VERY firm and poor brakes

[jiminwatford]

I recently decided to get my 1965 Moggy on the road. I bought it a year ago on the spur of the moment as it seemed like an opportunity a)to own a Morris Minor and b) to maybe make some profit by selling it. The owner was retiring from driving and wanted it gone asap

So it sat in my garage and last week i tried to start it for the first time. That went well, the fuel pump needed some tickling and with a fresh battery and petrol it started right up

Everything seems more or less ok except for the brakes. Initially the pedal would not move at all beyond the play at the top of the pedal. Whilst watching the linkage and piston in the master cylinder i persuaded it to move i think around an inch or so. Enough anyway to actually stop the car

But they are still very poor. I mean sort of "are we going to stop in time" sort of poor. And the pedal is very firm. I can push with virtually all my might and it doesn't go down that far

It seems obvious that some of the wheel cylinders may be seized but i thought i would look further towards the the master cylinder itself. I don't want to start replacing and buying parts (like cylinders) if the problem is further up the system

How should i go about testing this situation? Would it help to upload a video showing the action on the master cylinder when i press the brake pedal?

There is plenty of fluid in the system. It stops in a straight line. It rolls freely when not applying the brakes. The handbrake works. I think front and back are working as i found some gravel and i'm fairly both ends locked up when braking

Short of taking it for an MOT (which i might do) and getting on their rollers how do test the efficiency of an individual brake?

For funsies here's a pic of the old girl

IMG_20260517_113635633_HDR1.jpg (144.48 KiB) Viewed 8297 times

[oliver90owner]

Your thoughts are inconsistent. Why, if you suspect something is wrong, would you be initially looking for a fault elsewhere? Somewhat like having no spark, so dismantling the carburettor to look for the problem!

[jiminwatford]

Could you elaborate on that, please?

If you're asking why am i looking at the master cylinder if i think there may be a seized wheel cylinder, well i've never encountered brakes such as this. Firm with little braking efficiency. Other people have suggested seized wheel cylinder which makes sense except (i would have thought) a single seized cylinder on say the front would create an imbalance towards the one which isn't seized. And if it was one of the rears and the fronts were fine it would still stop ok

Or, is it the case that if one wheel cylinder was seized it alone would stop the pedal depressing? I would have thought the system would 'ignore' that cylinder and still operate the others

Because i think it is unlikely all of the cylinders have seized but there is no imbalance during braking i thought the fault may be with the master cylinder giving universal yet insufficient braking to all four wheels

[Bill_qaz]

Why not remove the drums clean out any rust or dust.
Visually check wheel cylinders for movement and leaks.
Adjust brakes.
Have you lubricated the mastercylinder linkage?

[simmitc]

Bill has written exactly what I was going to suggest. When sitting unused, particularly if the handbrake was left on, then the wheel cylinders do tend to seize. Front wheels have two cylinders each, so one failed on each side would give straight line poor braking. Brake and clutch pedals share the same shaft and can seize. Rusty drums can inhibit braking. Basically, service/clean/adjust all wheel cylinders/drums and lubricate pedal linkage. Visually inspect all components. Simple home tests like jacking and supporting a wheel off the ground, spinning it and then applying brakes can sometime show where problems lie. A good garage will run a brake test without an MOT, but is it safe to drive there?

[jiminwatford]

Of course you're both right, a problem i have at the moment is that i can't get to the car and when i do i'm not sure how long i will have with it to work on it

A day of tinkering and experimenting is what i would like to do but if i only have that one day i thought posting above may lead some to conclude it was more likely the master cylinder than anything else

I think it is this sense i have of it being a universal problem to all four wheels rather than an imbalance

If the consensus is ;you really don't know until you start looking' then that is what i'll have to do

I may get a video showing the pedal / linkage operation to see if that gives any clues to its correct functionality / condition

Thanks

[Bill_qaz]

Its highly unlikely in my experience for a master cylinder giving a hard pedal and locking all 4 wheels as you stated to be defective.
Usually the opposite spongy pedal or excessive travel.
Could it be just the brake pedal feel you are not used to, are you coming from a modern car with brake assistance.
If you have limited time jack up the wheels and wedge a piece of wood from the brake pedal to the seat frame to hold the brake applied. Can you turn the wheels if not then its working . Do they all release when wood is removed.
Lubrication of the brake pedal and linkage to reduce friction is the only other thing that can effect pedal feel.
Does the pedal return freely. Does the clutch move with the brake pedal or vice versa?

