Rear Brake Adjustment

[erictharg]

I just know I've missed something really obvious, but I'm struggling to get my rear drums to adjust correctly. The adjusters run out of travel before the shoes are snug enough to the drum. The shoes are pretty fresh, I've just fitted new adjusters (only to find the old ones were fine anyway), and today put new drums on.
Still the same problem.
I'll wind the adjuster in through the nice "clicky" bit of its range right to where is starts getting stiff and the wedges are basically sitting on the full diameter part of the adjustment screw. The shoes are still not close enough to the drum to give a good pedal.
I'm going to weld a 3mm piece of steel to the end of each shoe where they sit on the adjuster wedges as a last resort, but can't help thinking I've missed something.
Jan - have you come across this one?

[Westfield 129]

None of this sounds right. Don't weld anything. I don't think that you really have a problem.

Are you sure that the shoes are properly installed? Are the drums of the correct dimensions, and not excessively worn?

One tip is to disconnect the hand brake rods from the brake lever at the backing plate. This will allow the proper adjustment.

What happens is that the screw (also a wedge) goes in between the wedges, one pair of flats at a time. The brake screw is pointed, so that each adjustment pushes the wedges farther apart. It will "click" for a while, then get very tight as the screw needs to seat on the flats (the screw is a wedge, too). It is not on the round part, as that would be just about impossible as the screw would disappear into the drum back plate. It is bearing on the thick part of the adjustment flats. When it gets stiff, the wheel should not turn. Push it a little farther, and it will again "click" and the wheel should turn. IN that case, go for another turn. It will tighten, then click, and the wheel should turn. If it clicks, and the wheel has excessive drag, or is fully braked, back off a click.

I have never seen these parts wear out. I am sure that what you need to do is turn the adjuster farther, until it releases again, or stop when you can't turn it any farther. Note that when the adjuster tightens, the wheel should not turn.

Note how much better your brake feel is once you have adjusted the drums, especially if you are running a single .75 master cylinder.

[erictharg]

Tried all the above Jan, to no avail. It's only the driver side that has this problem. Sat and looked at it for a while today but can't see anything wrong. I had added a 1/8" steel shim to each adjuster wedge (gently tack welded in place, the filed smooth to fit OK). So now it adjusts OK. but still not found the root cause which is frustrating.
Don't want to go to discs until I embark on my narrowed Caterham DeDion concept. Not quite ready for that yet. But planning it...along with the Lotus 907 engine that I can't get out of my head. Looks so much like a twin cam Climax from a 15. And has Lotus on the cam covers...a better choice than the Lotus / Ford twin cam.

[adamwilkinson]

Go on Charles, go for the discs now. it's a fairly easy conversion and you won't need to worry about adjusting those pesky shoes anymore!

[Westfield 129]

The wedges don't wear, but maybe there is a problem with the levers, or one of the brake cylinders might be stuck.

[erictharg]

I don't want to go to the expense and hassle of fitting discs on the Midget axle. Especially when there's nothing fundamentally wrong with the drums (they worked fine so far...).
I'll go to discs when I build the De Dion rear end I have in my head! But that depends on a somewhat pokier engine. Once I've settled on a next generation engine / transmission combo, the new rear end will be needed. And revised front end...in fact pretty much everything!
Meanwhile I'll stick with the A Series for another season...and it's matching drivetrain. The great thing about the stock drivetrain it is that it is all nicely balanced. Everything copes - just!

[sgrant]

Did you get this sorted Charles?

s

[erictharg]

Can't see any obvious cause. Ended up making a 3mm steel shim that I've tack welded to each of the adjuster wedges. Works OK now and I have adjustment but still don't know why I had to do it. Only affects the RHS. Weird...