Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Trending News
Who has a SBC vacuum diagram?
I have a 78 Camaro. 350 V8 SBC, Edelbrock Performer intake, Holley 650 cfm carb, Flowtech headers by Holley, Cherry bomb glass pack dual exhaust directly bolted onto header collectors, and Comp cam with .470 lift.
The brakes (disc front and drum rear), rotors, and master cylinder / brake booster were recently replaced by a local shop. The car has a HARD break pedal with minimal stopping power which I suspect is due to vacuum lines improperly routed connected. Currently I have 1 vacuum line to the distributor. The other vacuum line is from brake booster to a T fitting, T fitting to PVC valve on valve cover and other hose to carb. What is the correct routing of vacuum lines OR other contributing factors to hard brake pedal and soft stopping power?
Please include experience in your answer. 10 points to best answer. All answers greatly appreciated.
5 Answers
- WayneLv 51 decade agoFavorite Answer
I believe that the PCV valve should be routed to the air cleaner assembly, and the brake booster to the intake manifold. The only time that vacuum should be routed to the carb is on vacuum secondary carbs - in that case the carb is using vacuum but not creating it. If you have the PCV valve and brake booster both hooked up to the same vacuum source, then your vacuum system is badly messed up.
- StanchfiLv 41 decade ago
Here is what I would do, have the distributor and the brake booster on the same "T" and the PVC valve on it's own line.
I would think that since the brake booster is currently on the same line with the PCV valve, the booster is not getting as much vacuum as it needs. Since the distributor advance does not really "use" and vacuum it would be better to pair it with the brake booster.
Should be simple to switch them around and try it out. If the lines are old, it's cheap to buy some new vacuum hose, and eliminate that as the problem.
I think having a different cam, may also affect the vacuum, there are vacuum accumulator canisters available to help out with this issue, I'm pretty sure Jeggs sells them, might be worth a try also.
- How do you think about the answers? You can sign in to vote the answer.
- Anonymous1 decade ago
Check a Haynes manual, or a 1978 Chevy repair manual. They are on ebay and amazon.com
