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Discussion Starter #1
Since my car is running better now, I'm becoming aware of the inadequate brakes (especially after reading GKulls post on CF). I want a Hydraboost if for no other reason than to get that big-a$$ vacuun booster out of the engine bay.
But--it seems to me all it would do is reduce the effort required to depress the pedal. Does it also increase the pad pressure on the rotor? And even if it does, still the only way to improve the braking abilities of the car itself would be to replace the rotors & calipers/pads with higher performance units, right?
I really can't afford new rotors, etc.--too many other priorities at this time.
Is my thinking correct? Any other ideas? Budget is a big concern, unfortunately.

John
 

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it reduces effort, the max. pressure you can make at the pads depends on the brake pedal ratio, the master cylinder size and the caliper piston size. For the same pedal travel the resulting force will be the same, however of cours it's esier to depress the pedal w/ the hydrobooster
 

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Discussion Starter #3
So really all the Hydraboost does is give me a Cadillac pedal and access to #7 plug.....Still probably worth it...
The better I make the car, the more it needs!
 

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My take on this is that if you can lock the tires, your brakes are good enough particularly on a budget. The hydroboost (which I am not a big fan of :)) simply allows less foot pressure to lock up the aformentioned tires .... :thumbsup:

Just my .02
 

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I'll put my .02 in on this. I had manual brakes for years and they could lock up the tires but with a lot of effort. It requires very little effort to really haul the car down now. It will not reduce your stopping distance because you are still using the same rotors calipers and pads, It just reduces the effort. My motor does not make much vacuum so the big vacuum system was out of the question. The hydroboost is small and is always there regardless of how many times you tromp on the pedal. I had a slight issue when I first installed it but Paul and I worked through this and it has been working fine since.
 

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My take on this is that if you can lock the tires, your brakes are good enough particularly on a budget. The hydroboost (which I am not a big fan of :)) simply allows less foot pressure to lock up the aformentioned tires .... :thumbsup:

Just my .02

Well, yes and no.....

I put on a HB system about a year ago, and shortly after that, upon seeing it worked EXCELLANT.....did an aluminum m/cyl.....and for the last year the brakes have been fine to the point of perfection....

I tore apart my old stock booster, and it was working well, not leaking, nor could I spot any defective parts in it....everything looked new and fresh enough.....BUT, I did spot a spring in between the input shaft, and the output shaft going to m/cyl.....that damn spring was pretty stout, dunno why it was there, but under enough pedal pressure, I"m convinced it allowed the pedal to hit the floor as some sort of limiting device....not sure what in hell was on the engineer's minds....

at any rate, when installing that HB, my first comments were, sharky is on his nose, and MY nose was in the steering wheel.....THAT good....lockem in a heatbeat.....I used to it now though....first time I have EVER had a GM passenger car without that damn squishy crappy soft brake pedal feel...and it's been a hallmark of GM cars for decades.....same as many others....

I like a pedal hard as a teenager ....

BTW, the aluminum m/cyl replaced that truck large bore iron cast monster I had on there....having a smaller/stock diameter....the truck one was just too much, which prompted the change....

the brakes have not been one iota of issue of any type since the swap....

except a l/front hose failure where it got constricted and locked the caliper/rotor.....~11 years old at the time....

BTW, I have gone the route with O rings/SS liners/no springs/ dot5/ hoses, bleeding/pads/ nothing unusual, but this is the longest time I have had these brakes working this well.....

change the freeking booster over to HB.....note, it does require a power steering pump.....
 

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I love my hydraboost

Best upgrade I've ever made.

I hate the mushy feeling vacuum pedals.

The hydraboost feels alot better.

Can't powerbrake it now though :down:

I believe stock brakes are adequate with ducts and insulated pistons.
 

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If you reduce your brake pedal effort you also reduce your ability to modulate your brakes. For a street driven car that might not be a bad thing but for a car that you might take to auto-x or the track, you might not like more boost.

This biggest problem I see with C3 brakes is a poor selection of modern friction materials for the pads. This is probably not going to change, most modern pads are much smaller in area because modern materials are designed for a higher unit area pressure that the old C3 stuff.
 

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My brake useage will be limited to being able to stop to turn onto the return road after 1/4 mile. Power brakes were extra weight. Weight = horsepower thief. I'm with rjent. As long as it stops in the distance I need it to stop in, I'm happy with manual brakes. BTW...locking up the tires is not the most effective way to stop. But ya'll knew that ;)

Dep
 

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My brake useage will be limited to being able to stop to turn onto the return road after 1/4 mile. Power brakes were extra weight. Weight = horsepower thief. I'm with rjent. As long as it stops in the distance I need it to stop in, I'm happy with manual brakes. BTW...locking up the tires is not the most effective way to stop. But ya'll knew that ;)

Dep
Yeh, BUT....when the pedal is 2/3 way to floor, and can be all the way with a bit of extra effort, and that's considered 'normal'...there is an issue wit the brakes...now my 6'5" frame and size 13 shoes can do some pressure, BUT, those brakes were never worth a damn UNTILL that HB went on there...

totally differant feel to them...they instill CONFIDENCE instead of FEAR in me....
 

