Piston Slap: The Self-Lathing CRX?
Gareth writes:
Good afternoon Sajeev,
Read your latest and I’m determined to help you out. I recently had a bone-stock 87 CRX Si follow me home from an impound auction and, if I can get the damn thing through an Ontario Safety Inspection, I’ll let TTAC’s very own Derek K drive it.
Therein lies the rub, or brake rub really. The front discs were rubbing, a lot. Constant grinding sound as the wheels turn. I have since removed/lubricated the caliper sliders (they were a bit stuck from sitting) and measured the discs and pads using a measuring tape and straight edge, everything is above min specs.
With the pin lube the grinding noise has abated somewhat but continues, worst is passenger side.
The discs don’t feel warped (no front shudder under hard braking).
Your thoughts?
Sajeev answers:
OMG SON, why can’t someone find ME a nice CRX in Houston? What’s so wrong with giving the Piston Slap Guy a ride in your whip, huh? I care not of the distance between us, I can still feel the pain inflicted upon me! How could this happen to me? It must be my fault!
Perhaps less self-loathing and more self-lathing is in order.
Your situation reminds me of an old road test of mine, where the subject’s rear brakes rusted shut waiting for a test drive. Popping them free was fun, actually. That said, I don’t know what’s out-of-place on the CRX. My gut says that driving more will wipe off the rust/squeaks like a lathe in a machine shop. Assuming you’ve only driven it a few yards…sorry, meters for you Canadians.
So either replace the discs/pads/calipers now (and flush all the brake fluid) OR drive it slowly another 0.25 to 0.5 miles kilometers to learn more. This depends on the population density nearby and your faith in this machine. Driving the CRX it will either clear things up or the offending part will come forward as the brakes continue to lathe themselves.
Who knows, it could be a bad hub! But I bet you have rusty/sticky calipers, so flush the brake fluid and put fresh pads/calipers/new or turned rotors on too.
Cheap insurance, totally worth it. Don’t mess with rusty brake systems, DK will appreciate it.
[Image: Honda]
Send your queries to sajeev@thetruthaboutcars.com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice.
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So the pads should have some retaining clips and springs holding them in place, check those to. They keep the pad in place and allow it to move away from the disk because the pad, when not pressed against the disk, literally floats, but, the wheel has to be moving. I to think wheel bearings could be worn out, possibly due to the dragging brake/s. Sajeev's advice is sound though, replace the entire assembly (pads, disks and caliper) + bleeding for peace of mind. I would advise genuine Honda parts or good quality generics from a reputable brand.
Seriously - nobody has asked the obvious here. HOW MUCH?! Great find. Great rims. Great advice.