dreamhope

Hi,

Went for maintenance yesterday, and the mechanic said that my front brake pads and discs could use a change. I figured it's an easy job, so I may just do it myself. I'd like to get some info first:

What are the sizes of the wrenches/sockets I'll be needing?
What should be the torque on the bolts?

I'd hate to find out I don't have everything after I take the wheels off.

Also, the guy suggested that the right upper suspension arm needs to be replaced. What would be the cost to have it replaced? Apparently I don't do this myself.

Thanks!

silverd2

Pads are always relatively easy. Rotors are a different matter...they usually require removal of the caliper and/or caliper carrier to clear the rotor off the hub. Depending on the brake type you have, the bolts type/size and location vary...usually very high torque, some models VERY high.

Brake types on specific years/models can vary with Euro models compared to USA models. I can't comment further on specific tools or mounting type until you tell me what brakes you have on the front...just 2 pads on each rotor with a single large hydraulic piston (not the little guide pins) in the middle OR 4 pads on each rotor with 2 hydraulic pistons?

Also, the need for new rotors, if they are not warped (badly pulsating pedal will braking) really depends on exactly how thick they are...if they are not close to their wear limit, they may very well be good for another set of pads only...most rotors will go though 2 sets of pads in their lifetime before "requiring" changing.

dreamhope

Thanks for your reply

I just checked and measured the brakes. At the front I think it's a single-piston design. Rear brakes have two pistons each.

As for the rotors. I measure roughly (it's already dark outside, and with a torch I can't position 0 precisely) 29.5 mm left on the front and 18.5 mm left on the rear discs. If 28 mm is the minimum (like this thread says http://www.motorgeek.com/viewtopic.php?f=17&t=51558), I think I can keep the old ones?

I suspect the original owner had never changed the rotors in 15 years and 98k kms (60k miles). They still look good (when I had the tyres changed I had a good look at them), and work well (so no warp). Just the outer pad on the left has maybe 5 mm left, and on the right 4 mm left (may not be accurate on the right as a spoke blocked the view, but it does look thinner).

Thanks again

dreamhope

I guess this is the correct pad.

dreamhope

I measured again under sunlight. The rotors are only 27.7 mm thick, definitely in need of replacement.

dreamhope

and the rear has a single piston as well

dreamhope

I'm so stupid. There're 4 pads on each side.

silverd2

That's more like it...it should be a steel HP2 (twin piston) caliper...those appeared on later model USA A8's. The pads are pretty easy to change on those...if it's a steel caliper, there should be 2 torx bolts on the front (in near hub) that once removed, allow you to compress the caliper with a large screwdriver slipped in between outer pad and caliper. If it's an aluminum caliper, there should be a large spring retainer (and no torx bolts) over the pads, that can be removed with large pliers...this spring retainer should not be there on the steel caliper.

There's a little more to it than that, if you've never done a disc brake job before...like thoroughly cleaning all the caliper contact surfaces the pads slide on etc..

Getting the rotor off on this model is tough, though...2 large bolts on the back that hold the caliper frame to the steering knuckle (bearing housing)...each are torqued to 140 ft lbs (190nm)...requires a big breaker bar and all the strength you have to break these loose...I've done it, doable but tough. You also need to unclamp the brake line bracket that's near one of these bolts. Once the bolts are loose, you can leave the top one in place and swing the caliper clear of the rotor to remove.

The rear pads are a bit tougher to replace...pads come out easy with 2 sliding pins unbolted (counterhold lock nut)...BUT, like most rear disc brakes the cylinder has to be turned while compressing with the proper brake tool...it will not go in unless it's turning while compressing. I use a set like this >>

http://www.ebay.com/itm/Disc-Brake-Caliper-Wind-Back-Tool-Kit-Piston-Pad-Car-Truck-Mechanics-Universal-/190909539863?pt=Motors_Automotive_Tools&hash=item2c73186617&vxp=mtr

dreamhope

Thanks. I found on Youtube two videos of a 2000 A6 change. I think the rear brakes are the same. The front ones are slightly different, but the caliper housing should be similar.

Btw, I was quoted 700 EUR for the front brake job at a small shop. The dealer asked 800 EUR for an oil change (that's one zero too much). No choice but to DIY. Yesterday I went to a shopping centre and could only back into the space slowly. There was less than a foot on either side, and I had to squeeze myself out. The road is like the surface of the moon, and you're lucky if the lane is 8 foot wide. France really has some of the worst infrastructure I've seen. Will leave as soon as I finish my PhD.

dreamhope

found nice instructions

http://www.audipages.com/Tech_Articl...ontbrakes.html
http://www.audipages.com/Tech_Articl...rakestwin.html