Brake Proportioning Valve

[Jeremy]

Like the header says, is a proportioning valve nessesary for my rear disc brakes? I'm just plumbing in the brake lines and if I need one of these it would probably be the best time to do it. Also do you need to run both brake light switches in the dual circuit master cylinder? Or just plug a hole and use one switch.

Thanks Jeremy

[Chris]

you wont really know until you drive it, use two switches you can wire them so that if one fails the other will work or use one and switch to the other if it fails.

[Darren Dilley]

i beleave disc brakes will need a 2lb Residual Pressure Valve  not really necessary to have a  proportioning valve

[AirCooledRules]

the proportioning valve is there to prevent rear wheel lock up, since your only using your rear brakes for 15-25 percent of total braking, you may not need the prop valve, but it doesnt hurt either.

[Bruce]

The rear brakes on a rear engine car do much more braking than 15-25%.  With 60% of the weight on the rear, the rear brakes can be made much larger.
I don't have no stinkin proportioning valve.  No check valves either.

[GMB]

No check valves or proportioning valved required and I agree with Bruce the rear brakes on a rear engine rear trans car should be way bigger that any of the kits I have seen or used out there. Be carefull!
   Gary.

[G-dog]

No valve in my car either-The 135's lock up nicely!!!

[Jeremy]

So the concensus is no extra valve needed and that disc brakes aren't big enough anyway? I would assume any disc brake would be better than stock.  

[Bruce]

True, any disc kit is better than stock.

One time I drove Lanny's car.  It had 135 bicycle tires with 205/70s in the rear.  KG discs and stock 67 drums.  It was scarey (from my point of view with 4 whl discs and wide rubber on my car)  What his car really needed was way more rear brake to slow down those big 205/70 flywheels.  One easy way to do this is to swap the stock 17.5mm wheel cylinders for late Beetle front wheel cylinders (22.2mm).  If you need to go more, Super Beetle 23.8mm wheel cylinders fit.

You have to ignore everything you know about brake bias as it applies to front engine cars.  Rear engine cars need a LOT of rear brake.  My rear discs are larger than the front discs on many economy cars today.

[Russ]

True, any disc kit is better than stock.

 

Erin,
is still running the stock brakes on the oval and she drives like a maniac.
i have been considering doing the conversion to disk brakes wondering if all 4 would be better than just the rears at this point?
anybody runnig 4 wheel disk for a daily driver?

[G-dog]

After the bigger brakes- bigger motor !IDAs ,beefy trans ,slicks,nitros, turbo-viola! 10 sec daily driver!!!  

[Bruce]

Erin,
is still running the stock brakes on the oval and she drives like a maniac.
i have been considering doing the conversion to disk brakes wondering if all 4 would be better than just the rears at this point?
anybody runnig 4 wheel disk for a daily driver? [/quote]
 Discs on the front first, not the rear.

Here's an economical upgrade for her car.  Early Type 3 drums all around.  They are both wider and bigger in dia.  Plenty of brake for that flyweight car with a featheweight driver.

I've had cuatro frenos disco for the last 15 years.

[Russ]

with a featheweight driver.

 

dude have you seen her she's pushing a 100 pounds

if the backs are doing most of the braking why replace the front first?
 

[Bruce]

with a featheweight driver.

 

if the backs are doing most of the braking why replace the front first?

I didn't say the backs are doing most of the braking, just that our rears do way more braking than the rears of front engine cars.  That means we can have more rear brake bias than front engine cars.

[Russ]

gotch-ya

[RoadRunner]

Must we discuss HOW fast I drive?  :blush:
How about just stickin to the topic at hand..................how fast I need to STOP :wacko:

 

[AirCooledRules]

correct, front disk brakes first always.

When you apply the brakes, even though you do not notice or feel it, your car is diving forward, thus the weight is shifted towards the front of the vehicle, thats why the front brakes do more work, and why the rear brakes can lock up. Beetles have more weight in the rear percentage wise then most cars, so their rear brakes will do more work then a V8 chevy.

[Tom H.]

While the t3 brakes may be a good upgrade, they are not economical. Go price good or new early T3 drums.........


and a proportioning valve installed in the front circut can be advantagous to balance big and littles.  

[AirCooledRules]

Proportioning valves are only used for rear brakes. For the front brakes you can install a Metering or (hold-off) Valve that holds off the front brakes, until enough pressure is built in the rear so that both front and rear brakes apply at the same time for even braking.

[Tom H.]

Proportioning valves are only used for rear brakes. For the front brakes you can install a Metering or (hold-off) Valve that holds off the front brakes, until enough pressure is built in the rear so that both front and rear brakes apply at the same time for even braking.

I will agree to disagree