brake problem for the experts

[puma]

Hey guys

Here is my problem, i drive my car like a *****, i am really not rough on it and i had a guy who drive lots of viper drive mine to tell me if he saw any problem with power or anything since i just bought and don't have any reference. He decided to try a hard braking and the front right wheel locked up. He did it three times and it did the same thing every time. He said that was not normal and that the pedal felt kind of weird.

I know the previous owner installed a brake proportional valve on the rear. In order to do that, he removed the little block that seems to dispatch the oil to each caliper, it is located in the engine bay, a little under the master cylinder and it has an electrical connector to it.

Now my connector is unplugged as there is no more block, he just T the two front calipers and he T the two rear after the proportional valve if i remember right.

Here is my question, in that OEM "block", was there some sort of proportional valve that would act on the front brakes? What is the role of the part, what is the connector or the sensor on it for? Is it a bad thing that i don't have it anymore?

I hope i am making myself clear, kinda hard to explain, hope you guys understand.

thanks a lot for any info you can give me.

 

[carguy07]

My right front locks up pretty easy, it is the lightest corner with no passenger. Yours may need sorted out, but that is pretty normal to me.

Get Tom's upgrade and you can actually use the rears.

 

[GR8_ASP]

And this guy drives lots of Vipers ??? Must only drive ABS versions. Yes the right front is fairly easy to lock up.I always learned to step into the brake, wait for the weight transfer and then proceed to modulate toward impending lock-up. Without a delay lock-up comes to easily.

As mentioned above Tom Hayden has a revised rear brake caliper (bigger piston) that will help add rear braking. But modulation is still in the foot of the driver.

 

[Tom F&L GoR]

The battery and the driver are on the left side of the car, so the left front weight is often 70 kg heavier than the right front. Consequently the right front slides first. This is typical of a Viper. It is not a normal adjustment, but if you really want to, you can shim the left rear or right front spring to change the cross weights and balance the front wheels.

Otherwise, the problem is related to the inadequate clamping force of the rear brakes. The stock rear brakes will never come close to helping slow the car much and since most of the braking is from the fronts, it guarantees one of the fronts will lock first. Yes, basic design of brakes will say that this should happen - but in the case of the Viper, it wasn't "engineered" that way, it was bumbled into production that way.

StopTech gave everybody a hint that this was the case when their first level upgrade front calipers had SMALLER pistons in an effort to shift more of the braking work towards the rear. Larger piston rear calipers are the easiest fix, and going from 36mm to 40mm balances the car nicely. Also, it's a DIY swap, reuses every stock or aftermarket part you have, and relatively inexpensive.

Four piston calipers in the rear will also cure the problem, but it's a little more work and cost. Then you will need the adjustable proportioning valve, since such a large caliper in the back is actually too large. The valve will let you control how much the rear caliper works.

It's not a performance problem if the OEM proportioning block was removed and an adjustable one put in it's place. They both do the same thing, but the OEM version is not adjustable. However, without the pressure switch (that dangling electrical connector) you won't have a warning should the brake lines lose pressure. That switch senses when one part of the brake system has lower pressure than another and turns on the red light in the dashboard. In fact, in your case I think it should now always be on?

 

[puma]

thanks a lot for the answers guys, i must admit this is not the kind of answer i was thinking of getting but I must admit i am a little releived.

i don't have any light that comes on in the dash, maybe the bulb was removed?

So basically what it means is that i shouldn't be worried about that, i just keep it like that and continue braking like i do, since i personaly never blocked a wheel.

I will probably upgrade some day with Dave's big brake or something like that but if my system is up to the task and safe as is, i will keep it like that for a little while.

thanks a lot guys, that's the kind of reply i was looking for.

 

[Viper X]

Daves big brakes will really help that problem.

Dan

 

[Vypr Phil]

Viper X is right!

One of our SoCal VCA member (Lance K) did it himself after purchasing the kit from "Dave's Big Brakes", website:http://davesbigbrakes.com/ and was kind enough to submit a most comprehensive pictorial history of his installation:

http://forums.viperclub.org/showthread.php?t=598315

As the commercial says: Just Do It!

You really need it.

Vypr Phil

 

[Schulmann]

Puma, your Viper is in perfect condition. I was very impressed. You got a nice viper.


Before I adjusted the valve you rear breaks were locking up.
It is better to have a front biais compared to a rear one.
Now you Viper brakes safer.
It is possible that due to some dirt your brake balance has changed.

I think your only issue is related to bleeding or some dirt on one side of your viper.
The passanger side rear wheel locks up before the driver side wheel.
The viper GEN 2 break system is not very complicated. It is likely something simple.

With the valve you can personnalize easily your setting once you fix your rear breaks (and likely front once too).
But be carefull turn juste a little your prop valve.