Help! I need help with C4 anti-lock brakes

[Greg Thurmond]

I'm building a C2 with C4 suspension and an LS7 utilizing a Newman Car Creations Chassis mod and I'm installing anti-lock brakes from an 86 on it. Iv'e tried two ABS modulators and they both seem to be blocking the fluid from going through. They are used parts so I don't have the history on the modulators. My source guarantees them to work but after trying two different units I wonder if I'm missing something. The brake fluid pressure is making it to the unit but won't pass through. I've already installed this same setup in two C2's with no problems but I can't understand what could be happening this time. If anyone has any ideas or knowledge on these units I'd sure appreciate some help. Thanks, Greg

 

[hcbph]

I have never had one apart but I have read where 'material' got into the system and blocked one or more of the orifices in the unit, preventing it from working or passing brake fluid through it. I personally wonder if it would be possible to 'back flush' the unit and push it back out but don't know if that might damage the ABS unit or not.

 

[Hib Halverson]

If you're doing a C2 body over a C4/Newman chassis and and LS7 engine, you need better brakes.

At minimum, you need the HD brakes (Z51, Z07 or ZR1 or 95-96 all) from an 88-96 and ABS-IIS rather than ABS-II.

That really old C4 ABS stuff is hard to find in good condition and impossible to diagnose when it fails.

Lastly, put a big front air dam on that C2 if you plan to drive it at high speed.

 

[Greg Thurmond]

Thanks

Thank you, I was hoping you would see my post. I've read some of your stuff. The car does have good brakes, they are Wilwood's. Do you know if the 88-96 ABS-IIS units can be used as a stand alone system like these earlier ones? I thought they were tied into the traction control system. I've had good success with ABS-II units in both of my midyears. Have you ever heard of them getting blocked or clogged up inside? There are some pics of my 65 on my home page if you have time to look at what I'm doing. Thanks, Greg

If you're doing a C2 body over a C4/Newman chassis and and LS7 engine, you need better brakes.

At minimum, you need the HD brakes (Z51, Z07 or ZR1 or 95-96 all) from an 88-96 and ABS-IIS rather than ABS-II.

That really old C4 ABS stuff is hard to find in good condition and impossible to diagnose when it fails.

Lastly, put a big front air dam on that C2 if you plan to drive it at high speed.