quest's beer money this weekend

[Quest]

06 Audi A4 Quattro 2.0T rear brake job:








chinese rotors and Wagner OE Spec semi-metallic pads.

1hr job on both sides using hand tools only.

Q.

 

[Andy636]

Good job!

One Q tho...why did you ditch the OEM that seemed in fairly good shape in favor of the PRC ones?

 

[Quest]

while there's still some "meat" left on the original rotors, fact is (applicable in North America in general): (a) getting them machined (trued) costs more than buying new here in my area; (b) I cannot guarantee any warpage post-work done (I have to eat my labour hours if warpage re-appears and customers come back within a couple of month's time).

Remember this: unless it's very badly casted @ the foundry, most new rotors made are capable of handling a few year's worth of thermal cycling (since new, not machined ones, including PRC ones) before they become warped. Machining them may only give them maybe half a year's worth of extra thermalcycling before they become warped again.

This is especially true with some Japanese made factory rotors, or rotors that are getting very close to min. spec. where there's not much "capacity" left on the rotor meat.

Q.

 

[NMBurb02]

Is that caliper just hanging by the brake line?

 

[beast3300]

I throw those set screws away. That thing will need calipers... I rarely do just rear pads and/or pads and rotors on a Audi/VW. Almost always calipers everytime they need a brake job.

BTW the rotor comes off without removing the caliper bridge on those. Just unbolt the caliper and the rotor will slide off the hub and clear the caliper bridge.

 

[dkryan]

Originally Posted By: beast3300
I throw those set screws away. That thing will need calipers... I rarely do just rear pads and/or pads and rotors on a Audi/VW. Almost always calipers everytime they need a brake job.

BTW the rotor comes off without removing the caliper bridge on those. Just unbolt the caliper and the rotor will slide off the hub and clear the caliper bridge.



Does anyone use caliper kits anymore?

And Quest, I like that wooden handled "factory adjustment tool" in the first picture!

 

[Quest]

Here in the PNW area: salt isn't an issue and rear calipers on VeeDoubleU or Audi don't seize up or leak like salt belts do.

Also: rotor doesn't come off like you described. You still need that hex socket drive to partially undo the caliper sliding bracket in order to get the rotors out.

Wooden woodworking hammer is to "negotiate" the otherwise frozen rotor off the hub...and of course: it will need some spray lube beforehand.

Q.

 

[artificialist]

Originally Posted By: Andy636
Good job!

One Q tho...why did you ditch the OEM that seemed in fairly good shape in favor of the PRC ones?

Typically in German cars, the rotors quickly become too thin to re-use.

A rotor can look nice, but if it isn't measured by a micrometer, and is proven to meet factory thickness specs, you can't re-use it. Also, if the rotor is close to the minimum thickness, machining it may put it below minimum thickness. The other thing that could happen is to have a rotor that meets thickness requirements now, but halfway into the life of the replacement pads, the rotor is too thin to perform properly.

China rotors aren't all bad. I have dealt with many cases where rotors from China are actually better than OE rotors made somewhere else. OEM Chrysler rotors are often made in Canada, but warp or wear far more quickly than mid-grade rotors from China.

 

[Vikas]

I see no beer in the picture :-(

 

[Quest]

LOL! I have to get the job done first, then get the money to buy beer...

Beer been through my systems already...the rest are in the fridge waiting for pappa to come home....

Q.

 

[Vikas]

Also, why am I not seeing a jack-stand and only a jack?

 

[Quest]

yup! unsafe practice in the pic indeed.

Note to all others: don't do what I did RE: no jack stands. practice safe sex (ahem! safe car repairs) by using car jacks underneath the chassis ...

*smiles*

Q.

 

[Vikas]

Although, to be fair, for doing brake jobs, I would probably do the same. There is no need to get under the car when you are doing a brake job, so you can get away without the jack stand but don't like to tell anybody about such a unsafe method.

So that was a gratuitous shot between couple of friends

 

[dailydriver]

Kind of shocked that Audi was still using SOLID rotors on the rear in '06.

 

[Vikas]

Most vehicles really don't need vented rear rotors.

 

[SteveSRT8]

Originally Posted By: dailydriver
Kind of shocked that Audi was still using SOLID rotors on the rear in '06.


So many still are. In a recent Car and Driver they tested the A3, 228i, and a CLA250 Merc.

Only the BMW had vented rear rotors! Always shows you a more driver oriented car IMO. And the BMW was the lightest car in the test.

 

[IndyIan]

Originally Posted By: SteveSRT8
Originally Posted By: dailydriver
Kind of shocked that Audi was still using SOLID rotors on the rear in '06.


So many still are. In a recent Car and Driver they tested the A3, 228i, and a CLA250 Merc.

Only the BMW had vented rear rotors! Always shows you a more driver oriented car IMO. And the BMW was the lightest car in the test.


Also the BMW is rwd with 50/50 weight distribution, the other 2 are fwd and probably have one rear tire in the air under hard braking and turning...

 

[ironman_gq]

Most warped rotors can be traced to a casting imperfection, a spot that is thinner or thicker than the rest will heat up at a different rate and expand more which eventually leads to warpage. Once one warps all that cutting it does is true the external surfaces to each other it will create worse thin/thick areas (with less mass overall to dissipate the heat) and the rotor will warp again only this time it will happen sooner.

I had OEM rotors on my truck cut and got about 3 months out of them before they were just as bad as when I had them cut. New ones have gone several years.

 

[SteveSRT8]

Originally Posted By: ironman_gq
Most warped rotors can be traced to a casting imperfection, a spot that is thinner or thicker than the rest will heat up at a different rate and expand more which eventually leads to warpage. Once one warps all that cutting it does is true the external surfaces to each other it will create worse thin/thick areas (with less mass overall to dissipate the heat) and the rotor will warp again only this time it will happen sooner.

I had OEM rotors on my truck cut and got about 3 months out of them before they were just as bad as when I had them cut. New ones have gone several years.


Beg to differ.

Most warped rotors aren't warped at all, they just have pad deposits welded into the surface. This is caused by sitting with the pads clamped down after a hard stop.

Many folks here, including myself, have confused a pad problem with a rotor problem so it happens to anyone, and there are a variety of specific runout concerns that need to be addressed as well...