Sunday, March 6, 2016

Golf brakes

Our '05 Golf has had sticky brakes for far longer than I should have left it so yesterday I finally got off my duff and fixed 'em. I'd planned on calipers, rotors and pads, a sticky caliper will quickly ruin a set of pads which ruins the rotor. Replacing one caliper will generally make the car pull under braking so its best to do them all at once.

IDParts had brand new calipers for only a bit more than re-manufactured so I went with those since it'll allow me to clean up the old ones and keep them as spares.

Everything was going fine until:

Its difficult to see in the picture but that screw isn't seated all the way. Thats the screw that holds the rotor to the hub. Really its not all that important, the hub and rotor are clamped together by the lug bolts when the wheel is installed, all the screw does is align things when the wheels are off, still it bugged me.

To fix it I used a tap to clean the hole in the hub,

and a die to clean the screw. With them cleaned up the screw seated nicely.

This is actually the heart of the whole problem, this is the caliper mount from the driver's side. Notice the two "bolts" at the top, those are actually caliper slide pins. Notice how the right side is compressed and the left isn't. The pins should slide freely (hence the name "slides") but that right side doesn't. I beat on it with a hammer, cranked it around with a wrench lubed it with Kroil and finally resorted to heat. The heat got it moving and I was finally able to pull the pin, clean out the nasty old grease and add some fresh. Now it moves in and out freely.

 The pin itself

The Golf has floating calipers which means that the two brake pads are actuated by one piston, this is possible because the whole caliper moves to pull on the outside pad. Because of this stuck slide pin the brakes couldn't retract and the inside pad never got released from the rotor. I'd thought this was happening because the parking brake actuator was stuck but you can't really judge with the caliper still on the car...

Anyway with all that work done theres no more squeaking from the dragging pad, performance is much improved and it appears that fuel economy has risen also although that will take some time to really judge.

Now the only mechanical thing wrong with the car is the driver's side power lock actuator seems to be hung up, this is a fairly minor complaint that I'll dig into once it warms up some.

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