Removing brake calipers

[Lincoln_Faller]

I'm in the middle of a brake flush procedure, for the very first time, following the very useful guidelines provided by Jamie and Leslie and also those by Dana Hager and Charles Gilman, as well as the urgings of people on this board when I complained two years ago that getting this done at the dealer cost me well over $500. It's taken me awhile to get my courage up.

 

So far everything is fine, and I've managed to install speed bleeders on the front and rear calipers without stripping any threads or breaking any bleeders. I have the tank off, with no quick disconnect problems (yet), and am all ready to start bleeding the wheel circuits.

 

But I do have a question: is there a trick to removing the calipers so that I can shim them? There's not enough clearance on the front wheel (I haven't yet tried the back) to wriggle them off the rotors. The BMW service manual says to disconnect the brake lines from the calipers, but that seems to be asking for trouble that I don't want. Hager and Gilman specify removing the brake pads, but Jamie and Leslie have a photo of the calipers shimmed with the brake pads still installed. If I remove the pads will I have enough wiggle room to get the calipers off the rotors? Or should I just remove the front wheel? Neither H & G nor J & L indicate this is necessary.

 

Thanks in advance for your help.

[dirtrider]

Afternoon Lincoln

 

No need to remove the calipers just pry the pads back and shim between the rotors and pads.

 

You can’t get the wheels off without pulling the calipers so that won’t help.

 

If you really want to remove the calipers first tape or otherwise protect the wheel paint in the caliper area , then remove the caliper bolts, then pry the pads back as far as possible (or grab the caliper and tilt it until the pads retract), then tilt the caliper off the rotor (just fits and will probably touch the inside of the wheel)

 

[Boffin]

On the 1150 I find the easiest way to remove the callipers is to pull the brake pads. Just remove the safety clip and unscrew the pad retaining pin, remove the anti-rattle spring and remove the pads. Once these are out of the way the callipers come off with ease.

 

Andy

[cris nitro]

Why do the brake pads need to come off when you flush the fluid? I did a front and rear fluid change this winter and left the pads/calibers alone.

[dirtrider]

Evening Chris

 

By the book you are supposed to push the caliper pistons back into their bores so none of the old fluid gets trapped behind the pistons therefore getting by-passed on the brake bleed service.

 

A lot of people (including a lot of dealers) don’t bother pushing the pistons back, in fact probably not even needed if the brakes are flushed at regular intervals. Probably not a bad idea to push them back if the service hasn’t been done in a long while.

 

[Lincoln_Faller]

Just an update: after posting I went back out into the garage, fiddled a bit more with the left front caliper and it slid right out. Ditto the right front, which for some reason came out a lot easier and went back easier. Getting the left front back on the rotor was harder, but it did happen.

 

What a wonderful discussion board! Merely posting a problem magically solves it--at least in this instance. But thanks to all of you who replied. I appreciate your willingness to help. And thanks of course, too, to all those others who at various times have freely shared their expertise. This is truly a remarkable site.

 

Now if Keith's far more serious problem were only so easily resolved.

 

 

[ESokoloff]

On the 1150 I find the easiest way to remove the callipers is to pull the brake pads............ Once these are out of the way the callipers come off with ease.

 

Andy

 

Now ya tell me.

Thanks Andy

[AndyS]

Evening Chris

 

By the book you are supposed to push the caliper pistons back into their bores so none of the old fluid gets trapped behind the pistons therefore getting by-passed on the brake bleed service.

 

A lot of people (including a lot of dealers) dont bother pushing the pistons back, in fact probably not even needed if the brakes are flushed at regular intervals. Probably not a bad idea to push them back if the service hasnt been done in a long while.

 

Another reason is if you do not push the pistons in when you do a fluid change with worn pads, the time comes for you to fit new pads and you end up pushing excess fluid into the master cylinder (R1100RT) and the brakes will drag (or the pistons just won't go in fully), or (R1150RT) the fluid over fills the servo unit, and has to come out of the overflow pipe, which then vents to atmoshere but in doing so, sprays itself along the torque arm and takes the paint of it, and it then goes rusty.

Andy

[SKYGZR]

The easiest way to push the pads back is to attach a hose to the bleed nipple, hose end to a container, open the bleed screw, and push/pull against the disk. When contracted, close screw, remove hose, withdraw the caliper.

 

This way, no fluid needs to be extracted from the master cylinder as the fluid is pushed out at the caliper end, not back through the system to the master cylinder.

[NonComp]

Another reason is if you do not push the pistons in when you do a fluid change with worn pads, the time comes for you to fit new pads and you end up pushing excess fluid into the master cylinder (R1100RT) and the brakes will drag (or the pistons just won't go in fully), or (R1150RT) the fluid over fills the servo unit, and has to come out of the overflow pipe, which then vents to atmoshere but in doing so, sprays itself along the torque arm and takes the paint of it, and it then goes rusty.

I'm not following this at all. If you do, or don't, push the pistons back when you do a brake flush, it has nothing to do with overfilling the reservoir later. The pistons go right back to where they were when you apply the brakes. The fluid level in the reservoir is always set as last step. You still have to pump/suck fluid through the rest of the system to finish the flush. Pushing the pistons in will always force fluid back to the reservoir(s). ???

[SKYGZR]

Pushing the pistons in will always force fluid back to the reservoir(s). ???

 

Yup, if you don't open the bleeders at the calipers, and try to retract the pistons, the fluid has nowhere to go except back to the master cylinder. If the cap is still on, it might be difficult to retract the pistons as the fluid has nowhere to go.

 

If the cap is off, and no fluid is extracted, then the master cylinder could overflow (depending on how full it is to begin with.)

 

That's the simplicity of doing as previously mentioned.

[NonComp]

My point was that if you are doing a purge of the entire brake system, then there should be no issue of overfilling. Many use some kind of suction device (turkey baster, for example) to empty the reservoir as a first step (servo brakes excepted, which have their own procedure) and replace it with fresh fluid so you don't have to waste time drawing/pumping the stale fluid through the system.

 

Personally, I don't want to be doing a purge/bleed with the caliper(s) dangling from wires, while trying not introduce air into the system. I use a small MityVac to draw the fluid out and leave the calipers in place.

 

If I am changing pads, I empty the reservoir first (leaving a bit in the bottom to cover the holes) then remove each caliper and change the pads, then replace the calipers, then remove any extra fluid from the reservoir, and fill the reservoir with fresh fluid and then finish the purge.

[SKYGZR]

Yup, ya wanna have the calipers mounted, with the pads installed while bleeding. I was just referencing the easiest method i've found to remove the calipers from their mountings in order to pull the nose wheel, or to inspect/replace pads.

[AndyS]

I'm not following this at all. If you do, or don't, push the pistons back when you do a brake flush, it has nothing to do with overfilling the reservoir later. The pistons go right back to where they were when you apply the brakes. The fluid level in the reservoir is always set as last step. You still have to pump/suck fluid through the rest of the system to finish the flush. Pushing the pistons in will always force fluid back to the reservoir(s). ???

Hi NonComp, if you do a brake fluid flush and re fill the system then do a bleed with worn pads, the fluid level will be set to a point where it is near the top of the resevoir when you have finished the bleed proceedure. Now, when you come to fit new pads, then the pistons will have to be pushed into the calliper housing further than when you flushed the brakes. So what I am saying is be careful, becuase this can leave you with too much fluid in the resevoir (R1100RT) or Servo unit (R1150RT), which can cause bad brake drag, or paint damaging drips from the overflow.