Will a B4 brake booster fit b3?

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dana
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Will a B4 brake booster fit b3?

Post by dana »

Seems like they would, but wondering if anyone has used a b4 brake booster on a b3 car?
current:
-mk4 tdi wagon with some mods
-TDI b3 90q, holset turbo, be strong little connecting rods!
-the turbo tractor
past:
-11 second 90q junker
-20vt swapped 90q winter beater
-efi 20vt 4kq
-way too many other long gone urs's, 200's 4000's, b5's
DE80q
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Re: Will a B4 brake booster fit b3?

Post by DE80q »

I remember the B4's booster being bigger, but don't remember by how much.
"If you can't find one, make one"

Dallastown, PA
1991 Audi 80 quattro (20vt project)
1991 Audi Coupe Quattro (project: my first 20v)
2007 Mitsubishi Raider(Dakota in disguise)
2019 Chevy Cruze RS hatch (wife's little red sporty car)
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dana
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Re: Will a B4 brake booster fit b3?

Post by dana »

DE80q wrote:I remember the B4's booster being bigger, but don't remember by how much.

hmm, that might be problematic. Bigger in diameter or depth or both?
current:
-mk4 tdi wagon with some mods
-TDI b3 90q, holset turbo, be strong little connecting rods!
-the turbo tractor
past:
-11 second 90q junker
-20vt swapped 90q winter beater
-efi 20vt 4kq
-way too many other long gone urs's, 200's 4000's, b5's
DE80q
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Re: Will a B4 brake booster fit b3?

Post by DE80q »

I'm pretty sure it was just diameter.
"If you can't find one, make one"

Dallastown, PA
1991 Audi 80 quattro (20vt project)
1991 Audi Coupe Quattro (project: my first 20v)
2007 Mitsubishi Raider(Dakota in disguise)
2019 Chevy Cruze RS hatch (wife's little red sporty car)
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Grillage
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Re: Will a B4 brake booster fit b3?

Post by Grillage »

I have a couple at home. I'll try to check tonight to see what I have and the differences. I know I used a B3 booster on my V8 Coupe but I had previously tried another
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varia
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Re: Will a B4 brake booster fit b3?

Post by varia »

b3 9", b4 10" diamter. it fits
¯\_(ツ)_/¯

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dana
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Re: Will a B4 brake booster fit b3?

Post by dana »

varia wrote:b3 9", b4 10" diamter. it fits

any deeper?
current:
-mk4 tdi wagon with some mods
-TDI b3 90q, holset turbo, be strong little connecting rods!
-the turbo tractor
past:
-11 second 90q junker
-20vt swapped 90q winter beater
-efi 20vt 4kq
-way too many other long gone urs's, 200's 4000's, b5's
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scubadave
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Re: Will a B4 brake booster fit b3?

Post by scubadave »

It fits Dana.
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PRY4SNO
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Re: Will a B4 brake booster fit b3?

Post by PRY4SNO »

Isn't the B4 brake booster the one people use to do the vac-assist swap in a B3, along with the modified PS pump?
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|| 2010 Golf Sportwagen TDI /// #farmenwagen
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Re: Will a B4 brake booster fit b3?

Post by scubadave »

That's what is in the picture..........
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Re: Will a B4 brake booster fit b3?

Post by varia »

PRY4SNO wrote:Isn't the B4 brake booster the one people use to do the vac-assist swap in a B3, along with the modified PS pump?


both B3 and B4 booster can be used. I used B4 90/cab ps pump (with 7A bracket on the 3B engine) and B4 90/cab ps pump rack-to-reservoir hose.
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dana
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Re: Will a B4 brake booster fit b3?

Post by dana »

PRY4SNO wrote:Isn't the B4 brake booster the one people use to do the vac-assist swap in a B3, along with the modified PS pump?

I've always used a booster from a b3 when I have done the conversion, but they seem impossible to find now. Looks like I will try a b4, might make my assist a little better too.
current:
-mk4 tdi wagon with some mods
-TDI b3 90q, holset turbo, be strong little connecting rods!
-the turbo tractor
past:
-11 second 90q junker
-20vt swapped 90q winter beater
-efi 20vt 4kq
-way too many other long gone urs's, 200's 4000's, b5's
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PRY4SNO
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Re: Will a B4 brake booster fit b3?

Post by PRY4SNO »

How's the feel and power compare to hydro assist?
Find me on Instagram @pry4sno

|| 2010 Golf Sportwagen TDI /// #farmenwagen
|| 2002 Dodge Ram 2500 24vt 4x4 #bertancummins
|| 1992 80 quattro 20v /// Eventual AAN'd Winter Sled
|| 1990 Coupe quattro /// Because Racecar
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dana
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Re: Will a B4 brake booster fit b3?

Post by dana »

It always seems a little easier to me, but im not sure I have ever had a power assist that worked perfectly. Hydro assist definatly feels more hydraulic and vac assist feels more airy? How is that for a description :drunk:
current:
-mk4 tdi wagon with some mods
-TDI b3 90q, holset turbo, be strong little connecting rods!
-the turbo tractor
past:
-11 second 90q junker
-20vt swapped 90q winter beater
-efi 20vt 4kq
-way too many other long gone urs's, 200's 4000's, b5's
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PRY4SNO
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Re: Will a B4 brake booster fit b3?

Post by PRY4SNO »

Haha kinda... one feels more solid, the other feels a bit... flimsy?

My 80q has the old g54 calipers and hydro assist. The brakes actually feel way more responsive/powerful than my Coupe (hydro assist) and B4 90q (vac assist), so I assume that means the hydro-assist on my Cq is on it's way out?

(sorry to threadjack :hide:)
Find me on Instagram @pry4sno

|| 2010 Golf Sportwagen TDI /// #farmenwagen
|| 2002 Dodge Ram 2500 24vt 4x4 #bertancummins
|| 1992 80 quattro 20v /// Eventual AAN'd Winter Sled
|| 1990 Coupe quattro /// Because Racecar
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