Rear brake piston

[learyd]

I'm restoring a 1959 4 door 1000, i'm stripping the rear axle and i've been trying to remove the rear brake cylinder/piston thing off the brake's back plate so i can clean the whole axle with angle grinder etc and not damage the brake cylinder. I've been using the haynes manual extensively and it says wiggle it out. Yet this is not as easy as it sounds, and suggestions to help remove it?

[mike.perry]

Disconnect the handbrake cable, shoes and brake pipes. Spray around the cylinder with WD40 or similar, taking care not to contaminate the linings, ensure that the wheel cylinder moves freely up and down the slot and find the position where it will passthrough the hole in the backplate then tap it out gently with a hammer.

[bmcecosse]

As above - it WILL come out - just hit it harder. It's extremely likely that you need new ones anyway - so don't worry about it too much!

[learyd]

Thanks very much for the post, i think i'm just being to delicate with it.

[Ted]

A good method is remove all surrounding parts especially those in the way. Use a penetrating oil spray, leave for a few hours while doing something else, then tap with hammer to at least get some movement, then cover with an old rag and undo bleed screw and blow compressed air down the screw hole and it will fire out. Make sure of two things [1] that the rag is secured adequately around the area to prevent any brake fluid that may be present from spraying around [2]to catch the piston when it is released - Ted

[mike.perry]

That method may work on the front cylinders but on the rears the handbrake mechanism gets in the way

[bmcecosse]

I've never known compressed air to move a stuck piston yet! At least - my 100 psi won't do it - maybe you have more ? My grease gun works wonders though - 'up to 10,000 psi' they say in the grease gun blurb - that's more like it! But as pointed out - there are two pistons in the rear cylinders and the handbrake one is secured with the lever pin - so no hope of 'blowing' it out.