Pattern cylinders too small?

Post by **winger300** » Fri Mar 25, 2005 1:32 pm

I recently replaced all four front wheel cylinders, and shoes.

It seems as though the new cylinders are too small, as its not possible to lock the drum, even with the cam adjusters turned all the way up. I've checked the position of the cylinders on the backplate, and they are as high as they will go. On driving like this there is too much pedal travel.

Any ideas?

Post by **rayofleamington** » Fri Mar 25, 2005 2:52 pm

are you sure that the adjusters can turn fully? it is very common for the adjuster to get caught on the shoe when it turns half way, therefore you can't adjust it properly.
However - it still sounds poor as you need the adjustment for when the linings wear!

Post by **winger300** » Fri Mar 25, 2005 4:05 pm

yeah, they turn to the top and then right over, so i know its not getting stuck half way.

I can't understand why they dont bind on the drum.

Post by **rayofleamington** » Fri Mar 25, 2005 4:46 pm

Are the shoes also different to the old ones?
If they are slightly smaller that will add to your problems a lot! Normally new shoes should be close to the drum on first assembly - and some times I had to trim the steel on the end of the shoe a little just to get the drum back on!

and as for

I've checked the position of the cylinders on the backplate, and they are as high as they will go

you shouldn't have any adjustment of the cylinder on the backplate at the front - only at the rear so I'm not really sure what you mean.

Post by **winger300** » Fri Mar 25, 2005 5:15 pm

well, the slot in the backplate is a little larger than the cylinder itself, so it can move maybe a mm or so.

I did replace the shoes for new ones. I've put the old ones back and its much better. So it appears the new shoes are smaller than they should be. They are certainly 8" not 7". How disturbing!

Post by **bmcecosse** » Fri Mar 25, 2005 7:54 pm

You can make little spacer strips of metal to fit over the back of each cylinder - and so take up the slack. If you don't do this then the shoes are not really concentric with the drum - and only the edge of the shoe - at the moving end of the cylinder - will be contacting the drum. Poor design really. The little spacers help considerably - and there is no risk - they are securely trapped in place by the shoes.

Post by **Willie** » Fri Mar 25, 2005 7:59 pm

WINGER...it should be easy enough to compare the original shoes
with the replacements to identify the differences? Either way they
are obviously NOT suitable replacements because the originals perform as they should do, so they should be returned to
the 'specialist'!!! who supplied them.

Post by **rayofleamington** » Fri Mar 25, 2005 9:45 pm

I did replace the shoes for new ones. I've put the old ones back and its much better. So it appears the new shoes are smaller than they should be.

Same recommendation as Willie to return them to the supplier (UK consumer law means they have to give you a full refund if the parts are not fit for purpose)

Post by **bmcecosse** » Sat Mar 26, 2005 9:27 pm

I agree - the new shoes should fit straight out the box. But have the drums maybe been skimmed at some time - and the 'original' shoes modified to suit ?