7 inch to 8 inch brake conversion?

[greg78]

Hello, Brand spanking new to the forum so here goes...

I've recently bought a 1957 4 door morris minor and after openning up the front brakes for servicing I measured the drums and noticed they were 8" diameter. I was under the impression that early cars like mine should have had 7" drums front and back is that correct? If so, then I presume someone in the past has converted it/upgraded it! The brake performance is still pretty lousy (I'm used to old cars so not expecting it to perform to modern standards) so my question is this.....when you carry out the 7" to 8" conversion, are there different wheel cylinders that need changing to go with it? I'm thinkng possibly someone has swapped the backplates,shoes and drums but maybe kept the original cylinders - could this account for the poor performance?

Any answers or advise would be greatly appreciated,
thanks

[aupickup]

keep the 8 "
cylinders are the same except the very early mm models
try mintex shoes as you may have the crap pattern ones

[bmcecosse]

Make sure the pistons are all free! And as above - try to source some decent quality shoes. And yes - same cylinders. The brakes should lock the wheels quite easily! Which is as good as you can get...........

[greg78]

Thanks for the replies, it's good to know the cylinders are all the same. Pistons are all free and everything actually seems in good condition - apart from not slowing the car down very well! I'll take your advice and get some quality branded shoes.

If that doesn't work then I might have to look at a disc conversion?
Thanks again.

[bmcecosse]

Make sure the rear brakes are working - they do a surprising amount of the braking too. Are the front wheels locking when you push hard ?

[greg78]

No, they won't lock up no matter how hard I press! Are there different grades of shoe linings? Not in terms of quality but actual material type? Maybe the ones fitted are too hard.

[bmcecosse]

Is it possible the backplates have been fitted to the wrong sides of the car? This would give 'twin trailing shoe' braking - which would indeed be hopeless.