80 Series brake hydro booster conversion installed (1 Viewer)

cruisermatt

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It's simple, a lot of people mistake a good firm brake pedal for good brakes. A good braking system results in proper stopping distance, which can sometimes be hard to judge. Since a hydroboost will provide a firm feeling pedal regardless of whats on the other side of it, it can act as an illusion or mask. That's all.

By the way, this was was kinda how my rig was late last year.
 

baldilocks

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It's simple, a lot of people mistake a good firm brake pedal for good brakes. A good braking system results in proper stopping distance, which can sometimes be hard to judge. Since a hydroboost will provide a firm feeling pedal regardless of whats on the other side of it, it can act as an illusion or mask. That's all.

By the way, this was was kinda how my rig was late last year.
Which is why the booster and MC need to be a matched. A person who is able to apply 1,000 pounds of force on the pedal could stop well with no booster assist at all.

A firm pedal happens when air is absent from the brake lines. Choice of friction material also has a bearing on stopping distance.

Let’s not turn this into another of those threads that ends in total confusion for those who may be interested and are still seeking experience through others.

I think most anyone would known that if their brake pedal felt firm but stopping the car took more time/greater distance, that something was wrong and needed to be addressed.

Mud is not a place to go for expert brake system advice outside the normal equipment, which is why I bought a kit from those who know.
 

SmokingRocks

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A firm pedal happens when air is absent from the brake lines. Choice of friction material also has a bearing on stopping distance.

Friction material and brake lines can also affect pedal firmness. But yes you are right, pedal firmness is mostly attributed to the absence of air in the line.
 

baldilocks

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Friction material and brake lines can also affect pedal firmness. But yes you are right, pedal firmness is mostly attributed to the absence of air in the line.
I already had stainless braided lines from frame to axle and felt it prudent to upgrade to new stainless braided lines at the calipers since the age of my rubber ones was unknown and the hydro booster increases brake line pressure.
 

RFB

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I think anyone thats going to go thru the time, money and effort to install this, should not need to be told to make sure your brake lines are SS, your calipers and rotrs should be the best you can find to start with or this will be all for naught. JMO
 

jjdeneen918

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I think anyone thats going to go thru the time, money and effort to install this, should not need to be told to make sure your brake lines are SS, your calipers and rotrs should be the best you can find to start with or this will be all for naught. JMO

I would imagine OEM would be best?
Does Mr. Toyota sell a rebuild kit for the calipers?
 

alia176

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Sorry for the newb question but why does an auto maker decide to go one way or the other in terms of hydroboost vs vac assist? My dinky 4runner has hydro but it's an '03, so a tad newer. I can only assume that the 3rd gen 4runners have vac assist, not sure.
 

Rollinns

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Sorry for the newb question but why does an auto maker decide to go one way or the other in terms of hydroboost vs vac assist?

I can't speak for the engineers, but most likely the choice is decided with at least 3 factors considered:
1. regulation - does a certain part(s) allow us to comply with the laws and goals we are trying to meet.
2. packaging - does this part fit in the space it needs to
3. cost - which part meets the above criteria (and possibly other criteria) for the lowest overall: part cost, labor cost, projected warranty costs, etc.

Other criteria may be that a diesel engine might not have a vacuum pump, so having a hydroboost setup avoids the complexity of adding a vacuum pump while providing all the braking needed for a unit that may be hauling a trailer, this may not apply to Toyotas sold in the USA, but other manufacturers have done this.


Getting back on topic - for those going the cheaper route -
What Toyota MCs will bolt right up to the hydroboost unit from a chevy/GMC van?
A Tundra MC was mentioned, what year?
 

jjdeneen918

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I can't speak for the engineers, but most likely the choice is decided with at least 3 factors considered:
1. regulation - does a certain part(s) allow us to comply with the laws and goals we are trying to meet.
2. packaging - does this part fit in the space it needs to
3. cost - which part meets the above criteria (and possibly other criteria) for the lowest overall: part cost, labor cost, projected warranty costs, etc.

Other criteria may be that a diesel engine might not have a vacuum pump, so having a hydroboost setup avoids the complexity of adding a vacuum pump while providing all the braking needed for a unit that may be hauling a trailer, this may not apply to Toyotas sold in the USA, but other manufacturers have done this.


