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Apr 26th, 2026 | | AD Chevy Trucks  Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
Lots of work on Brad's part ... pure enjoyment (and references) for you!
| | THANKS!
For helping keep this great
old truck web site
on the Internet for over 30 years! and not clogged down
with Ads!  Again, thanks!
| | | | Joined: Aug 2005 Posts: 1,186 Shop Shark | | Shop Shark Joined: Aug 2005 Posts: 1,186 | Cool short film on the basic principles of operation.
Click
Bruce | | | | | Joined: Dec 2006 Posts: 165 'Bolter | | 'Bolter Joined: Dec 2006 Posts: 165 | Very Cool!!!
Thanks for posting Bruce.
Kevin
| | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 |
Thank you, Bruce
As the film/video states at the end, "know your truck, know how it works". Now, when I push on the brakes in my COE, my sick little brain will try to visualize what is happening in the braking system.
| | | | | Joined: Dec 2011 Posts: 90 Wrench Fetcher | | Wrench Fetcher Joined: Dec 2011 Posts: 90 | So which is better/ more efficient? Hydrovac or power | | | | | Joined: Sep 2011 Posts: 1,453 'Bolter | | 'Bolter Joined: Sep 2011 Posts: 1,453 | Thank you, Bruce
Now, when I push on the brakes in my COE, my sick little brain will try to visualize what is happening in the braking system. Isn't that normal?
BC
1960 Chevy C10 driver 261 T5 4.10 dana 44 power loc
1949 GMC 250 project in waiting
1960 C60 pasture art
Retired GM dealer tech. 1980 - 2022
| | | | | Joined: Apr 2005 Posts: 1,107 'Bolter | | 'Bolter Joined: Apr 2005 Posts: 1,107 | So which is better/ more efficient? Hydrovac or power to me they're the same. they boost the ease of applying brake pressure. only difference is where theyre mounted. | | | | | Joined: Dec 2011 Posts: 90 Wrench Fetcher | | Wrench Fetcher Joined: Dec 2011 Posts: 90 | | | | | | Joined: Jan 2013 Posts: 1,384 Shop Shark | | Shop Shark Joined: Jan 2013 Posts: 1,384 | The big difference is that Hydrovac has it's own hydraulic cylinder making them more complicted. The vacuum boosters amplify pedal push directly and generally produce higher brake pressures with less pedal pressure. | | | | | Joined: Dec 2011 Posts: 90 Wrench Fetcher | | Wrench Fetcher Joined: Dec 2011 Posts: 90 | But is a hydrovac smaller.
| | | | | Joined: Jan 2013 Posts: 1,384 Shop Shark | | Shop Shark Joined: Jan 2013 Posts: 1,384 | That is a big plus for Hydrovac. Not every vehicle (especially old ones) have room to put a vacuum booster between the pedal and the master. The Hydrovac can be fit in out of the way places. If you have the room, the vacuum booster is simpler and provides more brake pressure. | | | | | Joined: Dec 2006 Posts: 720 'Bolter | | 'Bolter Joined: Dec 2006 Posts: 720 | When I opened up the Hydrovac on my truck I was surprised to find the guts were very similar to the innards of the pneumatic valves I worked on in aircraft that used small impulse pressure to operate huge valves. But then again, it's not uncommon for aerospace innovations to be used in the automotive industry, so,... I think that hydrovac also allows for larger volume requirements of large trucks with multiple slaves per wheel &/or dual rear axles without having to mount increasingly larger vac assist master cylinders on the firewall or under the floor. Just my thought anyway, I'm frequently full of it, ask my wife. 
1956 GMC 370 dump " 'Tater "1970 VW Volksrod "the Black Bomber" 2007 Chevy Avalanche 2020 Jeep Cherokee Trailhawk, 2005 Harley Davidson FLHTCUI I dig all cars, old and new, whether they were hammered out of American iron, German steel, or Japanese tin cans. Being unable to appreciate them all is missing out on a world of great things.
But thats just MY opinion! :P
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