I'm looking for a master cylinder recommendation

[liquidrush]

I've recently switched to 4 wheel disc brakes and I think my existing 3 port cylinder isn't enough. Can anyone recommend a suitable cylinder? It stops good but it seems as if the fronts are doing all of the work. I know the fronts should but it feels like the rears should be working a little harder.

[oprn]

Your problem is not with the present master cylinder then, it's a front/rear brake balance issue. Changing out the master cylinder will not change that. There are a lot of factors that go into a balanced system.

Front/rear weight bias of the car - move around components like battery, fuel tanks etc. Not an easy thing to change.

Wheel cylinder area/braking surface swept area - this is the big one and requires either next to an engineering degree, the experiance of others or a lot of trial and error.

Tire diameters front vs rear - this is an easy thing to change and one I believe is highly overlooked. Taller tires make the brakes less effective and vice versa.

Two master cylinders and a balance bar - not cheap but this is the best way to change the brake balance when all else has been done that can be done practically and a final "tuning" is still needed. This is the route serious racers take.

Proportioning valves - a final tune can be made with these, nearly all auto manufacturers have gone this route but note: THEY ONLY EVER USE THEM ON THE REAR BRAKES. These allow full pressure up to a certain point then limit the pressure after that. It does work well in the rear but if used in the front it can produce unpredictable rear lock up and a spin out in a panic stopping situation. This is fine for off road only use (it's just your butt at stake here) but should not be used on the street in traffic.

My sand rail brakes are a bit rear bias right now. Bus rear drums and Beetle front drums. I was warned by others on here that going the disc route on the front on a rail would result in it being far too front biased so I went with drums. My next step now is to put shorter tires on the front and taller ones on the rear and try that. The bias valve I bought for the rear was a complete failure. It blocked ALL pressure to the rear.
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[Wulfthang]

I went with four wheel disc brakes and finally gave up on the standard M/C. I went with a dual master cylinder brake pedal set up with a remote front/rear bias adjuster. The idea is to adjust it one way for street use and the other way for off road use.

[Bad_chopper]

I did 4 wheel disk, used larger single piston front brakes from empi, 4 piston smaller rear disk, 30 inch front tires 33 inch rears its Ballanced ok. In a full panick stop the rears lock up a little to soon I could probably use a perportioning valve.
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[liquidrush]

What MC assembly did you go with?


quote="Wulfthang"]I went with four wheel disc brakes and finally gave up on the standard M/C. I went with a dual master cylinder brake pedal set up with a remote front/rear bias adjuster. The idea is to adjust it one way for street use and the other way for off road use.[/quote]

[Wulfthang]

[JWHracing]

Your issue my not be proportioning, it may be that the master cylinder isn't supplying enough fluid volume to the calipers.

When I first put my Jamar 4 piston calipers on the rear, the stock dual circuit master was not enough to lock the brakes up, I had to pump them up to stop. Did the Latest Rage dual master brake pedal and a hydraulic clutch, and I can stop the car no problem. Added a balance bar adjuster knob and can adjust front to rear depending on the environment and situation you are in.
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2017 SADR 1300 Class Champion
2016 AZOP Limited Buggy Champion

Currently "retired" from racing

[oprn]

Bear in mind that the larger you go on the master cylinder the higher the force it will take on the brake peddle to stop the car! Bigger is not always better, there is a middle ground that works best. Go too big and younger drivers and sometimes the ladies will not be able stop the car effectively.
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)