4DM drum brakes

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Neil Jackson
Posts: 22
Joined: Sat Mar 31, 2018 6:59 am
Great Britain

4DM drum brakes

Post by Neil Jackson » Tue Jul 30, 2019 1:07 pm

I'm currently overhauling my 4DM drum brakes which are in need of new linings (at least). Does anyone have a good picture of a correctly assembled shoe setup? I know there is a picture in the workshop manual which I've downloaded (Fig M3 on page M5) but it's not very clear. My shoes are definitely installed wrong as the leading edge on both shoes are at the abutment end, plus the springs have been rubbing on the centre boss of the drum so they were probably in the wrong holes as well.
Regards
Neil



Neil Jackson
Posts: 22
Joined: Sat Mar 31, 2018 6:59 am
Great Britain

Re: 4DM drum brakes

Post by Neil Jackson » Fri Aug 02, 2019 9:19 pm

I found a nice picture in AKD3517:

Image

Now why didn't I think of looking there before :oops:

That sorts out my query about the shoes orientation, mine were definitely wrong. Looking at the above pic, it suggests the springs are hooked on behind the shoes, mine were in front. I'm thinking that might be why my springs have been rubbing against the drum centre boss.
Has anyone got any thoughts on this?

Regards

Neil

Neil Jackson
Posts: 22
Joined: Sat Mar 31, 2018 6:59 am
Great Britain

Re: 4DM drum brakes

Post by Neil Jackson » Fri Sep 06, 2019 3:25 pm

For anyone else that might struggle like I did, here's a couple of photo's of how I ended up assembling the brakes.
Nearside:

Image

Offside:

Image

I had big wear grooves in the back plates where the expanders sit, so I blasted them, welded them up and ground them back to flat again. A lick of paint and they're as good as new. The eagle eyed amongst you may notice that the friction material on the shoes is quite thick, in fact it's 8mm instead of the normal 3/16". That's because my drums have been skimmed a lot in the past and now measure 227mm ID instead of 220mm. The old shoes were standard and despite having plenty of thickness left on the friction material at the ends, they were down to the rivets in the middle.
Saftek in Cleckheaton did the shoes for me, cost was £17.20 per shoe which I thought was quite reasonable for a special.
My brakes actually work now, a massive improvement of what I had before.

Regards

Neil

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