Anyone have any issues with vacume brake boosters mounted under the floor? I've been looking at installing one and started to wonder what happens when the peddle is pressed. In the firewall mounted state the booster should draws air in to one side from inside the vehicle. If you mount it under the vehicle it now would draw air from under the vehicle. Not a big deal if the weather is nice. I drive my cars a lot and in bad weather. I'm pretty sure the "air" under the vehicle in the rain or on a dirt road is no good for a booster. Should it be vented back to the inside of the car some how?
DoubleJ52: Do you drive it in rain/winter? The question has come up for a slightly off topic truck I plan to use in the winter and around the farm. On a fair weather car I don't think there would be a problem. Thanks for the input. Anyone else have experience?
I put the booster under the floor on my 56 F100 and drove it in all types of weather especially in the rain. Never any problems. I believe that the vacum is pull from the intake not outside air.
As I remember most of the chassis mount Hydrovacs had a remote breather behind the seat in the cab. I know this does not answer the OP's question, which has my curiosity up too.
I wouldn't do it again, as the booster I used (common 7" double diaphram) didn't put out enough to make it worthwhile. It also rusted bad, quickly. If you've got power steering, get a HydroVac booster. Smaller, more assist, and just better, IMHO. Cosmo
I have one in my 26 t no problems, but I live in the south so we don't have alot of snow (so not alot of salt......).
My booster has a nice rubber boot on the brake pushrod. It's been in the rain many times without any problem...
I sealed around the pushrod with a cv boot and ran a tube into the cab for the booster to suck air through. You can just see the tube going up in this picture. This is going to be driven in wet pacific northwest winters and I was not comfortable about sucking water and salty slush through the booster.
Yes I have driven in a hard rain and in 100+ degree heat. Had it out Thanksgiving this last year, about 30 degrees out. My exhaust runs fairly close to it and the M/Cyl, I did make a shield and insulated it with some racecar heat material and have a heat shield (DEI) on the exhaust pipe, and the exhaust is ceramic coated but I did that more to preserve the exhaust. Hope this helps!
Thanks for the input guys. Just to be safe I think I'll add a vent line that route up under the dash.
I'd say unless you were planning on using it like a pedal-powered hippo you should be fine. I'm sure weather was taken into consideration when it was designed by the engineers back in the day.