Oh crap. I messed with my rear brakes and I think I screwed up.

1995E · June 7, 2015

Okay, so long story short. I did my tire rotation today along with removing the rear caliper to inspect the brakes and stuff. All I did was mess with the rears. I removed the bolts that attach to the sliding pins, remove the caliper, hang the caliper so it didn't hang off the hose, took the brake fluid cap off, and all I did was use those special tools that rotate the caliper while compressing it and compressed it.

I noticed that the pads closer to the car were unevenly warn out compared to the ones on the outside ( much less pad material ) so I decided I'd just swap the outside ones with the inside ones so they'd last a bit longer seeing as the ones on the inside of the car wore out faster. Anyway, I did that, then I just put the caliper back on, and my wheel on. That's all I did.

After starting my car, I noticed my brakes felt very loose and that it'd brake but then the pedal would slowly get closer to the floor. My parking brake is also hitting all the way to the floor.

Did I screw up? Am I forgetting something? I only touched the rears.

Bobmbx · June 7, 2015

1995E said:
Okay, so long story short. I did my tire rotation today along with removing the rear caliper to inspect the brakes and stuff. All I did was mess with the rears. I removed the bolts that attach to the sliding pins, remove the caliper, hang the caliper so it didn't hang off the hose, took the brake fluid cap off, and all I did was use those special tools that rotate the caliper while compressing it and compressed it.

I noticed that the pads closer to the car were unevenly warn out compared to the ones on the outside ( much less pad material ) so I decided I'd just swap the outside ones with the inside ones so they'd last a bit longer seeing as the ones on the inside of the car wore out faster. Anyway, I did that, then I just put the caliper back on, and my wheel on. That's all I did.

After starting my car, I noticed my brakes felt very loose and that it'd brake but then the pedal would slowly get closer to the floor. My parking brake is also hitting all the way to the floor.

Did I screw up? Am I forgetting something? I only touched the rears.

Brake pads are cheap. Put new pads on and you should be okay. I believe whats happening is the piston is extending (since you pushed them back in), and with the worn pad, it is extending to push the pad against the rotor, and you're running out of pedal. A few more strokes of the pedal should put the pads in contact with the rotor.

But I wouldn't do that. I'd start over with new pads.

1995E · June 7, 2015

What do you mean by a few more strokes of the pedal? I tried to keep pressing the brake hoping it would get better but it didn't. Also, the driver rear brake caliper can easily be moved back and fourth (as in the direction it's supposed to) and there is space between piston and the pad but the other side is not the case. How do I get that piston to extend all the way out? Maybe I compressed it too much? I don't know how this affected the parking brake either. I need to go to work tomorrow so I definitely need to fix this tonight.

SWEET ST · June 7, 2015

Some people will say a penny wise a dollar foolish...put new pads...

Bobmbx · June 7, 2015

1995E said:
What do you mean by a few more strokes of the pedal? I tried to keep pressing the brake hoping it would get better but it didn't. Also, the driver rear brake caliper can easily be moved back and fourth (as in the direction it's supposed to) and there is space between piston and the pad but the other side is not the case. How do I get that piston to extend all the way out? Maybe I compressed it too much? I don't know how this affected the parking brake either. I need to go to work tomorrow so I definitely need to fix this tonight.

You need to pump the fluid back into the piston. Each pedal stroke will push some fluid, but not very much. Your pedal is going to the floor because there is no resistance (pressure) in your brake system because it is still trying to close the gap between the pad and the rotor. You'll get there eventually, just make sure you don't run out of fluid in the reservoir.

Normally, when new pads are installed, there is very little gap between the pad and the rotor, and the brake pedal hardens up pretty quickly, with one or two strokes.

You haven't hurt anything.....yet. Like I said, don't let the reservoir level get low to the point you end up pumping air.

Halwg · June 8, 2015

Seeing how stopping is one of the more important things a car does, I would never mess with the brakes on a vehicle, and particularly not go switching pads around.

The_Bishop · June 8, 2015

You cannot switch the pads around. At this point, the safest thing you can do is install new pads. Make sure the slider pins are moving freely, that will cause uneven pad wear.

dco43054 · June 8, 2015

You have wound the inner piston all the way in without putting in thicker material into the caliper that would account for the additional space you created. If the pads can't grip the rotor, you will get no braking action and the pedal action you are feeling.

Will the brake system eventually return to normal action without replacing pads? Could be. But I wouldn't drive the car as is. Put new pads on it.

acschilling · June 8, 2015

HughCares said:
You're clearly not qualified to be working on them if you have to ask that question. Brakes are one of the last things an uneducated/experienced backyard mechanic should be dicking around with.

