This LRO reader emailed LRO.firstname.lastname@example.org seeking help with juddering Series I brakes.
When I reverse my 1954 Series I 86in pick-up I canfeel it juddering and the vehicle won’t roll, but there’s no problem driving forwards. I’m sure it’s the brakes because if I do this when the back end is pointing downhill and press the brakes, the juddering stops. It all started after I fitted new brake shoes, when I also cleaned the drums.
S Bracewell, Manchester
It’s unlikely to be the drum: presumably that was workingfine before you fitted the new shoes. You say you cleaned the drums – if there was brake fluid or oil, the cause of that contamination needs to be dealt with.
A typical culprit is the re- use of old pull-back springs (which hold the shoes awayfrom the brake drum). They don’t cost much, so they’re worth renewing almost routinely. But brake linings could also be the problem.
Back in the day, all brake linings were riveted in place. You bought linings to suit your vehicle with the holes ready-drilled to match your shoes. Because there were all sorts of lining sizes there was a good chance that if you offered up a ‘wrong’ lining to your brake shoe, that would be obvious because the holes simply wouldn’t line up.
But since the advent of bonded linings, provided the width of the lining material is same as the shoe, any length can be fitted. I’ve seen shoes with linings that were obviously longer than they should be. You’d think longer shoes would give better braking, but that isn’t necessarily the case: often, the shoes will fit and work. But too-long friction surfaces can also be more susceptible to grabbing on to the drum while reversing. When lining materialwas asbestos-based, this grabbing quickly wore the back edge of the lining and the problem would soon go away. Modern linings are much harder, and don’t wear down so easily.
Also, modern brake shoes have linings with a straight-cut leading and trailing edge. They should be chamfered, as they were originally. The drawings in the earlier Parts Catalogues show this clearly.
Take the brake shoes off, put each one in a vice and file a chamfer on the leading and trailing edges using a medium file (you may as well do both). This chamfer only needs to be a few mm.
This workshop advice appeared in the December 2015 issue of LRO. Back issues are available to download on digital devices here.