solid brake pedal

[cococola]

My 63 convertible having returned to the road recently has developed a problem today.
Roadtest the car no problems until I reversed and went to drive off again where I find there appears to be the brakes locked on?
1.pedal is solid with no travel whatsoever.
2.rear brake lights staying on (of course)
I felt the hub caps and both fronts are warm, rears are not.
Can anybody point me in a direction to fo please, Im wondering seized cylinders although Im maybe unlucky having both front wheels warm or brake master cylinder?

[ManyMinors]

Have you worked on the car recently - or had work done? Did you have the correct free travel at the brake pedal in the first place?

[Boomlander]

Quite possibly seized cylinders, especially if you have not used the car for a while.
I had the same problem with my old series 2. Had to back the adjusters right off and then tap the drums off with a wooden mallet.
Ended up renewing the cylinders, springs and shoes.

[kennatt]

don't think siezed cylinders would leave brake lights on,since they wouldn't be pressurizing the system, the brake lights work via a pressure switch,so even if stuck cylinders as soon as you take your foot of brake the lights would go out ,so... stuck brake pedal,or M cylinder,Have you tried pulling the pedal back up.

[geoberni]

My 63 convertible having returned to the road recently has developed a problem today.
Roadtest the car no problems until I reversed and went to drive off again where I find there appears to be the brakes locked on?
1.pedal is solid with no travel whatsoever.
2.rear brake lights staying on (of course)
I felt the hub caps and both fronts are warm, rears are not.
Can anybody point me in a direction to fo please, Im wondering seized cylinders although Im maybe unlucky having both front wheels warm or brake master cylinder?

I don't get some of this.

1 - Is the pedal fully up with no travel?
2 - Brake Lights staying on (of course) ..... that's not by any means an 'of course'. If the wheel cylinders were seized, that doesn't make the Lights stay on, that's entirely down to the system being pressurised.
Just from that comment about the Brake Lights, I'm thinking the system has retained pressure somehow.

Are they standard brakes? Some 6 months back you were talking about Brake problems.
What have you been doing to the brakes since then?

[Sleeper]

Do you have a servo fitted?
Have you removed the " hat" thing from the master cylinder?
Pedal solid in up or down position?

Johnn ;-)

[panky]

If you do have a servo a leaking air valve can cause this issue. Easy way to test is to remove the vacuum connection to the manifold, block it off on the manifold side and see if the brakes still jam on. Obviously you won't have any servo assistance to take care and allow for having to push harder on the pedal.

[ManyMinors]

Do you have a servo fitted?
Have you removed the " hat" thing from the master cylinder?
Pedal solid in up or down position?

Johnn ;-)

Removing the "hat thing" from the master cylinder has nothing to do with the fitting of a servo. It is necessary when converting to disc brakes.

If the brakes have been modified from standard then obviously we should be told of that..........

[cococola]

Many thanks to replies, I have answers to queries asked...

1 - Is the pedal fully up with no travel?..yes fully up and no travel
2 - Have you tried pulling the pedal back up...as above
Are they standard brakes? Some 6 months back you were talking about Brake problems...standard brakes and this is another vehicle to the Morris of 6 months ago.
What have you been doing to the brakes since then?...no work has been carried out on the brakes that Iam aware of
Do you have a servo fitted?...no servo fitted
Pedal solid in up or down position?....up position
If the brakes have been modified from standard then obviously we should be told of that...correct no modified brakes

[les]

I think I’d start by removing the master cylinder cover to see what’s stopping the pedal from moving.

[Mick Lynch]

I think I’d start by removing the master cylinder cover to see what’s stopping the pedal from moving.

Yep, check for blocked vent hole in cap preventing pressure release
Have any of the pipes taken a hit and flattened
Collapsed hose

Jack up car, are only the front binding (the pressure switch circuit) or all?

[Sleeper]

I'll guess seized master cylinder piston.
Next guess seized brake pedal pivot.

John ;-)

[kennatt]

you can easily check for pressure retention,which if the brake light is on,then thats what it is , just crack open one of the bleed nipples. if it squirts fluid instead of just a dribble and the brakes free up then you know where to look. M cylinder or pedal pivot.

[cococola]

After the car had stood overnight the brake lights were not stuck on as before so I have carried out another road test to cause the fault to return. On returning to my garage the problem was back so I continued to the suggested checks on here..

Master cylinder cap is all okay and venting, I removed and refitted with no pressure change on pedal or brakes.
Brake pipes and hoses checked all round and no damaged or squashed pipes.
The front wheels are the only ones that are not free moving now particularly the lhf...rears are free and fine.
Brake pedal pivot is free as is the return spring after removing cover on floor.

The brakes were stuck on along with the brake lights again so by jacking the front wheels I removed the left front brake drum by loosening off the adjuster screw which in turn,caused the brake lights to go out and the brake pedal travel has now returned from having previously no movement in the pedal at all. Iam now at the next suggestion stage as would I be correct in saying that the fault area is from the lhf brakes?
Another point of interest is that the wheel cylinders have been replaced as new all around the car by the previous owner.

I've tried to explain as clear as I can so for some,please bear with me if descriptions aren't as clear as I try to make them.
many thanks

[cococola]

Just to add to my previous message.. I have attached photos of the wheel cylinders. I cant refit the drum on as it is as I pushed the brake pedal with my hand so I will have to push back the cylinder.

[Mick Lynch]

Something in your system is behaving as a non-return valve

I had something similar on an Austin A55 clutch whereas you pressed the clutch, it didn’t disengage on pedal release bit took minutes. The hose to the slave cylinder had collapsed and was not letting the pressure return to the clutch master.

I would slacken your bleeder on the cylinder that is all out. If it returns by the pressure of the springs then I’d bet your LH front hose has collapsed internally.

In any case when a cylinder has nearly popped out the bore like that it’s best to bleed that line.

[paul 300358]

As your likely to be bleeding the brakes, it may be worth checking the condition of the rear flexible hose, they have been known to perish inside which causes a blockage and has been reported to act as a one way valve, as pointed out above.

[jagnut66]

As above, replace all your hoses (x3 -- links below), they're cheap enough (so no sense in renewing just one when they could all be of the same vintage) and they do collapse internally over time when using standard Dot 4 brake fluid.
Bleed the system through completely, thus renewing the fluid (as Dot 4 degrades over time as well**).
Then let us know.
Best wishes,
Mike.
https://www.morrisminorspares.com/brake ... le-p829350
https://www.morrisminorspares.com/brake ... ut-p829351
https://www.morrisminorspares.com/brake ... se-p829352

** Silicone brake fluid (Dot 5) is the answer but that's a post in itself......

[Sleeper]

Do you have the required amount of free play in the master cylinder push-rod?

John ;-)

[kennatt]

if only one wheel is sticking it could be that side brake flexy is delaminating and acting as a non return valve,but I'm not really sure that that would pressurise the whole system to switch the light on,or hold the pedal hard,however I suppose it could eliminate all the adjustment on that side and mean that the pedal was hard with no movement, but still can't see how it would hold enough pressure in the system to switch the light on since the pressure is after the light switch between the hose and cylinder not in the rest of the system .Again crack open the bleed nipple on that side and see it there is pressure in the cylinder. It could also be a fault in the brake light pressure switch but again can't see how. Slowly undo the switch from the union and see if the brakes free off,if you do it slowly usually no air gets into the system(obviously after putting the drum back on.don't press the brake again before this or the piston will fall out and bleeding will be required)If you can't get the piston back in by hand again just slacken the nipple then when you push the piston back in you will eliminate air entry as the fluid is being forced out, bit of a puzzle .