A place for things that don't fit into the automotive world

Speaking of caliper cleaning...

  • Noah
  • Noah's Avatar Topic Author
  • Offline
  • Moderator
  • Moderator
  • Give code definitions with numbers!
More
5 years 4 months ago #24625 by Noah
Tutti got me thinking about posting this question with his thread about caliper cleaning methods here: www.scannerdanner.com/forum/off-topic-se...r-cleaning-tool.html

All of a sudden I've acquired a few customers with BMWs, and I'm less than enthusiastic about working on them for lack of experience.

I did a 4 wheel brake job on a 2006 x3 last night for one of my new customers, and went out of my way to get OEM parts after the owner had expressed that the brakes had been squeaking for years despite having been changed.

When the parts came in I noticed there were no stainless steel shims for the area where the pads slide on the rear caliper brackets.

There was also nothing of the sort installed on the car. It had Bosch pads and the rotors looked like quality zinc coated units, so I assume this car wasn't the victim of a driveway pad slap where the hardware was hastily destroyed and disposed of.

So for the present I believe this is just the way they are...

But to the point, I observed that there were the beginnings of divots in the caliper mounting bracket where the pads had settled into riding.

I entertained a brief fantasy of welding up the divots and grinding them smooth again, but came to my senses immediately :P

I'm worried about the pads potentially hanging up in the bracket in the future and having an unhappy customer..

Does anyone have any experience based input they'd like to share?

Thanks,
Noah

"Ground cannot be checked with a 10mm socket"

Please Log in or Create an account to join the conversation.

More
5 years 4 months ago - 5 years 4 months ago #24630 by Andy.MacFadyen
That's the way the come all thing to beware of is bent guide pins --- Some euro Nissan models use a similar TRW caliper and I have seen bent guide pins and uneven wear on those, If you do find a bent guide pin you need to MvGyver a puller to draw it out using an M8 bolt and a socket.

Front calipers on BMW are usually Teves -- no stainless shims on those either but no issues either.
The real BMW brake pita are the handbrakes on the e46 -- a combined disc and drum the pins for hold down springs for the shoes pull through the brake back plate. There is a work around for this using the brake shoe hold down parts from the Girling brakesas used on older UK Ford models, the handbrake compensator that links the right and left cables also tends to fail.

The pad wear indicators sensors need to be changed with the pads as they usually get destroyed if you try to un-clip them. From experience always check the new pad wear sensors will fit the new pads because if they come from different manufacturers some times they don't fit -- not unknown to reuse old sensors with a dab of 2 part epoxy adhesive to 100% ensure they stay in place --- tried and tested.

Pad wear indicator circuit has the right front and right rear wear sensors connected in series -- right rear is connected to ground then to the front right which is connected to the instrument cluster forming a pull-down circuit to extinguish the warning light.

" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)



Last edit: 5 years 4 months ago by Andy.MacFadyen.
The following user(s) said Thank You: Noah

Please Log in or Create an account to join the conversation.

  • Noah
  • Noah's Avatar Topic Author
  • Offline
  • Moderator
  • Moderator
  • Give code definitions with numbers!
More
5 years 4 months ago #24685 by Noah
Thank you for your input Andy, valuable as always ;)

Man am I glad the pins weren't bent! I hadn't considered that possibility.
I also was unaware that the pad sensors were on the same series circuit. Thankfully I have a friend who owns a European repair shop, and he was able to get me all OEM pads rotors and sensors, so it all fit together perfectly.

It did come back with ABS, traction, brake and 4x4 lamps illuminated the next day.
The right rear wheel speeed sensor was contacting the tone ring on the axle. Not because of anything I did during the brake job, but I usually see the gap increased by rust on the spindle. Does this happen a lot in these?
I'm thinking the fix is an axle shaft and sensor, but I was able to shim up the old sensor and all is well.
It also appears as though shimming up that sensor cured a strange noise that was coming through the cabin. This thing howled like it was haunted once you reached 20mph, now all of a sudden, not...

"Ground cannot be checked with a 10mm socket"

Please Log in or Create an account to join the conversation.

More
5 years 4 months ago #24824 by Tyler
BMW's are strange creatures, sir. :silly: I try to avoid them, but people keep buying them.

Late to the party, but for what it's worth, I've seen the same divots in the caliper brackets on almost every beemer I've worked on. I usually try to 'smooth' out the divot so the pad won't catch, and it's always worked out. Certain Volvo models do the same thing.

I'm thinking the fix is an axle shaft and sensor, but I was able to shim up the old sensor and all is well.
It also appears as though shimming up that sensor cured a strange noise that was coming through the cabin. This thing howled like it was haunted once you reached 20mph, now all of a sudden, not...


Big mistake here. Huge. :lol: You fixed it! Now they'll expect you to fix all their other thumps/bumps/noises.
The following user(s) said Thank You: Noah

Please Log in or Create an account to join the conversation.

Time to create page: 0.260 seconds