How i converted my '72 to Hydroboost for $35! (Lots of pictures)

[Dean'smeanmachine]

Hi all! First off, I am working on a 5.3/th400 swap into a '72 Chevy c/20.

I was thinking one afternoon while working on the thing, "i've got 100 more hp than i did with the old 350, i should probably do something about the brakes" Now keep in mind the Brakes were NEVER that great. even with the disks up front. So i decided to go Hydroboost (and go through all the brakes, replace pads, shoes,and so forth) So i headed to my favorite local junkyard and pulled a hydroboost unit off a late 80's 1 ton Chevy truck. I also grabbed all the lines and pulled some lines off of other hydroboost vehicles.

Now you may be wondering, What the heck is hydroboost? Hydroboost is a Booster than runs off power steering pressure rather than Vacuum from the engine. it creates more steady break pedal feel and transfers more pressure. it also has many other advantages such as it takes up less room, great for diesels and cammed engines that don't create enough vacuum for a regular vacuum booster.

I'm creating this thread in hopes to help anyone who is planning on going hydroboost. of course the results with vary depending on your engine type and what vehicle you are working on but this is how i did it.


Ok i'll start here.

Junkyard Hydroboost and lines: $30

Can of black rustoleum spray paint: $5

[Dean'smeanmachine]

Lines can be the most expensive part of a Hydroboost swap. I recommend sourcing all the lines you need from the junkyard . get it ALL never hurts to have more line than you need. it can get tricky with mix matched components. For example, My power steering pump is metric, my hydroboost unit is metric, but my steering gearbox is standard. if you find a hydroboost unit at a junkyard most likely it will be metric and on a later model vehicle. the older standard hydroboost units are harder to find and if you do find one it is probably seized up and rusty from sitting for who knows how long. You will find them in Astro vans, 1 ton trucks, heavier vans, and other stuff. it's easy to tell metric and standard fittings apart from each other because the standard fitting will have a regular flare like a brake line, while a metric will have an o-ring on the end with a straight piece of the tubing coming out past the o-ring. My later model booster was o-ring, so i grabbed all the lines from that unit, then found an old mid 70's Gmc motor home and grabbed all the booster lines off of that as well because it had standard fittings i could make work with my setup. the standard fittings are not a big deal because all you need to do it cut the metric nut off and put a standard of the right size on the end and flare it. the metric is a bit more complicated because of the o-ring flare end. you are going to want to get every metric line that you need and worry about the standard end later. if you have all metric, or all standard, well great it just makes it easier .


T-fittings and pumps with a return line are one of those things you will get mixed answers on. some people say that T-fittings reduce flow and cause problems, others say they work great. truth of the matter is, GM used T-fittings for many years from the mid 70's to early 80's when they came up with the idea to make a pump with a return fitting welded to the reservoir. as long as the T is big enough there should be Zero problems with running one.
you can go either route Pump with return line fitting, or a T-Fitting. In my case i went with the T because i found one on the old 70's GMC motor home. seeing it was already on a bone stock hydroboost system, I knew it was big enough to handle the job and have good flow. all the lines and the hydro unit came to a grand total of $30 at the Junkyard window

[Dean'smeanmachine]

I started by pulling off the old Vacuum booster.

[Dean'smeanmachine]

I decided to mount the hydroboost right to the Firewall. The plan was to modify the Brake pedal to accept the stock hydroboost push rod length so it would be a shelf item if i ever had to replace it

[Dean'smeanmachine]

I then removed the hydroboost bracket so i could modify it. It is held on with a snap ring and a nut. you can go out and buy a $50 socket to fit the special nut, or you can chisel in a groove to hammer it off. that's what i did.


I then cut off the edges of the bracket so i had a nice square piece to work with. the original bracket layout has 6 holes and two studs through the center holes. I just hammered out the studs. The top set of holes can also come off to get it square as seen in the picture.

[Dean'smeanmachine]

Square bracket left

[Dean'smeanmachine]

More coming when i have time got lots of pics. just need time to load them.

[jjzepplin]

What a tease! I'm in!

[Dean'smeanmachine]

I then used the old booster as a reference where to drill my new holes. The new holes overlapped where the old hole was, so i welded up the old holes. you can see the light shining though the old holes in the picture.

[Dean'smeanmachine]

pics

[Dean'smeanmachine]

Welded up holes and smoothed out.

[Dean'smeanmachine]

Then i marked and drilled the new holes

[Dean'smeanmachine]

I cut the lower corner to clear the steering column bracket and rounded all the edges.

[Dean'smeanmachine]

There is a little tab on the bracket that keeps the booster from moving. I cut it off and welded a new one on the opposite side so the fittings on the booster would be facing up do to clearance issues. you can use the hydroboost right side up or upside down, it doesn't matter.

[Dean'smeanmachine]

Then I did a quick mockup of the booster

[Dean'smeanmachine]

The stock pushrod length on the booster came about an inch short of the brake pedal. I decided to modify the pedal instead of the push rod so in case i ever have to replace the booster it will be a bolt on.

[Dean'smeanmachine]

I then yanked out the brake pedal Assemble (what a pain in the butt) but with a little muscle and some choice words it popped out.

[Dean'smeanmachine]

I welded a piece of steel on the back of the pedal arm so i could drill a hole back further to line up with the pushrod, and bring it down about 1/4 inch to give me a better push ratio.

[Dean'smeanmachine]

I put the pedal assembly back in and marked where the hole needed to be. I drilled the hole and cut off the access metal on the piece i welded on, Then i welded up the old hole.

[Dean'smeanmachine]

A little paint

[Dean'smeanmachine]

I then cleaned, primed,and painted the booster.

[Dean'smeanmachine]

When the paint was drying, i re installed the Brake pedal assembly.

[Dean'smeanmachine]

Then i bolted up the booster and the master cylinder. i used the same master that i had on the vacuum booster because it is only 2 years old and i know it works. i compared it with the one i got at the junkyard with the hydroboost and the piston and everything was exactly the same. Make sure to bench bleed your master or you'll be bleeding the brakes for ever.

[Billyburban]

So you ran your original master cylinder from your factory booster c10 c20 c30 ? It’s been working just fine like that. I have a c10 but I’m running the c20 booster thought it would better braking but not much.

[Hammered 77]

Any updates on how it works?