[jiminwatford]

Thanks

I am coming from a modern car but my first Mini had drum brakes and i'm pretty sure it stopped better than this. I think part of the symptoms are the pedal doesn't modulate. Even though i'm pressing very hard it doesn't seem to increase the braking

The pedal moves back freely and the clutch pedal does not seem affected by its movement. However, when i first tried the brakes they did not work at at all and the pedal did stay partially down as i noticed the brake lights on when i got out of the car. But with some pressing of the pedal it loosened up to the point that the brakes worked just in a limited sense

I think i'll get a video of the pedal action which i think will show the pedals aren't seized but there is limited piston movement in the master cylinder

Hopefully at the same time i can do some investigating on the individual wheels or take it to the MOT man and see if he wouldn't mind doing a brake test

Thank for the replies. I'll hopefully update this in a week or two

[jiminwatford]

I'm with the car now. Before moving onto the brakes themselves I thought I would upload to these two videos

What I think they show is that the pedals aren't seized and move independently of each other. Also the brake pedal seems to return ok. They also show how much depression of the pedal I am achieving

I thought if I was wrong in that (that maybe the problem is at the pedal) someone might point it out before I spend too long taking the brakes apart if I don't need to

https://youtube.com/shorts/aivY9Ohm8o0?feature=share
https://youtube.com/shorts/M_KEzW1hl4c?feature=share

[neilmorey]

Unless it has been modified the brake switch works on pressure in the brake lines rather than the movement of the pedal like most cars. If the brake lights stay on it suggests there is pressure remaining in the system once the pedal is released. That could be collapsed/ swollen Flexi hoses.

If the car is parked up with handbrake on for a long period of time there is a strong chance a rear cylinder has seized. on but would expect you'd notice that when driving away?

Have you checked the fluid level? If full it might be worth opening a bleed valve in turn to see if you can push fluid through the system.

A few things to check.
Fluid level
Leaks/ seized wheel cylinders
Condction of Flexi hoses (3 on minor)
Master cylinder rod adjustment.
Master cylinder seals.

Hopefully it's an easy one to trace.

[jiminwatford]

Thank you!

Just jacking the car up now so can test the nipples and see if I can some flow to come to through

[Bill_qaz]

The brake pedal travel to a firm pedal position looks perfectly normal in my opinion.
Needs some lubrication on pivot, clevis and return spring, probably rust from standing, this maybe part of the initial issue of pedal not moving. It doesn't appear hydraulic as you say the wheels locked on gravel.

[jiminwatford]

I progressed a little. Got the car off the ground and placed a piece of wood between the seat and brake pedal

The fronts locked up but the rears didn't. They still ran free. The handbrake works well btw (i don't yet know how the handbrake interacts with the cylinder meaning you can have seized cylinders but a good handbrake)

I took the drum off and pressed the pedal. No signs of movement
https://youtu.be/kolTUJNkiGU

I thought if i took the bleed nipple out and pressed the pedal fluid might come out. But it didn't

I thought maybe the flexi was blocked so i disconnected that wheel's metal pipe from the flexi and pressed the pedal. This time fluid came out of the t-piece and the pedal went to the floor. So it seems fluid is getting down the flexi ok

The metal line from there to the banjo looks in good condition. Fairly new i'd say

So it looks like the cylinder is seized. The part which is confusing me is why fluid didn't come out of the open nipple

I have ordered two cylinders and tomorrow i will remove the existing ones ready for the new install. Whilst they're out i may see if i can jolt the old ones into life. Not sure how i'll do that yet

[Bill_qaz]

Progress
Be aware the rear cylinder needs to slide in the back plate as a single piston.

[jiminwatford]

Sorry, do you mean that when it's fitted it needs to slide up and down? I've seen people putting copper grease behind the cylinder on the backplate presumably to help with that?

[Bill_qaz]

Yes it pushes against one shoe then slides to push the other, so yes small amount between cylinder and backplate.

Bit confusing trying to suggest solution because you previously stated

"I think front and back are working as i found some gravel and i'm fairly both ends locked up when braking"

Take a look at this video, 'morris minor changing rear wheel cylinder' https://share.google/hOV3X4QUiRpMOWYls

It may help you, there are several on YT

[jiminwatford]

Yes i'm confused by what i thought was front and rear locking up. That was after i had been driving quite a bit and maybe with longer use the rear start to work a little. I'm not sure. even though it's £50 i'd rather not spend i think i'm doing the right thing replacing the cylinders

Any thoughts on why fluid didn't come out with open nipple? I'm not really concerned as hopefully the new cylinder will solve things. It just seems a bit odd. Tomorrow i'll take the banjo and brake line off and make sure fluid flows through them

Thank for the link

[Bill_qaz]

Did you take out the bleed nipple completely ?
Possible there is corrosion in the banjo it screws into. Brake fluid is hygroscopic so you may have a rust build up.
When you fit the cylinder make sure banjo and the nipple are clean and allow fluid to gravity feed 1st, before pressure bleeding.
Use new copper washers.

[jiminwatford]

Cool. Thank you

Yes i removed it completely. We'll get it sorted i'm sure

[jiminwatford]

Problem is somewhat fixed. Rear cylinders replaced and all brakes bled

Pedal is a lot more progressive and it stops sharper. It could do with another round of bleeding as they take a little pumping and the pedal can go all the way to the floor sometimes. So obviously not really sorted but it's better

Thanks for all the advice above. i quite enjoyed working on the car and learning how it went together. I've never worked on drum brakes before and i am quite pleased i managed to get them back together and working (kind of )