Getting back on topic - for those going the cheaper route -
What Toyota MCs will bolt right up to the hydroboost unit from a chevy/GMC van?
A Tundra MC was mentioned, what year?

So we are trying to find a Toyota MC so brake lines mate up? Not sure why otherwise a GM MC could work? A factory MC would be ideal, opposed to aftermarket (Willwood) for repair/replacement in an emergency/roadside repair situation.

The MC needs a larger bore than the 80-series? If so, the only one I could find (Toyota) was one from a T100 1-ton truck- 1 1/16” bore. Everything is same or smaller, including Tundra.
 

AlbertoSD

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I *think* all toyota diesel engines have an alternator driven vac pump or is that a Mercedes thing?

Some Toyota Diesels (mostly the older models including the early B-series and perhaps the early 2H series) have the vacuum pump behind the alternator. The later generations Toyota Diesels have the vacuum pump directly moved by the crank (1HZ, 1HDT's), typically in front of the power steering pump.
 

Rollinns

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I was wanting to know if the Tundra MC that was mentioned would bolt directly to the Hydroboost unit without an adapter plate.

Now looking at the T100 1-ton MC instead, I'm guessing the brake lines will probably bolt right up, but looking at the T100 (1-ton) master cylinder and the GMC safari Hydroboost (which is what I have), it looks like an adapter is needed to bolt them together.

It's not a big deal to make an adapter, I already need an adapter to bolt the Hydroboost to the firewall. Someone on here mentioned buying the gaskets between the MC and the vacuum brake booster (and also the gasket between the firewall and vacuum booster) to use as a template for making the adapter(s). Using a gasket as a template is a great idea to make sure an adapter will work without having to unbolt anything to get the bolt pattern/measurements.

I'm not sure who mentioned the gasket tip, but they deserve the credit. Useful tips like that are just another reason we all like this forum so much.
 

baldilocks

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So we are trying to find a Toyota MC so brake lines mate up? Not sure why otherwise a GM MC could work? A factory MC would be ideal, opposed to aftermarket (Willwood) for repair/replacement in an emergency/roadside repair situation.

The MC needs a larger bore than the 80-series? If so, the only one I could find (Toyota) was one from a T100 1-ton truck- 1 1/16” bore. Everything is same or smaller, including Tundra.
After putting a few miles on the new hydro booster and MC, I would say go no bigger than 1.125” MC. 1 1/16” would be a size that I’m sure pretty much no one would have issue with.

As for emergency repairs, Summits sells the Wilwood MC rebuild kit for $23.95.

Power Brake Service sold me the MC I chose but offer others for less money. No matter which one you buy (some come from China) when it decides to leak, a repair will be needed. I would feel confident carrying a Wilwood rebuild kit in my boonie box.
 
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At the bottom of this LINK there's a list of Toyota master cylinders and their specifications. T100 1-Ton should bolt right in place of the 80. Since the piston bore diameter is slightly larger this will create a firmer pedal with less travel than stock on our 80's.

But keep in mind though putting 50lbs of pressure on the brake pedal on a larger bore MC will actually create less brake line pressure than smaller bore MC using the same 50lbs of pressure on the pedal(given the use of the same booster). Results in less brake rotor torque. Firmer pedal though does mean you're typically applying more pressure, but just thought I'd mention this.

I just found that Low Range Offroad does sell a Toyota 4 bolt to GM 2 bolt MC adapter HERE. Optionally they sell it with a GM 1.25" MC for use with D60 tier axles and much larger bore brake calipers where pedal travel increases significantly. I only mention this as it can open things up to other 2 bolt MC's perhaps.
 

J2P

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At the bottom of this LINK there's a list of Toyota master cylinders and their specifications. T100 1-Ton should bolt right in place of the 80. Since the piston bore diameter is slightly larger this will create a firmer pedal with less travel than stock on our 80's.

But keep in mind though putting 50lbs of pressure on the brake pedal on a larger bore MC will actually create less brake line pressure than smaller bore MC using the same 50lbs of pressure on the pedal(given the use of the same booster). Results in less brake rotor torque. Firmer pedal though does mean you're typically applying more pressure, but just thought I'd mention this.

