Hi guys,
I've started on installing power brakes and did my first purchase of parts: 7" brake booster, corvette style master cylinder & proportioning valve. When bolting the cylinder up, there is approximately a 1/8" gap between it & the booster.....is this supposed to be there? It seems like maybe it should be so that the booster actuator is always mated up snugly against the piston.
Thanks in advance,
Jon
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the master has a o-ring around the nose that seats inside the booster, no worry about that small gap, what one needs to be aware of is when bleeding a system using GM proportioning valves ,one needs to use the combination valve centering tool to keep the valve centered ,https://www.mpbrakes.com/accessorie...ol.asp?catid=8BD31DDF6D734593B18F34FBF49B9855 it screws in where the switch goes, no need to worry about air as this area is sealed between the internal o-rings , if not used you will have problems bleeding as the valve moves off center and find the valve leaking from under the rubber flap seal
i do auto restoration work and have screwed my self a few costly times having failed to do so, https://www.mpbrakes.com/ has a very good FAQ area and many times i have found their prices are close to the big names with much better parts,

 

Thank you captchas, I appreciate your prompt response and the great advice! Not knowing about the centering tool, I am really in your debt & will have one installed when it comes time to bleed the system. Just in case some one is wondering about this same thing at a later date, I've added a link to their video on the centering tool/proportional valve.


The MP brake guys have a great site, they even have an adjustment tool for the gap between the power booster & the master cylinder piston. Being such a new guy, I didn't even know there is an adjusting post on the booster (it was adjusted 100% down).


I had to machine about .050 off of the master cylinder insert to get a good fit.....put a little blue loctite on it & she's good to go.
Thanks Again & Best Regards,
Jon

 

your welcome, happy to help and maybe save some one time i lost from being DUMB!!!
and yep, they sure have one great site with prices for better parts "non china in most cases" than summit and jegs, issue comes up? call man are they helpful

 

PS
if your using the copper.nickle brake line, when double flaring, don't over flare or tightly make the flare, shape it to the double but leave it just a little thick than when you tighten the line into the combo valve it will finish making the flare and NOT leak . that nik/cop line is soft it is easily over done. when to tightly flared the seat is too thin into the combo, feels tight but not properly seated step on the pedal LEAK
should i say been there done that 100 times??