Weak

orangesoda123 · June 8, 2015

HughCares said:
You're clearly not qualified to be working on them if you have to ask that question. Brakes are one of the last things an uneducated/experienced backyard mechanic should be dicking around with.

Why do you even bother posting here if all you do is insult people? Do you not have anything better to do?

Anyways like everyone else as said you should get new pads. In the scheme of things there are very inexpensive so you might as well throw some new ones on there.

1995E · June 8, 2015

HughCares said:
You're clearly not qualified to be working on them if you have to ask that question. Brakes are one of the last things an uneducated/experienced backyard mechanic should be dicking around with.

I am one of those people who like to watch youtube videos and try to do things myself to save money as I am a 21 year old college kid. Also, I just love doing things involving my vehicle because it's a learning experience for me. I replaced my friend's 2002 Volkswagen Golf brakes and I put new pads in there, and didn't have a problem. The caliper in the rear of that Volkswagen was the same as the Explorer, requiring a rotating compressing brake tool.

I'll take everyone's advice and just replace the pads. I took the bus to work today instead and I'll be trying to upgrade my brake rotors. Does anyone know if the police package brakes and rotors will fit with my current caliper? I want to upgrade to those.

tmg19103 · June 8, 2015

1995E said:
I am one of those people who like to watch youtube videos and try to do things myself to save money as I am a 21 year old college kid. Also, I just love doing things involving my vehicle because it's a learning experience for me. I replaced my friend's 2002 Volkswagen Golf brakes and I put new pads in there, and didn't have a problem.

+1

I have saved thousands on my 12 year old Saab over the years DIY with parts sourced online for 30% less than an independent shop would charge and not having to pay $80-90 an hour in labor doing the job myself. Since I have two cars at my primary home, I can have one out of service for a while as I take my time and figure it out.

Not very tough as the Saab Central forum has detailed YouTubes by users on just about every single repair the car could need.

HughCares · June 8, 2015

orangesoda123 said:
Why do you even bother posting here if all you do is insult people? Do you not have anything better to do?

It's one thing to save money doing something yourself especially when you are qualified and/or the job is very basic in nature. But when you have to ask the question "what did I do wrong" or I watched a how-to YouTube video on how to fix one of the most important parts of a vehicle where (public) safety is concerned....you are most likely in over your head.

Sometimes the truth hurts....but it shouldn't be considered insulting....

tmg19103 · June 8, 2015

HughCares said:
It's one thing to save money doing something yourself especially when you are qualified and/or the job is very basic in nature. But when you have to ask the question "what did I do wrong" or I watched a how-to YouTube video on how to fix one of the most important parts of a vehicle where (public) safety is concerned....you are most likely in over your head.

Sometimes the truth hurts....but it shouldn't be considered insulting....

Disagree to point. At least in my position since I have two cars and don't have to drive the one I am working on if, say, I screw up a break job. So I can take my time to learn to do it right or take it to the shop if I can't figure it out.

Where I agree is if you mess up a brake job and start driving the car around. I don't know the details here if the car is sitting or if he is back to his daily driving routine with questionable brakes. The latter is not a good idea at all.

Generally, this stuff is not rocket science if you are handy and take your time. Some people can't imagine doing this type of work on a car. For others it comes pretty easy.

1995E · June 8, 2015

HughCares said:
It's one thing to save money doing something yourself especially when you are qualified and/or the job is very basic in nature. But when you have to ask the question "what did I do wrong" or I watched a how-to YouTube video on how to fix one of the most important parts of a vehicle where (public) safety is concerned....you are most likely in over your head.

Sometimes the truth hurts....but it shouldn't be considered insulting....

I understand your concern, and that's why I decided to take the bus to work instead of driving. All I did was test my brakes along my drive way when no one was around and took it for a spin around the neighborhood at a very slow pace. I wouldn't drive on bad brakes.

I also did what people normally did, except for the fact that I put back in the old pads. I guess I should have taken a class on fluid dynamics before I did that. I am going to buy new pads and replace them on my way back from work today. If I still have a problem, I'll just have a mechanic do it.

swshawaii · June 8, 2015

Glad you're taking the advice of everyone who has replied in this thread. Quality pads are relatively inexpensive, and for everyone's safety brakes are the most important part of your vehicle. To prevent uneven wear on your new pads you must find the cause. As previously mentioned, sticking or binding caliper slide pins, hardware, or restrictive brake hoses are culprits of uneven pad wear and often overlooked when only doing a "pad slap". If not corrected you will be doing this again in short time. Also, a complete brake fluid flush is highly recommended if over two years or it's never been done.

