strange brake problem on willma, aka nobby-

[nslocomotive2]

Ok the pedal is soft and travels further on first application, second press the pedal returns to its usual hardness. This lends me to believe a leak in the system somewhere.

The system is standard, apart form a reservoir mod and marina disks on the front. I'm considering fitting a servo at a latter date.

I have so far gone round the front and checked hoses pipe-work and opened up the rear drum on the drivers side to check the cylinder isn't leaking, the whole system works really well and the car does stop. I have only the passenger rear drum left to open up and check but it looks as though on the outside it isn't gonna yeald an answer.

Although I notice under the driver-side where the master cylinder is located, the oily grunge on the underside looks a bit more wetter than the rest of the car so I'm planning on opening up the floor to take a look at the thing.

Any thoughts as to what might be causing this problem.

Obviously im not driving her at the moment and its driving me mad because I have a week off this week and would like to be taking her out for a run and blow some cobwebs off her at some point.

[Stig]

Ok the pedal is soft and travels further on first application, second press the pedal returns to its usual hardness.

Sounds like there's air in the system and it just needs bleeding.

[mike.perry]

Still got the same problem with mine, not as bad as it was but have not managed to clear it completely. Tried the gravity feed bleeding method the other day, one push on the brake pedal and a cup of tea and it worked fine.
One thing worth checking is the condition of the flexible hoses. When the get old they can expand under pressure so the first push on the brake pedal expands the flexible hose, the second applies the brakes.

[kennatt]

hard pedal on the second or third push is 99% caused by poor adjustment of the brakes ,not air in the system(Allthough it can imitate the same fault)If the brake shoes are not in close contact with the drums it takes two of three pushes to get them there then you get a good pedal,Air in the system causes soft brakes at any push.One way to check without stripping everything down,(Allthough some will say it causes damage Its never damaged any that I have tried)clamp up the flexible hoses one at a time Obviously two at the front and one at the rear.Use mole grips and spread the load of the jaws with something say two ten pence pieces.Do one at a time and try the pedal you will isolate with wheel is causing the trouble, bet you the two 10ps that it's brake adjustment

[nslocomotive2]

well I've checked the adjustment on the two rear drums, on the font I have disks, so adjustment isn't an issue. Im gonna go with the idea of bleeding the brakes, I like the idea of the gravity bleed system, whats the difference to just getting someone to wap their foot on the pedal???

[alex_holden]

It could also be a faulty master cylinder. If the seals are starting to fail they sometimes don't work properly on the first push but 'catch' the second time.

[Judge]

Although I notice under the driver-side where the master cylinder is located, the oily grunge on the underside looks a bit more wetter than the rest of the car so I'm planning on opening up the floor to take a look at the thing.

In view of this, I'm inclined to agree with Alex.

[bmcecosse]

If there is any play in the front wheel bearings - that will push your pads away from the discs when the wheel turns - and give a 'long' pedal. To get the rear brakes correctly adjusted - you should first loosen off the handbrake cables, then adjust the shoes up so they are 'just' rubbing - then re-adjust the handbrake cables to put the lever where you like it, ie 2, 3 or 4 clicks. Were the discs already on the car when you got it ? Do you know if the master cylinder seals have been modified (by removal of 'top hat' seal) to suit the disc brakes ?

[nslocomotive2]

ok, Ive adjusted the rear drums, with the handbrake off, and set them so that the adjusters where right tight, then ran them back a few clicks, so that the wheel turned but you could just hear the shoes rubbing on the drum. the hand brale is now miles better with just 3 clicks, however the pedal is now harder as you would expect, but the problem is still there, I notice though it dosent seam to happen when the car is stood still, so this could be the wheel bearing issue you describe. The disks were fitted before I had the car so I couldn't say about the internals of the Mater cylinder, and I don't really feel confident to start poking around inside it yet. I wonder if swapping it out for a new one would eliminate it from the whole thing. Mind you if I was to clamp up the hoses I could eliminate the master cylinder by clamping all three hoses, as this should give me no travel in the pedal.

[mike.perry]

If you have disc brakes and change the master cylinder I believe there is a seal which everyone keeps talking about which needs removing. I haven't got discs so I don't know which seal.

[nslocomotive2]

hmm indeed, I will be taking another look tomorrow and I will keep pressing away until i get to the root cause, I would rather do the clamping and see if i still get some travel in the pedal, because if its solid then I need not disturb said item, as its a bugger to get in and out so I've heard.

[PSL184]

When backing off the adjusters just one click back is required, not a few ;-)

[nslocomotive2]

ok will give it another try spot the new morris driver

[bmcecosse]

Yes - the rear brakes need to be pretty tight. To check front wheel bearings - jack the wheel off the ground and try to move it in a vertical plane ! If it moves - get someone to watch behind to determine if the movement is in the bearings - or in the king(swivel) pin. Some of the disc brake kits I believe use an Al alloy hub - which sometimes develops slack around the bearings! Any movement will push the pads back - and yes that only happens when the car is moving. It will be ok if not moving. New master cylinder would have to be modified if to be used with discs. But i'm sure it won't be the master cylinder - many of these are renewed needlessly!

[Kevin]

The system is standard, apart form a reservoir mod and marina disks on the front.
Any thoughts as to what might be causing this problem.

One thing not mentioned so far is the reservior the type mounted on the inner wing as some types have an inferior plastic outlet that can fracture and often use a plastic type of pipe that is often prone to weeping so check this out as well.

[jonathon]

If the M/C had not been modified then the brakes would be locking on. Make sure that the top cap on the M/C has been blanked off correctly. We have just had a Minor in for work that had been modified by a well known specialist who had left the old cap in place, hence poor brakes, a chassis leg full of fliud and a sodden carpet.
I'd try the adjusting rod on the end of the brake pedal, see how far in it has been adjusted, too far in and it can lock the brakes too far out and you will need to pump the brakes up.
However if you have a fluid leak at the M/c then either a seal is faulty or the caps/unions are incorrect or loose. If you have the header tank with the black flexi pipework, check that this is not weeping, or split where it feeds into the rear cap.

[bmcecosse]

" We have just had a Minor in for work that had been modified by a well known specialist who had left the old cap in place ........ "
Sadly typical I suspect!!

[jonathon]

Well I'd hope not, but it was a bit of an oversight to say the least.

[nslocomotive2]

well I know this master cylinder has a cap in place on the top, but I haven't yet managed to get all the botched screws out of the floor to get the panel off, gonna get the drill out this morning then have a proper look around. It has a plastic pipe from the resi mounted on the bulkhead near the old regulator i think this could be a possible suspect for fluid leakage, but Im not sure it would explain my pedal issue.

This suggests that there may be an issue with the conversion, the brakes are not locking on, so I think the seal jobby has probably been done, I'm gonna keep going, I've learnt loads about all this in the past few days, and I'm enjoying it, this one aint gonna get the better of me.

Any how I have lots of thoughts and ideas to work with today, thanks guys, Ill see how i get on.

[kennatt]

if the problem is with the car on the move it could be that the disks or disk is warped slightly this then taps back the pads into the clipers so they are not in close proximity to the disk then same as poor adjustment needs a push to get them out to the disk before hard pedal. Can you feel a slight up and down pedal movement when you apply the brakes Classic sign of a warped disk Good luck