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MG Midget and Sprite Technical - rear brake cylinder circlip

I am sure this has been covered before but couldn't find it

How do you get that damn circlip to fit on the back of the rear brake cylinder ?

Do you remove the bleed nipple and try and fit from above then tap it round once fitted and replace the nipple ?

cheers Ben
Ben Brown

yeah, you remove the bleed nipple first

also, if you hate the E clip, you can use the original C clip and wave washer but you have to buy them from a supply house like Grainger, because Moss et. al don't carry them:


for those who hate the E clip that comes with rear cylinders (and who doesn't), I did a bit of research and found retaining rings and spring washers that are very close to the original factory ones, and as a bonus, are available in stainless steel:

Grainger #5DA81 = 11/16" external retaining ring, stainless steel. $12.94 (10)
Grainger #6ZA12 = 11/16" wave washer (3 wave), stainless steel. $16.42 (10)

Because they are only available in packs of 10, I now have enough of them to last me for 100 years (at the rate that I replace my rears).



Norm
Norm Kerr

And, unlike "normal" e-clips, it cannot be slid into place. You have to get one corner into place then pry it over the top. Even so, the trashy clips supplied break regularly. I also pull out the roll-pin, tap its hole for 12-32 threads (I believe there is a metric size that also works) and use that to eliminate the slop incurred by using just the e-clip and results in the brake drum cutting through the dust boots.
David "I don't care to rebuild my brakes too often" Lieb
David Lieb

metric Is M1 to M1.25 IIRC.
Prop

The metric size is M5.
Dave O'Neill 2

Ben,
The E clips are not that hard to fit. But there is a very small slot between the flange of the axle casing and the back plate that the back edge of the E clip needs to locate into. The slot is usually full of crud or paint and not easy to spot. If the back edge of the clip isn't fitted into that slot it will still go on, but is much more difficult and the bleed nipple seems to be in the way.

Locate the E clip with the rear edge wedged into the slot mentioned, and then use a broad bladed screwdriver to lever the outer prongs of the clip over the boss of the brake cylinder, first one, then the other, a bit at a time. 2 minutes work does it!

I, like many others, have drilled and tapped the cylinders so that they will bolt on and not flap about. But this isn't the correct way and indeed the "slop" when fitted with circlips is part of the design intended to assist the shoes in self-aligning to the drum.

Problem is that if there is too much slop (because the hole in the backplate wears) then the rubber boot on the cylinder wears away on the drum. I suspect also that the modern rubber boots are a bit more bulky than the originals.

Guy
Guy Oneandahalf Sprites

I use the special fitting tool. Seemed quite a lot for such a small tool, but it does make the job really easy. Got this info from Octagon Services:

"First you need to remove any sharp edges from the clip where it has been pressed - a slight chamfer on the legs of the clip will help it slide down the cone of the tool.

Carefully grinding the rim of the cone so that it matches toe brake cylinder boss save the E clip being over stretched and distorted.

Grease the cone before fitting and tighten the nut in stages, backing off and allowing the clip to "settle" a couple of times during the fitting."
TonyJHamilton

Ben. What Guy says is the tried and tested way and works for me every time.

Bernie.
b higginson

Buy a circlip like the original and fit with no hassle in 15 secs. Why make it difficult ? A
Anthony Cutler

That rear brake cylinder was one of the main reasons I decided to fit my car with rear disks.
The job of engineering and fitting disks to the rear was very difficult but still preferable to fitting the damn cylinders. :)
Robert (Bob) Midget Turbo

fitting the cylinders with the original C clip and wave washer only takes me a few seconds, with no special tool, or technique. I have always wondered why Moss and the others stopped carrying the original fasteners.
Norm Kerr

We have a local machine shop thread the casting the circlip attches to and have a nut made.

This also prevents any unwanted movement of the wheel cylinder if you are fond of handbrake turns or leaving the handbrake on tight for extended periods of time.

The e-clips are a nightmare, but they will go on without removing anything once you find the small indent that Guy mentions above.

File down the inner edges of the legs so they are smooth and not pointed, this helps sooooooo much, i have also filed out a slot in the past so the clip doesnt touch the bleed nipple at all when fitted.

But we prefer the threaded option, having had the clips fail in the past.

Pete
PeterJMoore

that is the big question, is it "unwanted movement of the wheel cylinder", or is it desirable movement that helps the shoes self-align to the drum?

Since the original design is "sloppy" like this, it does seem intentional. But, then again, a carefully set up shoe/drum ought to have shorter travel if the cylinder was solidly fixed to the back plate (less lost motion).

On drum braked motorcycles, one is supposed to fit each shoe to each drum (glue sand paper to the drum and turn down the shoe to fit), and once that was done I am sure that fixing the cylinder would work very well indeed.

On the other hand, since probably no one does that on MG rear shoes, is the small amount of cylinder movement helping the shoes to self align, and is that more beneficial to pedal travel than what that cylinder movement is taking away?

In interesting question.


Norm
Norm Kerr

Norm,
I believe that some movement is part of the design - and helps to self-align the shoes.

But being part of the design doesn't make it a Good Design!

The small amount of intended slop means that wear occurs in the backplate from this movement, and the desirable amount of "self adjustment" quickly becomes excessive and defeats the object.

Guy
Guy Oneandahalf Sprites

Norm - the unwanted movement turns into circlips coming off and the wheel cylinder dropping out of position.

With no movement of the cylinder everything still works, and we dont have to worry about losing the cylinder with every yank of the happy handle.

No brainer decision there for me.

The other option is to get rid of the midget rear brakes and either go the disc route, or bigger drums from the likes of a wolseley or riley 1500
PeterJMoore

I drilled and tapped mine to M5 as above and to my surprise it was a piece of cake, thanks in particular to Bill sdgpm and others here. It was particularly helpful to have the bolt on modification when I realised when fitting the brake shoes that I'd got the handbrake lever in the wrong place and the only way to shift it was to take the cylinder off again. I wouldn't have wanted to bugger about with the circlip twice! If I as an engineering dunderhead can do it then anyone can.
Matt1275 Bucks

The 'movement' with circlips allows the shoes to align better; there's no 'lost motion' after this, except for taking up wear.

A
Anthony Cutler

This thread was discussed between 24/09/2010 and 27/09/2010

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