Possible fault?.......

[Handy]

Hi all,
I have noticed that the first time I use my brakes,after my Moggy has stood for a few hours, the pedal almost goes down to the floor but the brakes work. The brakes are then fine with the usual amount of pedal travel.
I can only assume that it's something related to expansion and contraction as the brakes warm up then cool down when standing??

Is this normal??

Thanks,
Ian

[Cam]

Hi Ian, that sounds like air in the system. It's compressing after the first 'pump' and then remaining so until it's left for a while whereby it decompresses.

If I were you, I'd adjust the brakes (with the brake adjusters), then fully bleed the system to see if you get any air out.

If this has just happened then you could well have a leak somewhere or a duff master cylinder. Check round for leaks!

[rayofleamington]

It does sound like brake adjusters to be honest - and maybe some of your pistons are not fully returning under spring force.
Therefore a good look with the drums off whilst someone else presses the pedal should give you an idea if the pistons are slow to come back (they should come back quick).
Also make sure that the other person only presses the pedal once - a few presses will push the pistons all the way out!!!

[lowedb]

An over adjusted master cylinder (to try to cure a leak, or instead of adjusting the brakes at the wheels) could also be at fault. Check if the brake lights are staying on!

Has it done this since you had the car, or just started?

[Handy]

Hi,
It's always done it.I've only owned it for 2 months though.

Thanks for your replies.
Ian

[bmcecosse]

The brakes are just needing adjusted up. When the car lies for a time the brakes fully retract - but when they are in use there is a slight residual pressure in the system (on purpose, held there by the master cylinder) which holds all the little brake pistons 'just not quite touching' the drums - in other words they are pushed back just a little by the slight out-of-roundness of the drums. So when they are like that - they are ready for instant action. If you adjust all the cams up properly you will minimise this long travel effect first thing in the morning.

[lowedb]

which holds all the little brake pistons 'just not quite touching' the drums

surely thtat's what the adjusters are there for?

[Cam]

If I were you, I'd adjust the brakes (with the brake adjusters), then fully bleed the system to see if you get any air out.

Best bet is to check the adjustment, then if no go, bleed the system.

[bmcecosse]

Yes -exactly - that's what the adjusters are for - hence my advice to adjust up the brakes ! But Morris built-in the little pressure holding valve to save owners having to keep adjusting their brakes every 10 minutes. Eventually it becomes obvious thet a good old adjust-up is needed to sort out the long travel first thing.

[Willie]

If the brakes work ok but with a long pedal travel which improves if
you pump the pedal then the shoes are too far away from the drums!
As BMC ecosse says adjust the brakes! If the pedal feels 'spongey'
then it should continue to feel spongey when you pump the pedal because
spongey means air in the system.