Xoutpost.com - bad caliper?

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The Audi/Febi silicone brake grease is amazing stuff!

Man, that is a ton of rust bits. I've *never* seen a guide pin rust before! That's what immediately caught my eye.

Might be time to order up a factory caliper, bushings, and pins. If they are rebuilt, maybe hit them with some high-temp paint (black BBQ grill paint?). Hopefully keep the rust at bay. They bead blast them during the rebuild process and take off all the plating/rust preventative coatings.

I used the "new" guide pins that came with the $62 rebuilt because they looked all shiny and newer than my originals. They were probably crap pins and I sent back my originals with the core charge.

My newest theory on the grinding noise - the excessive heat of the wheel overheating flexed the back plate shield to make temporary contact with the rotor. Thus when it cooled, no noise. STICKING To that theory - at least for tonight.......

THANKS!

The chances of that happening would be rare....

Is it just me, or is that piston out way too far? Even with fully worn pads, it seems to be extended pretty far.

Nope your eyes do not deceive you. Rusted stuck

Past story:
Worked on an X5 a few months ago that had "rear brake noise". The backing plate ears on the RR pad was bent out 1" hitting the rotor after wearing down a few MM. Made one hell of a grinding noise and scared the heck out of the owner. The tech who did the brake work must have dropped the pads or never looked at them before installing them.

When it comes to brakes never say "I have seen it all".

Examples:
Pad installed backwards (metal towards the rotors)
One pad left off
Friction material pulled off one pad (NOT over heated)
No drum on RR (Wheel cyl popped out and fluid leaking down wheel)
Brake line pinched off (Couldn't bleed brakes so....)
Only the outside pads installed (Hey, see the new pads?)
Anti-noise paste all over the pads, caliper and rotors. Looked like red meat juice dripping.
I am sure there are others who can chip in on WTF? experiences.

Bottom line: Check everything twice. There is something going on.

Yes, piston looks far extended but I was able to yank it off the rotor without manually compressing it, and yes my pads about about 1/2, 3/4 worn.

After I replace I will peek under the boot and see the condition of the piston. Scary when I rebuilt the other 3 calipers and realize a flimsy rubber gasket is holding back all that pressure and stopping your car.

While i was getting the rotor back on and adjusting the emergency brake shoe - that was making a similar grinding noise, MAYBE heat buildup expanded the shoe enough to get it to scrap.....?

I did try to compare free movement of the 2 back wheels and thought this one dragged a bit more - BUT, way too complicated, car on stands, worried about being in nurtural, and the turning of the axel.

Updated tracking number, I wont get the replacement caliper until Monday, UGGG...all weekend long to keep thinking about it.

Quote:

Originally Posted by kevinkay (Post 1082474)

Scary when I rebuilt the other 3 calipers and realize a flimsy rubber gasket is holding back all that pressure and stopping your car.

Scary indeed. That same type of $2 square cut seal is what's often holding up the car for guys that refuse to use jackstands/supports/ramps and rely solely on a floor jack.

Quote:

Originally Posted by srmmmm (Post 1082430)

The rust on the assembly (especially the piston) is surprising for just one year's use. Almost speaks to potential contamination inside the caliper itself. As for greasing the pins, I've always used a hi-temp silicone grease on the caliper bolts/pins on all my vehicles without any issues.

2002 X5 3.0 305,300 miles
2014 428i 19,600 miles

2004 325i sold at 123,600 milesrake
2001 325i sold at 66,000 miles

1970 Firebird Under restoration

When did you replace the brake fluid last? Brake fluid is hydroscopic, which means it absorb water.

When I rebuilt my calipers on my PORSCHE I replaced the pistons with stainless steel pistons.

Quote:

Originally Posted by kevinkay (Post 1082382)

had the right real caliper sticking, heating up - TONS of brake dust.
replaced it with a rebuilt $62 caliper found at a local independent truck parts store (they ordered it and got it next day). Fit, looked like a new piston, only discrepancy was the bleed screw was 1 mm smaller wrench size than the rest.
Next week, ordered rebuild kits for remaining 3 rotors $25 a wheel - rebuilt and heavy flushed and bled system.

fast forward 1 year:
driving slow speed in a parking lot noticed awful "grinding" noise with rotation of wheels. (fist panic is bad bearing and I HATE doing bearings).
Stopped, checked it out - again right rear caliper is HOT, smells and rotor looks too shinny. Let car cool for 2 hours, drive home about 1 mile, no noise, that wheel hotter than the rest, but not overheated.

I ordered a new rotor FCP $300 it should come tomorrow.

Anyone have bad experience with rebuilt calipers? I have read that once a caliper heats ups/cooks that it should not be rebuilt?? (and assuming the one i bought had been cooked)
Should I fear an issue with master cylinder this being the wheel furthest and not getting enough pull back pressure?

OR - you get what you pay for - $62 for the rebuilt caliper?? when the rebuild kit costs $25 re-using the old piston.....

THANKS

Dude My rear calipers froze up on me last week I drove about 4 miles ,F-ckin thing was super hot.I let them cool off , they open, Now I am going to have all of them and the parking brake pads.replaces too.$1800. I drive long distances so I want piece of mind .Broken down on a cross country trip with a BMW is not going to happen to me.