Hydro boost

Kev'C3

Member
Joined
Feb 14, 2015
Messages
18
I have a hydro boost from 2000 Suburban and I like to install it in my Vette,so I don't have to worry about vacuum brakes and can run a high lift cam. Has anyone installed one on a C3 Vette?:confused:
 
Yes, and it works wonderfully.....I dunno what vehicle it is out of though....

I just know the vette is happy on stopping, and so am I....

1/2 the pedal travel, and no sag at the bottom, ALL GM vacuum boosters I have ever driven could be pushed through the floor, and never failed to actually top the car, but that pedal feel sucked....the HB unit feels solid as a rock, and put my nose through the wheel first time I drove it.....

:1st::beer:
 
Was it difficult to install? How did you connect the hy boost to the brake pedal? Mine doesn't have a clevis! :confused2:
 
Was it difficult to install? How did you connect the hy boost to the brake pedal? Mine doesn't have a clevis! :confused2:

Mine came mounted on a large metal plate, and the top two bolts lined up and so the centerline was good both horiz and vert....the bottom bolts I had to drill the plate for the studs...I THINK the clevis from the old booster was used, I had to cut the booster shaft and thread the end for the jamb nut and clevis...measure carefully from old booster same from face of mounting plate, obviously...I used the hoses the unit came with....it was bought off ebay so a pix showed the complete unit....the HB I have has a short 'dick' on it, meant for a later shark divot in the master cyl piston, so if you have a m/cyl with the deep hole like stock on a '72 you need to add a metal shaft in there....

I have had 4 m/cylinders on this car in 20 years, this last one is an aftermarket aluminum unit of stock diameter pistons....has a screw on top, it's from Pirate Jack Racing.....two stock m/cyl were the one it came with then another stock unit....fighting that super soft pedal....I even eliminated that brake switch bullshit up front on the frame, back brakes to the m/cyl rear port directly....front got the same sort of splitter the rear brakes have near the t-arm in back.....I found that damn switch somehow managed to allow air into the front lines....that never did fix the squishy pedal though, just allowed the car to stop...:devil: the car had a truck diameter 1 5/16? diameter piston, huge heavy unit on it as the last gasp to get the stock booster to have less pedal travel, it helped, but no cure.....

I kept the truck master cyl on the car when doing the HB, never moved a line, direct A-B comparison, sharkey slammed my nose into the wheel, has he stood on his nose.....course I wasn't used to the NEW FEEL.....

every damn car I drive in now that has a vacuum booster just makes me nervous.....especially GM production......

:lol::stirpot:
 
Was it difficult to install? How did you connect the hy boost to the brake pedal? Mine doesn't have a clevis! :confused2:

It's probably been 5 years or so...time flies. My 70 had factory power brakes. I wanted to get rid of the vacuum canister to make room for valve covers on a BB and more spark plug access. Removing the factory vacuum canister was very difficult. It has to be done from inside the passenger compartment. Laying on your back with extensions and u-joints to get the top two nuts...I think the nut nearest the centerline is the hardest. You can't see what you're doing. It has to be by finger feel. This is a 6'2" 220 lb guy laying on his back with the driver's seat out. To mate the hydrobeast onto the car...wrestling to get the vacuum canister off had took the fight out of me. I removed the steering column...a surprisingly easy thing to do! Voila...everything now became sooooo much easier. My 70 was a close to 100,000 mile car, so at this juncture I redid completely the shaft with the brake and clutch pedals. Replaces all the nylon sleeves which act as bearing. Put in a new clutch pedal metal arm...Volunteer Vette.

