345 low on vacuum

My two bobs worth, nah better make that two cents

It should develope vacuum pretty quick as in 30 seconds or less
I would isolate the system so no external vacuum operated things are connected to the motor
Then see what the vacuum is actually on the motor

Once its tuned up better start hooking other stuff up and see if you have a vacuum leak any where


Paul

The engine can pull full vacuum in a few seconds ,due to capacity......but the vacuum line to the brake tank needs a restrictor so that the air from the tank doesnt upset carburation and stall the motor when you push the pedal with the truck idling ......going down a hill doesnt matter .......Even so ,you can usually see the idle speed up when you pump the brakes standing still..............Diesels dont have any manifold vacuum ,so they need a vacuum pump ,and this can take ages to get the tank down to buzzer pressure....So you cant compare any diesel .

Ok , when I bought the vacuum gauges they were cheap enough so I bought 2.....seems the one in the dash wasn’t showing correctly (11hg) at idle, when it was pointed out to me that it wouldn’t idle I put the other one on and it shows 17 hg at 650-700 rpm and it does this in a few seconds , all I need now is to find the wires that the previous owners banished from in behind the dash ....the two tanks have funny looking sensors ? And wires coming from both tanks which would be a on or off like a oil pressure switch ??

Nothing to do with vac......but tilt cab ACCOs ,you need to always check both cab hold downs are properly engaged ........I used to regularly see them them with just one engaged ,and the other one knocked out of line with the pointed rod....A lot of drivers thought if the clip lock in the cab closed ,all was OK.

We seem to have crossed channels, I’m talking about getting the vacuum tanks connected to a warning light on the dash, im not talking about cab locks