EXACTLY WHAT YEAR S10/Blazer does the brake booster come from? I think I heard 1996...but I want to make sure.

I'm looking for cheap upgrades that I can do easily to help update the feel of my 88 Base Coupe 3.4L
the brakes stop smoothly. and when I push really hard suddenly I can lock up all 4 wheels (only done twice thanks to dumb drivers)
I'd like to have a "newer feel" to my brakes, so I want to do the S10 brake booster conversion.

I'm a mechanic and love doing things with my fiero.

I'd be buying new parts or tested used parts.

I LOVE MY Stock 15" 88 black wheels...so a brake rotor upgrade is not happening anytime soon...I will be buying drilled/slotted/vented rotors though (stock size)
HOWEVER!!!! If I get another Fastback and it's an 88 GT I will be doing the 13" GURU swap if hes still making them by that point in time.

let me know!!!

THANKS!!!

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F.I.E.R.O. - Fantastically Imaginative Engineering Racing Object

I'm here to Help, just ask

www.fquick.com/GTXBULLET
Tech/Mechanic (Restorations, Modifications, and Maintenence)
1988 FIERO 3.4L Getrag Base Coupe (the show car ;-) )
1986 Fiero SE Auto (parts car, still in Tenessee )
1984 Fiero SE 4-speed with A/C and Trunk Pop
Size 13 Feet with Cracking Ankles and Tired Knees

[This message has been edited by gtxbullet (edited 03-01-2012).]

You keep the stock Fiero master cylinder

If you're brave enough to try it, you could look into hydroboost. Astro vans came with it, and it was also available on Regals T-Types/GNs & later ('82-'85ish) diesel powered G-Bodies. You would also need a hydroboost master cylinder. I'm not sure what the bore size is but I imagine braking would still be improved. You would also need to add a power steering pump (or electric equivalent).

Using bigger truck MC w/ stock calipers will Always Reduce system performance. Is a Basic Hydraulic rules.

Better stock brake first restore the system then maybe upgrade the booster.
1. Fix any Hydraulic problems.
2. Check/fix/replace rear caliper. 88 have save problem as earlier years.
3. Check/fix booster, its vacuum pluming and check valve.
4. Turn or replace all rotors.
5. Get Premium pads. Wagner Themoquiet etc...

See my cave, brake section.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

[This message has been edited by theogre (edited 03-01-2012).]

Ogre is correct.

The 88 brakes should be better than you describe, are you sure the rear calipers are working properly?

Do you use your emergency brake frequently? You need to, as this is what adjusts the rear caliper.

If you want to find out the bore size difference - the parts guy at NAPA or other real car parts place (not A/Z) will have that information on their database.

Steve, did you mean S10 BOOSTER as opposed to S10 master cylinder?

The booster would make a heck of a lot more sense. Haha, just feel like you mixed the two up.

the larger bore master cylinder will increase braking power as it will effectively be moving more fluid through the same system. hence why there are big bore brake masters for sale for pre 88 fieros.
and why people install them.

I don't want to have this thread get side tracked on why/how it's wrong to do it.

I am asking in hopes someone else on the forum has done the same swap. as the one I spoke with recently but never wrote down their name...(figures)

I am installing Drilled and Slotted Rotors, braided stainless brake hoses, and new pads.
my car is rust/corrosion free, the brake lines are all good. even the rubber ones are good. they have no dry rot. calipers are all good. and yes I use my parking brake. since my 3.4L install in december I have yet to reconnect the lever.
I have replaced one caliper due to bleeder hole threads getting stripped out

when I put the new rotors, pads, and lines in (doesn't "need" any of these, I'm just getting the best available bolt on upgrades over stock.) I want to do the upgrade so it'll all take effect at the same time so I don't have to bleed the system multiple times by myself.

quote Originally posted by gtxbullet: the larger bore master cylinder will increase braking power as it will effectively be moving more fluid through the same system.

More fluid, but at much lower pressure. That's the trade off. You need more pressure to improve braking. The booster upgrade increases pressure.

Get the S10 Booster, mod it to work, and make sure everything else in the system is in factory correct working order and you will have what feels like a huge brake upgrade.

You don't even need to bleed the system to do this upgrade.

FYI, the 88 Fiero master cylinder is .944" (24mm). the Blazer master cylinder is 1.25" (31.75mm). So the Blazer Master will put out just over half (56%) of the pressure that the Fiero's master would given the same pedal effort. That's why you have 5 people telling you NOT to do this upgrade, and to DO the Booster.

If you apply 100 lbs to the brake master pushrod, the stock 88 master will result in 149 psi of line pressure. Do the same with the S10 brake master and you get 82 psi. The line pressure then acts on the piston diameter of the caliper. If the caliper diameter remains the same and you switch the masters as you are wanting to do, you will loose clamping pressure and resultant braking force at the calipers.

About the only time you want to increase the diameter of the brake master is after you have swapped out the brake calipers with ones with a larger piston diameter. Then the lower line pressure is offset by the larger caliper piston area and keeps the overall clamping force at the caliper in the safe range.

The brake booster is a means of assist and does not change the hydraulic balance of the brake system. It merely uses the force of engine vacuum to increase the force that is applied to the brake master. The larger the booster, the more overall assist for a given amount of vacuum.

On the 88's:
Adding the S10 brake booster is a decent idea and will increase braking force.
Adding the S10 brake master is a very bad idea... It will make the pedal very hard and greatly reduce the braking performance.

quote Originally posted by Fierobsessed: More fluid, but at much lower pressure. That's the trade off. You need more pressure to improve braking. The booster upgrade increases pressure. Get the S10 Booster, mod it to work, and make sure everything else in the system is in factory correct working order and you will have what feels like a huge brake upgrade. You don't even need to bleed the system to do this upgrade. FYI, the 88 Fiero master cylinder is .944" (24mm). the Blazer master cylinder is 1.25" (31.75mm). So the Blazer Master will put out just over half (56%) of the pressure that the Fiero's master would given the same pedal effort. That's why you have 5 people telling you NOT to do this upgrade, and to DO the Booster.

Thanks for the measurements!!!! I'll save those for future use in my Indy Pace Car