S8ilver

I was planning on replacing rotors and pads this weekend and have found conflicting specs for required bolt torques for the Brembo calipers.

2002 S8
345mm front
280mm rear

Carrier to knuckle torque (F&R)?
I think I recall reading 145 ft-lb (front), not sure of rears.

Caliper to carrier torque (F&R)?

Thanks in advance.

silverd2

For all it's worth, this is what I've found:

Bentley doesn't differentiate brake types in the section for bearing housing removal...190nm (140 ft lbs) for carrier bolts, BUT look at the drawing for Brembo front brakes AND the specs in the Mitchell table below.

Bentley seems to call the carrier bolts "cylinder bolts" in their drawings for rear brakes (and front?...I'm unfamiliar with the look of Brembo front carrier bolts)...and the Mitchell table seems to comply with the same torque ratings.

Hope this helps some.

From Bentley >>




From Mitchell >>

S8ilver

You are correct...Bentley calls them "cylinder bolts" on front but those are the carrier-caliper bolts. The carrier-bearing housing bolts are not shown here. On the rears in that diagram, the "cylinder bolts" are the carrier-bearing housing bolts, and the "guide bolts" are the carrier-caliper bolts. Very misleading.

I've found that table Mitchell in the past and was a bit confused (still am).

I think this is what I know:

Front
Caliper to carrier (cylinder bolts) - 81 ft-lb
Carrier to knuckle/bearing housing bolts (don't know what Audi calls them) - also 81 ft-lb? Or is this 140 ft-lb? I don't think the FL S8 had the HP2 caliper which took 140 ft-lb. If I'm wrong I'd like to know before I put 81 ft-lb on something requiring 140 (I'd rather do that 1st then the other way around).

Rear
Caliper to carrier (guide bolts) - 26 ft-lb
Carrier to bearing housing (cylinder bolts) - 44 ft-lb if steel, 52 ft-lb + 90deg if aluminum (I'm assuming aluminum but I'll find out when I'm in there).

I'll snap a photo of the fronts when I get the car back later this week (in for a trans fluid drain/fill).

S8ilver

Ok, so I definitely have the Brembo calipers as shown in this:

http://www.audipages.com/Tech_Articl...tbrakesS8.html

Anyone out there change their S8 rotors and have insight on torque values used during reassebly? I'd love to see 81 ft-lb in the Bentley manual for the carrier to bearing housing bolts, but only see the 140 ft-lb.

silverd2

If I'm seeing the drawings correctly in ETKA, Brembo calipers (solid mounted) are held on with M12 bolts (81 ft lbs would make sense) inserted front rear to front of car. Doesn't appear that the carrier has to be removed to pull the rotor.

HP2 (mine) carriers, held on by M14 (140 ft lbs) have to be removed (inserted inside of car toward outside) to clear the rotor...this is after the floating caliper is removed. I've done this myself.

If you need to remove the carrier after removing the caliper and it's held on by M14 bolts, I would assume that connection would be 140 ft lbs(?).

Am I correct in assuming that, due to a completely different solid mount caliper design, the carrier stays in place during rotor changes?

S8ilver

Oh man, that would make my day! I have a 30" breaker bar standing by just in case

silverd2

Looking at drawings, there seems to be no sign of a carrier for front Brembos...Looks like they bolt directly to the knuckle(?)

Not sure.

silverd2

PS..I'm 99.9% sure that A8 bearing housing (steering knuckle), made for HP2 brakes, is different than the S8 knuckle....I think the brake attachment is the main difference(?)

S8ilver

Now seeing two 81 ft-lb values makes sense; it could be the same bolts. This is also probably why they say to replace with new each time (not much redundancy with the same hardware doing all the work). I'll report back after I dig into it this weekend.

I'm surprised not one S8 owner has chimed in...someone surely has replaced their S8 rotors?!

S8ilver

Well, got the brakes on this weekend. Sure enough, the front calipers bolt directly to the bearing housings...way easier than the rears.

The pads I chose did not come with wear sensors (knew before I ordered). I was having false brake pad warning lights prior to the job, so knew I had to short the connection. Unfortunately, I STILL have the pad warning. What gives? I cleaned up both connections very well, and used a solid crimp on connection on the old pad wiring. I don't feel like ripping the instrument cluster apart to address it there.

Is there another place I should be looking for an open circuit...i.e. the permanent wiring? Everything appeard to be in good shape.