Getting rear calipers off rotor
#1
11-27-2009, 09:35 PM
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Getting rear calipers off rotor
Hi all,
I'm in a bit of a bind and hoping someone here can help. I was replacing the brake pads today on my wife's 2003 X-Type. I started on the left rear and was unable to get the calipers off the rotor. I couldn't get the piston to back in at all. This is my first attempt with a threaded piston. I even bought the tool that allows you to do it properly, but that can't be used until the pads are off.
Is there some trick? I spent an inordinate amount of time on the back left before giving up, then did the front set pretty quickly. I just apply a little pressure with a C-Clamp on the fronts to get some slack to get it off the rotor, but obviously that's not going to work in the back.
What am I doing wrong? Is there someway to disable the parking brake mechanism from the outside? I just detached it with the little spring clamp, the spring and the crimped nut thing to remove it from the wheel well (the caliper itself). There's a little spacer in the piston bore that's visible through the top of the caliper, but I suspect that's just random luck as it could easily be rotated another 30 degrees and you'ld never see it.
Thanks for any help,
David
I'm in a bit of a bind and hoping someone here can help. I was replacing the brake pads today on my wife's 2003 X-Type. I started on the left rear and was unable to get the calipers off the rotor. I couldn't get the piston to back in at all. This is my first attempt with a threaded piston. I even bought the tool that allows you to do it properly, but that can't be used until the pads are off.
Is there some trick? I spent an inordinate amount of time on the back left before giving up, then did the front set pretty quickly. I just apply a little pressure with a C-Clamp on the fronts to get some slack to get it off the rotor, but obviously that's not going to work in the back.
What am I doing wrong? Is there someway to disable the parking brake mechanism from the outside? I just detached it with the little spring clamp, the spring and the crimped nut thing to remove it from the wheel well (the caliper itself). There's a little spacer in the piston bore that's visible through the top of the caliper, but I suspect that's just random luck as it could easily be rotated another 30 degrees and you'ld never see it.
Thanks for any help,
David
#2
11-28-2009, 04:34 AM
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#3
11-28-2009, 05:33 AM
The rear pistons rotate the opposite way to what some might think!
The LH is wound back anticlockwise while the RH is wound clockwise,they can be quite diificult to turn at first
Also on the back of the brake pads is a lug that sticks up,make sure the slot in the piston aligns with this when refitting the caliper onto the new pads.
The LH is wound back anticlockwise while the RH is wound clockwise,they can be quite diificult to turn at first
Also on the back of the brake pads is a lug that sticks up,make sure the slot in the piston aligns with this when refitting the caliper onto the new pads.
Last edited by BuckMR2; 11-28-2009 at 05:48 AM.
#4
11-28-2009, 05:36 AM
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Dallas, look at the gap between the pad and the caliper. Do you see what looks like some silicon there? If so, someone used some pad adhesive and what you are experiencing is the pads are catching on the rim due to wear and they are holding the caliper in place. When lifting the rear calipers, you only need to remove 1 bolt. There are 2 bolts holding the caliper in place, but one should have a large donut attached to it. You need to undo the other bolt. Then the caliper will swing out of the way. What I would tell you to do is to find a large screw driver or other pry bar type tool and slide it between the caliper and the rotor, then pry on the side of the caliper (causing it to lift away from the rotor) on the end where you removed the bolt. This should allow the caliper to slide off of the pads.
If you have that slight gap, you may want to try using your fingers or another tool to separate the pad from the caliper momentarily to see if the pad is stuck to the caliper. THe surface between the pad and the caliper is a smooth surface, so, there should be nothing holding them together (other than the silicon looking stuff I talked about earlier).
If you have more questions, just ask.
If you have that slight gap, you may want to try using your fingers or another tool to separate the pad from the caliper momentarily to see if the pad is stuck to the caliper. THe surface between the pad and the caliper is a smooth surface, so, there should be nothing holding them together (other than the silicon looking stuff I talked about earlier).
If you have more questions, just ask.
#5
11-28-2009, 05:48 AM
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Oh yeah, one other thing. Once you get the caliper free from the pads/rotor, to push the piston in, if you don't open the vent port, I don't care how strong you are, you will not be able to push the piston in. I don't think the Hulk could push in the piston with the vent port shut. So, save yourself a lot of effort and crack open the vent port.
Now, with that being said, also have a 4 foot section of clear tygon tubing handy (3/16" ID tubing as I recall). You will need to bleed the brakes as you more than likely got a little bit of air into the system. Getting it out is easy. Starting with the vent port shut, you attach the tubing to the nipple there. Run the tube up to the top of the wheel well. Attach the center of the tube there using a little bit of masking tape (preferable to use 2 pieces off center so you can see if there are any air bubbles in the line). Run the other end of the tube into a container that can handle brake fluid (old glass pickle jar or the like). Now, open the hood, top off the brake fluid reservior. Crack open the vent on the caliper you are venting, pump the brakes 5-6 times, check the fluid level to make sure that you still have plenty in there (don't want to add air into the system via the front end of the car-refill if necessary). The tubing should now have a nice column of brake fluid in it. Check for signs of air bubbles. If in doubt, pump the brakes a few more times making sure that there is enough fluid in the reservior to handle the number of pumps you are doing (use of a second person may be handy). Pump the brakes until you are sure you have no air in the system. Shut the vent and remove the tubing. All done. Repeat on the other tire(s) as necessary.