1995E said:
I noticed that the pads closer to the car were unevenly warn out compared to the ones on the outside ( much less pad material ) so I decided I'd just swap the outside ones with the inside ones so they'd last a bit longer seeing as the ones on the inside of the car wore out faster.

Pad Wear Chart Helps Diagnose Caliper Problems
http://my.cardone.com/techdocs/PT 18-0005.pdf

cheapjeep2 · June 8, 2015

tmg19103 said:
Disagree to point. At least in my position since I have two cars and don't have to drive the one I am working on if, say, I screw up a break job. So I can take my time to learn to do it right or take it to the shop if I can't figure it out.

Where I agree is if you mess up a brake job and start driving the car around. I don't know the details here if the car is sitting or if he is back to his daily driving routine with questionable brakes. The latter is not a good idea at all.

Generally, this stuff is not rocket science if you are handy and take your time. Some people can't imagine doing this type of work on a car. For others it comes pretty easy.

I agree with tmg19103: I disagree to a point, we all can't be good at everything and you have to learn somehow. The best thing I see here is that he is listening. I started working on cars when I was 16, now 44, never had anyone but me do my brakes on any car I've ever owned, if I ran into a problem I used my resources: elders, how-to manuals, internet etc, to fix the problem and learn. I've since replaced engines, transmissions and just about everything you can think of and I do IT work for a living.

Biggest thing, don't be discouraged rather be safe and methodical. All these things are is giant Legos.

DeepBlueSC · June 8, 2015

To the OP: You have a number of factors working in concert here. Because the inner pad (Closer to the car as you described) is being pushed directly by the piston, it makes first contact and therefore CAN show SLIGHTLY more wear than the outer pad. In a perfect system, this should be almost imperceptible to the untrained naked eye. If really noticeable then you have a caliper that is not moving freely when the brakes are applied. If they show angled wear that is a great indicator that there is axial movement along with the linear movement. As was pointed out by someone else, all moving parts/slides/pins should be thoroughly cleaned and properly lubricated. Properly lubricated means using a serious high temp dedicated brake grease, not just whatever you find laying around the garage. Follow this with a manual movement of the parts to ensure they move freely before reassembly.

Follow the advice and install all new pads. Keep in mind, unlike the front pistons, the rears have to rotate on a screw. It will take a LONG time to get those pistons all the way extended out to start contacting the worn pads again.

wifes2011xlt · June 8, 2015

Front brakes provide like 80-90% of total braking power. Rear brakes alone should not create the "low pedal" situation that the OP described. My guess is air got into the brake lines when the OP opened up the reservoir cap. Usually not a big deal when opening up but if the pads were pretty worn, then incrementally more fluid is needed to create the pressure in the lines and the brake fluid level gets lower and lower, which allows more space for air to enter.

OP - Did you pump the brakes before you replaced the cap? Agree with others to change with new pads (and don't forget to bed them in) but I'm guessing you need to bleed your brakes too. And make sure to retorque the lugs to specs. Over-torquing can lead to warped rotors.

Also agree with others that you can't swap around brake pads. Pads when bedded properly follow the specific contours of the rotors to which they are attached. Swapping them out is almost like trying to put a round peg in a square hole.

DeepBlueSC · June 8, 2015

wifes2011xlt said:
Front brakes provide like 80-90% of total braking power. Rear brakes alone should not create the "low pedal" situation that the OP described. My guess is air got into the brake lines when the OP opened up the reservoir cap. Usually not a big deal when opening up but if the pads were pretty worn, then incrementally more fluid is needed to create the pressure in the lines and the brake fluid level gets lower and lower, which allows more space for air to enter.

Sorry, but that is just plain bogus info:
1. Even old disc/drum set-ups weren't 80% front bias under any condition except having no back brake system.
2. Additionally, as little as 1/8" distance between the piston/pad and rotor will allow the pedal to bottom out in most systems.
3. As air ALWAYS seeks higher ground, there is no way air could be introduced into the lines from having the reservoir cap off. That is an absolute physical impossibility. In fact, you could stick a straw into the reservoir and blow and still not introduce air down the lines!
4. The OP pushed all the fluid from the system into the reservoir when he compressed the pistons, so now he needs to get it back from the reservoir to the pistons. Keep in mind that filling 2 piston bores with fluid from worn pads can trigger most brake warning lights.

Prove your theory: Push any piston all the way in and put an 1/8" shim in place of one pad. Show the video of how far your pedal traveled...

Oh crap. I messed with my rear brakes and I think I screwed up.

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