Page 1 of 1

Servo system

PostPosted: Fri Jan 04, 2013 7:24 pm
by SteveC
Brakes don't feel to great, and I know it could be many other things, but what should the servo vacuum pressure be, and how can it be measured?

Re: Servo system

PostPosted: Fri Jan 04, 2013 7:49 pm
by holywood3645
Vaccum in the US is typically measured in 'inchs of mecury' (inHg)' Anything over 25 is good. But it is more important the systems holds Vaccum after the engine stops. Otherwise you could have a leak, and could be running lean of the cylinder the Vac tap comes from. The Check valve can also cause problems if leaking by. You can test your system using postive pressure (around 20 PSI) to find leaks and check leakdown.

James

Re: Servo system

PostPosted: Wed Jan 09, 2013 11:20 pm
by rfurzer
I have had an interesting experience. I had my newly acquired +2S/130 (webers)inspected for rego and was told that one of the brake pipes didnt meet the Australian Design Rules and needed to be replaced. (F!)

After bleeding the brakes, went for a run- ran lumpily rough but not as though it was on 3 cyl.

After a while came right -

The vacuum system refilling and running one carb lean rings true

R

Re: Servo system

PostPosted: Thu Jan 10, 2013 12:08 am
by holywood3645
Does the engine run better with the Vac disconnected and servo tee blocked off?. Sounds like you may have a leak and losing Vac' on a cylinder.
Sorry i didn't fully understand you second post.

James

Re: Servo system

PostPosted: Thu Jan 10, 2013 12:35 am
by rfurzer
I havent bothered with diagnostic manoeuvres as she is now going 100%.

I did edit that post - the second paragraph didnt make sense