As a side note, if you are seeing a change in the color of the brake fluid (new is clear, the old stuff is probably a dark green), it would be advisable to bleed all 4 calipers to ensure the old fluid does not damage the calipers (oxidation causes the internals to corrode and bind up). Not required, but this is one of those pay me now, pay me later things. Will it fail tomorrow. NO. 4 years from now, possible. your call. New brake fluid is cheap insurance.
Now, with that being said, also have a 4 foot section of clear tygon tubing handy (3/16" ID tubing as I recall). You will need to bleed the brakes as you more than likely got a little bit of air into the system. Getting it out is easy. Starting with the vent port shut, you attach the tubing to the nipple there. Run the tube up to the top of the wheel well. Attach the center of the tube there using a little bit of masking tape (preferable to use 2 pieces off center so you can see if there are any air bubbles in the line). Run the other end of the tube into a container that can handle brake fluid (old glass pickle jar or the like). Now, open the hood, top off the brake fluid reservior. Crack open the vent on the caliper you are venting, pump the brakes 5-6 times, check the fluid level to make sure that you still have plenty in there (don't want to add air into the system via the front end of the car-refill if necessary). The tubing should now have a nice column of brake fluid in it. Check for signs of air bubbles. If in doubt, pump the brakes a few more times making sure that there is enough fluid in the reservior to handle the number of pumps you are doing (use of a second person may be handy). Pump the brakes until you are sure you have no air in the system. Shut the vent and remove the tubing. All done. Repeat on the other tire(s) as necessary.
As a side note, if you are seeing a change in the color of the brake fluid (new is clear, the old stuff is probably a dark green), it would be advisable to bleed all 4 calipers to ensure the old fluid does not damage the calipers (oxidation causes the internals to corrode and bind up). Not required, but this is one of those pay me now, pay me later things. Will it fail tomorrow. NO. 4 years from now, possible. your call. New brake fluid is cheap insurance.
#6
11-28-2009, 07:31 AM
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Is the vent port the same as the bleed valve? If so, I did open that. Not much fluid came out, but it came out at a fairly steady rate whether I was was pushing on the piston or not. I think just draining out of the system. I plan to bleed once I get all four done.
In reading post #4, I think I may have approached this differently (incorrectly), but I would have had the same result. I dismounted the caliper completely from the car except for the brake line. I should have been able to separate the halves enough to get it off the rotor at that point I think (but the rotor came with it). Only later did I take the 'right' bolts apart, and since I had the thing in my hands, I took the one with the donut off too. It didn't make sense why it was there, but I now realize it's probably so you don't have to disconnect the parking brake mechanism.
So to be clear, I'm unable to get the piston in the caliper to back in at all. So, I can't get the pads off the existing rotor, because there's the smallest lip around the rotor where the pads have worn down the main part, leaving a raised rim or lip around the outside. The lip is infuriatingly small.. it doesn't look like it would hold the pads on, but without being able to make that space at least a little bigger, I can't get it off.
The brakes themselves aren't binding, as I can rotate the rotor around in a circle in the brakes.
In reading post #4, I think I may have approached this differently (incorrectly), but I would have had the same result. I dismounted the caliper completely from the car except for the brake line. I should have been able to separate the halves enough to get it off the rotor at that point I think (but the rotor came with it). Only later did I take the 'right' bolts apart, and since I had the thing in my hands, I took the one with the donut off too. It didn't make sense why it was there, but I now realize it's probably so you don't have to disconnect the parking brake mechanism.
So to be clear, I'm unable to get the piston in the caliper to back in at all. So, I can't get the pads off the existing rotor, because there's the smallest lip around the rotor where the pads have worn down the main part, leaving a raised rim or lip around the outside. The lip is infuriatingly small.. it doesn't look like it would hold the pads on, but without being able to make that space at least a little bigger, I can't get it off.
The brakes themselves aren't binding, as I can rotate the rotor around in a circle in the brakes.
#7
11-28-2009, 01:41 PM
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Dallas, yes, vent port/bleeder valve, same difference.
As for the pads and rotor issue, can you get the caliper off of the pads? If you can, then you need to slide the pads horizontally, away from the rotor, not try to lift them up or any other way. The pad you can see comes straight at you, the inside pad moves towards the center of the car. Use of say WD 40 may help them slide a bit easier. if the pads are stick on the caliper, use the screwdriver/prybar trick. The first time I did my brakes, I had a similar problem. Use a bit more force and all will be fine.
As for the pads and rotor issue, can you get the caliper off of the pads? If you can, then you need to slide the pads horizontally, away from the rotor, not try to lift them up or any other way. The pad you can see comes straight at you, the inside pad moves towards the center of the car. Use of say WD 40 may help them slide a bit easier. if the pads are stick on the caliper, use the screwdriver/prybar trick. The first time I did my brakes, I had a similar problem. Use a bit more force and all will be fine.
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