[saket77]

DIY is the best thing which can happen to your vehicles for TLC, but only if you know what you are doing. Expensive labour charges and compromised job quality at times by service centers add another strong reason for going the DIY route. Hemmed in by such thoughts, I put the last Sunday to some good use. My humble Honda Stunner (as many of you would know by the thread of my Mandarmani/ Tajpur ride) is my vehicle of choice for most city errands, including being the transport for office. It's frugal, stylish and most importantly, reliable as a rock. However still, proper service at stipulated time interval means the machine is up for anything, anytime.

But from the last few days, my bike had decided to steal the punchline from Maruti A-star: Stop @ Nothing! That is, of course an exageration; not that the brakes were completely gone, just that the front disc system was not performing to the best of its efficiency. And it was not without a reason. The background to the story is that last week I decided to bleed the brakes and inadvertently spilled some brake fluid on the disc which ultimately made its way to the brake pads. Due to this blasphemy, the braking efficiency was reduced. After a half hearted service attempt by a mechanic (which did not made it any better), I decided to get my own hands dirty. And thought of sharing the process with the community; hoping you guys will find it useful.

So here it is, a guide to service motorcycle disc brakes. This will cover 2 aspects: cleaning/ replacing brake pads and a brake bleed to wrap it all up.

Tools required:

1. Ring wrench (of your bike specific size),


2. Small hammer,


3. A thin screwdriver (to hammer out the caliper through the thin hole),


4. Sand paper (if re-using the old pads)/ new brake pads (if they need replacement),


5. a long & strong four head screwdriver,


6. Brake fluid (refer to the Dot no. on fluid container or bike manual),


7. A small bottle container to avoid spilling fluids and;


8. A thin pipe which can fit on the bleeder valve.


9. Caliper Grease.



Please note that since I was short of helping hands, I could not click pictures of the job, so I am providing necessary illustrative pictures from the internet. Please pardon the non-continuity of pictures since all are from different sources and different bikes.

PART-I: Cleaning/ replacing brake pads:

Step 1:
Clean the disc first, else you may end up with slippery pads again when the cleaned pads makes contact with oily disc after service. (mine was a case of oily disc & pads). You can use any good oil remover or de-greaser. I did not have such thing, hence I used Pril. Works just fine for the job. So, gave the disc a good wash with Pril and made sure that there are no traces of slippery oil on it.

Step 2:



Locate these 2 bolts (marked in the picture) to get the entire brake assembly out from the frame. For my bike, all it needed was a 12 no. ring wrench. Size may differ for other bikes.

Step 3:
Once you have unscrewed the two bolts completely, slide out the entire assembly from the disc carefully.




Step 4:
Locate the caliper lock pin in the lower side of the assembly. To open this lock, simply slide it outwards and without much effort, it should come out. This is a lock which keeps the caliper from sliding in & out inadvertently, thus securing the brake pads in place. For those who are newbies at the task, the caliper is what holds the brake pads in place by providing a pivot at its end. The picture below is for the rear brakes, however, similar arrangement will be for the front brakes too. Pardon for poor continuity of pictures.


Step 5:
Once you have got the lock pin out, you need to slide the caliper out so that you can take the brake pads out from assembly. You may need a thin screw driver or a nail which can let you hammer out the caliper from place, if its a little tight. Hammer gently. Slide out the caliper completely.


Step 6:
Once the caliper is out, the brake pads should come out easily, as they are only held by the caliper. But before you take out the pads from place, have a good look at it. The inner brake pad is different from the outer pad. You will have to keep in mind this fact when you assemble them back.


Step 7:
When I took out my brake pads, they were all dirty & greasy due to the spill. They had good life left, hence I took a metal sanding paper and rubbed the brake pads against them for a few seconds. This cleaned the pads and exposed the new, efficient layer of brake shoe.


*Imp*: Do not press the brake lever while the assembly is out of its place. This will make the pistons come forward (since disc brakes are self-adjustable) and you will not have the required clearance to fit it back. If accidentally you have pressed the lever, you will need to loosen the bleeder valve to lose pressure so that you can push the pistons backwards.

Step 8:
Clean the innards of assembly. You will find a lot of dirt & brake rust there.

Step 9:
Assemble back by putting the new/ cleaned brake pads in place. Put grease generously on the caliper before sliding it back in place so that the pivot action on the caliper is smooth.


Do not forget to lock the caliper in place by sliding back the lock pin. Now put the assembly back on the fork by aligning the disc in between the brake pads. Match the holes and put back the bolts that you opened in step no. 2. Tighten them well.

Test the brakes by pressing the brake lever while pushing the motorcycle with your hands. Make sure that the brakes are working.

