Let's talk about Hydroboost Brakes (3 Viewers)

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BAM!
 
Just for clarification I'll post this picture and we are talking about the Baffle & Spring Retainer, Piston Return Spring and the Output Rod. None of these items came with the new unit I originally bought and had to be sourced elsewhere, my problem came from not knowing that there is several sizes of output rods and only the correct size will work.

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Because we are posting about this in a Toyota section if you’re not running 1 ton axles like Lil’Jon the Cardone 10-1584 master has a 1-5/16” bore and is too big for the Toyota calipers, you need a Cardone 10-1576 or something similar with a 1-1/8” bore.
 
Yeah, that had my head spinning. I went with Hydratech's universal kit. It uses a Wilwood master 1 1/8" bore and a Bosch booster. They match them up with everything you want/need in the kit.
 
Just want to chime in ... I've used a number of Jim's (Hydratech's) systems and he's so great to deal with. My 66' 40 stops as fast as any modern car ... its actually pretty insane how good they work. I am using Wilwood 6 piston fronts and GM rears ... same is planned for Killer Piggy

Cheers
Steve
 
Hydratech supplies a mounting plate with their universal kit. The plate comes with mounting holes that don't match the firewall, so I welded them up and started over. You need that plate because it has a locking tab in the big hole to hold the booster to the plate. I made a 1/2" spacer in order to move the push rod back to make sure I can get the full pedal travel before bottoming out, might not need it.

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you just need a disc/drum prop valve and you will be set. They are like 30-50 bucks.

So another advantage that doesn't effect me but I hear guys have trouble with room for the vacuum booster and the clutch SC. The Hydroboost has less of a diameter to it.
 
You can use just the MC if they’re setup with the residual valve for rear drums. The residual valve keeps 5-12 psi on the rear circuit so the wheel cylinder cup seals didn’t pull back.

you don’t want the residual valve if you’re running discs, as you do want the piston and pad to pull back a little.

I bought a proportioning valve for the setup on the 80, but didn’t need it. Remember: fronts lock first (or simultaneously).
 
Digging digging digging
Trying to assemble more info pertaining to this topic and overall braking upgrades that work well and convey it in a way that’s understandable.

Inevitably, this thread keeps popping up over and over.

Several pages deep, I finally encounter some hard info I’m looking for.

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The idea starts with having a completely stock brake setup with a disc front, whether it’s a 55 or 60 series. If you just switch to a Hydro-boost and nothing else, you’d want to try to find a close GM MC to the OEM LC, which is 7/8”. As you go up in that diameter, the pedal gets stiffer and brakes don’t feel to work as well.
If you change out the calipers to the early/mid 90’s 4Runner with the larger pistons, the brakes will feel squishy but the stopping power improves. At that point if you slightly increase the bore diameter of the MC, it will slightly even out to feel more OEM normal. It’s very relative, and increasing the MC bore size too much even with the larger calipers will still cause the brakes to feel stiffer than they should.
So then, if the rear is converted to disc brakes, this introduces another change in hydraulics, whereas then another increase in MC bore size will help to balance the works back out to a more OEM feel. This looks to be the combination that settles in on the 1.125” GM MC size that evens the hydraulics out on this complete brake system change.


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The second part of this regurgitation is that if a person were to be keeping stock rear drum brakes, what GM master cylinder would work in conjunction with a Hydro -boost? So far I have found this chart. 1993 - 1997 GM F-body (Camero) has a 1” bore size.
Will it hook up to a Hydro-boost?

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Bosch hydroboost manufacturer recommends a 1 1/8 bore master cylinder with their booster.
 

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