924Board.org

[txjake]

Light car, no real need for boosted brakes. Anybody convert to non boosted brakes?
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1978 924, aka The Red Rocker

[fiat22turbo]

CorsePerVita did on his 77, hopefully he'll chime in with his solution.
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

[CorsePerVita]

Yes, I used a rabbit master cylinder with manual brakes to convert it. The pressure required on the pedal is more significant than boosted brakes though of course. But I prefer less room for failure, fewer variables. I want to say it was a '76 master I used.

The issue is that you have to modify your brake pedal. Essentially, the way I did it was to use a very long SS bolt with the same thread as what the stock rod on the pedal had. I ground the head off, then pointed the tip so that it would fit into the master cylinder the same way the stock rod fit for the master cylinder. Then you can adjust it with the nut the same on the pedal with no difference.

I've only had the car briefly around the block when it first ran, but they worked fine. The pressure difference is significant though with how much pressure it will require to press down upon. At least if you're using bigger brakes. There is less variables, which I like. So that means less things to "go wrong" in my opinion.

The other reason I like the rabbit master is that it has a proportioning valve built into it, although it isn't significant. But it'll at least apply what feels to be even pressure. But this means you can't really "adjust" it though. I may decide to go with another master type later.

The only thing I would mention that seems a bit interesting though is that you can't use the plate that came off your master cyl (it's held to the firewall with 3 bolts, then 2 bolts that go into that), so you do have to drill the firewall, and it seems that it flexes a bit. I've considered reinforcing it in several areas because I'm not sure how it will affect it longterm.
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- 1977 Porsche 924 2.0 N/A (Trackday Project)
- 1979 Porsche 924 2.0 N/A (The other daily)
- 1980 Porsche 931 (Daily)
- 1987 Lamborghini Jalpa
- 1999 Ducati 900SS

[txjake]

Thanks want to do this for same reason, plus clean up the looks under hood. Did you have redo any of the piping?
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1978 924, aka The Red Rocker