Brake boosters - std single-diaphragm type or 'heavy duty' twin-diaphragm ?

[sunrk]

I only have very basic understanding of hydraulic systems. Terrain Tamer now sells twin-diaphragm brake boosters for 80's and other landcruisers.

What's so special or good about a non-standard one? If it matters, my 80 is non-ABS.

 

[AussieHJCruza]

I thought that an 80s standard booster was dual diaphragm.

If you install a GVM upgrade, big tyres, power-up mods etc, the extra braking power provided by the booster upgrades can be very helpful.

Terrain Tamer, Bendix, PDI and a few others sell upgraded vacuum boosters and Marks is now offering a Hydroboost setup.

 

[Woofythewolf]

Yeah AFAIK the factory unit is already a dual 8"+9" booster, so it's a bit scary that they might be selling a non-double diaphragm as a replacement. Just cause it bolts in from a toyota truck doesn't mean it's right... Then again I may have read that wrong somewhere.

If correct, the hydraulic ratio is set up from the factory with the expectation of nearly 1000 lbs of assist. (113 in^2 of total diaphragm area, at 18 inHg or 8.8 psi of vacuum at idle. You'll have more assist if the engine is being spun by the drivetrain with the throttle closed).

Edit: A1 Cardone says its a dual diaphragm 9.25" for the factory unit. So none of these aftermarket units are upgrades unless they're both a dual diaphragm and a bigger diameter which would be quite a squeeze. Terrain Tamer's specific 30% increase in braking power claim for their heavy duty units definitely doesn't apply if it's the same diameter as our factory unit.

 

[Obrokoff]

Twin diaphragm booster one of the most useful upgrades

 

[sunrk]

Ok so are the generic aftermarket Aisin ones that pop up on Ebay, etc. the same as the original factory ones? Most of the factory part number boosters are NLA.

Twin diaphragm booster one of the most useful upgradesView attachment 3338298View attachment 3338299

Can you explain how this makes a difference when the factory setup is considered legal and meets engineering standards for compliance in all markets where 80's were sold?

I've never driven or even seen in person with the hood/bonnet up an ABS-equipped 80 or Lx450 to compare how the braking feels or how the components are different.

 

[AussieHJCruza]

Yeah AFAIK the factory unit is already a dual 8"+9" booster, so it's a bit scary that they might be selling a non-double diaphragm as a replacement. Just cause it bolts in from a toyota truck doesn't mean it's right... Then again I may have read that wrong somewhere.

If correct, the hydraulic ratio is set up from the factory with the expectation of nearly 1000 lbs of assist. (113 in^2 of total diaphragm area, at 18 inHg or 8.8 psi of vacuum at idle. You'll have more assist if the engine is being spun by the drivetrain with the throttle closed).

Edit: A1 Cardone says its a dual diaphragm 9.25" for the factory unit. So none of these aftermarket units are upgrades unless they're both a dual diaphragm and a bigger diameter which would be quite a squeeze. Terrain Tamer's specific 30% increase in braking power claim for their heavy duty units definitely doesn't apply if it's the same diameter as our factory unit.

The TT and other upgraded boosters are larger in diameter than the factory booster.

 

[Obrokoff]

Can you explain how this makes a difference when the factory setup is considered legal and meets engineering standards for compliance in all markets where 80's were sold?

I've never driven or even seen in person with the hood/bonnet up an ABS-equipped 80 or Lx450 to compare how the braking feels or how the components are different.

by replacing the booster, I got a more adequate reaction to pressing the brake pedal. less pressure is required for better braking.

 

[sunrk]

FYI this is the Aisin one on Ebay claiming to be a replacement for the factory original. No cross-reference to Toyota part numbers is provided.

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