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Rear Brake Shoe Adjustment.

October 2019 - Rear brake shoe adjustment

Recently while balancing all the brakes to bite at the same time I couldn't get the nearside rear brake to bite hard on the drum, even when fully adjusted via the snail cam adjuster.

After checking for any brake drum reskimming or brake show wear I was still puzzled. Brake drums are still the original 9.00 inches diameter and the brake shoes are new. The snail cam adjuster was original, looking in good order. 

Decided to check the offside rear brake setup, and all appeared the same but the adjustment here was good!

Overnight I recalled changing the nearside brake cylinder after one leaked. I had bought a new pair and still had one unused. 

After checking the effective length of the nearside and offside brake cylinders I found the new one was 5 mm shorter than the other! Thus the adjuster needed to cope with an extra 5 mm of adjustment to get a hard bite.

Went back to the original supplier (MEV) and a second source and both confirmed the length at close to 55mm. The offside cylinder measured close to 60 mm!

MEV did suggest a new snail cam adjuster that they say is larger than the original to compensate for brake wear. Ordered this.

However in the meantime I removed the pressed metal bearing shoe stop (fig 1.) and made a new one from a piece of 8 mm square steel door handle spindle. Made the base 2.5 mm thicker at 4 mm (was 1.5 mm) and the sides 1.5 mm thick per the original. Made two centre punch marks each side of the new shoe stop, to hold it in place, and tapped it gently in place to hold.

Reassembled everything  and it did make and improvement but the adjustment was still near the max. 

Next day the new snail cam adjuster arrived and was clearly larger in size.

Fitted this and all was good. Now needs about 6 clicks to get a solid bite.

Didn't go back and take out my modified shoe stop....the new adjuster may work with the original shoe but there are only so many times I can remove and refit brake shoes...especially those beehive springs!! Anyone got a good alternative for those little perishers! 

If you have a similar problem try the snail cam adjuster from MEV Spares first it may well do the trick.

Fig. 1 Shoe stop before removal...easily remove ...needs  little force. 

With shoe stop removed

Square bar from domestic door handle
Modified Shoe Stop .. hacksawed and filed to shape. 

Existing Snail cam adjuster

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