PART-II: Bleeding the brakes.

Hydraulic Braking systems require fluid action to work. However, with time, air & moisture tends to enter the system which reduce the effectiveness of the brakes. Brake bleeding is the process to remove the air in the system and restoring back the efficiency. Ideally it is a two person job, esp. in car, but it is not too difficult to perform it on a bike even with no helping hands. If you have smart help available, so much better. You also need to know this procedure if you want to replace that ageing brake fluid. So, lets get hands on it:

Step 1:
First things first. Prepare a bleeder bottle where you will collect the waste brake fluid coming out from the bleeder valve. It is a very simple process. Brake fluids are nasty fluids, both for you & your vehicle paint and hence, proper care should be taken to avoid spillage. Also, collecting the waste fluid in a bleeder bottle is environmentally the better way of doing it. For preparing a bleeder bottle, get a thin transparent pipe which can fit on the nozzle of the bleeder valve. The other end leads into the waste bottle. Consider wearing plastic gloves for the job.



Step 2:
Identify the position of bleeder valve. See the picture for reference:


After you have prepared the bleeder bottle & identified the bleeder valve, put a 11 no. ring wrench on the bleeder valve as in the picture. Once the ring wrench is in place, open the bleeder rubber boot-cap and insert one end of the thin pipe. The other end of course leading to the waste collector bottle.


Also, open the brake fluid container on the handle bar with a four head screw driver so that you can monitor the level of fluid while performing the job.


Also, you will need to add fluid in the container as you will end up draining some during bleeding.


Step 4:
Now pump the brake lever 3-4 times quickly and hold. While the brake lever is held, open the bleeder valve by moving the wrench counter-clockwise. You should see brake fluid escaping from the valve to the pipe. You may also notice small air bubbles within the fluid.


Now, as the fluid escapes, the brake lever will sink fully. Do not get scared that you have screwed the system; just keep on holding the lever and do not let it go under any circumstances. Now, tighten the bleeder valve and let go the brake lever finally. Repeat this step 3-4 times to get all air out from the system. While performing this step, make sure that the fluid level in the brake fluid container on your handle bar (near the brake lever) does not dip to the bottom. So, you may need to keep adding new fluid during this process too.

Step 5:
Once you are convinced that no more air bubbles are coming out with the fluid, tighten the bleeder valve fully. Failing to tighten the bleeder valve completely can lead to complete loss of hydraulic pressure and eventually a brake failure. Hence, double check it. Put on the rubber boot cap on the bleeder valve back.

Step 6:
Once the bleeding is done, you should feel that lesser effort is required to press the brake lever and that it has become softer than before. Again, before riding, check the efficiency of brakes by pushing the motorcycle for a few feet by hands and applying the brakes. After affirmative test, ride the bike in a safe place with scant traffic/ people like your apartment basement/ garden/ compound. Take the bike to the roads only when established that the brakes are efficient and working perfectly.

Step 7:
Take a breath and feel good about the job you just did. If no one is around, you can pat your back too! The process for bleeding your car brakes is the same. Just make sure that you bleed the wheels in order of farthest to closest to the brake pedal. This means for a RHD car, you start from Rear-Left wheel> Rear-Right> Front-Left and finally Rear-right wheel. In case you have any confusion about disc/drum thing, then yes; even if your car has drum brakes at rear, they still require bleeding as bleeding is for any fluid -action hydraulic braking system. Disc or drum does not matter. And just to remind, bleeding car brakes is strictly a two person job.

I hope this guide comes handy and useful to fellow members and all readers. If you have questions, do let me know and I will try my level best to answer them. Also, in case you feel like I have missed a useful step whose addition can make this guide even simpler, please let me know or ping the mods. I would be more than just happy to get your contribution in this thread. Ride safe fellas!

Thanks,
Saket

[bblost]

Moved from Assembly Line
Thanks for sharing

[aargee]

Step #9 - Extreme caution; have a C-clamp ready in hand or be prepared to rely extensively on a screw driver's back & your muscles or if your caliper piston's are struck...prepare for the worst!! After cleaning, the caliper doesn't get into the rotor easily & it is mandated to push the pistons back, fit the pads & then mount on to the bolts. It is also strongly suggested to apply some DOT3/4 oil on to the side walls of the piston without damaging the outer surface of the piston



Part #2 - Step 2 - Proceed with extra caution not to damage the bolt & if you're already having a semi damaged head on the bolt, I would strongly suggest staying away; but yes, WD40 to rescue.

Last but not the least...if you're first time doer, have a backup vehicle incase you're unable to put back things into place OR have someone do it & watch it before you make your first attempt.

