Tree
"Cleaning up" my engine bay. No HVAC system. Can I delete vacuum motor/pump? Thinking of connecting brake booster to a Tee section which leads to two outlets on the intake manifold. Thoughts?
Angus242164
Volvo would have added the pump because they felt there might be a lack of vacuum to the brake booster under some circumstances, so the pump would help keep constant vacuum to the booster.
With that in mind, 760T's didn't have the pump, nor did later 740T's, I think the pump was '87 only, or maybe '88 as well, and they were pretty much identical in other ways, and suffer no lack of vacuum.
As long as the booster is connected directly to manifold vacuum with a large fitting, it will be fine. It's best practice to have a dedicated hose from the manifold to the booster, without other things T'd off it.
Tree
Thanks Angus, very informative.
If booster goes to one outlet do I just blank the other one? I might try no vacuum see how that goes.
And would deleting charcoal canister be in similar fashion?
Angus242164
To be honest it's been a long time since I've looked at a stock 740T engine bay, but there is also a vac tank behind the front bumper (or on the engine crossmember on early models) which might be better to keep, one of the hoses most likely goes to that.
I wouldn't advise removing the charcoal canister, if it hoses are blocked pressure will build up in the tank on hot days and something will eventually pop, and the cap will blow off with a fair bit of force whenever you take it off. If you leave the lines open you'll have flammable, smelly fumes, and will be breaking laws. Removing it gives no performance advantage.
However, the 700 series canister is big and ugly and sort of in the way. What I did on mine was get a smaller canister from a VR Commodore, and mount it behind the bumper, below the LH headlight, using a slightly modifed canister bracket from an early 240, which happens to have the same diameter canister as a VR.
I then extended the hoses to it, and it's out of sight/out of mind, but still fully functional and legal.
Tree
Nice little mod on the charcoal canister! I just thought it would be the perfect position for the catch can as mine has a drain tap on the bottom.
nickm
The pump was to stop the vents shutting down under boost.
I don't think it effects your braking as they are off different sections on the manifold. And the vacuum reservoir is not in the available to the booster.
Latter models with the electronic climate didn't have it
Vee_Que
It currently is not connected to power, so its just dead weight and has been for a while. So this is acedemic.
A vacuum pump can help with pcv however when setup right on a high boost system. And it is linked to the brake booster. But it is primarily for the hvac. Later cars use two check valves instead.
deleted_user_160
Mine doesn't have it. Was never in the car when I got it
Tree
Well I tried no brake booster and good lord i was getting dizzy after only a few right foot leg presses lol
The vacuum pump weighs a few kilos too!
nickm
Jay I removed it because it didn't work.
In general when you lift off you get vacuum and the Brake booster also stores a couple of pumps
Vee_Que
Tree;77387 wroteWell I tried no brake booster and good lord i was getting dizzy after only a few right foot leg presses lol
The vacuum pump weighs a few kilos too!
You're meant to run the vacuum line from the booster into the intake manifold dude.
Tree
Haha relax I connected immediately after. Btw you want my vacuum pump since I recall you regret taking it off?
Vee_Que
If it works, yep. As I lost mine.