Minimum Friction Lining Thickness

Post by **Pyoor_Kate** » Thu Oct 20, 2005 7:17 pm

Okay,

Anyone know the minimum friction lining thickness for the rear shoes on standard drums for a 1098cc minor?

Only, mine have got 3mm, and the adjuster's run out, so I'm wondering if my drums are, in fact, so worn as to be meaning I'm ditching brake-shoes early...

Post by **rayofleamington** » Thu Oct 20, 2005 7:20 pm

The shoes originally had rivets, so you would be getting close to the rivet heads by now?

Post by **Chris Morley** » Thu Oct 20, 2005 7:27 pm

I seem to recall the figure of 4mm in a manual, not sure whether this referred to front or rears though. I think it's time for a new set!

Post by **bigginger** » Thu Oct 20, 2005 8:00 pm

None of my manuals (including the proper official Workshop manual) commit to any particular figure, thay just say "When the linings are worn replace them"

and then tell you how to rivet new ones on... If they're worn enough for you to worry about them, it's probably replacement time.

Post by **Cam** » Thu Oct 20, 2005 8:30 pm

But also check the drum internal diameter too as if that's too worn then you will be increasing the 'reach' of the shoes past what they should be as you say.

I have never checked but I would assume minimum lining thickness and drum I/D would be listed in the workshop manuals?

Post by **bigginger** » Thu Oct 20, 2005 9:31 pm

Not that I can find

Post by **Pyoor_Kate** » Fri Oct 21, 2005 7:37 am

But also check the drum internal diameter too as if that's too worn then you will be increasing the 'reach' of the shoes past what they should be as you say.

This is what I was wonderibg, but I guess 3mm might be rather less than is expected on cars... I've only (really) done drum brakes on my bike and 3mm there is a hell-of-a-lot

The shoes originally had rivets, so you would be getting close to the rivet heads by now?

That's quite possibly true, actually. Bleh, should have looked more closely, but didn't want to get rained on again... I saved that for when I was down at Andrews - who now has a lot more sympathy from me for his restoring a car in mud and gravel location

I have never checked but I would assume minimum lining thickness and drum I/D would be listed in the workshop manuals?

I couldn't find it in the Haynes one or the offical BMC workshop one :/

Okey dokey, I shall check the drum diameter and probably order some nice shiny new shoes then

Post by **Multiphonikks** » Fri Oct 21, 2005 7:39 am

Great - then we can do two sets of brakes in a week then

Post by **Cam** » Fri Oct 21, 2005 4:40 pm

I have never checked but I would assume minimum lining thickness and drum I/D would be listed in the workshop manuals?
I couldn't find it in the Haynes one or the offical BMC workshop one :/

Okey dokey, I shall check the drum diameter and probably order some nice shiny new shoes then

I had a trawl last night and I can't find any either!

Just a reference to the series MM stating 5mm, but it does not say if that's minimum or not.

You'd think those type of details would be specified!

Post by **Onne** » Fri Oct 21, 2005 6:27 pm

As long as you do make sure you drive a save car my dear! don't want any accidents!

I can assure you it's no fun

Post by **ColinP** » Fri Oct 21, 2005 6:40 pm

Kate,

Okey dokey, I shall check the drum diameter and probably order some nice shiny new shoes then

You might be better to order non-shiny ones (this post is supported by the Pedantry Society)

Seriously, though, all my old references state to replace the linings when the linings reach the rivets - and I've seen cases where the heads of the rivets were worn down as well!

Just be careful of the dust from the old linings.

Have fun,

Colin