Reflections on the BMW big brake booster mod

[jwallis]

I had no intention of doing this mod but I thought that my old booster was hosed. Turns out it's actually fine but I had already gone through all the work and bought the BMW part so I went for it. Guess I'll be keeping the old one just in case

I had not really thought it through and I had been thinking that I would get more breaking power but that's not what this mod does, you're really limited by the discs, the drums, and how much rubber is touching the road, which with the stock tires, isn't much.

This was my experience
- I would not recommend this mod, I don't really see the point
- a used vanagon brake booster is almost impossible to find
- a used BMW booster (BMW e30 e28 ATE 34331154262) was pretty easy to find on eBay for $100
- I also had to buy a tap to cut some threads in the new booster cable thingy
- I can't imagine doing this job without removing the dash but people have done it (see videos below)
- the BMW booster is bigger and does not fit with a combination of the awesome slowbridge https://www.slowbridgeinnovation.com/ dash light wiring harness mod and the older rectangular break fluid reservoir that doesn't have the little wings on the side
- stopping power is the same
- the pedal feels very soft like our Mazda... for better or worse
- there's a little shhh sound when I hit the pedal and occasionally a little sort of chirping noise
- no problems after maybe 5k miles

Videos (not by me)
- some guy
-- https://www.youtube.com/watch?v=JhBI1QJoMTo
- some other guy
-- https://www.youtube.com/watch?v=zuhLBdvFK-8
- and some other guy
-- part 1 https://www.youtube.com/watch?v=UrCSenyCSG8
-- part 2 https://www.youtube.com/watch?v=7sAdDAgyfuY
-- part 3 https://www.youtube.com/watch?v=r34DOtxeedU[/list]
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50+ YouTube videos - brakes, bearings, CV joints, 1.9/2.1 cooling system, mods, Bostig and more...

[MarkWard]

I agree. You could fit a larger diameter master which is documented here to improve pedal feel.

[jwallis]

I can imagine people not liking the pedal feel, but I never minded it. Definitely one of those "wow, this car has lots of CHARACTER" kinds of things, ha!
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50+ YouTube videos - brakes, bearings, CV joints, 1.9/2.1 cooling system, mods, Bostig and more...

[wesitarz]

Wooshing sound was what my old vanagon booster was making. BMW did not. Added a slightly larger 25mm BC and braced it, sinced it moved when brake applied (lighter aluminum compared to heavier old cast MC?). Added caliper stiffeners to front G57 (VanCafe) bigger front brakes to fix caliper flex. It's softer, but I could feel the pads making contact quite high on pedal application. One quick pump before full braking worked better. Four wheel disc. All ceramic pads. Maybe semi-metallic pads would be better but too much brake dust and rotor wear?

[4Gears4Tires]

I would recommend anyone wanting more brake boosting on their vanagon to go to an electric booster at this point. If anyone is in the DC area or Staunton, VA area you are welcome to test drive my Westy.

Pedal feel is very "soft" like a modern car, brakes clamp very effectively. I was very annoyed at the whooshing gear noise it makes, but with the motor running I can't hear it. The brakes will put you through the windshield with only a moderate amount of foot power applied. I like this because I don't want my foot power to leave any amount of braking on the table. It's certainly something you need to adjust to.
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'87 Syncro Ferric Oxyhydroxide Superleggera Edition
'85 Westy Sciuridae Domus Edition