Fluid leak after changing pads

xabi

I changed the brake pads this evening, all went well until the last corner, when I pushed the piston back in the caliper I got a leak of fluid running down the wheel well. It was only about 50ml or so, is there an overflow in the master cylinder and me pushing the piston caused it to overflow? Do I need to do anything else?

visual

When the calipers are pushed back the fluid is also pushed back up to the brake reservoir bottle. This can cause it to overflow. Wipe or wash away this fluid as it will damage the paintwork.

There is a minimum and maximum level on brake reservoir bottle.

With new pads and discs it should be at maximum. As the pads and discs ware the level will fall giving a good indication of how worn the brakes are.

However sometimes the brake fluid is topped up to maximum when all pads and discs aren't new. Its not a problem untill you change pads and the fluid is forsed back into a full reservoir and over spills.

xabi

visual wrote: »

When the calipers are pushed back the fluid is also pushed back up to the brake reservoir bottle. This can cause it to overflow. Wipe or wash away this fluid as it will damage the paintwork.

There is a minimum and maximum level on brake reservoir bottle.

With new pads and discs it should be at maximum. As the pads and discs ware the level will fall giving a good indication of how worn the brakes are.

However sometimes the brake fluid is topped up to maximum when all pads and discs aren't new. Its not a problem untill you change pads and the fluid is forsed back into a full reservoir and over spills.

So I haven't broken or busted anything, is it designed to do this?

visual

xabi wrote: »

So I haven't broken or busted anything, is it designed to do this?

If the fluid coming out at the brake reservoir cap its normal nothing broken. .

When your finished just clean off the brake fluid as it destroys paint.

Dark sun

More than likely it just overflowed, your best keeping an eye on the level when your pushing the pistons back, no harm just don't let the brake fluid come in contact with paint, will destroy it, if you have a syringe you can remove the extra brake fluid, don't go below min level.

mickdw

I hate the idea of pushing fluid backward through the system. I let it out a bleed nipple always, then do a quick brake bleed when finished running a bit of fresh fluid through to each wheel.
I figure if the op is getting a good pedal now, there is no ongoing leak to worry about and it did most likely just overflow.

CJhaughey

I do the same as Mick^^ Old fluid in the caliper is usually full of crap, opening the bleed nipple and pushing the pads back in gets the old fluid out.
Using a brake hose clamp tool stops the fluid going back, very handy.

visual

It is a good time when your doing all 4 corners to do a brake fluid change.

Syringe out fluid from reservior and top off with fresh fluid then bled all four calipers making sure reservoir is kept topped up.

I like to start at back wheel furthest from ABS pump and work my way around to front wheel closest to pump.

CJhaughey

visual wrote: »

It is a good time when your doing all 4 corners to do a brake fluid change.

Syringe out fluid from reservior and top off with fresh fluid then bled all four calipers making sure reservoir is kept topped up.

I like to start at back wheel furthest from ABS pump and work my way around to front wheel closest to pump.

As long as the seals in the master cylinder don't flip over and loose all pressure this works.
I think a vacuum bleeder is better if you can do it.

mickdw

CJhaughey wrote: »

As long as the seals in the master cylinder don't flip over and loose all pressure this works.
I think a vacuum bleeder is better if you can do it.

I don't see how that method can mess up the seals. Fluid is just being pushed through the system in normal manner via the brake pedal. Forcing fluid back through the system would be much more dangerous imo. Vacuum is ideal alright.

CJhaughey

mickdw wrote: »

I don't see how that method can mess up the seals. Fluid is just being pushed through the system in normal manner via the brake pedal. Forcing fluid back through the system would be much more dangerous imo. Vacuum is ideal alright.

I have had it happen with a Citroen once, just the fact that the pedal travels so much further means the piston travels further and it flipped the seal over.
Maybe not common but I would avoid pushing the piston down fully on one again!

mickdw

CJhaughey wrote: »

I have had it happen with a Citroen once, just the fact that the pedal travels so much further means the piston travels further and it flipped the seal over.
Maybe not common but I would avoid pushing the piston down fully on one again!

True enough. Wise to use only the normal range of the pedal though avoid ripping up the seals on unused portion of the cylinder barrel.