[SunnyBoi]

May I suggest you elaborate further on the bleeding part? It seldom is as easy as you've mentioned. For my first times, I've been bleeding a.k.a pumping the brakes for over 90 minutes and still could not get rid of all the bubbles.

Originally Posted by aargee

Step #9 - Extreme caution; have a C-clamp ready in hand or be prepared to rely extensively on a screw driver's back & your muscles or if your caliper piston's are struck...prepare for the worst!! After cleaning, the caliper doesn't get into the rotor easily & it is mandated to push the pistons back, fit the pads & then mount on to the bolts.

Fret not. Open the top reservoir cap, put in a ring spanner between the caliper body and the piston, push the piston in using the caliper body as leverage. Longer the ring spanner, easier it is to push it back. Constant pressure is the key and jerky motion won't help. Don't push the piston in one move, you'll have a huge fountain coming from the top reservoir; any painted part the fluid falls on will be knackered for good.

[saket77]

Originally Posted by SunnyBoi

May I suggest you elaborate further on the bleeding part? It seldom is as easy as you've mentioned. For my first times, I've been bleeding a.k.a pumping the brakes for over 90 minutes and still could not get rid of all the bubbles.

I hope you maintained the fluid level in the top reservoir during the entire process. If the fluid level falls below a certain threshold where air can be sucked in again from the top reservoir, one will not be able to get rid of air bubbles in the system. Also, some air may be drawn from the bleeder valve threads while bleeding (when you loosen the valve), hence you may not get rid of tiny air bubbles. If done correctly, it is hardly a 5 minute job; given that one is not flushing the entire fluid.

[latentpotential]

Note that when you top up the reservoir and press the caliper to increase the pressure in the system, prior to loosening and release from the bleeder valve, it is best to put the reservoir tank cap back and make sure it is firmly in place. Else you will have a fountain of dot3/dot4 fluid everywhere.

For safety, I request members to get 3m safety glasses from ebay or stores. MRP of INR 100 only, and long length plastic gloves, as well as wearing old shoes in case of spillage.

Please avoid shorts and open type footwear, as skin can react badly with dot fluids.

[Sheel]

Originally Posted by SunnyBoi

I've been bleeding a.k.a pumping the brakes for over 90 minutes and still could not get rid of all the bubbles.

Normally, if you feel there is air, tie a cloth as hard as you can to the front brake lever & leave it overnight. Next day, you will be surprised to note the play & that, all air has gone.

[aargee]

Originally Posted by SunnyBoi

Fret not...on will be knackered for good.

Yes, so many alternatives, for people who've done things; like Saket 100% rightly said...

Originally Posted by saket77

If done correctly

Done correctly is THE KEY; and when most people do it first time, its much easier loosing hope to put things back than fixing it.

I suffered with broken brakes for weeks; fortunately I had 2-3 backup vehicles & I could also afford to wait indefinitely which is luxury for most. That's why the word of caution.

[SunnyBoi]

Originally Posted by Sheel

Normally, if you feel there is air, tie a cloth as hard as you can to the front brake lever & leave it overnight. Next day, you will be surprised to note the play & that, all air has gone.

Sorry if I sound smug but I have moved away from the traditional bleeding method years ago. Built my own DIY reverse bleeding rig, I can flush all the brake fluid, fill it up air free within 5 minutes and zero pumping :-)

I'm bad with guides but this video demonstrates a method similar to what I use

https://www.youtube.com/watch?v=lBk00597EyE

[ArizonaJim]

@ saket77

A well written instruction which I'm sure will help many tackle the job of rebuilding their disk brake.

I should point out that different motorcycles/scooters may have disk brakes that are somewhat different than the one you show.
This leads me to suggest to all: If you have any doubts about your ability to rebuild your disk brake(s), leave them alone. Take your motorcycle/scooter to a good mechanic who knows what he's doing.

Your life and the lives of people riding with you or the people you may run into are at stake if your brakes fail.

As for brake pads contaminated with brake fluid or oil, replacing them is best but not the only solution.

Methyl Ethyl Keytone (MEK), Lacquer Thinner, Acetone or Denatured Alcohol along with the best thing to remove brake fluid: Disk Brake Cleaner, all will break down the brake fluid that is fouling the brake pads and disk. Throughly saturate the disk and brake pads with the fluid, rotating the wheel to work it onto the brake pads face.
Any good automotive repair place that services disk brakes should have one brand or another of Disk Brake Cleaning fluid.

Do not use diesel fuel, turpentine, kerosene or any other petroleum based fluid. They do not break down the brake fluid. They will at best just dilute it leaving a film behind that will keep the disk brake from working.

