Rear Brakes

[David53]

Just re did the rear brakes after leaking seals got oil all over them. Have also replaced the seals.

Once all together the shoes are catching every couple of turns and moving the wheel cylinder in it's slot. The wheel cylinder kind of "floats" in the slot, nothing holding it tight. As I turn the wheel the cylinder shudders every couple of turns. Any ideas? Should I just back off the shoes a little? Do I have the shoes on correctly? (This picture shows pre changeover but new shoes are ion the same positions.)

[kennatt]

no beehive retainers fitted could be the cause,chamfer the leading edge of shoes,have you applied the brakes hard with drums on to centralize the shoes,the cylinders should be free to move that's the design

[les]

The semi circular recess in the bottom shoe doesn't look like it is sitting in the adjuster properly. Could be the picture I suppose, worth checking though.

[David53]

Yes I wondered about the beehives. None on the shoes when I removed the old ones. I know they're a pain to fit. Main thing I want to know is if I have the shoes on the right way round.

[les]

Not easy to see the ends of the shoes now you have assembled them. They look wrong to me and you have the wrong springs fitted. Download the workshop manual that shows all you need. Plus put some beehive springs on. Some folk give up, that's why a lot of assemblies have them missing.

[philthehill]

The brake return springs are correct for the car/axle.
It appears that the behive springs were not fitted to these particular brakes as they do not appear in the wksp man brake section for this particular car/axle, they only appears in the brake section for the later axle.
If there is no behive spring eye on the brake back plate then that indicates that they were not fitted originally.
The brake shoes are fitted the right way round but as above make sure that the brake shoe notch for the snail cam is fully home and fitted correctly.
I suspect that your brakes just need to be bedded in and then all will be well.
Phil

[les]

My mistake, different model, must pay attention! Still wonder about the adjuster though.

[David53]

Thank you. Yes, this is an MM style rear axle. I will pull drums off again and check.

[don58van]

Hi David

The wheel cylinder kind of "floats" in the slot, nothing holding it tight.

The rear cylinders are intended to float on the rear brakes. This allows the shoes to apply even pressure when the piston is pushed out. In fact, if there is too much friction between the cylinder and backplate, thus preventing the cylinder from moving, braking problems will result.

I hope you get it sort sorted very soon.

Don

[philthehill]

The rear brake cylinder has only limited radial sic. float in the back plate slot but that float must be free moving with no resistance.
To help keep the cylinder body against the back plate the cylinder body has an integral hook which fits through the back plate slot. If the rear dust cover is fitted correctly it also assists in keeping the cylinder against the back plate.

With the single leading shoe braking system as fitted (photo) - when the brake is applied the rotational forces acting on the brake shoes will try to reduce the pressure on the trailing brake shoe (top in the photo) and increase the pressure on the leading shoe (bottom in the photo).
These forces cancel each other out and the pressure on the brake shoes when activated are virtually equal.

With the twin leading brake shoe set up (as per the front brakes) the directional forces assist in increasing the forces on the brake shoes.