Guest romko Posted December 16, 2016 Share Posted December 16, 2016 Hey can anybody tell me the difference: I want to put a booster for my break's master cylinder. I found 3 types that can fit my car. One is a 11 1/2" dia. booster for a 1" bore M.C. one is a 9" dia. booster and another is a 7" dual diafram booster. They are all compatible but which one does what? Link to comment Share on other sites More sharing options...
TerryB Posted December 16, 2016 Share Posted December 16, 2016 It's brake not break Link to comment Share on other sites More sharing options...
CarlLaFong Posted December 17, 2016 Share Posted December 17, 2016 1 hour ago, TerryB said: It's brake not break Unless his brakes are broken. Why won't you tell us exactly what you're trying to do??? Is this a stock restoration or are you attempting to upgrade? As I stated in the original post, to which you still haven't responded, you can get all of the correct, OEM style parts from a number of vendors. If you are deviating from stock, then it is a crap shoot as far as getting something that will work well Link to comment Share on other sites More sharing options...
plymouthcranbrook Posted December 17, 2016 Share Posted December 17, 2016 (edited) 2 hours ago, TerryB said: It's brake not break Remember, in the "Post Truth' world what you believe is more important that what others call "truth". So maybe to him, the correct spelling is "Breaks" and thus you must be wrong. Edited December 17, 2016 by plymouthcranbrook (see edit history) Link to comment Share on other sites More sharing options...
TerryB Posted December 17, 2016 Share Posted December 17, 2016 It's tough to find what you're looking for if you can't spell it! I'll ease up and give him a brake! Or is it break? Terry Link to comment Share on other sites More sharing options...
MyJetstar1 Posted December 17, 2016 Share Posted December 17, 2016 Hmnn, can't catch a break on your first question. I'm sure you'll be eager to ask another, lol! So, different boosters are for different applications, I suspect you currently have a 4 wheel drum manual set-up. If that's the case, you will probably be looking at an 11 inch (actually slightly less) booster. They are based on vehicle options. Some options are 4 wheel drum, front disc rear drum, 4 wheel disc, and even engine size. The smaller boosters are generally big block applications, with front disc, or all drums. Pick the booster that most closely matches your current set-up, with which you merely want to add the power option. Keep in mind you may have to experiment on the rod length. Hope this helps a little. Jim Link to comment Share on other sites More sharing options...
Rusty_OToole Posted December 17, 2016 Share Posted December 17, 2016 What kind of brakes? Disc or drum? What size? Stock or aftermarket? Based on the information you gave us, any of those should work. It is mainly a matter of how much room under the hood. A big block engine may not leave room for a big booster. Link to comment Share on other sites More sharing options...
dictator27 Posted December 17, 2016 Share Posted December 17, 2016 diafram????? Terry Link to comment Share on other sites More sharing options...
joe_padavano Posted December 17, 2016 Share Posted December 17, 2016 Power BRAKES were a factory available option on this car. Get a factory replacement booster. Understand that a vacuum brake booster uses atmospheric pressure on a rubber DIAPHRAGM to create the power assist. Since air pressure is pretty much constant at 14.7 PSI, changes in diaphragm diameter (and thus area) will change the amount of boost available from a given booster. A 9" booster has only 2/3 the diaphragm area of an 11" booster and thus only provides 2/3 as much power assist. A dual diaphragm 9" booster, however, has 33% MORE area than an 11" booster, and correspondingly more boost. It's larger size may present a fitment problem, however. The stock booster was an 11" single diaphragm unit. Link to comment Share on other sites More sharing options...
Guest romko Posted December 18, 2016 Share Posted December 18, 2016 22 hours ago, joe_padavano said: Power BRAKES were a factory available option on this car. Get a factory replacement booster. Understand that a vacuum brake booster uses atmospheric pressure on a rubber DIAPHRAGM to create the power assist. Since air pressure is pretty much constant at 14.7 PSI, changes in diaphragm diameter (and thus area) will change the amount of boost available from a given booster. A 9" booster has only 2/3 the diaphragm area of an 11" booster and thus only provides 2/3 as much power assist. A dual diaphragm 9" booster, however, has 33% MORE area than an 11" booster, and correspondingly more boost. It's larger size may present a fitment problem, however. The stock booster was an 11" single diaphragm unit. Thanks Joe! this was very informative . I'll go with the 11". It seems to be the best match with the Delco model. Link to comment Share on other sites More sharing options...
Guest romko Posted December 18, 2016 Share Posted December 18, 2016 On 12/17/2016 at 10:57 AM, MyJetstar1 said: Hmnn, can't catch a break on your first question. I'm sure you'll be eager to ask another, lol! So, different boosters are for different applications, I suspect you currently have a 4 wheel drum manual set-up. If that's the case, you will probably be looking at an 11 inch (actually slightly less) booster. They are based on vehicle options. Some options are 4 wheel drum, front disc rear drum, 4 wheel disc, and even engine size. The smaller boosters are generally big block applications, with front disc, or all drums. Pick the booster that most closely matches your current set-up, with which you merely want to add the power option. Keep in mind you may have to experiment on the rod length. Hope this helps a little. Jim Thanks Jim, Both you and Joe gave me good info. I appreciate it. Link to comment Share on other sites More sharing options...
joe_padavano Posted December 18, 2016 Share Posted December 18, 2016 On 12/17/2016 at 10:57 AM, MyJetstar1 said: The smaller boosters are generally big block applications, with front disc, or all drums. Not really. The booster diameter was the same for both SBC and BBC in this application. As I noted above, if you do the math, you find that a smaller single diaphragm booster provides LESS assist than a larger one, so you DON'T want a smaller booster for a heavier BBC application. Similarly, since disk brake are not self-energizing, you DON'T want a smaller booster for that application, either. A dual diaphragm booster can provide more assist while increasing valve cover clearance, but Chevy didn't seen to need this for factory installations. Again, why reinvent this? You can buy factory replacement boosters everywhere. Link to comment Share on other sites More sharing options...
F&J Posted December 18, 2016 Share Posted December 18, 2016 On 12/17/2016 at 10:57 AM, MyJetstar1 said: Keep in mind you may have to experiment on the rod length. ^ this is very important on installation of a booster, when bolting the master cylinder to it. This part may need adjusting if the booster arrives without a master cylinder, and you have to get a master cylinder elsewhere. If the adjustable rod between the booster and master cylinder is adjusted "too long", then it won't let the inside piston of the master cylinder to fully retract. If it does not retract enough when the brake pedal is released, two things could happen: One would be that the brakes are still slightly engaged, which could cause the brakes to overheat/swell up, and stay locked up when the car is brought to a full stop( if hot enough..) 2nd thing that might happen, is that it will be very difficult to bleed the brakes when you are finished installing everything. . Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now