1.Disk brake fluid is very corrosive and can damage paint so cover the bike parts with some cloth.
2. You should be very careful in following the instructions and have patience otherwise you may end up air in the disk brake system and zero braking.
What we need:
- 100 ml of DOT3 or DOT4 brake fluid. I could find DOT3. Only use from sealed bottle.
- 8 mm Ring spanner [Warning : Open end wrench/spanner will not work here and may damage the nut!!]
- Philips screw driver
- Transparent pipe around 12 inch in length.
- Empty plastic bottle
Step 1: Open the Main Fluid reservoir using Philips screw driver and you will see white plastic cover.
Warning : Be very careful while removing screw with screw driver. first fix the screwdriver properly into screw head use some force downwards as well and then remove it . The head of screw is made of very soft metal and it can get damaged even if screwdriver slip even once !!!! If screw head is damaged , you will not be able to remove it.
Step 2 : Remove White cover , you will see rubber diaphragm .
Step 3: Remove Rubber diaphragm and you will be able to see old disk fluid.
Step4: Here is the bleeder nut on the disk brake assembly .
Step 5 : Remove the cap from bleeder nut and fix 8 mm spanner to it . Attach it at such an angle so that you can move it freely up and down.
Warning:Don’t open this nut yet.
Step 5:Attach transparent pipe to it and put another end of pipe in to the empty plastic bottle.
Step 6: The reservoir should be filled so that air should not be able to enter in disk pipe.
Loose the bleeder nut by pressing the 8 mm spanner downwards.You will see the fluid coming out of the pipe.
Step 7: Be very careful in following step : Press the front brake lever to increase the pressure in system Keep holding the brake lever completely and tighten the bleeder screw again to prevent air entering in the circuit AND then release the brake lever.
Whenever disk brake lever is pressed you will see old fluid going to the bottle. Make sure you don’t release the brake lever with bleeder nut open otherwise it will suck the air through bleeder nut.Also always keep enough fluid in master cylinder.
Step 8: Top up the Fluid reservoir with fresh fluid from bottle.
Repeat the step 6 , 7 and 8 multiple times. i.e. [Loosen bleeder nut ---> press the brake lever—>close the bleeder nut—> top up the main cylinder —>release the brake lever ]
Things to keep in mind :
Never Release the front disk brake lever when bleeder nut is loose.
Never let the Master Fluid reservoir be empty otherwise system may suck air through it.
Eventually you will see fresh fluid ,good in color coming out of pipe and getting stored in to bottle.
Finally all the fluid is clean and fresh in Fluid reservoir .
Tighten the bleeder nut and close everything in order.
Dispose off the old fluid carefully. It is highly corrosive in nature.
Amardeep,
ReplyDeleteVery well written and important points noted out... Im happy to see the only page on the net showing detailed instructions to bleed the Royal Enfield brakes :)
I would like to add that we in India use DOT 3 & 4 brake fluid, which is low grade as compared to
international standards... I prefer DOT 5.1 which has very high boiling point and superb performance.
The other point which I would like to note out is that if the Bull is running regularly, then the brakes should be bled every 4months instead of the usual 1year, this helps in avoiding internal corrosion of the brake system whereever there are aluminium or tin parts (Pricol).
Thanks Sushil for encouraging words.
ReplyDeleteAmardeep, I tried a lot but could not find the correct size/spec of the Bleed Valve on our Enfield's Pricol caliper.
ReplyDeleteWhich among the below is the correct size, could you please help?
M8 x 1.0 x 35.54
M8 x 1.25 x 27.99
M8 X 1.25 x 32.54
M8 x 1.25 x 38.09
These figures are in mm. I understand that taking the bleed-valve out from the caliper and manually figuring out the spec with a scale would be an easy job.
Thanks and regards.
Hey Amardeep great Blog and sushil thank you for adding .. As I have had problems finding genuine mechanics and my enthusiasm to DIY which really thrills me.. I was speaking to one of my friends who misguided me on how to replace brake fluid and the system be cleaned with petrol ( is that advisable ??) . he also told me that you have to pump continuously to drain the fluid .. as I read here the system is otherwise, also he told me to loosen the other nut not the bleeder nut which was another flaw when I asked him which I know now as the bleeder nut he said it was something which he tried to cover-up for not knowing .. anyways it always feels good to know the right way of doing things. Also another 2 things I learnt from http://bikeadvice.in/engine-oils/ . I was looking for a solution to flush the engine oil . The uncle who sold me my battery told me no need for flush just fill full of diesel and drain it out .. again which I read is wrong since It may damage the bearing surface and it’s oil filming also another thing my friend told me .. that his mech put car engine oil of apparently the same grade and he feels his bike smoother but I read … Do not use car engine oils for motorcycle purpose. That may harm the motor. Car engine oils content with friction reducers. Two wheeler engine oils – specifically four stroke engines with a wet clutch multi plate setup do not need oils with friction reducers as they can increase or decrease the friction, If we use friction reducer then the clutch will start slipping fast at high rpm or at the time or heavy load and high torque.. I wish I could upload a pic of what has happened inside my main fluid reservoir. I haven't changed the fluid in 4 years and once my friend rubbed the brake pads with sandpaper and aftr that the fluid became kind of greyish. After that i opened it sometime later and i think due to water seepage from below the cover, there is sort of fungus around the rim of the inside of the main fluid reservoir. I will follow these instructions and change the fluid .when i was in noida I went to a really co-operative mech .. he said that tryin to clean the reservoir would damage the main pump and could render the whole mechanism a failure which really scared me since the bikes now are so delicate and have to be taken care practically every day which invariably makes you a self-mechanic . Also .. sushil have you have used the DOT 5.1 in which model will it work for the Thunder Bird Twin Spark 2010. And for how long have you used it, I could possibly get it from the US .
ReplyDeleteDo let me know a solution for the cleaning of the main fluid reservoir .. do i remove the fungus with a cloth from above .. will the tube get choked if a little fungus goes through, awaiting your replies . Thanking you
Very well explained and a wonderful job sir. It helped me a lot. Thanks a lot for updating such good details
ReplyDeleteThank you for sharing such great information.Rubber Diaphragm in IndiaIt is informative, can you help me in finding out more detail on Silicone Braided Hose,i am interested and would like to know more about this field and wanted to understand the basics of Silicone Tubing.
ReplyDelete