Any adjustment in booster pin? - Page 2 - Chevelle Tech
Brakes, Suspension & Steering Conversion questions & more.

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post #16 of 23 (permalink) Old Jan 20th, 15, 11:29 PM
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Denny
 
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Re: Any adjustment in booster pin?

Bolt on correctly your m/c to your booster and slowly & carefully depress the brake pedal with the reservoir cap off. You should see 2 little geysers every time you depress the pedal. That means everything is OK.

If at least one geyser is missing, then your m/c is not fully returning to its rest position and your compensating ports are blocked (which will lead to pressure build-up in your hydraulic system); Something must be done. If everything else checks out, then you will have no choice but to shorten your push rod (Never shim your m/c). The correct GM procedure was to use a «service adjustable push rod» but, these days, you won't find any.

More info about push rod length.


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post #17 of 23 (permalink) Old Jan 21st, 15, 12:02 AM
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Re: Any adjustment in booster pin?

Great info, thanks Jack!
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post #18 of 23 (permalink) Old Jan 21st, 15, 7:56 AM
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Re: Any adjustment in booster pin?

Quote:
Originally Posted by JWagner View Post
I think we now know who the resident brake booster and master cylinder guru is. That was some pretty good info. Thank you.
Agreed! Thanks for your contributions Denny.

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post #19 of 23 (permalink) Old Mar 15th, 16, 6:03 PM
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Re: Any adjustment in booster pin?

Still the best post ever on this issue that seems so common these days.

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post #20 of 23 (permalink) Old Aug 15th, 16, 8:29 PM
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Thumbs up Re: Any adjustment in booster pin?

Going through this fiasco for myself at the moment.
Delco booster with 409 1970 master with deep rod well in piston.

Deep rod measures 4.041" long and .365 diameter

Got a new MBM master # MBM7074 (which I think is wrong as it is stated as a 1" bore instead of a 1 1/8 but the bore measures 1 1/8***) but the pin that was supplied is .371' in diameter (2.592" long) and it will not fit in the bore of the booster. Any comments on the pin diameters? I'll deal with the master issue separately. This one does use a short pin.


*** May just be bad internet documentation????

Aug 21 Edit MBM Booster is a 1 1/8" bore.


Search words: booster master pin diameter

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Last edited by LevonH; Aug 21st, 16 at 11:52 AM. Reason: MBM Master confirmed at 1 1/8"
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post #21 of 23 (permalink) Old Aug 16th, 16, 7:33 AM
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Levon
 
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Re: Any adjustment in booster pin?

Anyone have a factory pin that they can measure? Denny recalls 2 3/8 length but I could sure use the diameter.

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post #22 of 23 (permalink) Old Aug 16th, 16, 1:20 PM
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Re: Any adjustment in booster pin?

Quote:
Originally Posted by LevonH View Post
Anyone have a factory pin that they can measure? Denny recalls 2 3/8 length but I could sure use the diameter.
LOL, read my recent thread. It covers this very issue (in addition to variations in diameter of the "bullet" spacer). The OEM rod (short or long) is .36 and change. All of the aftermarket long rods I have are .375. All of the aftermarket short rods I have are .36 and change, like OEM. Sounds like you found a wide diameter aftermarket short rod. You can get an OEM short rod (.36) from Steve Gregori at brakeboosters.com

https://www.chevelles.com/forums/16-b...t-1-2-dia.html
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post #23 of 23 (permalink) Old Aug 19th, 18, 1:38 PM
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Re: Any adjustment in booster pin?

I know this is an old thread but I'm hoping to add some info, I replaced a 1" bore MC with a 1 1/8" for 68 corvette, the pin or rod in the 1" bore was too large in dia. to fit the 1 1/8" so I made one out of .50 steel rod stock, the one I made isn't pretty but works like it should and is very close to .48
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Last edited by shovelrick; Aug 19th, 18 at 1:38 PM. Reason: added text
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