brake booster question

[chev74]

i know this has probably been asked before, but how much work would it take to swap my non-power brakes over to power brakes? just add the booster or would i need a new master cylinder as well?

[Ivan D.]

Yes, you will need a master cylinder too, but they're cheap. What power brakes are you going for, vacuum assist or hydroboost? I went with the hydroboost cause of my oversized tires, it works ridiculously well and is also much more compact than the vacuum brakes. You will need good brake lines and hose for it tho, or you may end up blowing something like I did when I was testing them at my place before I drive it.

[tyjoja]

wow, I was just going to post almost the same question, sorry about jumping in. I have a 73 with manual brakes and a 76 parts truck with a power booster and no master cylinder. I think I can bolt the booster on mine, but do I need to buy a master cylinder for a 76? Also the booster doesn't have a push rod hanging out of it, can I get one and do I need it? My truck has a straight six, where do I hook up the vaccuum hose. Thanks in advance, Bob

[Ivan D.]

Bob, the hose for the vacuum supply is supposed to go to a strong manifold vacuum source, usually the 3/8" port on the back of the carb. The booster may or may not bolt to yer firewall, I seem to recall something about them studs being weird - the brake booster has at least 4 studs already attached to it that need to go through the firewall and have the nuts on the inside of the firewall, but the firewall of manual trucks already got two studs sticking out of it where the old MC bolted in. It may be possible to punch those studs out of the firewall and bolt in the brake booster, but in my hydroboost conversion I did just the opposite - punched the two studs out of the hydroboost and slided it onto the ones sticking from of the firewall. As far as the rod goes - my hydroboost units always had one attached to them, I'm thinking the vacuum one you go should have something too, unless it's a detachable part (not the case with the hydroboost, can't remove the rods there) - really I'd suggest finding a vacuum-boosted truck and looking at its setup, that should give you some better info than I can come up with.

Edit: master cylinder - there are two types of master cylinders, one is for hydroboost, and the other is for vacuum assist, difference is the depth if the blind hole in the back of the piston that the rod from the booster goes in - bring the booster with you when you go to buy the new master cylinder.

[tyjoja]

Thanks Ivan appreciate the info, sounds like it will work out for me just fine I think it will be a nice addition. Thanks again. bob

[Mr79C10]

Hmmm, So I want to do the same thing. I got myself a booster, So I need to change the MC??

[Ivan D.]

Man, that's one nasty brake booster, pleas hit it with the wire brush and the rattle can before you install it But yes, you will need a new master cylinder, reason is the stock pushrod is attached to the stock master cylinder just like the "new" one is attached to the brake booster. As I said, when you go to the store bring the booster with you to make sure you get the right master cylinder as the ones for vacuum and hydroboost look perfectly identical except for the depth of the slot in the master cylinder piston for the booster pushrod.

Also, notice how the vacuum assist booster has 6 holes on the bracket, the top ones you will not be using as the firewall behind them is solid - if you want you can drill and insert studs I guess, but tis not necessary. So from the stock firewall loosen the 4 nuts (two for the master cylinder, two below it covered in dirt and grease and grime), and the vacuum assist booster will slide right on the studs - reuse nuts and tighten them with a box wrench, a socket and ratchet will likely not fit because of the bracket's shape. From there on tis as simple as bolting up the new master cylinder, filling it up, bench bleeding it with the supplied kit, and bolting up the brake lines.

[Mr79C10]

So the 2 bolts holding the M/C and the 2 bolts on the plate,, And that booster will bolt up?

But oh yea.. will be taking a wire brush to it and por15 aswell.

[Captkaos]

Since you have manual brakes those top 2 holes are where the studs would normally go to mount the bootser. You need those holes to house the studs as it takes 6 to hold the booster on.

[Ivan D.]

Originally Posted by Captkaos

Since you have manual brakes those top 2 holes are where the studs would normally go to mount the bootser. You need those holes to house the studs as it takes 6 to hold the booster on.

Are those things all that heavy? Those are 3/8 or 7/16" studs after all, I tried cutting one just for a test once and they are pretty darn strong. By the way all new Chevy vans have the hydroboost attached with just 4 bolts, I was thinking of snagging an extra one from work just for neatness purposes as it will bolt right up at the firewall.

[Mr79C10]

So whats going to be involved in getting those 2 bolts in on top?

[Eddie47]

Originally Posted by chev74

i know this has probably been asked before, but how much work would it take to swap my non-power brakes over to power brakes? just add the booster or would i need a new master cylinder as well?

Check with Mike at http://www.bumpandgrindgarage.com/ has all the stuff you need to do this I just did one cost was less than buying used parts that did not work or fit. Then when you are done it is wright and all new remember you depend on the brakes for your life. Talk to Mike hin self or PM him he will make sure you get all you need for the job at the right price. Say hay to him for me.

[wicked_sky_gazer]

If i may?. how difficult is it changing from vacumme to hydro, thats a change that i am going to be making as the cam in mine kills my brake pressure at lower rpms,

[Ivan D.]

you need to swap the vacuum booster out for the hydraulic one, it should hook right up to your brake pedal. Master cylinder may or may not need changed, new master cylinder can be had for under $30 usually. Remove the high-pressure line you now have, hook up the two pressure lines that come with the hydraulic booster (one goes to PS pump, the other to the steering box), T-ee the return lines from the booster and the box together, and that's about it.

[Ivan D.]

Originally Posted by Mr79C10

So whats going to be involved in getting those 2 bolts in on top?

It'd take drilling the firewall and finding a way to reach up there under the dash with a socket for inserting/tightening the studs/bolts. Tho as I said you don't really need them, new Chevy vans use only the lower 4 studs, the bracket don't even have provisions for the top two.