(Posting so this has a chance to help someone else)

2008 G35x

I recently had the dealer put on new tires. This was the first time I had the dealer do it, vs the specialist shop where I normally get my tires done.

For the next few days, I consistently experienced bad vibrations at 65+ MPH. The vibrations felt equally strong through the seat as well as through the steering wheel, In other words, the problem did not obviously seem to be coming from the front end vs the rear.

So I figured wheel balance was off.

I went back to the dealer. One of their mechanics patiently troubleshot with me, including flipping the tires around on each wheel, which seemed to help a little, as well as swapping on a different set from another car on their lot. There was no change in behavior with the other set of wheels, so I concluded the problem was somewhere in my car, and not due to a bad wheel balance job.

In this same timeframe I had noticed that my left rear wheel seemed to be hotter than normal after one morning commute. After the morning I spent at the dealer troubleshooting the vibrations, I took the temperature of the rotor with a laser thermometer: > 300 degrees F, vs @120 F for the other side ! So, apparent stuck caliper.

I replaced the caliper the next day (easy job on the G35x) and solved that problem.

On the very next commute, I noticed: the vibration at high speeds was gone !

So all along the bad vibrations were due to a stuck caliper.

 

Super common issues sadly with these rear calipers. The slide pins or pistons get frozen super easy.

 

Replaced 3 calipers over 8 years of ownership. 2 for frozen slide pins and recently had one leak from the piston. Brake fluid dripped on the wheel and started peeling the powder coat

 

I had the same problem last month. I started to notice a smell when I would exit the car, then the vibration / shudder started. I put my hand at the wheel on all 4 sides and found the hot one right away. This was on the rear of my 08' G35x with 125k miles. I'm pretty sure my brothers 08' is doing the same thing.

 

Do you guys do anything to avoid sticking pins? I've heard people recommend NOT applying grease in the slide pins as you typically would on most cars. Last time I did my rear brakes, my dad applied grease to a pin without letting me know, and that was the one which stuck on the caliper.

 

​​​​​​In my case both times it was the pin with the rubber bushing. I think the grease caused the rubber to swell up and get stuck. You definitely need the grease though, just the right type. If you buy a reman caliper they almost always come with the pins greased

 

Good tips. Thanks for sharing man.

 

Thanks for the feedback. I did a little digging, and it sounds like 100% silicone grease had the best results for owners that had sticking caliper issues:

https://www.bigclassaction.com/featu...t-lawsuit.html

 

On my 08' it was the piston not retreating like it should. I only replaced the caliper with a reman unit and reused my pins and brackets. I always use high temp grease designed for disc brake applications. I have had to rebuild quite a few G20 rear calipers myself since they cost big $$$ these days and almost every one that I have disassembled have had erosion on the pistons. I wish I would have tore down the G35 caliper to see if it was a similar problem.

 

Now that you mention it, the last time I swapped out my rear pads, the passenger rear caliper was a major pain to push back in. Instead of the small C-clamp I used on my first change, this time it wasn't budging. I had to used a much bigger clamp (similar to the kind you use to press out bearings) with an old pad over the cylinder. It took a few attempts and a lot of force before it started going back in.

After I put it back together and drove the car, I smelled something off and pulled over. One of my rotors were cooking. I let it cool down for a bit, drove it home and took the pads off again. I figured it was the slide pins and clean them out, then pushed the piston back in again to reinstall everything. Maybe it was actually the piston instead of the pins.

 

I'm having the same issue. I thought it was the support bearing from the driveshaft. COME TO FIND OUT THE LEFT REAR CALIPER IS STUCK.THANKS

 

To anybody reading this in the future, a stuck caliper will put off noticeably more heat than it's non-stuck counterpart. Take a quick drive on the highway then pull over, put your hand near the center of the rear wheels, the stuck side will be considerably hotter.

This issue is what ultimately made me swap out for OE Brembos. Also OE Brembos look cool and make me feel like the special boy my momma always told me I was c: