Xsara Brake servo leak?

[Danh200484]

Hi
I had a mot yesterday and was advised Front Pads needed changing. so I changed the front passenger side pads first, Pushed the pistons back
to fit new pads, then slipped new ones in and sorted.
I went and jacked the drivers side up and got covered in fluid (not sure what it was until I looked after i fitted pads)
After fitting pads fine, I then checked and see I had brake fluid dripping down the Brake servo. I cleaned it up as i thought its just the excess
spilled out when pistons were pushed back in.
Took car for a spin to check brakes and they work fine stop the car well. come back check for fluid around servo only to find a leak running down servo just
under the Master cylinder.
There were no issues with the servo etc.. before doing the pads.
Can anyone suggest where the leak might be coming from? could i have damaged a O-ring on the master cylinder? just be a leak from the fluid that leaked out while changing pads (gave a thorough clean before but u know what fluids like! plus fluid level is still on Max)

[Peter.N.]

If the fluid had been topped up with very worn brake pads, quite a lot of fluid will be displaced when you push the pistons right back, check the level and see if it's at the top.

Peter

[Danh200484]

Hi
yes i checked the level and it was full to the top of the filler cap after i changed the pads. I drained some out and it now at the MAX line.

[Peter.N.]

Should be OK then, just that there wasn't sufficient capacity in the reservoir for the contents of the calipers.

Peter

[Danh200484]

I wanted to double check, so I took the whole brake cylinder off cleaned all around it and put it back together.
I took it for a spin and It looks like I still have a small leak coming from under the reservoir where it sits in the cylinder.
Could I possibly have done a O-ring and that's causing the leak?

[Peter.N.]

Can't say I have ever come across that. The reservoir is normally part of the cylinder casting, are you sure its not still coming from the vent in the rest reservoir filler cap? See if its wet on top.

Peter

[lexi]

Always possible that something has went in coincidence ie. ready to go anyway. When pushing pistons back in wheel calipers, it is good practice to put a tube on bleed nipple, then open and push the fluid into a jar. This avoids pushing any dead or dirty fluid back up the M/C.

[Gibbo2286]

Can't say I have ever come across that. The reservoir is normally part of the cylinder casting, are you sure its not still coming from the vent in the rest reservoir filler cap? See if its wet on top.

Peter

I'm not sure which master cylinder is being discussed but many of the modern ones have a separate plastic reservoir that. plugs into the top of the casting through a couple of rubber seals, if you're not careful when plugging it in you can crack the plastic or score the seals.

https://www.google.co.uk/search?q=Brake ... 272292693

[CitroJim]

I once had a Volvo where brake fluid from the mater cylinder was leaking into the servo...

No real effect on servo performance until it became full but for months I could not work out where the brake fluid was going as there were no obvious leaks!

The one-way valve on the vacuum line from the inlet manifold to the servo prevented any fluid being drawn into the inlet tract and being burned - the smoke of which would have given the game away a lot earlier perhaps...

All I know is a servo full of fluid is bloody heavy!

[Peter.N.]

You're quite right Gibbo, my memory has skipped a few years - often does that.

Peter