Installing hydroboost brakes on a fbody
I'm going to try my best to do a write up on installing a hydroboost braking system on a fbody. Before starting this project I did alot of research on the subject mostly due to the fact I never heard of hydroboost brakes until recently. I could not find any info of anyone doing this on a fbody so I got most of my info from the grand national crowd. Benefits to this braking system is that it increases the clamping force of a conventional vacuum braking system by almost double. The hydroboost unit replaces your stock vacuum assist unit with a hydraulic system that runs off your power steering unit. The more rpm's you make the more hydraulic pressure you create. If you own a turboed car this braking system can hold your car on the starting line with plenty of boost (reason for my conversion).
Turbo cars loose vacuum as you apply boost. With the hydroboost brakes you are adding clamping pressure as you build boost.This system can take the place of a trans brake with less shock to the drive train as you leave the starting line.
If your looking just to upgrade your existing braking system this is all you need. Step down hard on the pedal and hold on to the wheel!
A couple things to remember I have a 94 3.4 liter camaro. I upgraded to ls1 front brakes and lt1 rear discs with a removed abs system before starting this project.
First step is to find a hydroboost unit and all the hoses and fittings.
Your options are the junkyard, rebuilt unit or buy brand new. The new ac delco unit was so cheap $75 off e-bay and since the price was right I decided to go new. One thing to remember you do not get all the parts you need when you buy this. The mounting plate, brake pedal pushrod, master cylinder pushrod, spring and retainer is not included. You will have to find these parts elsewhere. I will post some of the places where I got most of my parts. This was not a straight forward install but I will try and give as much info as I can for the conversion. I will add more info and pics that I took along the way.
First thing I did was to remove the vacuum booster from the car. You do not have to disconnect the master cylinder just unbolt it and move it out of the way. Be careful not to bend any of the brake lines. Remove the vacuum line going to the intake. Inside the car remove the clip holding the brake pushrod to the pedal then the (4) nuts behind the brake pedal holding the vacuum booster to the firewall. The brake booster can now come out. The stock master cylinder can be reused.
Next I drilled out the mounting bracket from the vacuum booster. There are (4) rivets that need to get drilled or ground off. Mark which side is facing up or down with a piece of tape as shown in pic.
Next I had to remove the studs that were on the hydroboost mounting plate.
I did this with a sawsall.
Next is to mount the stock mounting bracket to the hydroboost plate. All I did was eye it up on center and then clamp the bracket to the plate. I drilled out the (4) holes and then used (4) 3/8-18 bolts with lock nuts to hold it together.The hydroboost plate did not come with the new unit, I had to use one off of an old unit. The plate is held on with a large nut and a safety "C" clip.
Here is a pic of the hydroboost mounting plate holes. Notice the (4) sided nut and clip holding the plate on in this view.
There is a rubber boot that comes off the vacuum booster which you can reuse before installing unit back on the firewall. It does not seal as well as the original booster so you will have to rig something up.
Here are some installed views.
Notice how close master cylinder is to shock mount.
Now for the parts which do not come with the new unit or if you purchase a rebuilt unit. My biggest hurdle was locating these parts. They are the pushrod, spring, spring retainer and pushrod retainer. These parts install in the hydrboost unit bore. Be warned though not all hydroboost bores are the same size. I believe there are two different diameters. I purchased my parts at Tallon hydraulics.
http://www.tallonhydraulics.com/stor...0j1tfna5agqhq6
The pushrod needs to be cut down so purchase the longest one they sell.
There should be a gap of .065 between the master cylinder and hydroboost unit when the pushrod is at the correct length. As shown in last picture.
If you buy a new hydroboost unit you might not get the mounting plate and brake pedal pushrod. As shown in picture.
Here's a mounting plate a found on ebay that would work.
http://cgi.ebay.com/ebaymotors/Astro...-/290405742848
Here's a link to an exploded view of the hydroboost unit showning where the parts install.
http://www.remanbrakes.com/pdfs/hydr...stallation.pdf
You will also need a pushrod to connect to the brake pedal. Here is where I ran into some problems. I used the pushrod off of a rebuilt unit. The length was a little shorter than the stock rod which is not a big problem but you need to adjust the brake and cruise switches on the pedal. The other problem was the hole diameter on the pushrod was larger than the pin diameter on the brake pedal. I made a brass bushing to make up the difference. I'm sure you can order one from tallon hydraulics if needed. The last problem was the alignment of the pushrod to the pin on the brake pedal. You want the rod to push in the center of the hydroboost unit or it will wear and you will have leakage problems.
I moved the pin on the brake pedal upwards 5/16'' and rewelded it. An easier fix is to buy a pushrod with a 5/16'' offset as shown in the first pic.
The other 2 pics shows the pushrod that I used off a Cardone # 52-7359 rebuilt unit from advance auto.
The last pic is showing the HB pushrod connected to the brake pedal. This picture was taken from a buick grand national.
Next I'll get into the hoses and fittings needed. I used aeroquip TFE -6an braided stainless steel hose which I ordered from summit racing. See link below.
http://www.summitracing.com/parts/AER-FCC0615/
I used a 45* fitting to connect 2nd return line to power steering pump. See below.
http://www.summitracing.com/parts/AER-FBM1112/
Next I used (3) 90* fittings to connect lines to the HB unit. See below.
http://www.summitracing.com/parts/AER-FBM1122/
These two fittings install in the power steering rack.
http://www.summitracing.com/parts/AER-FBM2517/
http://www.summitracing.com/parts/AER-FBM2521/
I used this bulkhead fitting to install a second return into the power steering pump.
This is recommended for quick brake pedal release.
http://www.summitracing.com/parts/SUM-220682B/
I had to remove the power steering reservoir and drill a hole in it to insert fitting.
I drilled the hole in the drivers side of the reservoir just below the fill level.The fitting should be under the fluid level to prevent any aeration of the fluid.
Here is a link to the fittings which install in the hydroboost unit to convert it to -6an fittings. THI 1001-AN6 combo set. Call before ordering for the correct set.
http://www.tallonhydraulics.com/stor...0j1tfna5agqhq6
