2004 XC70 Center wheel bolt coming loose

aikomama · Post by **aikomama** » 26 May 2015, 00:14

A few months back my brake and ABS light would flash only when making a hard right hand turn. Took it in and found that the wheel bolt was loose. The mechanic tightened it and it was fine. A few months later I saw my center cap was missing and when I looked, the center bolt was completely gone. Mechanic replaced it with a new bolt and it has been fine for months/several thousand miles. Recently the ABS light has been coming back on again and I just popped off the center cap to find that the bolt is loose AGAIN! What could be causing this? And what damage can be done driving with a loose or missing center bolt?

Post by **abscate** » 26 May 2015, 03:43

This bolt has to be thrown out each time it is removed. The tightening torque is such that the bolt deforms by stretching so it cannot be reused. The torque is something like Xx Nm, plus 120 degrees of tightening which is really, really, tight.

My guess is ypur mechanic just under torqued it, especially since s/he re-used the old one the first time..not good.

Get a new bolt and do it yourself!

If this bolt gets loose, the axle can move withing the front wheel bearing splines, and can machine them nice and smooth, which costs you a new wheel bearing and front axle. Ugh.

Post by **JRL** » 26 May 2015, 04:24

Also glue them with some Locktite.
Read about P2 Volvo axle bolts

Post by **oragex** » 26 May 2015, 06:33

Maybe the previous owner overtorqued the bolt and now the threads inside the axle shafts are worn. Or there is lubricant were the bolt touches the wheel. Try the bolt sold by volvo for the XC90, it has a rubber washer to prevent it from slacking. But before installing it, have the axle side threads inspected/cleaned and make sure the mechanic tightens the bolt with the right procedure http://www.volvoforums.org.uk/showthread.php?t=193319 - don't just turn it until it sits tight, as mentioned this is a special one time usage bolt that needs torqued then angle torqued to have it stretched.

Post by **abscate** » 26 May 2015, 09:59

Front axle nut specs M10

Tighten in two steps

Drive Shaft in Front Wheel Hub (M10)
Step 1 35 Nm
Step 2 Angle Tighten 90°

****THIS IS FOR THE SMALL M10 bolt on late P80/P2 cars not the 36mm castle nut on early P80 cars!! ****

aikomama · Post by **aikomama** » 28 May 2015, 13:08

Thanks so much everyone! I was able to find a Volvo specialist and took it in before the trek home. He replaced the bolt and torqued it to spec and everything seems ok. I'll keep an eye on it and see if it happens again. The shop did say that they see at least one(if not more) Volvos a month come in with the exact same issue so obviously I'm not alone.

Post by **oragex** » 28 May 2015, 13:45

Indeed, a pretty common issue, I think on the XC70's. Good to hear it's been fixed

Randdaddy · Post by **Randdaddy** » 19 Mar 2019, 08:47

New wrinkle. The ABS light went on Sunday and bolt was dangling in hub. Screwed in and found this blog post. Called Volvo dealer and gonna pick up new bolt tomorrow (day off). Today (Tuesday) ABS light goes on again and rush back to house to screw in bolt. I find bolt still snug but its slid out half inch or so. I slide/push it back in, still nut tight. What gives? I'm guessing a trip to the mechanic.