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    Power brakes vacuum pump

    Thinking about adding a vacuum pump to increase brake boost on my 67. Has anybody got any experience of fitting / using one of these ? Or would you recommend a different unit ?

    https://www.cjponyparts.com/master-p...p-kit/p/BBVK2/

    Simon

    #2
    Unless you have a big cam you shouldn't need one. If your brakes are crap then do something like check the system over or upgrade to large twin or 4 piston fronts with good pads
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      #3
      Yep... big cam ... not much vacuum ...

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        #4
        Moroso pump then. Or fit a diesel alternator like transit van which has a built in pump
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          #5
          I was looking at this pump as well, I have big cam in my 66, willwood brakes are ok now, but performed better prior to engine upgrades. Was thinking over the closed season whether to pursue with this set up. Install seems pretty straightforward.

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            #6
            I have a friend with a '56 Chevy with a wild cam and he's fitted a hydroboost system where the power steering pump provides the power assist for the brakes (the unit goes where the servo normally is between the pedal and master cylinder). He rates it and it's been reliable. You can get them for classic Mustangs so it might be worth a look?

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              #7
              Yep -I have Wilwood discs front and rear too... but not enough vacuum to make them as good as they should be... Think Iíll go for it...

              cheers

              Simon

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                #8
                Originally posted by nuggets View Post
                Moroso pump then. Or fit a diesel alternator like transit van which has a built in pump
                Hi, yep I can see the advantage of a Moroso - being belt driven. They do kits for 289 and 302 but not for a 390 - which is what Iím running. Not really skilled enough to custom fabricate so unless I can find a kit may go with an electrical pump.

                More research needed on my part !

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                  #9
                  Simon, what size servo do you have. Most of the kits for Mustangs use a 7 inch dia servo (booster) unit. These need a good 17-18 inHg vacuum to work reasonably well. My cam gives 16 inHg vac at idle so I have fitted a 9 inch dia servo from a 90's Mustang and this has overcome the problems. This said if you have a manual transmission with the clutch release bar then you can't easily fit a 9 inch servo.

                  Before committing to the expense of the vac pump I would first do a simple brake test. Find a slight hill and drive down it then take your foot off the throttle so the engine over runs. This will build up a good vacuum, even with a lumpy cam, then apply the brakes. If they work well under these conditions then the issue is lack of vacuum. If the brakes are still not good enough it is lack of servo and you need a bigger one or you need a master cylinder with a smaller bore piston. The problem with the smaller bore master cylinder is that pedal travel will increase and if you already have plenty of pedal movement then a smaller bore master cylinder is not really an option.
                  Allan

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                    #10
                    Originally posted by ALLAN R View Post
                    Simon, what size servo do you have. Most of the kits for Mustangs use a 7 inch dia servo (booster) unit. These need a good 17-18 inHg vacuum to work reasonably well. My cam gives 16 inHg vac at idle so I have fitted a 9 inch dia servo from a 90's Mustang and this has overcome the problems. This said if you have a manual transmission with the clutch release bar then you can't easily fit a 9 inch servo.

                    Before committing to the expense of the vac pump I would first do a simple brake test. Find a slight hill and drive down it then take your foot off the throttle so the engine over runs. This will build up a good vacuum, even with a lumpy cam, then apply the brakes. If they work well under these conditions then the issue is lack of vacuum. If the brakes are still not good enough it is lack of servo and you need a bigger one or you need a master cylinder with a smaller bore piston. The problem with the smaller bore master cylinder is that pedal travel will increase and if you already have plenty of pedal movement then a smaller bore master cylinder is not really an option.
                    Thanks Allan,
                    thatís a good idea for a test. Iíll go try it this weekend and Iím also going to check the whole system over for vacuum leaks etc

                    cheers,


                    simon

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