Brake servo unit

[chil]

The air is leaking from the unit which power assists the brakes . There has been a hissing noise for some time, rather like air brakes. This morning something seemed to 'give ' and braking became very hard. Is there a quick Fix?

[HWKE]

Hissing means it is likely that your vacuum diaphragm is torn, leaking vacuum. If it works when it warms up, it's a worn seal. The fix is to replace the diaphragm. This usually means replacing the unit.
I'm sorry I couldn't give you better news. In the meantime, your brakes are working on manual power.

[chil]

Thanks HKWE I suspected the news would'nt be good. Its probably going to cost more than the vehicle is worth!

[HWKE]

You could try getting a replacement unit from a scrap yard. I had the same problem a while ago and got one. Fitting it in my case was only to disconnect the brake pipes and remove two bolts and it came away easily.
Even easier if you have a friendly mechanic.

[byrnesix]

Your problem could be nothing worse than a collapsed or punctured vacuum hose that runs from the engine to the servo. If this proves to be the case be sure to get the correct vacuum hose as a standard rubber hose will collapse. An easy test for the brake servo is to push the brake pedal hard with the engine off. Start the engine then if the brake pedal moves the servo is working OK.

[chil]

Thanks for your help. I did in fact locate a replacement from a breakers. Have got to say though that replacing it was probably the hardest thing I've ever done. It was positioned under the dash board and every little thing was hard to do. But perserverance won through and I now have my old banger back on the road for the princley sum of �50. Thanks again