Hit a pothole today then every bump I hear a horrible banging

bronco · Post by **bronco** » 05 Sep 2020, 11:16

1998 V70 . Driving about 30mph , hit a pothole or raised manhole cover and heard a loud BANG !!! pull over looking underneath expecting to see broken control arm or strut but I see nothing wrong. Drive away slowly nothing then hit another pothole BANG! step on the brakes horrible grinding noise.

I'm only about 5 miles from home so I limp home jack it up tire doesn't move everything seems ok so I remove the tire and look and the edge of the rotor looks weirdly shiny . go to take a caliper bolt out , put the allen in twist the ratchet and the caliper moves !

Long story short the lower caliper bracket bolt is gone and the upper bolt is half out of the hole.

basically every bump was bouncing the caliper and bracket up and down pivoting on the remaining bolt and using the brakes was pulling the caliper too far in on the bottom bracket making the caliper touch the edge of the rotor

Ive owned the car about 2 years I have never touched the brakes the PO did them. He gave me the receipts new everything pads calipers rotors CV joints etc.

He did a lot of work to the car but had a big oil leak from the turbo line and from a cam seal( he had installed backwards) and gave up basically.

Anyway I went to the other side and both caliper bracket bolts were hand loose .

About a year ago I had a few lugnuts fall out and the loose ones were covered in a black goo , these caliper bolts had the same substance on them.

He apparently did not want his threaded fasteners to seize and made sure they wouldn't with whatever this crap is.

I feel for the guy , I have seen these stupid lug bolts freeze in so tight they snap off when you put a wrench on them. And I have seen caliper brackets you needed to heat with a torch on these cars too.

Whatever the black goo is , it looks nothing like any standard axle type grease i have ever seen .

Tomorrows project will be looking through the receipt pile and checking various bolts .

Post by **cn90** » 05 Sep 2020, 15:12

Black goo is probably grease.

I use antiseize on caliper bolts and wheel lugs now for > 25 yrs. Zero issues.

Post by **abscate** » 05 Sep 2020, 16:05

Unconfirmed, but I believe Volvo says to replace these when removed and the torque is in the tty regime.

Confirmed. Volvo says replace, 100 Nm torque

bronco · Post by **bronco** » 05 Sep 2020, 16:56

I always use anti seize on those too. It wasn't like grease though it was a strange feel to it , almost sticky .

Like the texture of honey .

maybe something old-timey

Post by **Sveedy** » 05 Sep 2020, 17:27

Cosmoline ?

Post by **abscate** » 05 Sep 2020, 18:05

Mother in law saying

“ let me out!!!”

bronco · Post by **bronco** » 05 Sep 2020, 19:00

Sveedy wrote: ↑05 Sep 2020, 17:27Cosmoline ?

maybe! cosmoline with brake dust in it would be black huh?

Post by **scot850** » 05 Sep 2020, 19:49

I thought the caliper bracket bolts use thread locker on them? I have re-used these bolts for years many times with no issue. Please note I am not advocating others do this but my personal experience is they can be re-used. These take less stress on them than the caliper slider pins which have a muck smaller thread diameter.

Neil.

callahanoffroad · Post by **callahanoffroad** » 07 Sep 2020, 06:10

Dang bronc that stinks! Unless you thoroughly enjoy checking the torque of all your bolts that is.