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I had some time before going to a 4th of July party, so I did the testing using the SST. The SST is spring loaded so as you spin the adjustment wheel, and the internal piston will keep tension on the tip of the pushrod. I started at no vacuum and adjusted the small brass wheel until no gap is present. The SST internal piston is therefore snug against the pushrod. After 19.5 mm HG using a vacuum pump, the gap widened to between 0.15 and 0.20 mm using my feeler gauges. Therefore, vacuum caused the pushrod to extend toward the MC by this amount. It's not much, but since the spec for the recommended gap is between 0.1-0.4 mm, it could put one out of spec since it is about 50% of the spec range. For my car, I found out that my pushrod is actually currently too long rather than short (which is what I thought given my perceived free play). Using the feeler gauges between the SST (once I removed it from the brake booster), it is long by about 1mm. I will have to shorten the pushrod by 0.6 to 0.9 mm to bring it back into spec.
IMHO, the takeaway in practical terms, is anyone changing their MC or upgrading their MC to a 929 or something else, could use the H-type tool to adjust the pushrod at first and simply shorten the pushrod after adjusting to the H-type tool determination by approximately 0.25-0.30 mm (spec gap of 0.1 mm and the vacuum adjustment of 0.15-0.20 mm).
Mike
How are your brakes not dragging if it's a full 1 mm too long?
Just noticed you are in Alabama. Haha.
How are your brakes not dragging if it's a full 1 mm too long?
Just noticed you are in Alabama. Haha.
Yes. I would be close to the point where the release hole for equalization would be covered. I'm glad it didn't happen.
Have been in Huntsville, AL since 1998. Born and raised in Chicago.
Mike
Update. The Honda SST for the brake booster came and fits great and the booster holds vacuum with the SST in place. I will do the assessment and if necessary, the adjustment of the pushrod in the next few days and will report back. I will do the assessment with and without vacuum to see if it makes any difference in the measurement. If it doesn't, then the SST would not be necessary, and the simpler H-type brake booster pushrod adjuster would be all that is needed.
Mike
Spoiler
Mike, it sounds like you've thoroughly investigated and addressed many potential issues with your brake system, but the persistent difference in performance suggests there could still be a subtle adjustment or compatibility issue with your modified 929 master cylinder and brake booster setup. Since obtaining the Mazda SST has proven challenging, exploring if Honda master cylinders share a similar cylinder size for compatibility could be a viable option. The $100 investment in the Honda SST might provide the precise adjustment capability you need under vacuum, potentially resolving the discrepancy in brake feel you've been experiencing. Additionally, ensuring all seals and adjustments are correctly matched and functioning optimally with the booster is crucial. Good luck with your brake system overhaul! If you want to know more let me know, and I will help you out. I also would like to help you by sharing the https://academized.com/buy-personal-statement-online website with you. If you are interested in buying a personal statement online then you can visit the given website. I am also using that website link to find the best essay writer over there to help me writing my personal statement.
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