I haven't driven my 70 with the hydrobeast in it yet. From reading other people's experiences, it appears the hydrobeast low/no pressure line must be able to dump into the PS pump reservoir with no back pressure. Apparently any tiny amount of back pressure on this line, will make the hydrobeast sensitive to lock up. (I'm repeating what I've read...I have no actual experience that tells me how true this statement is.) The hydrobeast was stock equipment on GM vans and also apparently a Cadillac sedan. Best I remember, posters who had driven stock GM vans and the Cadillac, reported that the braking sensitivity of their hydrobeasts was similar to a stock vacuum unit (at full vacuum). It was recommended that the low pressure hydrobeast retutn line NOT be joined to the low pressure return line from the PS hydraulic ram....instead braze a separate fluid return line into the Saginaw PS pump housing...aka the reservoir, or the "ham can." A poster suggested brazing the return port into the fluid fill tube for minimum return pressure...Getting to the punch line now...GM Saginaw engineers (Jim Shea, Mike Shea?) determined, with a clear plexiglass model of the PS pump reservoir (the ham can) where an optimal low/no/negative pressure? point was in the PS pump reservoir. The vans and the one Cadillac model sold with hydrobeasts had a PS pump reservoir with two return lines..one for the PS and one for the hydrobeast. I bought one of these PS pumps for my 70. It was only about $90 new from Rock Auto. It's in my garage and I have the part number. ...Heavens! will this story EVER end? This hydrobeast specific PS pump has a press on pulley. Bottom line, I need the older style keyed pulley. So, I have yet to pull the PS pump out of the stock reservoir and the PS pump out of the hydroboost reservoir and interchange them. It's pretty easy to do, I just haven't done it yet.

Mrvette alluded to some sensitivity with his hydrobeast and from his comments he's happy with it's performance. I'm assuming he doesn't have the hydrobeast specific Saginaw PS Pump reservoir can. I'm guessing, he has an adequately unrestricted return line. .............Anyhow, I've never driven my 70 hydrobeast equipped car, so I'm kinda dry lab'ing everything here.

Will this story EVER end, Part II. I think if you get the GM PS pump designed to be used with the hydrobeast, not only will it have a pressed on pulley, but it will have a metric high pressure output. I had a custom made high pressure line made for about $80...I didn't know that an English/metric adapter coupling made out of brass cost, from NAPA, $7.50. I don't want to use a pressed on PS pump pulley. I have March billet aluminum pulleys, and I'm afraid that if pressed on, they just break lose and spin.
 
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Back about '95 when I bought this '72, I put on a '88-91 vette serp drive....and a SI17 alternator for the electric fans..... I swapped the P/S pump fitting assy for the older style, not knowing of any flow/pressure changes.....ran it with the older leaky p/s crap for some years, decided to go for a rack/pinion and TT helped me with some connections to parts and the guy who first did it over in Europe.....so using that intelligence I finally clued in on what rack was used, and so did my own before any kits were marketed.....so it worked fine and when the HB setup was installed years later....the return line was plumbed in through a T fitting.....

the HB had the straight shot through the T, and the steering had the stem.....

works fine .....trick is....

I had a Motor Home project and plumbed the return just the opposite, and the HB seems to have a MUCH HARDER pedal, as in no assist....so never found out why, sold it....stopped ok but you needed a contractors/marine/army brogan to do it.....

:shocking:
 
Another comment about power vacuum or hydraulic actuated power brakes.

I went through a many year process with a technology upgrade restore of my 68. At the time, technology upgrades were carefully considered, and many implemented: ZZ4, TKO600 tranny, SSBC brakes, Serpentine accessory drive, Be Cool radiator, etc.....but astoundingly I never gave a thought to my mechanical brakes!! I should have converted to power brakes in the 68. I'm astounded that I was blind to this item. It wasn't until I drove the car, after about 25 years!..that I immediately realized I had manual brakes when I, for the first time, applied the brakes on an around the neighborhood drive.

Actually manual brakes are NOT that bad. They take more pedal pressure, but at 73 years old, I can still lock up the wheels on braking. I don't drive my 68 with shoes on. I drive in my socks. When I brake, or clutch, I wrap my toes around the top of the pedals for extra gripping. (Like a monkey!!) I'm worried that as I age, the manual brakes may become a problem.

Converting from manual to power brakes is fussy....my previous post about getting rid of the vacuum canister to install the Hydroboost is a clue.

For what ever it's worth, my 68 has all stainless steel brake lines and fittings, Stainless Steel Brake Corporation (SSBC) aluminum calipers, rebuilt stock SSBC Master Cylinder and silicon brake fluid. A lot of people have soft pedals with silicon..I have a stone hard pedal. When I did the bleeding myself, the pedal was a little soft...I had Guldstrand Motorsports bleed the system to get the stone hard pedal.
 
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I use DOT5 synthetic fluid also....because of rust...

Pedal is hard like previously stated, just need let the bubbles rise to the surface, kinda like doing power steering....

:drink:
 
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