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S2a 109, new front brakes binding.


Betsy

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I have renewed the front brakes a few times in the 15 years I have run the 2a. It has the 11" twin leading shoe brakes. This time, I have renewed all the cylinders and shoes.

I find that I cannot get the drums back on easily, the shoes seem to be too big. The adjusters are backed right off, the shoe faces are at 90 degrees to the back plate, there is a small wear ridge on the inside of the drums.

If I force the drum on, I can turn it by hand only just.

Is this a regular occurance for others? I had thought about grinding a little material off the end of the shoes to create a bit more clearance. The parts are not genuine, they are Britt part shoes, and the cylinders are unbranded but made in Taiwan. These are the only parts my supplier had, indeed I don't think genuine parts are available any more?

Any other ideas before I grind the shoes down a bit?

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The wheel cyls from Delphi / Lockheed are OK,I'm having good brakes from Mintex linings on my IIA at the moment.The Ferodo linings I was using seemed to have the adjuster peg in the wrong place and the snail cam would go right round long before the linings were right down.

Goodridge stainless brake hoses make a big difference too.

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Grind the raised lip of the drum off and if it's still to tight - carefully file or sand the shoes until you can get the drum on.

Les.

Also the leading edge of the new shoes are usually the culprit when they don't fit properly. Using a file, you can take the edge off of them so that the drums can slide over.

Todd.

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The best,(And safest.) thing to do is to throw all that carp away and buy decent quality brake parts - they tend to fit properly and make the brakes work.
I echo that advice. Britpart cylinders are notorious for leaks, and I have read comments about them having a mixture of different linings on shoe sets, and of the linings being incorrectly aligned on the plate and becoming detached.

The specific fit problem may be due to the pistons not fully retracting in their bores - I had this problem on one of my cylinders (twin leading show system) when I fit four new Lucas (OEM) cylinders a few years ago. I couldn't see any fault, but something was stopping the piston from retracting is last 1/4".

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After a good close inspection last night, it seems the problem is either the pegs that sit on the snail cams are in the wrong position, or the snail cams are for some reason over sized. With the cam backed right off, the peg on the back of the shoe is still sitting hard on the cam. This is preventing the spring pulling the shoe back any further.

The cams do look original, and appear to be peened onto the bolts that come through the back plate. There are spring washers behind each bolt head, and they are 11/16 AF size. I have never changed the cams in the time I have had the vehicle, so it looks like it is the Brittpart shoes that are out of measurement.

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After a good close inspection last night, it seems the problem is either the pegs that sit on the snail cams are in the wrong position, or the snail cams are for some reason over sized. With the cam backed right off, the peg on the back of the shoe is still sitting hard on the cam. This is preventing the spring pulling the shoe back any further.

The cams do look original, and appear to be peened onto the bolts that come through the back plate. There are spring washers behind each bolt head, and they are 11/16 AF size. I have never changed the cams in the time I have had the vehicle, so it looks like it is the Brittpart shoes that are out of measurement.

Hi,i have had the same problem my self with a 109 when i fitted new after market wheel cylinders and britpart shoes,in the end i did a bit of grinding of the steel part of the shoes on the ends where they go in to the wheel cylinders(piston side),if you take about 2-3 mill off the steel and keep the same profile it narrows the overall diameter of the shoes,helps them line up better and allows the drum to go back on easeir,O.E parts are best but the price and availability are not.

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Thanks for all the help chaps. Rebuilt everything again this evening, but this time took the lip off the outside edge of the drum, and thoroughly cleaned out the carp from the inside of the drum with a wire brush on the grinder. There really was a lot of crud that was rock hard, and I can only think it was rubbing against the outside edge of the new shoes when the drum was clamped by the wheel.

It was still binding a little, and the wheel would not spin freely, but at least I could turn it by hand. After a good bleeding, and a few laps of the village including some robust applications of the brake. I then readjusted the brakes and the wheels spin freely.

So, job done. Moral is clean the drums out properly.

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