leaking rear wheel slave cylinder

[joe winkfield]

at the start of june I replaced the two rear slave cylinders because the seals had gone. however the ones I put on in june seals have gone again already. is their any reason for this. they were both brand new slave cylinders. could i be bleeding wrong or seting them up incorrectly. also i have marina discs on the front not sure if that effects it.

[bmcecosse]

Oh dear - were they 'genuine' or 'replica' cylinders? In general the reports on the replica rears have been good (but not so on the fronts). Nothing you do should cause this (unless you used contaminated fluid - or have mixed normal and silicone fluid?) - I would contact the supplier and ask what they will do about it........

[MarkyB]

or have mixed normal and silicone fluid?

This is new, has it happened to you, or someone you know?

[bmcecosse]

Mixed fluids cause the seals to swell/fail very rapidly. It's highly unlikely here - but I mention it just in case. A new cylinder - repro or genuine - failing in this short a time must surely have an outside factor at play.......

[minor_hickup]

Usually filthy brake fluid. It is always a good idea to bleed through the cruddy fluid before fitting the new cylinder so as not to pump it all through the cylinder when you fit it. Especially on the rear as bleeding will not allow the fluid to flow through with the bleed nipple being before the cylinder. Unfortunately with the master being in the floor it is very easy for dirt to get in when topping it up!