Morris Minor Owners Club

I have seen others have the same problem of running out of snail adjuster adjustment while still having brake lining left. After searching and finding no definitive answer I have gathered some information which may be helpful.
Austin Seven with hydraulic brakes using Morris Minor modified backplates
I have Morris Minor backplates with offset in middle modified to fit Austin 7 axles (to all intense and purposes this equates to Morris Minor equipment). The Austin drums are also 7 inch diameter and take the 1.5 inch wide MM shoes acting on cast iron drums. I have always had the problem of running out of adjustment to take up wear while still having plenty of lining left on the shoes. I have seen on the MM forum that several MM owners have had the same problem.
On each side of the MM there is one adjuster snail at the back and 2 adjusters at the front. I understand that the rear adjuster is larger because it has to take up wear on 2 shoes whereas the front 2 smaller adjusters each only have to take up wear on 1 shoe each.
I found my rears had 17 notches and fronts had 15.
The adjuster for the later 8 inch brakes is larger again.
Part of solving the problem was to use the larger rear snails on the front.
I have also found that the 8 inch adjusters have the same width mask (the bit the snail sits in) so fits on the cylinder and can be used to take up even more wear where drums have been skimmed. The slot on the end of the brake shoe has to be opened out slightly back to front, but no need on depth, because the 7 inch adjusters have a spindle diameter of 6.2mm while the 8 inch is 8.78mm.
Table of measurement between base of mask and snail spindle on turning notch to notch. All measurements in millimetres

ADJUSTER MINIMUM 1 4 8 12 MAX No of notches at max
7 inch front (small) 10.66 12.25 14.11 16.07 17.11 15
7 inch rear (medium) 10.35 12.06 14.30 16.64 19.54 17
8 inch (large) 13.96 15.50 18.18 20.60 22.48 15 (14 = 21.94)

left to right - 8 inch, large rear, small front Dennis

Will try again to get photos to show up

Different snails front and back for 7' drums?

That's a new one for me!

Don

Me too. They all look the same on my earlier car.
The only time I have had problems with the rear brakes running out of adjustment was when I purchased new (Borg and Beck) shoes. I welded a shim onto the bottom of the adjuster mask and got over the problem but the new shoes were an incorrect size.

Its easy if you have a mig welder,one stroke of the mig on the round side tip of the brake shoe and a quench to keep the heat off the linings then file or grind the tip smooth . Makes the shoe longer so more adjustment at the cylinder end.

Its easy if you have a mig welder,one stroke of the mig on the round side tip of the brake shoe and a quench to keep the heat off the linings then file or grind the tip smooth . Makes the shoe longer so more adjustment at the cylinder end.

I just checked -- ESM only lists one design for 7" drums.

Don

one stoke of a mig on the fixed tip of the shoe and quench to keep the heat off the linings,file the end smooth, makes the shoe slightly longer and gives more adjustment at the cylinder end.

The posts are getting repeated several times.
The posts are getting repeated several times.
The posts are getting repeated several times

But seriously...
I used a shim under the mask similar to MM above. However I bent it in a U shape so that it locked to the mask. So no welding was involved. Welding would no doubt provide an extra margin of safety.

Don

My reaction to this is.... WHAT!?

I don't follow the original post argument, reference the 3 adjusters shown.
This statement is incorrect.

left to right - 8 inch, large rear, small front

I believe that shows: New Oversize 8", New (with a very rough casting) 7", and original MOWG 7"

The Standard adjusters for 7" and 8" brakes are the same size cam. I posted about this on here a few weeks ago in answer to an earlier question about Cams: viewtopic.php?p=676706#p676706
I wasn't sad enough at the time of working on my brakes to count the notches, I just knew that they shouldn't be the same on my car which had been fitted with replacement, donated 8" fronts; but the cams are the same size, it's just the diameter of the shaft that's different.


I believe the nice shiny 'larger cam' that Dennis has identified as being for the 8" is actually the deliberately OVERSIZE Cam offered by ESM for Skimmed brakes. https://www.morrisminorspares.com/brake ... s-p1238194

The standard 8" adjuster cam is only available second-hand. These oversize cams are deigned for use with skimmed drums to return the normal range of adjustment. At the lowest adjustment setting they are 1/8" taller. To use with standard drums and new shoes you may need to slot the brake shoes to allow the drum to fit over.The actual snail cams don`t usually wear out, they are not meant to be sharp ! The retaining mask FBK111 is more likely to need replacing.

In the original MMOC part List there were different part numbers for the adjusters, Front and Rear, when the brakes were all 7", perhaps that accounts for the different number of teeth that Dennis has observed, but the masks were the same.
Here' s the Parts List details from AKD341 in one image, Top are the Rear Adjusters, Front below.
The actual Adjuster Cam was never the identical Pt no front and rear. ....