Clint's tips and tricks on brakes
First and foremost – brakes are a no joke thing on your car. If you are new to brakes have someone teach you how to work on them. Despite all the reading in the world on this subject this is something you should be taught to do instead of trying to figure it out yourself.
Second – If you are new to brakes get someone to teach you. Yes, it had to be said twice. It’s that important.
Now, this is by no means an all inclusive document on brakes. Instead it is a few tips and tricks I have learned over the years.
Some background on my brake experience: I started helping Dad work on the brakes on the family cars and trucks when I was seven by handing him tools. By 12 I was doing the disk brakes myself with his supervision. By 15 I had the arm strength to do the drum brakes on my own. By 16 I was doing brakes unsupervised by him. Now, this does not mean I am immune to learning new things. Far from it. Quite often I see someone with lots of experience post up a new tip or trick to working on brakes, and if it makes sense I try it out. Most of the time it works nicely.
On to the tips and tricks. I will try and keep this brand generic as we can cover that later.
Run the proper pad for what you are going to be doing with the car!!! Do not run street pads on the track. They can’t take the heat.
Do not run high end track pads on the street. They need time to warm up to operating temp.
Do not run track pads and expect to get low dust and no noise. In a race environment dust and noise fall WAY down on the importance list.
Buy the best pads for your application that you can afford.
Be aware of the limitations of these pads, and don’t out drive them. Remember, no matter how fast you go eventually you have to stop.
Regular street level fluid on a NORMALLY driven street car – change every two years.
Good fluid that sees aggressive driving on the street – change once a year.
Good fluid that sees heavy autoX usage on a “race on Sunday drive to work on Monday car” – change a couple of times a season at the very least.
Good fluid that sees hard track use – fresh fluid for each event.
Buy good rotors. Not unknown cheapy ebay ones that you have no idea who made them.
Slotted – not really necessary unless you are heavily racing in the rain
Drilled – NO NO NO a thousand times NO!
Two piece, semi-floating or fully floating – there’s a time, a place and a budget for these. 99% of the cars on this board will never need this time place or budget. Quite honestly they are not necessary unless you're REALLY into autoX or the track, and chances are if you are into those things I'm not going to tell you anything you don't already know about them.
Turning the rotors – if you feel they need it then do it, but don’t fall into the “warped” rotor myth. If you can see pad impressions on the rotors then get them lightly turned after a bed-in (see below).
NEVER run a rotor that is below the recommended thickness spec. It’s just not worth the risk. Period.
General tips on pads, fluid or rotors –
Brake squeal – this is actually a vibration you are hearing. It’s the pad backing plate chattering against the pistons. Anti-squeal rubbery goop is supposed to help prevent this. I’ve never really cared for it. For many years I ran a good grease on the backing plates and it worked just fine. Until! I got a suggestion to run high temp anti-seize instead. I gave it a shot. I will never go back to grease.
Fluid – Use good fluid for your application. Please note – DOT 5 is NOT what to run in our cars. It’s a silicone based fluid made for preservation of lines in classic cars. DOT 5.1 is the stuff to look at for actual driving if you choose to use a DOT 5 series fluid.
Whenever you replace pads OR rotors, not both, but EITHER you should do a bed-in process. Here’s the process I have used for years:
45-10 using medium pressure 3-4 times
Drive to cool for a little bit
55-10 using medium pressure 3-4 times
Drive to cool for a little bit
65-5 using hard pressure but not locking them up 3-4 times
Drive for 20 minutes to cool them.
If you must come to a stop in that time do so gently, and just hold the car at the stop with the least amount of pedal pressure that you can (or use your hand brake).
Please note, you can do a bed-in process at any time. In fact, if you are starting to feel a slight vibration in your wheel during light braking due to pad deposits do a bed in process before thinking about getting your rotors turned.
If you are changing shoes as in on drum brakes (remember your handbrakes are drums in the rear. They just happen to be in the hat of the rotor) do each side one at a time from start to finish. This way you can go and look at the other side in case you forget how it goes back together (and you will forget).
Couple of general points –
Use brake cleaner spray to clean machining oil and finger oil from rotors
Use brake cleaner spray and a rag to clean up stuff in there.
If you use an airgun for spraying dust out don’t breathe it. While pads are no longer made with asbestos I’m sure breathing that crap still isn’t exactly good for you.
Wipe things down so you can see what you’re doing.
Apply grease or anti-seize to the slider pins on the frame that holds you pads in place.
