed it well with DOT 3... i use dot 3 with my hot rods & i never had an issue

I would put in the recommended fluid. usually the rubber in the seals is formulated to work with a specific fluid. I know when silicone fluid first came out a lot of us in the Street Rod community used it, and it did not always work well.

I certainly wouldn't use DOT5 unless I was absolutely sure that all the seals and hose linings were both compatible with it and untouched by any other fluids. I too have suffered from it in the past when it first became generally available.

Agreed, and unless brake corrosion is a frequent issue, I'd stay with DOT4 LMA (Low Moisture Absorption) fluid.

I've only used DOT5 with a brake re-build when I could be sure all was clean and fresh. Where I've used it, I have not experienced any issues at all.

Don't stress out, using dot3/dot4 Wouldn't be that much difference. I drained all the fluid out & used dot 3..touch wood all is fine & now i can push the mog around easily. I want to enjoy it without repairs before sending it off to the factory for upgrades this summer.

Just coming home yesterday, doing about 50 mph, I go to slow for traffic and the brake pedal goes to the floor without stopping me. Luckily there was some space and I was able to avoid a collision, but it was quite the "holy dermot" experience. I havent even put 100 miles on it since the last trip to the dealership.

This constant breaking of important components is getting old, and rather expensive.

Brake failing would result in selling off the beast
Most likely getting a lawyer activated when 100miles past service

MMC is misusing early M3W customers as human guinea pigs.

Yes, this is the most likely course.

The MMC were almost using early M3W owners as crash test dummies.

My first thoughts through my head as the pedal hit the floor were, "I must somehow be on the clutch," then when I wasn't, "I wonder how bad this will hurt without airbags," then I downshifted and smashed the pedal down hard and there was just a little bit of stopping power there, enough that I did not smack the car in front of me.

1st..Check for oil leaks
- check the bleeding nipples if they are tight or not
-then bleed the brake system.

And next time try the "emergency" brake.

👍

There should have been some braking effect as its a dual circuit system. Think the split is front/rear.

Tim

My breaks went last on the Albert ball run , the rubber nipple shot up in the air as my foot went to the floor , break fluid all over the place , limped back to hotel tightened up the bleed nipple and limp home back to uk

Don't understand where the failure was - one of the front calipers? What bit shot up in the air? If it was a loose bleed nipple, should have been able to re-bleed the brakes and be good to go (or stop, as the case may be...). But I've never seen one work loose before.

The rubber cap on the bleed nipple left hand calliper went 10 foot in the air , these was a lot of us , stop, start , did you the breaks got hot and the nipple come lose because the heat, nipped it up and I had breaks but a lot of travel , the car went in for a service, breaks got bleed , be fine , may not have been that tight to start with ?

There should have been no pressure on the bleeder cap to blow off like that. If it did have pressure, it would be brake fluid and you would have a BIG mess.

It's good that you got it to the dealer for brake bleed service.

Unless the bleeder was loose, which would have been apparent fairly quickly I'd think at the first serious application of the brakes... I've never seen one "work loose", only ones that were left UN-tightened.

Looking at the 2012 (1st edition) parts book on pages 8 and 9, it appears that the master cylinder (part U120008) is located on the back side of the pedal box with the reservoir up under the bonnet. This doesn't look like too hard of a job at least.

Any cause of this failure identied as yet?

It is being picked up today by the dealership, should know more by this time tomorrow.

Please keep us informed Charlie.

Rear brake cylinder leaking fluid, fluid got on brake shoes; replacing broken parts, shoes and flushing lines - $1200, getting that feeling that you are about to have a near death experience - priceless.

Really? Just a single hydraulic circuit on our cars, not dual-circuit, as has been around for about 50 years....?!

I have been told that Morgan is shipping a new wheel cylinder and brake shoes.

I had a bad wheel cylinder that would hang up the shoes, create heat, boil the fluid and result in loss of pedal.

I was assured at RTCC today they are dual circuit......

Is there a stainless option for the rear brake cylinders now? Think a rear one might of seized after about 4 years and was wondering if there is any better options now…

There is a company that will put you a stainless sleeve in them, it's on here somewhere, I just replace the fluid regularly and renew the cylinders when necessary it's a simple enough job and the cylinders are cheap too.

Exactly the stainless steel sleeve saves old cars whose parts do not exist.

Past Parts will refurbish old brake cylinders with stainless sleeves. I did get a quote from them but it seemed fearfully expensive to me. In the end, I decided just to use some red brake grease to keep the corrosion at bay.

Edit - I've just looked up the quote and actually it was £60 + VAT + shipping which I guess isn't too bad in retrospect. Problem is that you can get brand new ones off eBay for nearer to £10 all in.

Ok might just stick with the standard.

Many thanks

Past Parts as per Andy's link above are very good & turn work around in sensible timescales, excellent for brake components that are no longer available