New rear break pads won't fit!!

[luke01]

Just installing some new break pads, fronts went in fine, no worries, pushed the piston back, fitted on perfectly....but the rear pads both won't fit into the break caliper, ie. the pads are too fat. its nothing to do with the piston, its in far enough. Any ideas?

On another note: would you use anti-sieze on the caliper bolts?

[joshua43214]

What does "too fat" mean? do you mean too thick? Also, by "in far enough" do you mean the piston went ALL the way back in so the dust boot in nicely accordianed and the piston protrudes about 1-2 mm? Are the caliper slides frozen? with the pads off you can bolt up the caliper and move it back and forth with firm hand pressure, or you should be able to push the slides out with thumb pressure. Assuming you piston is really pushed all the way in, the caliper slides are free to float, and you mean the pad is too thick, then you have either the wrong pad or the wrong rotor. If your rotors have not been machined, the outer edge should still be near original spec. I have also seen many aftermarket pads that "exceed OE specs" by making the friction material thicker.

yes, a small amount of anti seize on the threads and some caliper lube on the slides is a very good idea. A bit if antiseize where the pad contacts the piston is not a bad idea as well for preventing noise.

[piman]

See if you can file them down. Recheck part numbers if they are correct.Go to a different part supplier and size another set. Use super lube in caliper boots, anti-s on rotor/rim mating surface and wheel threads and slide points on pads.

[genphreak]

See if you can file them down. Recheck part numbers if they are correct.Go to a different part supplier and size another set. Use super lube in caliper boots, anti-s on rotor/rim mating surface and wheel threads and slide points on pads.And check the thickness of your rotors (if new) they should be 10mm thick on the rear of your car... similar ones also come in 12 and 20mm- jic that's your problem...

[Kalevera]

I suppose you could use antisieze on the pins, but the correct stuff is Plastilube:

http://www.bimmerworld.com/html/atebmw-plastilube-anti-squeal.htm

If you do lube the pins, do both sides of the car and make sure the pins are clean.

best, whit

[Zeuk in Oz]

Just installing some new break pads, fronts went in fine, no worries, pushed the piston back, fitted on perfectly....but the rear pads both won't fit into the break caliper, ie. the pads are too fat. its nothing to do with the piston, its in far enough. Any ideas?

On another note: would you use anti-sieze on the caliper bolts?
I think you will find that you have to remove 2 hex head bolts under plastic caps on the back side of the caliper that hold the caliper together to get the pads to fit properly.
This was my first question of this forum.

[632 Regal]

thought Bill says to clean them and dont use anything on the pins???

[joshua43214]

thought Bill says to clean them and dont use anything on the pins???

Ask 100 tech's what prep to do to brakes and you will get 100 different answers. read the OE shop manuals and service bulitins for different car makers and they will give you different descriptions of work to be done. Lube every thing or it sticks. Lube nothing because it attracts dust, Lube some things but not others. It goes on and on, its a tired argument and very boring. Just make sure all the parts move, every one agrees on that, then do what BMW recomends, that way you can feel warm fuzzies, and no one has to cast disparaging remarks about professionals doing their job all wrong.

[F4Phantom]

I had the same problem. My solution was to put one new pad in with one old pad. There is only around 2 or 3mm needed to get it to fit so thats only 1.5mm per pad. My oldies had a few mm left so this solution is ok except if you are already metal on metal, then get out the grinder.

[632 Regal]

im fuzzy now...

[Zeuk in Oz]

I had the same problem. My solution was to put one new pad in with one old pad. There is only around 2 or 3mm needed to get it to fit so thats only 1.5mm per pad. My oldies had a few mm left so this solution is ok except if you are already metal on metal, then get out the grinder.
No need.
Just take the caliper apart as per my previous post in this thread - simple as anything once you remove the hex head bolts. :)

[luke01]

Excellent, thanks guys.

[Bill R.]

getting to be a tired argument. Bmw feels that its important enough to mention it no less than 4 times in the factory service manual and numerous times in service bulletins on various models
http://www.bimmernut.com/%7Ebillr/images2/brakepinlube1%20copy.jpgahttp://www.bimmernut.com/%7Ebillr/images2/brakepinlube2%20copy.jpgbhttp://www.bimmernut.com/%7Ebillr/images2/brakepinlube3%20copy.jpgchttp://www.bimmernut.com/%7Ebillr/images2/brakepinlube4%20copy.jpg

[632 Regal]

so we should lube them with honey... ok, off to the store i go...

:D