Waferboy

Looking for some advice... A while back I changed out my 93 LX Brakes for the SSBC front/rear Cobra 4 lug discs. The problem is that my rear brakes chirp and here is what I know:

• Originally I put in Hawk Ceramics, I changed those for no-name Semi-Mettalics... no change
• Originally disc were out of the box, cleaned, scuffed and installed. Since, they have been turned and reinstalled... no change
• Thinking there may be some drag, I've adjusted the brakes power booster plunger in, pulling it farther from the master cylinder and the brake pedal now dives much deeper to the floor before something happens. .. no change
• I've pulled, cleaned, reinstalled, greased brake pads multiple times... it helps for a few days, but the chirping always comes back
• I've added/changed the pad shims, added/removed CRC brake quiet... no change
• The chirping always happens after the brakes are used a few times. Heating things up seems to create the problem.

So what do I do next? I've debated about new discs or new calipers and am leaning towards the discs. Looking for some help and or ideas. This is driving me nuts and it's a bit embarrassing to drive this thing around.

Thanks everyone!

Waferboy

Currently in the stable:
93LX hatch VIN...4800
93LX hatch VIN...5028

88 orangepeel notch

Does the chirping go away when the brakes are applied ? Or is it constant while driving and not on the brakes ?

Waferboy

Yes, it does go away when the brakes are applied. Also, it tends to go away or at least change in tone when I make a slight turn right or left. Going straight, it's there though. Anyone know what types of discs there are? Majority are straight cast iron, but there must be some other alloys. I'll have to do some research on that. I presume mine are the cheapest cast iron ones you can get as they were part of the kit.

dawson1112

Have you ever changed the rear wheel bearings?


Is the emergency cable hanging up or to tight?

mongolchuck

Could be the rotor isn't perfectly square on the axle, causing a high spot rubbing somewhere on a backing plate or pads. Could be slight amount of rust or grime under the rotor hat. Hanging cable or bearing is also a possibility.

Waferboy

Bearings have been changed within last 15k miles. That could be a possibility though. The parking brake has not worked since the upgrade. I got the 70" cables as a replacement during the disc upgrade... too long. I have the 67" cables to install soon.

As soon as the other '93 gets out of my garage (engine rebuild), I think the wheel are coming off and I'm going to run the car on jackstands to see if I can actually catch it in the act.

Thanks for the feedback!

yurizx6r

It seems like your parking brake cable could be too tight. That would be my first suspect. It could also be that one of your pistons are somewhat seized or at least not functioning properly. I'd check that before you get into spending any more money or checking your brackets.

mjr46

unless you did the mod to the ebrake handle, your e brake won't work , I've done a few cobra brake conversions in the rear and a fox drum brake to disc needs a mod done to the handle...iirc there is a tac weld to do.

Waferboy

So after more fiddling I found that with the hand brake cables removed the rear brakes would not fully release. So I finally bought a new set of rear calipers and problem solved!

So the SSBC rebuilt calipers were bad from the beginning. I broke down the old calipers this weekend and there was definitely a catch in one and the other was not smooth. The return spring just didn't have enough to return the lever that the brake cable hooks into. After tearing them down fully, I didn't see anything really wrong, but I took some 400/800 grit sandpaper to the internal part of the brake cable lever that and now they work smooth as silk.

My kid is talking about putting rear discs on his 93, so I'll rebuild these and he'll have a set of calipers for him.

Thanks for the help everyone... glad the problem is fixed but what a pain.