2004 MINI Cooper S

Brake sensor went off and I took it in for a brake job. I had them replace all the rotors and pads. When I got it back, the pedal was very mushy and would go all the way to the floor. The tech bled the breaks and master cylinder again but it didn't change anything. He noticed a tear in the brake caliper boot so he got a $5 kit for replacing the boot and rebled the whole system again including the ABS. I took the car out and warmed the brakes up and did a couple hard stops but it was still very mushy and not stopping well. He bled everything once again, but nothing changed. The tech said the rear pads didn't wear even. One side was completely worn down and the other had more pad on it.

What i noticed is that the rotors come with the surface all scored up. The front brakes have smoothed out all of the scoring, the rear left brake has only smoothed the inside half of the rotor (the outside is still scored) and the right rear rotor is completely scored still and looks like it has been barely used.

Is this most likely bad calipers on the right rear and left rear?

If so, what are my options for repairing them? The tech made a comment that there aren't rebuild kits available for it yet and the calipers are like $495 each. I have a friend with used calipers from a 06 MCS with like 50k miles

Also, why would the brake pedal feel tight before the brake job but go to completely mushy afterwards?

Here's some pics:

FRONT LEFT:


FRONT RIGHT:


REAR LEFT:


REAR RIGHT:

 

My 2003 MCS also wore differently in the rear. Actually my rears wore out before the fronts. Some people have said it is due to the braking brake. However, even with the uneven rear wear, I had good pedal feel. I suspect you had good pedal feel before the brake job (when the pads were wearing uneven). Thus, I would suspect air in the brake system or a bad line (probably just air in the line). If the tech has bled the system many times, it is probably air in the ABS. There have been posts of people having a difficult time getting the air out of the ABS. Sounds like Mini cycles the ABS during the bleed to get the air out. Some have stated that driving and actuating the ABS (hard braking on a soft surface) will help move the air bubble in the ABS and then another bleeding will get the air out.

 

All of your discs look normal. The rears do not do the same amount of work as the fronts, so you will notice different wear patterns front to rear.

Could be the caliper hanging up, but I would check a few things first.

Make sure the parking brake is not sticking. Jack up each rear wheel and spin, is there resistance? This would also tell you if your caliper is hanging as well. Your tech should have done this if he suspected a caliper!

Make sure pads are in their proper seat, not cocked or hanging up.

How did he bleed the system, at each corner? Did he use a pressure bleeder? If so, did he cycle the pedal a couple times while it was bleeding? - Sometime air can get caught in the master cylinder using a pressure bleeder will not always get it out with out a few pumps.

If there is a pedal, but you have to press fairly hard to get it to stop, you might give it a few miles for the pads to set into the new rotors.

 

True. Although, the braking did get a little squirrely before I brought in. Maybe the low pads were heating up enough to cause the old calipers to finally seize up.

He said he put the car up on the lift and actuated the ABS and bled the ABS...

 

What about the fact that the rear right one looks barely used while the rear left one is worn smooth on the inside of the rotor?

Correct, he used a pressure bleeder. He did cycle the pedal while bleeding and he said he bled the master cylinder as well.

I don't have to press hard... It's just that the pedal moves like an inch before it even starts braking, sinks a couple inches, and is pretty much sitting on the floor during a fast stop. Before the brake job, the pedal moved like 1/2" total to a complete stop.

 

Can you pump the pedal and get a good firm pedal? if so, It sounds like air in the system to me. Did he say which bleeder valve he used, which corner? You may want to go to each caliper and bleed each caliper the old fashioned way. Not sure how he bled the master cyclinder by itself.

I doubt you boiled the fluid, especially in the rear. I'd still check for drag from the caliper as you free spin a wheel.

 

What kind of pads did they use? It kind of sound like you got more performance oriented pads and they aren't bedded in yet.

 

No. Pumping the pedal doesn't change the softness.

The pedal is firm when the car is off and sinks as soon as the engine is started.

I did a test and cut the engine while rolling in neutral and the pedal was still soft.

I'm not sure what he did the first time, but when we bled it the second time, I did see hime go around and bleed each caliper pumping and holding the brake pedal.

 

They are Axxis Ultimate pads.

I followed a bedding-in routine very similar to this one:
http://www.zeckhausen.com/bedding_in_brakes.htm

 

Where did you do the brake job? maybe not from Mini dealers?

Some brake shop guys don't know how to install rear brake pads on Minis.
There are clips on the back of the rear inside pad. If you don't install inner pads directly onto the caliper piston by sliding them in, those clips may be out of position and that can give you that mushy brake pedal feel.

A guy in a local brake shop near my place installed rear pad like this and I was wondering why. I disassembled and reinstall all again correctly and that mushy feeling went away.

 

By the way, did you wash your calipers recently? they are shiny!!

 

Have someone else bleed the brake lines, they have air in them............

 

And the only real way to properly cycle the ABS is with the MINI service machine, not something most shops will have.

They definitely did something wrong somewhere.

 

The mechanic said the pistons were scored and he is positive the calipers are bad...

I've driven around a little bit and the right rear rotor still has all the original scoring on it as if it were brand new and the left rear rotor barely has any wear on the inside of the rotor and the rest is still scored like new.

I just slapped down $380 for a set of NTH Premium Powder-coated Black Calipers, so hopefully they solve the issue.

 

Hope that works out for you! Let us know!

 

Then why did they work fine before he did anything to them?

I would surely look for a new shop.

 

He said the right rear pad was almost completely gone and the left rear pad had some pad left. He said the RR caliper was sticking, causing the pad to wear excessively. When he replaced the boots and screwed the piston back in, it just never came back out again. If I look at the RR rotor, it doesn't even look like the brake is touching either side; all the original scoring is still on the rotor.

If the caliper was fine, i would get at least SOME contact with the rotor, correct?

 

Not saying that you don't need new calipers, but to not ask the shop to replace a part they obviously messed up is my concern. Was working before you went in.

Did you see the parts they took off?

 

What part did they obviously mess up?

If the pistons in the caliper is scored, I highly doubt the shop did it.

And everything wasn't "fine" before I went in.... The pedal was just a lot more firm. However, my brake sensor light was on and hard braking was a little squirrely.

 

Another update...

The pedal feel stiffened up a bit. I checked the right rear and it finally started wearing on the rotor. The unfortunate part though is that I believe it is indeed sticking because the right rear rotor and rim were hotter than the other 3.

 

What order did he Bleed the brakes from? he needs to start from the right rear as that is the farthest one from the master cylinder. This sounds stupid but i have seen it happen, right rear first, then left rear followed by the right front and then left front.

 

I think your mechanic did not get the rear pads in correctly. It is possible to put them in wrong. The peddle will feel somewhat spongy from this. Have the mechanic check the rear pads.

What you need to know is in here on page 2.

https://www.northamericanmotoring.co...ginners-2.html

 

This is late but if the caliper boot was replaced then I suggest looking at the slide pin and their boots. Maybe upgrade to brass bushings.

 

The shop can definitely mess up a caliper by replacing the boot. Unless you were experiencing the same braking symptoms before and after the work, then no problem with the shop. If the brakes were better before the work, then they did something.

There may very well have been a problem before, but don't let the shop off the hook simply cause they said they didn't do anything wrong.

If they didn't rotate the caliper piston correctly they could have scored the sleeve and caused some problem there or it mught have been bad before. This can cause the piston to stick and rub on the rotor.

 

Any update?

Did the new calipers resolve the problem?