While on the subject, I must point out that any of the DOT brake fluids except for DOT5, makes an excellent paint remover.
Just a drop of it on your nicely (or poorly) painted fuel tank, mud guards or anything else with paint on it will eat the paint right off of the part.

[saket77]

Originally Posted by ArizonaJim

Methyl Ethyl Keytone (MEK), Lacquer Thinner, Acetone or Denatured Alcohol along with the best thing to remove brake fluid: Disk Brake Cleaner, all will break down the brake fluid that is fouling the brake pads and disk. Throughly saturate the disk and brake pads with the fluid, rotating the wheel to work it onto the brake pads face.------
Do not use diesel fuel, turpentine, kerosene or any other petroleum based fluid. They do not break down the brake fluid. They will at best just dilute it leaving a film behind that will keep the disk brake from working.

Thank you AJ for chipping in with some great information. Something which I wasn't aware of.

Originally Posted by ArizonaJim

While on the subject, I must point out that any of the DOT brake fluids except for DOT5, makes an excellent paint remover.
Just a drop of it on your nicely (or poorly) painted fuel tank, mud guards or anything else with paint on it will eat the paint right off of the part.

And may I just add that while you can mix DOT 3 & DOT 4 fluids, never mix these with DOT 5 as the base is different.

Thanks,
Saket

[aargee]

Originally Posted by SunnyBoi

Sorry if I sound smug...method similar to what I use

I use the same method, but upside down. Means, connect the tube to the bleeder, loosen the bolt, but keep toping up the master cylinder as the oil keeps draining through the bleeder. No pumping, ZERO air but no pushing or extra gadgets; just make the connections & let the gravity do its job

[SunnyBoi]

Originally Posted by aargee

I use the same method, but upside down. Means, connect the tube to the bleeder, loosen the bolt, but keep toping up the master cylinder as the oil keeps draining through the bleeder. No pumping, ZERO air but no pushing or extra gadgets; just make the connections & let the gravity do its job

You must also realise air bubbles are lighter than brake fluid and this tend to rise upwards. If you're letting brake fluid come down using gravity, you're working against the objective. It does work however it takes a lot more time and more brake fluid to be used up.

[latentpotential]

Originally Posted by SunnyBoi

Sorry if I sound smug but I have moved away from the traditional bleeding method years ago. Built my own DIY reverse bleeding rig, I can flush all the brake fluid, fill it up air free within 5 minutes and zero pumping :-)

I'm bad with guides but this video demonstrates a method similar to what I use

... url

This is good, seems less messy and actually faster for a one man job. Will try this out soon and post back my feedback.

[Jeroen]

Nice article, thanks for the write up.

A couple of additional thoughts;

When you replace the pads there should be no need to bleed the brakes. The one thing you might want to watch for is overspill from the reservoir when you push the calipers back to fit the new thicker pads.If you find air in the brake system there is something wrong with the brake system and you need to fix it asap. It's a myth that over time air will enter the system, its is correct that hydraulic oil is hydroscopic and thus over time will absorb moisture/water. Hence always replace the hydraulic oil every 2-3 years.

If you're into bleeding your own brakes regularly you might want to invest in an Easy Bleed system or similar. See http://www.team-bhp.com/forum/attach...o-img_1850.jpg

Although bleeding the brakes by working the brake lever, or stepping on the brake pedal in a car is a well established practice there is a problem with it. Especially on older bikes/cars. Over time there will be a built up of residual material inside the master and slave cylinder. This material will gather at the far end of the piston stroke across the full diameter of the cylinder. The problem is that when working/pushing the brake lever during the bleeding action will push the piston and its seal through this little 'ridge' of material. This could lead to failure of the seal. Rarely immediately, but a few hundred or thousand kilometers afterwards. If you ever find yourself holding an old/used master cylinder feel inside for this little 'ridge'. Chances are you can feel it. So I prefer to use an easy bleed or better yet if you access to it a vacuum system to bleed the brakes.

One of your pictures shows the caliper pin that holds the assembly. On it shows two cotter pins. These should always be renewed, don't try and straighten out the old ones, get new ones. Costs next to nothing.

It is advisable to use some special brake pad compound on the back of the pad and the sides where it touches the caliper housing. This will avoid your typical screeching of the brakes. I'm not sure if that is the same stuff as you are using and shown in the photographs as 'grease'?

A bit nitpicking perhaps but ideally you should not use screwdrivers to drive out the caliper pin and or cotter pins. You should use a proper sized punch. Reason is the screwdriver might damage or you might damage the screwdriver because they are not meant for it and are actually quite brittle when you start hammering away on them. So bits could break of and typically they end up in the enthusiast eye!

Jeroen