I have struggled with vacuum related braking issues. To fix, I have decided to go the hydroboost route. I am also looking forward to the braking performance increase. After some reading, here is the plan: 1. Hydroboost unit from a mid 90's astrovan - $45 2. Wilwood master and proportioning valve - $300 (overkill, but I had $200 in summit gift cards, otherwise I would have used my existing master cylinder) 3. Power steering pump from a 78 Chevy Truck with hydroboost (my current pump is weak, has struggled with the Jeep Cherokee box I put on...time to put a new one on with a built in return line) - $58 and new pulley from 1980 camaro $20 4. Lines....not sure yet.....trying to avoid spending $150-$250. Looking at options. I have a few I took off of various vehicles from the U Pull It yard...will see if I can get those to work. Have used lines from u pull it $20 I will use an old A Body vacuum booster for parts. I plan to cut/weld the rod onto the hydroboost. To save money, I am also going to try and drill/cut/modify the existing hydroboost mount plate rather than purchase a new one at $75-$100. Here is the victim: I currently have a unit from a mid-late 80s Camaro installed - smaller vacuum booster and lighter better master - all feeding 4 wheel discs. I have had this on since the 90s....worked well until I installed my new engine that just doesn't make enough vacuum to run the brakes always. Started with the sacrificial units: Cleaned the hydroboost up Cut the old mount off of the vacuum booster to use as a template to drill new holes. I think I will go the flush mount route rather then use both brackets mounted to hydroboost....but using the brackets would have been easier. Very little modification to get everything to line up. I then drilled and cut the plate to be able to mount up to my existing firewall studs: Next steps, trial fit....get the rod length right and get it welded up.......but I have a roller cam and gear vendors install going at the same time....so it may take awhile.
I experimented with a few mounting options using and modifying the existing mounting plate from the Astro van. I want to use the stock hoses to avoid having to purchase the aftermarket ones (which are pretty pricey), so I am going to stick with the stock orientation of accumulator on the passenger side. I tried to use the booster brackets from the stock vacuum booster to get an angle on the unit, similar to stock, and it would work fine, but I did not like the space between the firewall and how far it made the unit stick out. I also tried the flush mount. The issue with flush mount is that the retainer nut on the back of the unit is larger than the hole in the firewall. Reading other threads, some people have solved this by widening the hole. Some use the mounts that create space between the nut and the firewall. I don't like any off the shelf options I can find because they aren't really any better or are expensive ($75-$100). I had previously cut about 1.5 inches off the top of the mount plate to make it almost flush with the back of the hydroboost. I decided to just try and flip the mount backwards and redrill the holes....the existing bend in the metal provides just enough offset from the firewall to clear. Simple....problem solved. I also read about many people cutting/welding or cutting/threading a stock clevis on for the pedal. While I am not opposed to this, as I looked at it I can't see why I can't use a bolt/nut/washer combo to attach the rod to the pedal. I rounded off a nut so it fits flush in the hole of the existing rod, then used washers and a nut on each side to secure. The pedal is at about stock height/position. There is only a slight angle to the rod, and it seems to function fine.......anyone have any ideas why this would not work? Just not sure why others don't do this and use a seemingly more complicated solution.....want to make sure I am not missing something.
All painted. I decided to cut the rod and thread it for the stock clevis. The stock rod with the modified bolt would have worked fine but since I had the parts I decided to use it. I got it installed and all the lines routed. Looks like a spaghetti mess with the cruise control. Once the engine is back in I will route stuff to clean it up.
I couldn't find a solution for the hoses I liked. The ones from the junk yard I took from a chevy truck were too long. The astro van lines would not fit. I should mention I had previously installed a jeep gran Cherokee steering box. I had put in the oring to flare conversion fittings. I pulled them back out of the steering box so I could use the o ring line ends that were the right shape. I took the truck lines to a local shop and they made me some custom lines using those parts. I am happy....they look and fit great....but they were $120. Cheaper than the $250 kits.....but still more than I wanted to spend. I read in a few threads the grand national Hydroboost lines may work, but I didn't want to mess around with them. Here are the installed pics so far - the 78 chevy truck pump is working out nicely....2 low pressure return lines. And a larger reservoir....although had to bend a line in a 180+ to connect under the pump. Probably a better way to do it, but this will work for now. I think I am going to leave the orientation as factory instead of flipping 180 like some people do. Still plenty of room to get to plugs and headers. I am going to have to bend the oil dip stick. Since I installed flat against the firewall the master is now in the way.
Awesome job, looks really good. I love my Hydroboost on my Camaro, of all the mods I did (and I modded everything, I mean everything...top 20 show car in Oz), the Hydroboost was by far and away the best mod. When I get some more cashflow, one is going on the 61 Buick also
Well, it has been a loooooong wait, but I finally got the car on the road today for a long drive. Long story short, roller cam upgrade uncovered engine issues. New motor had to be built. Finally done. I really love the feel of the brakes now. Fantastic braking and no issues due to vacuum. I also love the extra room to work in the engine compartment now. Maybe do a vintage air conversion on the other side and have room for miles! Bottom line, I recommend this conversion to anyone looking at it. I should add that bleeding this system was a PITA. I have never had so much trouble with any other brake system change I have made on any car.......including major changes like new calipers, master cylinder swaps, rear disc additions, etc. I don't understand why. I was very careful to plug the lines during the swap. I had a perfectly working system before. The only thing I swapped out was the new master and I bench bled the heck out of that thing....twice. I checked everything. Became convinced the hydro boost was not moving the master plunger enough, took everything apart more than once to measure and make sure everything "should" work. I ended up using a pressurized power bleeder and bleeding 4 Quarts of fluid through the system before I got pedal pressure.
Awesome right up on a cool mod! Well done Sir. If you do a vintage air install, please do another write up with pics like this one! That's on my list, and your thread reads like good instructions!
