I have a 1958 ford pickup, that I am putting power brakes on. I ordered a kit for my truck from No Limit Engineering. I just got it yesterday. I decided to play with it a little bit as I have never worked on a vacuum brke system. With the unit not installed and no fluid in the unit (master cylinder and vacuum booster) I tried to blow into the vacuum line on the vaccum booster. I was not able to blow into it, but when I tried to suck as much air out as possible, I could hear slight air comming in at the bottom of the master cylinder where it bolts to the vacuum booster. There is a place formed at this spot that looks like it probably should have this. I am able to build up a little vacuum, but it does not last long, and my method is not very scientific. I was wondering if there is a good way to test the vacuum booster with it out of the vehicle. I called the vendor's support but they did not know if was supposed to or not, local mechanics and web searches pull back different opinions. Please help, I really do not have time send this back, and would rather take the loss and fix it here if possible, if I even have a problem.

Thanks
klc

 

You could hook a vacuum line to one of your other cars and see what happened but I don't know what you expect. It's not going to act right if you don't have fluid in the master cylinder and something for the master cylinder to develop pressure against.

 

Actually, I am not trying to test the master cylinder. I am trying to test the Vacuum booster. As far as what I expect, I am not clear as to what to expect, that is why I posted. If this is not the forum for such a question, you have my apologies.

I guess the short question would be:

How do I test a vacuum booster that is not in the truck? How long should I expect it to hold the vacuum?

 

I would probably hook a vacuum pump up to the booster although I've never tried to test one out of a vehicle.

Tim in Burien
'56 F100 (now big back window ; soon to be with a Mustang II F/E)
tkbowman@qwest.net