hissing servo

[chin up]

Due to go away for a month and guess what? Car throws a wobbly and gives me a job to get on with when I get back. Marvleyous.

The brake servo is hissing reasonably loudly, ie you can hear it whilst sat in the driving seat with the engine running. The actual assistance given and braking power available seems not too have changed at all but clearly something is amiss and it needs sorting.

I have searched the forum for clues, and I have two questions........
1. Anyone hazard a guess as to where the air is leaking into the servo? The hiss seems to be coming from the rear of the servo, where it butts up to the bulkhead.....there's a seal in there somewhere I believe....could this be it, and if so, is it a naus to replace?
2. Is servo replacement difficult? I have heard of servos being sods to remove from the bulkhead even with all the bolts removed. BAH!!!

Thanks in advance guys. I may not be able to reply for a few days due to travel, but I will get back to you sooner or later.

Cheers, chin up

[chin up]

Great stuff Johno, thanks a lot. Yep, Saab servo and new master cylinder when I get back. I did a 'suck it and see' check on the one-way valve and all is well there. Right then, I'll fix it and try and come along to an 's' meet to see your shiny paint! I was at the first vw meet but have had bad timing for the rest....being away for them. Never mind, cheers for the info,

chin up.