brake master cylinder question :)

[polecat]

Is there any reason that I should not flush my master cylinder with engine oil, as in would it cause any damage?

reason being I want to use engine oil to flush the cylinder out of the caliper using the master to obtain the preasure needed.

Once done I would then flush it out with brake fluid before refitting the brake?

If that makes sense..... question is would engine oil damage the master ?

ps I do not have a vice or air compressor so this seemed logical to use the thing designed to push out the cylinder to remove it completly

[Guest Hodgy]

I don't know if it would cause any damage, but I don't think its a good idea, it could contaminate the brake fluid when you refill, even if you flush it there would still be some remaining in there?

I'm not sure I understand why you want to do it, why not just use brake fluid?

I've never ever heard of anyone doing that before

[polecat]

I could use brake fluid but I have not got any

I do have a lot of new engine oil though and I thought that brake fluid was a kind of oil anyway but if not I will have to get some cheap brake fluid.

[Guest Hodgy]

I really wouldn't do it, I think you could be causing yourself lots of problems.

If it's the piston in the calliper you're trying to get out, 1st of all, don't try an use WD40 to lubricate it, it will cause the seals to swell and make it much worse, don't ask how I know

You could try using a bicycle tyre pump, or a garage air line to blow it out? But cover the calliper / piston with a cloth first or it might shoot out and damage it

Good luck

[polecat]

I really wouldn't do it, I think you could be causing yourself lots of problems.

If it's the piston in the calliper you're trying to get out, 1st of all, don't try an use WD40 to lubricate it, it will cause the seals to swell and make it much worse, don't ask how I know

You could try using a bicycle tyre pump, or a garage air line to blow it out? But cover the calliper / piston with a cloth first or it might shoot out and damage it

Good luck

Thanks M8 but too late on the WD40

Update :

You just reminded me I have one of those 12v tyre inflators and unbelivably it just poped out the piston

Sorted thanks for the input

Edited April 22, 2011 by polecat

[Guest Hodgy]

Shame, it caused me no end of problems, you'll need new seals too.

I would connect it all up, put new fluid in, bleed it and and push the piston out that way.

[polecat]

Shame, it caused me no end of problems, you'll need new seals too.

I would connect it all up, put new fluid in, bleed it and and push the piston out that way.

I have new seals on order as a matter of course so I am delighted now its out cos I can start cleaning it up

[Guest Hodgy]

Excellent, glad you got it out

I would get a sachet of red brake grease to lubricate the new seals before re-assembling it

[megawatt]

Hey mate, serious respect to you for doing your own maintenance, something I will always encourage, but please, please don't cut corners with brakes etc. Engine oil is completely different from brake fluid, and yes you can use it to pop the pistons out, but flushing it out could produce other problems. Always use brake cleaner for degreasing where seals are present, brake fluid for brake systems and MOTORCYCLE engine oil for your engine. Keep up the good work, Alan.

[Decor58]

Good call on using the tyre inflater, wouldn't have thought of that myself although I do think putting engine oil in your breaks would be a very very bad idea!

Nothing but break cleaner and break fluid goes near my breaks, just not worth the risk on something so vital.

[polecat]

Thats why I love this forum ........It stops me doing something Stupid