Hydroboost How to

[Devs93]

I did this on my 04 silv and love it so far. The only thing I want to do is space out the booster some so it takes up the 1/2" of play before the braking starts, but thats no big deal. I have locked up my tires (well, the abs kicks in anyway) and dry road going 60mph and wouldve face-planted into the windshield if I wasnt wearing my seatbelt. Pedal effort is near nothing and is much smoother and more liner whereas with the vacuum setup you felt like even though you were pressing harder you werent stopping any faster - not the case with hydroboost, the harder you press on the pedal, the more force it exerts on the calipers, and the faster you stop, period.

I do have 14" powerslot rotors, with hawk pads front and rear, and stainless brake lines, so that definately helps as well. I would say I can stop better than stock now, even with my tires that are twice as heavy. This is definately a worthwhile mod.

I picked up everything to do this swap for under $200 at a salvage yard off of an 06 tahoe and autozone,
- $100 hydrobooster
- $0 lines (salvage yard: "yea you can have those, no problem")
- $30 master cylinder (didnt even need it actually)
- $20 power steering fluid, vac cap, clamps, brass T
- $35 pedal from gmpartsdirect (salvage yards wanted over $70!)
So that comes out to about $185, which if you can get it without the master cylinder your down to $150, but most places sell them together.
If you cant get the hoses like I did, rockauto sells them for around $20 each (3) and autozone/advanced around $45 each.

If you were to do this new the break down would be something like,
15295853 - Hose 72.53
15804952 - Hose 73.06
15295840 - Hose 70.35
15734409 - Brake Pedal 35.99
15234828 - Power Steering Pump 176.59
18047512 - brake master cylinder, includes reservoir 205.06
15854060 - booster 399.05
Which comes out to around $1032...yea...no thanks.
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Tools Needed:
-pliers (for hose clamps)
-16mm and 18mm wrench for hose fittings (im guessing, my 19 was too big for the big one and 17 was too small, and my 15 was too small for the small one and 17 too big), creasent wrench also works but is bulky in a tight space
-flat head screwdriver
-power steering pulley puller kit (rent from autozone or advanced), you need both the puller and the pusher to put the pulled back on
- 15mm and 18mm sockets with extensions
- shop towels for fluid leaks
- 1 quart of power steering fluid (should be more than enough)

So on to the install

This is basically all you will need. This is assuming you are going to T the low pressure return instead of buying a new pump. If you get the new pump just plumb the return to that fitting instead of T'ing it.


Step 1:
Unbolt the master cylinder from the vacuum booster unit with the 2 screws on the side. They are 15mm I think. There is only two and its not hard to get to. There is no need to remove the master cylinder since the vacuum one will work fine with the hydroboost one. No need to take it off and have to worry about getting air in it, so once you un bolt it just move it out of the way being mindful of the hardlines. Whatever you do, do not bend them where they crimp or youre in for a big headache, they will give some, but be mindful.


Step 2:
Remove the stuff attached to the brake pedal. The brake sensor and rod linkage are both held down by this guy,

-The easiest way to get it off is put a screw driver inside, turn in 90 degrees and slide it down and off. It is key shaped so you have to slide it down to get it off. Its kind of a pain, but stick with it.


Step 3:
Remove the brake pedal and 4 bolts that hold on the vacuum booster.

-This is the hardest part about this conversion. If you have big hands and shoulders like me it makes it difficult to maneuver in there and get those out. An air ratchet would be invaluable.


Step 4:
Remove vacuum booster and drill hole in firewall for the offset bolt of the hydrobooster.

-Once you remove the nuts from inside and disconnect the rod from the pedal, there is nothing holding the vacuum booster on so with some wiggling it will come right out. Put it aside and sell it on ebay, you will no longer need it.

-Now you may notice that your hydrobooster has one offset bolt from the other 3. You have two options: either drill a hole in the firewall where there is a dimple (see above pic), OR try to press out the offset bolt and drill your hydrobooster mounting plate. I tried to press the bolt out but wasnt having any success so I drilled the firewall. Either option works fine, except if you drill the firewall you will need to cut come rubber to place the nut over the bolt, or leave it un-nutted (ha), your choice.


Step 5:
Once you have the hydrobooster mounted in place you can now bolt it up from the inside and install your hydroboost pedal.
This is why you need the new pedal:

Notice the position of the rod stud in comparision with the top of the pedal. If you kept the stock pedal, your pedal would stick out past where it should be making it very uncomfortable and difficult to press. It is in your best interest to buy the pedal since modification of the rod will most likely destroy your booster.
-The mounting bolt for the pedal only goes in one way, right to left (nut on left side), so dont sit there for 10 minutes wondering wtf is going on before test fitting the bolt without the pedal in the way and realizing you had it backwards the whole time, mmk?
-Reinstall the brake sensor and rod to the pedal using the clip you removed earlier, except this time you press it over and slide down so its locked in place.


Step 6:
Attach the master cylinder to the hydrobooster the same way you took it off. Dont forget the brake line holder thing when you bolt it back on, it goes between the MC and the nuts.

So at this point you have the pedal installed, and hydrobooster and master cylinder installed and ready to go, and now you need to run the lines.