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Gene: I don't have the master cyl or lines run yet. They all have to be changed since I removed the PB booster and master. I'll let you know how they feel, but I've had manual drum brakes and they stopped quite well.

Dep
 

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Discussion Starter #12
Gene,

So I'm deducing that you installed a 'junkyard' hydraboost from a truck which had a different size bore &/or stroke master cylinder from OEM 'Vette. You then changed the master cylinder to an (aluminum) one with OEM bore/stroke specs, which improved the useability of the unit, right?

OK, Friday night rambling here--A) I understand hydraulic leverages from motorcycle modifying. B) Don't the manual brake 'Vettes have a smaller master cylinder bore than the power brake models? C) Therefore, a manual brake master cylinder with a hydraboost should give better brake modulation/control than my power brake m/c with hydraboost, at the cost of a bit more peddle pressure required than the power brake master cylinder w/hydraboost, right?

John
 

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yes, a manual has a smaller bore but smaller bore means the dluid pressure also rises more rapidly, requiring less pedal effort. It will do you no good. Sure it will increase the stroke needed to displace an x amount of fluid but w/ even further reduced effort. Modulation is not about how long a pedal you have but how much feel there is in the pedal so that you can brake at the thin line between locking up and maximizing the grip of your tires
 

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I went the j/y route and built one using the Vette m/c that was on my old vacuum power booster.

The difference is night and day. My wife had a C5 for a few years, and I remember when we first bought that car how effortless the brake was and how very little movement was needed to bring it to a hard stop. My C3 never had that kind of feel.

The good news is the effort is minimal, travel is minimal, but the "zone" between stopping and locking is an ultra fine line. You have to learn how to drive the car again, because just a hint of "panic" stop will lock them up and put you in a slide (not cool).

However, once you learn the limits and feel...you are back in business. My wife is 4'11" tall and I have 94 Vette seats in my 69. She didn't like to drive the car much before because the brake travel was (compared to her C5) too far and mushy. Now, she can hop in the car and rip out of the drive like a pro.

Its all good.
 

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Gene,

So I'm deducing that you installed a 'junkyard' hydraboost from a truck which had a different size bore &/or stroke master cylinder from OEM 'Vette. You then changed the master cylinder to an (aluminum) one with OEM bore/stroke specs, which improved the useability of the unit, right?

OK, Friday night rambling here--A) I understand hydraulic leverages from motorcycle modifying. B) Don't the manual brake 'Vettes have a smaller master cylinder bore than the power brake models? C) Therefore, a manual brake master cylinder with a hydraboost should give better brake modulation/control than my power brake m/c with hydraboost, at the cost of a bit more peddle pressure required than the power brake master cylinder w/hydraboost, right?

John

OK, as time and money allow to address various issues, or try to with the vette here, I have replaced the m/cyl with a larger bore unit which was on the car, the same, without breaking the brake lines loose...when putting on the HB, it was SO sensitive, I went to a more stock diameter aluminum aftermarket m/cyl to get some travel/feel back, I suppose I could have kept the truck larger diameter on there, but it's done now....

the truck unit with the olde junk vac booster was an attempt to get more pedal feel, less throw to the brakes, it worked, but they allways did feel crappy.....or very rapidly would soon after tweeking it up....sometimes in a few months, sometimes in a week.....like I said it's a time/effort type thing....

and of course tearing apart that old vac booster showed me where the lousey feel was from.....

BTW, that HB unit beleive it or not is no heavier than that olde junk Vac canister/booster...
 

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the hydrobooster is a good bit heavier :) but it is a much sleaker design than that ugly vac booster.
 

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the hydrobooster is a good bit heavier :) but it is a much sleaker design than that ugly vac booster.
HUmm, you sure?? I hefted one naked unit in each hand upon the install, and thought they very similar in weight.....true I"m left handed...but.....
 

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Discussion Starter #19
yes, a manual has a smaller bore but smaller bore means the dluid pressure also rises more rapidly, requiring less pedal effort. It will do you no good. Sure it will increase the stroke needed to displace an x amount of fluid but w/ even further reduced effort. Modulation is not about how long a pedal you have but how much feel there is in the pedal so that you can brake at the thin line between locking up and maximizing the grip of your tires

:thumbsup:

The weight is not really an issue for me personally, it's to clean up the engine bay & improve drivability.
It's going to be a long time before I can actually do this conversion, but I like to think & plan ahead so I don't screw myself as I sometimes do....I have differential/driveshafts rebuild on the immediate agenda, then wheels & tires, and then a TKO 600 after that. And sometime before next fall I need to do a heater core replacement as well.

Thanks all,
John
 
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