Apply grease or anti-seize to the backing plates of the pads
Apply grease of anti-seize to the clips that hold the backing plate tabs
Bleeding process –
Now, this is the part I know there’s a good bit of interest in. This is my thoughts and experience on bleeding. It is by no means all inclusive.
Why we bleed brakes –
Pushes air out of the system. Air is bad because it is compressible. That means energy is going into squeezing bubbles instead of brakes.
Flushes old fluid out of the system if you are replacing it.
NEVER let the reservoir go below the min mark while bleeding. Doing do and you risk pushing air into the master cylinder, and getting air out of the MC is a total pain.
Now, onto the bleeding. There are a few ways you can do this – traditional 2 man system, 1 man system using something like speedbleeders, 1 man system using a pressure pump or vacuum pump.
Let me cover the 1 man systems first. I don’t like them. Why? I just don’t. Now, don’t take that as gospel. There are MANY MANY people who prefer one system over the other, and their brakes work just fine. It comes down to personal preference on this. Mine just happens to be the 2 man system.
The two man system –
You’ll need a box end or flare wrench that properly fits your bleeders on your brakes. DO NOT use an open ended wrench. That’s just asking for trouble. Me? Trouble is good at finding me so I don’t invite it.
You’ll need some clear plastic tubing that fits tightly over the nipple on the bleeder. You could use something that’s not clear, but I find it’s easier to use clear as you can see what comes out.
A container to catch old fluid.
A buddy or hottie with a strong leg and a good bit of patience.
Roll down the windows of the car so you can talk to each other and communicate what is going on.
The actual bleed–
Top off the brake fluid
ABS systems work on diagonals so you want to bleed on the diagonals. The Subaru service manual calls out FR, RL, RR, FL.
Get on the first corner. Put your wrench on the bleeder, put the tubing on the nipple, and put the end of the tub in your catch container
Have your helper get in the car, and with it off pump the brakes. This is NOT a stabbing motion, but strong steady pumps.
When the pedal will not sink any more the vacuum has fully been evacuated from the booster, and the system is under pressure.
Do not let them remove their foot from the pedal.
At this point have your helper press the pedal with firm, smooth, steady pressure.
While they do this open the bleeder ¼ to 1/3 turn. Fluid, maybe some air, and on occasion some kind of alien will start to come out.
When the pedal is close to the floor have your helper warn you.
When the pedal hits the floor, have them call out floor, but do NOT let them release pressure.
Close the bleeder. Please note – you do NOT need to he-man these. Do not over tighten them.
Once closed call out for them to pump the brakes.
When they are hard have them call out they are ready, and repeat the bleed.
Do this a few times at this corner.
TOP OFF THE BRAKE FLUID before moving to the next corner.
Repeat for each corner in named order above.
If you are replacing fluid go around and do this a few times. Don’t try and get each corner in one go.
If you have replaced lines or caliper give the lines and caliper a few taps with the end of your wrench to dislodge any air bubbles. This is kinda like the bubbles on the inside of your glass of beer.
If replacing calipers the bleeders go UP!!! That’s where the air goes. I know this sounds dumb for me to mention, but believe me it does happen.
Overall, this is not all inclusive, and I am sure I and others will post other tips below, but I do really feel I must reemphasize my very first point. If you are new to brakes have someone who knows what they are doing teach you.
Great writeup, thanks!
great info man
wow, good stuff. STICKY
Good info here. :)
I'd like to add one thing to the bleeding process.
Do not to press the brake pedal all the way down to the floor once you relieve pressure (open nipple). This will prevent damage to the piston seals in the master cylinder. You may have to bleed a couple of times more per corner but it is worth the peace of mind.
Edit: Did not see post #6
wow so informative yet so simple
It is an awesome write-up, but like Clint says: If you are new to brakes get someone to teach you. Yes, it had to be said twice. It’s that important.
That was a really great write up! Thanks!
But a question. I have not bled brakes on anything but pre-ABS cars before. Elsewhere I read that the ignition should be on? Is this correct? Thanks.
I've been bleeding the brakes every 15k, and I'm always surprised at what a big improvement in pedal firmness it makes. Anyone else experience something like this? I guess I didn't expect the fluid to break down so much in just a few months and few thousand miles. I'm using Valvoline SynPower DOT4, which I've been using in various cars for about five years without experiencing this.
Perhaps I'm removing the factory installed air from the system, but no bubbles show up. We got the same difference in a friend's '04 WRX, so maybe it's a Subaru thing.
|All times are GMT -6. The time now is 01:47 PM.|