I just found that Low Range Offroad does sell a Toyota 4 bolt to GM 2 bolt MC adapter HERE. Optionally they sell it with a GM 1.25" MC for use with D60 tier axles and much larger bore brake calipers where pedal travel increases significantly. I only mention this as it can open things up to other 2 bolt MC's perhaps.

Hi I’m curious how that can be “But keep in mind though putting 50lbs of pressure on the brake pedal on a larger bore MC will actually create less brake line pressure than smaller bore MC using the same 50lbs of pressure on the pedal”? Shouldn’t the 50lbs create the same throw but with a larger bore move larger volume?
 
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Hi I’m curious how that can be “But keep in mind though putting 50lbs of pressure on the brake pedal on a larger bore MC will actually create less brake line pressure than smaller bore MC using the same 50lbs of pressure on the pedal”? Shouldn’t the 50lbs create the same throw but with a larger bore move larger volume?
This is where it can get confusing. Same pedal travel(you can also use piston throw) doesn't actually mean same pressure on the pedal with different size MC's. I'm speaking of driver input on the pedal. Let's say on a larger bore MC, to reach 50lbs of applied force on the pedal the pedal needs to travel 1". On a smaller bore MC, to reach the same 50lbs of applied force, the pedal needs to travel 2". All dependant on size differences between the two of course...

If we're talking throw, then yes the larger MC will push more fluid creating more line pressure. You can go to the point that a MC bore is so large that the driver can't apply the force required to reach the same amount of brake torque.

Here's a reliable brake calculator you can play with that may help:
TCE Brake Bias Calculator
 

J2P

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This is where it can get confusing. Same pedal travel(you can also use piston throw) doesn't actually mean same pressure on the pedal with different size MC's. I'm speaking of driver input on the pedal. Let's say on a larger bore MC, to reach 50lbs of applied force on the pedal the pedal needs to travel 1". On a smaller bore MC, to reach the same 50lbs of applied force, the pedal needs to travel 2". All dependant on size differences between the two of course...

If we're talking throw, then yes the larger MC will push more fluid creating more line pressure. You can go to the point that a MC bore is so large that the driver can't apply the force required to reach the same amount of brake torque.

Here's a reliable brake calculator you can play with that may help:
TCE Brake Bias Calculator

Ok thank you, makes sense.
 

jjdeneen918

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At the bottom of this LINK there's a list of Toyota master cylinders and their specifications. T100 1-Ton should bolt right in place of the 80. Since the piston bore diameter is slightly larger this will create a firmer pedal with less travel than stock on our 80's.

But keep in mind though putting 50lbs of pressure on the brake pedal on a larger bore MC will actually create less brake line pressure than smaller bore MC using the same 50lbs of pressure on the pedal(given the use of the same booster). Results in less brake rotor torque. Firmer pedal though does mean you're typically applying more pressure, but just thought I'd mention this.

I just found that Low Range Offroad does sell a Toyota 4 bolt to GM 2 bolt MC adapter HERE. Optionally they sell it with a GM 1.25" MC for use with D60 tier axles and much larger bore brake calipers where pedal travel increases significantly. I only mention this as it can open things up to other 2 bolt MC's perhaps.

So going to the T-100 MC, but keeping Toyota booster will give you less braking force?
That seems like a step in the wrong direction.

The Low Range Offroad Kit you linked is for mating a GM MC to a Toyota booster.
Also seems like a step in the wrong direction.

I thought this thread was about getting a GM style HYDRO-booster, since it’s better than (more braking force) an Toyota VACUUM-booster?

Mating an off-the-shelf Toyota MC to a GM HYDRO-booster, to hopefully mate up Toyota brake lines for ease & simplicity of install, & have an easily available MC for roadside replacement too?

Am I correct? I’ve been wrong before.

If a booster-to-firewall adapter or MC-to-booster adapter was necessary, hopefully someone can make & sell a kit so it’s all plug & play once the best MC & HYDRO-booster was figured out. 👍🏻

Hopefully someone like Joey at Wits-End @NLXTACY would pick this up as he appears to have the resources & connections for production & a platform to sell & distribute such a kit.

That was what hoping could come to fruition.
And I think it would be a nice upgrade to compliment his, about to be released, bolt-on turbo kit. 😁
 

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