2007 Base, A6, Z51, 28,000 miles: I heard a little noise from the front end so I pulled the wheels for a look. Passenger side caliper is loose. Both bolts are torqued to 23#. Braking is fine. No fluid leaks. I can move the caliper side to side about 1/8" +. Movement is at top and bottom but a little more at the top.

Any suggestions would be appreciated.

 

You checked both the caliper and caliper bracket bolts to make sure all where correctly tightened. Could be that someone pulled the brackets off, and did not loctite those bolt in place, they are loose now and where you are feeling the movement.

brake caliper guide pin bolt (JL9, J55) 23 lb ft
disc brake pad pin (J56) 30 lb ft
all front & rear caliper bolt & bracket bolt (JL9. J55. J56) 129 lb ft

As for if is the caliper on the guide pins , might have to pull the caliper off the pins to see which part is worn. The pins to channels should be greased, and if they where not, would end up with wear to cause the slop of the guide pin to the channel.

If you suspect that the problem is in the guide pins to their channels, then pull the caliper off the pins, then pull the guide pins, clean them and work them in there channels to see how much slop you have, and which part is worn and needs to be replaced.

Guide pins are the lower part in blue, and the seal will pop off as you pull the pins out to clean, grease, check them.

 

The slop is coming from the caliper bolts/pins. I pulled the pins and they had grease on them and look and fit good. The slop is an in and out movement of the pins (side to side on the car). The bracket and bolts are tight and do not move. The caliper bolts into the pins are tight but the pin is moving in and out. What keeps the pins from moving in and out (side to side on the car)?

 

Guide pins are just that, and allows the pads C holder section to center on the rotors, so the guide pins should move in and out freely in the pin receiving channels.

As for side to side movement/slop while the guide pins are moving in and out, that is caused by wear that could be the guide pins, or the guide pin receiving channels instead.

Guide pins are cheap enough to replace if suspect that they are worn, while if the guide pin receiving channels are hollowed/egged out instead, might want to give Gene a call get a new z51 brake bracket.
www.gmpartshouse.com

 

I am probably not giving a good explanation of the movement. The is no slop with the pins. Everything is tight and the pins look good. The whole caliper assembly is moving in the direction that the pins slide. The pins seem perfect and slide nicely in and out without any slop. When everything is bolted up tight, the entire caliper assembly moves. The caliper bracket does not move

 

I think you may be seeing normal movement. This movement would be even greater if the caliper pistons were pushed in further.

 

Sorry about that, brake bracket is the guide pin receiving piece, and it's easy replaceable.



The entire assembly that is bolted to the guide pins (part with the fluid bleeder on it) should move in and out with the pins, stationary brake bracket, which allows the pads/Caliper to center on the rotor.



Now the next in line, what condition are your wheel hubs in?
The rotor is sistered to the wheel hub via the rim, and if your hub is on the way out, could be the problem instead.

With the front tire off the ground, grab both top and bottom of the tire, and try to flex the hub. Also, spin the wheel and listen for any abnormal sounds of the bearing.

As for hub problem, it not only the basic bearing problem of the bearing itself going south, but when the bearing is going out, allows greater brake kick out from the rotor since the bearing allows the hub plate to flex on the inner bearing section, which in a hard turn, translates to the pads being forced open more than normal when you are tuning the car hard. Hence called brake kick out, and the 350Z's had very bad problems with this, since the hub flex was so bad on hard turns, it could kick the pads/ caliper so far open/out that when when you pressed the brake pedal, it went to the floor before the pads would close up enough to grab the rotor.


Really here, If you can just make a short video of the problem and post it, should be able to determine if you do have a problem and how to solve it if is a problem.

 

here is a video

 

It is a floating caliper and is supposed to move that way. Try all 4 and you should see the same thing. As the pads wear the piston pushes the pad in from the inside and that also pulls the pad in from the outside. If you have brand new pads the caliper won't move as much since all of the movement space is taken up by the pads.

Bill

 

Thank you Bill. I was really stumped because I could not see any way to tighten this up. I only have the fronts off tonight but there is almost no movement on the other side.

 

That kind of movement is normal...it is floating so that the two pads wear down equally. On lots of motorcycles, they have the disc floating also.

 

Thanks to everybody for the help. I pulled both of the pins on all four corners, lubed and torqued them and all is good. When I started searching for the noise I was hearing up front the first thing I felt was the caliper and it worried me. After all of this input I started looking elsewhere and it turned out to be the end links. Just replaced them and silence has returned! Thank you again for all of the input.

 

If the front sway end links gave up the ghost, then replace the back ones as well.


As for your brakes, the tire is not installed to hold the rotor tight to the hub, so that is why the you are seeing movement (rotor allowed to move off the hub, and the caliper just following it.

As for a quick check next time, large fender washers on a few of the tire studs cross corner, then a few lug nuts installed will hold the rotor tight to the hub. Not only will this allow you to see if the caliper/brakes are good to go, but will allow you to spin the rotor to check for major warping/high lower spots in the rotors as well.

P.S, if you still have the star washer retainers on the studs that hold the rotor on, you can pull and throw them away. The are used for production assembly line construction of the car to hold the rotors on before he calipers are installed. Even worse, some after market rims do not have the counter sunk back sections for the washers on the rims, and when you install such rims over the retainer washers, cause the rim to not sit flush against the rotor.

 

Thanks Dano. I did replace all four end links. As you said, after the wheel is installed the calipers are fine. I had never seen movement like that before and assumed that was the cause of the noise. Replacing the end links was a snap. I read a few threads and was surprised at all of the people who say they cannot get a torque wrench in there. With the tires off, I had plenty of room for a 1/2" drive. A couple of different extension sizes made it easy. I really appreciate all of the info you sent my way.