Brake shoe lining thickness

[Howard Wright]

Hi All

I’m setting up semi Girling brakes on my Trials axle.  I inherited a box full of brake shoes, some with what look like new linings.  However the linings on these shoes are 3/16” thick and even with the adjusters pulled right back I can’t get the drum on.  Other brake shoes in my collection have linings that are about 1/8” thick (although they may be partially worn), these fit fine with minimal tightening of the adjuster.

So my question is what thickness should the brake linings be?  And is the thickness supposed to be the same on both Semi Girling and Austin brake shoes?

Cheers

Howard

[AustinWood]

Are you sure the cable isn't too short and is holding the brake slightly on?

[Howard Wright]

Hi Jim

Thanks 

I’ve got the axle off the car with the levers loose so I don’t think it’s that.  The adjusters are screwed right out.

Cheers

Howard

[Bob Culver]

The shoes vary and may have been built up. You might have the only set of drums not turned ovesize! Are the expanders in the correct slots? I have found the adjusters well out even with good drums and linings. maybe not with Sevens but I have seen many brake errors  due exchange shoes not exactly the same (hyd pistons popped out despite professional work etc) 3/16 is not thick.

[bystander]

Semi-Girling linings are definitely thinner than those on ali shoes, but I do not have any way of checking the actual thickness at the moment. Also any re-lining carried out in the recent past would likely be using metric sized material so may also deviate a little from the original.

["Slack Alice" Simon]

How worn are the drums?

There is often a lip around the outside edge which stops the drums fitting over new linings.

It isn't just wear, it seems to accumulate muck, can be filed off.

[Howard Wright]

Thanks Bob, Simon and bystander

I’ve cleaned the drums and run emery paper around them.  One is quite scored but the other quite good. Both are round (not oval). I intend to give the scored one a light skim.

This afternoon after some rubbing down with emery I’ve got the shoes to fit. I’m sure you should not need to take as much off as I have done.  I’ve decided to have some shoes professionally lined but am a bit anxious that I give the right dimensions to the lining firm.  

Thanks for your replies

Cheers

Howard

[Bob Culver]

The fancy profiling of the professional job may not be helpful as the shoes do not self centre as moderns and seating them to the fitted drums will likely still be necessary. With NOS particularly beware asbestos. And no doubt you know that old style lining material is critical for reasonable stopping and all been well covered here.

[Peter Naulls]

Howard,

I have a box of new semi-Girling linings which have come from various sources over the years. Most vary from 4.1mm to 4.3mm, one heavily textured set at 4.9mm. Please excuse the metric measurements but it looks as though yours are a bit on the thick side.

Peter.

[David Stepney]

I have recently relined the brakes on the RP. Even with the cables disconnected and the cams set parallel to the ends of the shoes, the linings still needed a certain amount of 'fettling' to get the drums to go on, even after I had cleaned the drums up.

The linings that came off were rope material.It was not that the linings were badly worn, but that someone in the past had fitted a couple of the rivets weirdly so that one side of the head was beginning to touch the drums. Although the brakes were adequate before, changing to more modern lining material has improved the brakes quite noticeably!