Rear drum brakes

[Steve55]

My 1000 has just failed the MOT on equalisation of the rear brakes? The bloke said maybe a lazy cyllinder? Has anybody had this problem, and how do l make sure thay are equal??? Is it just adjustment or is there more to it?

[Cam]

Make sure all the brakes are free (not sticking). If the cylinders are fine then there should be no problem (assuming they are adjusted correctly). If it's a sticking cylinder, then it's best to replace it. They are not too expensive and to ensure a good balance, replace the other side at the same time.

[rayofleamington]

the rear brake cylinders are meant to slide on the backplate as it's a single-ended piston design.
There is a second piece to the piston operated by the handbrake, so if the cable is over adjusted, this can cause poor efficiency. (slack off the cable, re-adjust the shoe adjusters, then re adjust the cable.)
Brake balance is also affected by the shoes and the drums so if you can't find any mechanical issue you could try swapping the brake shoes from one side to the other - then see what the brake readings are.
If it is the shoes that cause the problems, then you need a new set, however as the new shoes seem to be badly made you need to do a good few hundred miles to bed them in - otherwise the brakes will be poor and you still fail the MOT (ie it's best not to change brake shoes just before an MOT)
You may also have a faulty drum, causing one side to grab, giving a higher reading than the other.

Therefore there's quite a few things to check!
My traveller failed on front brake balance in April and I needed to change the shoes around to get it to pass - however I'd done a day of work checking the pistons etc.. before realising that I was going in the wrong direction.

[Steve55]

THanks guys, l'll go and mess about woth the pads and adjustment first and give it a go.

[bmcecosse]

Errr - there are no 'pads' ! Could be a wheel cylinder has leaked fluid, or the half-shaft seal is leaking oil into the drum. If so - the cure is obvious - but you will need new shoes - it's impossible to recover oily shoes. Was the imbalance on the foot brake reading - or on the handbrake reading - or both ?

[Steve55]

Now passed. I adjusted the shoes (not pads, oops) and that was about it. Thanks for all your help.

[bmcecosse]

I guess it was the handbrake then !