0MrPickles

Anyone have experience removing/bypassing the ABS in a C5? Specifically 97/98 since they are located on the rear K-member.

I know the line sizes as well as fitting sizes, just looking for someone that may have done this already.

Thanks!
Michael

davidfarmer

I would just pull the fuse (or disconnect one of the speed sensors) and run it with the ABS shut down, but still on the car. If you can live with the performance, then removal is as simple and taking it off and running new lines. You can get weatherhead fittings/adapters at NAPA. The system may or may not be biased very well, since OEM relies on the ABS to take up any slack, so to speak, in the biasing equation.

Personally, I'd never remove the ABS on a Vette unless it was required by the rules to do so. Even with a dual master cylinder, balance bar setup, you can't control each individual wheel as precisely as the ABS does.

weatherhead fitting catalog (old)

http://www.davidfarmerstuff.com/weatherhead.pdf
http://www.davidfarmerstuff.com/weatherhead2.pdf

It is a bit of a pain....look at catalog 2, GM uses the "bubble" flair, but I think they use metric threads. It takes some mixing and matching to get a true "bolt on" setup. I'd probably just buy line and start from scratch.

0MrPickles

Thanks for the info. I did run it for a while without the ABS fuse, and it still was a pain. Eventually I want to replace the whole system and get rid of the ABS all together. Mainly since the controller for the 97/98s were redesigned and around $800 for a replacement!!

I hate losing my ABS "somewhere" on course, then a slight tap on the brakes..locks them all up! Its got to be the control module, although I still should check the relay #37 (maybe even replace it) as well as the wheel speed sensors, and replace them. Not sure on the cost.

The controller itself, does weigh about 10#s which is a plus to getting rid of it.

I do have a brake bias controller already, I got from JEGS. My idea, was to remove the rear unit. Get a female connector for the bubble flare (M12) and T it off to the rear connections (M10) for the rear. Then up front, splice the Front line and T it off running to the existing 3/16 lines up front. Driver's side would be easy, passenger side a little harder but will route around the front frame cross-beam, keeping it away from a very hot motor.

ScaryFast

I recommend against this idea unless you're planning to re-do your entire system - pedals, master cylinder, and booster. These components are sized very differently for a car that never had ABS to begin with.

The stock system is intended to be able to stop the car with a 98 pound grandmother at the wheel applying 1/10th the force that you can. In other words, without ABS control your system will be waaaaay overboosted, and you'll have very little pedal resolution between no brake an brake lockup.

ABS is your friend...you will save the lives of many many tires if you just get it working again. I tried simply killing it on my car and it's a nightmare. I'm redoing the entire pedal configuration to fix it.

BrianCunningham

Why do you not want to run ABS?

yakisoba

I can think of three potential reasons:
1) It's on less thing to fail
2) It's possible that the driver is used to no ABS cars (race driver)
3) It's harder to adjust the brake bias and still have the system work as designed, as I understand the C5 brake system. Thus, you get to play with the bias more if you pull the ABS.

I'd love to be able to just change a spring, but it's not that simple in the C5, as far as I can tell.

0MrPickles

Actually if you are talking about the brake bias spring, that's pretty easy. I can tell ya how

The reason to remove it is I have a 97,which is the WORST year for the ABS control modules and its design. Its about $800-$1600 for a new control unit... and I'm tired of it being so touchy that if the ABS goes..I tap the brakes and I spin the car.. NOT good during track and AX stuff!! ...see above post.

The unit does weight ~10#s...getting rid of that is nice

0MrPickles

This feedback is VERY helpful and you hit it right on the head here. KNowing that someone has gone through this already, is good to know.

I 100% agree, its either no brake or brake lockup ..which the dash chimes in "DING! ABS Inactive...please prepare to spin"

I've lost many races due to this issue.

I'm torn between replacing the unit or doing away with all together. From what ScareyFast stated, its a Pain in da **** removing it and dealing with all that.

GrantB

I'd love an easy way to remove my '99 FRC's, for a few reasons:
Its in the way of a lot of things in the engine bay.
The mount, motor and electronics are 12 lbs right over the front axle.
Even after cleaning every ground, checking a ton of circuits and replacing the ABS computer ($342 shipped from AC Delco), I still get random error codes now and then. I don't like to rely on it for that reason.
I'd be a better driver without it.

But I don't feel like running a ton of new brake lines, so it stays. The brakes are a bit over-boosted for no ABS, but then I could always ditch the booster... Its steel, looks heavy, and I'm fine stopping the car without it.

One thing I did notice was that if you lock up the rears, you can knock the crank pulley bolt loose when it would otherwise stay tight. This can be more than annoying if you don't have a wrench that will fit in there to tighten it.

ScaryFast

I understand your logic for removing it, if it's failing mid-race then it's extremely dangerous. Back when I ran ABS it failed once on track. It's a rude awakening when you're expecting it and it's not there; I went into the gravel at the end of the straight.

As for removing it, I didn't necessarily say it's a PITA, just that you should be ready to do more than just pull the module. If you're actually racing your C5 then it's probably already gutted and stripped. To pull the booster you just need to machine a spacer. You might even be able to get away with the stock master cylinder, I don't know the size for your car. Most likely you'll want to change your pedal geometry a bit, too. Without the booster you may actually be a bit underboosted. You can always try it out at a lower speed and see.

I have a C4, and the booster is a 4:1. The pedal adds approximately another 4:1 mechanical advantage. Total boost, 16:1. This equals LOCKUP I'm pulling the booster, resizing the MC, and either replacing the pedals with a Wilwood set or cutting and lengthening the brake pedal.

The bottom line is that you should figure out which way is going to be cheaper and easier, and go that route...it may be fixing the current system. You can probably upgrade the ABS module to the newer years. I know they made improvements to the ESC in 2001, perhaps the ABS was improved as well.

ScaryFast

Forgot to mention this...you should also remove the ABS actuator. Good point. I pulled mine long ago. I also added a brake bias valve, adjustable inside the car. These were attempts to help the lockup issue, and were not good enough. Hence the rebuild mentioned above.

Can you explain this? Thanks.

GrantB

When the rear wheels lock (or begin to lock) with the car in gear and the clutch engaged, it stops (or at least slows down) the engine. The crank pulley has a lot of inertia, partially supplied by the accessory belt and all of the accessories its attached to. These want to keep spinning, so its possible the crank pulley can spin on the crank, loosening the bolt.

...actually, I think I've got my directions of rotation backwards. Maybe it happens when you let off the brakes and the rear wheels and engine suddenly accelerate again? All I know is, the only times I've had my tightened crank pulley bolt come loose were at track days where I was experiencing some rear-wheel lockup.