Shared Knowledge
"BMW X5 - How to Replace the Rear Brake Calipers"
28 July 2011
Summary: easy enough do-it-yourself (DIY) but note that rear calipers are not the same size as those on the front. The rear calipers are smaller than the front calipers. Make sure you get the correct rear caliper.
Background:
BMW X5, 4.4i, model year 2000, 151,000 miles.
Rear pads needed changing and decided to replace rotors, calipers and pads.
Ordered rear calipers for my specific X5 from Internet parts supplier but once I had one old caliper off, found rebuilt shipped me would not work.
Rear calipers are smaller than those on the front. Might seem logical that both front and rears are the same but they are not.
Rebuilt rear calipers for the X5 can be had for about $50 after returning the core or old caliper. Significantly cheaper than dealer.
How to replace BMW X5 rear brake caliper:
First see "BMW X5 - How to Replace Rear Brake Pads"
Once you have a caliper off the carrier, have your replacement caliper right by the hub.
If you have not already done so, check the brake fluid reservoir. In the United States, the reservoir is on the driver's side up near the windshield wipers. You may have to remove a plastic cover to get to the reservoir. The cover is held on with plastic "screws" that you push down and turn to release or tighten.
As the SAV is going to loose some brake fluid when you switch out the old caliper for the new one, you want to have the reservoir at least half full of fluid.
Now take a look at how the brake fluid line attaches to the caliper. You will notice that it comes in flat against the caliper body and has a pin sticking out of the caliper than holds the line from turning as you loosen or tighten the 11mm bolt.
Warning: brake fluid is highly flammable. Do not smoke or have an open flame around where you are working.
With whatever floor you are working on protected via cardboard or other, using a 11mm wrench, unscrew the brake fluid line from the old caliper. This bolt was tight on my calipers.
Some brake fluid will begin seep out as soon as you crack the bolt open but do not worry.
Note here, that when I removed the brake fluid line from the old caliper, I saw a small cooper washer on the brake fluid bolt but to me anyway, it did not seem to want to come off and the new washer supplied with my new caliper was much too large, SO, I kept the old washer. If you can swap out your cooper washer for a new one, do it.
With the brake fluid line bolt loosened, completely unscrew it and immediately threat it into your replacement caliper making sure you have the line properly seated such that it fits correctly against the stud sticking out of the caliper.
Tighten the brake fluid line bolt down tight. Do not know recommended torque, if there is one, but the bolt on the one caliper I did take off and then have to reinstall, tightened down as if it could not be torqued any tighter.
Time to back away from you X5 and wash your hands as they probably have brake fluid on them.
At this point, the carrier should already be clean, so time to grease the backs of your pads and install them in your new caliper.
With pads in place, fit new caliper into carrier and align caliper bolts with holes in the hub.
Once more, 7mm Allen wrench to tighten down caliper bolts.
With both caliper bolts installed, replace plastic caps on caliper bolt rubber boots.
If you are working on a side that has a brake pad wear sensor, install it now. Looking into the caliper, you will see a slot in the inner brake pad made for this sensor and using needle nose pliers push the sensor into the pad slot.
Time to bleed caliper.
Find bleed screw on new caliper and if it has a rubber cap on it, remove it.
Have found that the size of the bleed screw can vary and thus you are going to have to find a wrench that fits yours.
Now open the bleed screw and let some fluid make its way into the new caliper and out the bleed hole.
Close the bleed screw but not tight, tight.
With someone in the driver's seat, instruct them to push down on the brake pedal and hold it and keep pushing, no matter what happens.
When the driver says he is pushing the brake pedal hard, quickly open the brake fluid bleed screw and get a nice big pulse, stream of brake fluid to shoot out.
Then as quickly as you opened the bleed screw, close it off.
Tell the driver to release the brake pedal.
Once again, check the brake fluid level in the reservoir. You do not want the reservoir to run dry. Add Dot 3/4 as needed to get reservoir at least half full.
Repeat caliper bleed process one more time and then tighten bleed screw down hard and place rubber cap on it.
Once again, walk away and clean your hands.
Now look the rear caliper, carrier and rotor over carefully. No extra parts on floor? Bolts tight?
Using spray brake cleaner, spray caliper body around brake fluid line and bleed screw, removing any surface brake fluid.
Once you are certain all is correct, remount tire and lower X5 off jack.
Because you opened brake lines, you are going to want to check for leakage on the tire or floor where you park it and also check the brake fluid reservoir.
If a caliper is leaking fluid, do not drive SAV until you fix it.