Hi all,
Been a while since I've posted. Back in early '21 my LT panel was totalled with a tractor trailer not paying attention in a parking lot. Damage was primarily cosmetic to the passenger rear quarter, but since those replacement panels aren't available anymore the insurance totalled the car. I wound up retaining the car, and absolutely dragging the insurance company for enough cash to have it rebuilt, which it has been. So far, so good - a little more wind noise than there used to be, but I can deal with that. Previous to that I did the SS rear brake upgrade and the front brake upgrade (non-Brembo). Within a few months of doing that upgrade, the front rotors warped - I can't recall what I had bought, but they weren't the cheap Amazon brands.. I think they may have been OE AC Delco. So... bought another set and has been good up until yesterday - long road trip with lots of hills... and the da** rotors are warped again (steering wheel shakes while under braking). The hotter they get, the worse the shaking. Cooled off, they're ok. The question now is: is there a "better" brand / rotor to mitigate this? Not that they are hugely expensive, but darn it, my 2500 series Chevy pickup with 4 wheel disc has the original discs still on it at almost 95K miles! Would a slotted/drilled rotor be any better?

Rick

 

2 questions
1. are the rear brakes working? That is the usual cause of warped front rotors.
2. have you inspected the Lower Control Arm bushings? They produce similar symptoms.

 

Answers: Rear brakes - I can only assume that they are. Discs are bright at the end of the day. Now, whether they actually have the balance front to rear I don't know. I was following several threads on the forum here with people that did the beam swap and what was used and there was an unanswered question whether the stock LT antilock modulator would be sufficient for the new discs or if the SS servos were needed. I did try to install the SS modulator it didn't want to play with the system, so the stock modulator was retained.
LCA's - I have not personally inspected them. They should have been inspected when the truck was through the enhanced inspection when it was re-titled last year after the crash. I'll have to get under there and visually check them out.

 

Double check the rear bushings in the front LCA’s. And try to remember, did you install the SS rear hubs or the drum brake rear hubs? The SS hubs in ABS drum brake cars don’t work properly, if you have the drum brake hubs install those.
as for those front rotors, I install PowerStop brand, I have their rear drum and shoe kit also along with the SS non Brembo front rotors and pads, no warping, no pulsating pedal.

 

I'll check the LCA's when I can get it in the air at the shop. As for the rear - just a direct swap, beam, axles and all. So yes, the SS hubs are still in there. How would putting drum hubs back change the fluid bias? The anti-lock still is active and works with the disc/drum modulator and rear discs (no codes)... trying the disc/disc modulator did not work with the BCM.

 

As far as I understand the Hub from the SS reads different voltage then the drum brake version, but your correct, there should be a CEL. I’m leaning more towards the rear bushings of the LCA’s, possibly ball joints.

 

That's correct with the voltage - but it actually originates in the modulator. I think the only way to really test the rears is to jack it up and manually spin the tires! I will be at the shop tomorrow to put it on the rack to see what's going on up front. Truck only has 62K on the clock.. I'd be very surprised if any bushing was giving up the ghost, but you never know!

 

I had to replace Oldblue’s bushings at 58,000 miles. Cold weather, rougher roads , potholes, train tracks all add up.

Your welcome, Donbrew!!

( he hates it when I post that photo , you know of my before and after bushings in my dirty greasy hands )

 

The wheel speed sensors produce an AC current/voltage that is read by the EBCM as a frequency. The EBCM does not send a current/voltage.