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2CVGB News article – SPOG September 2016

“Hey, Mr. Tambourine man, play a song for me” the lyrics of that infamous song written and performed by the legendary Bob Dylan although taken to No I of the UK Charts by the Byrds back in 1965. Now that’s history? And while Taffy is rattling his own tambourine and singing along, I’ll “beat the drum” about our cars’ rear brake drums.

If you have ever received an MOT advisory note or indeed a failure certificate regarding the state of the bearing in an A Series rear brake drum I know only too well how depressing this can be. Changing this bearing can be a most arduous task requiring specialist tooling in order to achieve a satisfactory result. But firstly one has to remove the brake drum to work on it.

The business of jacking up the side of the car, suitably supporting it on axle stands before removing the rear wheel and then unscrewing the hub nut over the affected bearing with a 44mm socket, I’ll leave for the standard DIY manuals to describe. It’s where one goes from here that I’m focusing on as the next task requires specific equipment, a puller.

The rear drum sits on a tapered hub being part of the suspension arm. As you can see from the photographs it is not beyond belief to make a puller from the central aspect of a wheel rim using a length of threaded stud bar and a welding torch. I have heard it said that once the hub nut is removed the rear wheel can be replaced back over the drum and re-bolted down. Then the tyre is to be hit from around the inside with a “soft” hammer thereby knocking the brake drum off its taper. Myself I’ve always used a puller which seems a much more scientific approach.

So now the rear brake drum is in your hands ready to address the faulty bearing problem after prising off the dust cap cover. Again I’ve had a special tool made to assist here as it’s difficult to operate on a brake drum simply held in a vice. To prevent the drum slipping within the vice-grips causing damage I’ve had a piece of 10 mm plate machined to which the drum can be attached using the standard wheel nuts. This plate has a central hole to allow access to the bearing mechanicals plus two ridges (strips of metal welded into position) that fit between the jaws of the vice to enhance the ability of things being held tightly. Then one can start to attack the locking ring that retains the bearing.

A locking ring, being tightly fitted into position by Citroen staff during manufacture, has two peenings in its circumference which need to be drilled out before ever removal of the ring is attempted. Then I fit a specific lock ring tool I purchased at a 2cv Meeting many years ago to this rear drum/plate assembly with everything held firmly in the vice.  This is followed by heaving on the socket’s operating rod which usually has to be extended with a length of steel pipe to overcome the 200 + (or metric equivalent) ft lbs torque. Obviously ones needs to use a vice securely attached to a bench, my photographs being purely for demonstration purposes.

With the locking ring removed the duff bearing can then be changed (once again as per the manuals) to be followed by further use of a thick metal plate/locking ring tool for returning the ring to its required torque. But why bother with the expense of all this intricate tooling when a hammer and plugging (fluted) chisel could possibly suffice? It’s easy to answer that one. If a brake drum on a 2cv, Dyane or Mehari becomes damaged and/or its associated locking ring, yes the usual trade circles can supply new replacement items, no problem.

However if you are doing this type of procedure on an Ami 6, 8, Super, or Van from 1970 onwards to include the AK350, AK 400 and Acadiane one can still buy an appropriate new larger sized locking ring (they’re  not cheap) to accompany the new bearing. But if the actual drum itself (Citroen Part Number 460 – 0) on these vehicles is, or has become damaged or badly worn, then “you’re stuffed”. Ditto for the internal threads where the bigger “36 x 76 x 29” bearing is housed.  There are no new replacement drums available, the 2cv etc. equivalents simply do not fit here. In that scenario the only definitive option is to acquire a reasonable second hand rear brake drum if you can find one, or have had the foresight to keep a good spare.

And finally when you know of the above, should SPOG consider re-manufacturing these discontinued rear brake drums or investigate the possibility of producing the necessary tooling to limit the damage when such described work is done? Answers on a postcard please or better still e-mail. Many thanks.

David Eden

SPOGman