- What do the letters mean on Motul motorcycle oil?
Modern multi-grade oils can have different viscosities at different temperatures and it is important to know what these are to understand how they will affect your engine. This is why Motul motorcycle oil and other oils on the market will tell you the weight (thickness) of the oil at the start up cold temperature and also the hot running temperature. This is shown as the coldest temperature first such as 10w/40. Multi-grade oils will protect your engine in a range of conditions and are a practical choice for modern bikes.
- Do I need to use different oil in the winter?
Quality 10w/40 oil will provide your engine with good protection on most temperatures but if you live in an area which experiences very cold, harsh winters then you may need to consider options for lower weight oil such as 5w/40. This will help to protect your engine in the lower temperatures and ensure all the parts are lubricated right from the moment you start up your engine.
- What types of oils are available for motorcycles?
Motorcycle engine oil is split into two basic categories, oils for 2 stroke engines and oils for 4 stroke engines. Older dirt bikes and some road bikes have 2 stroke engines but in general these types of engines are no longer being produced by most of the big manufacturers. 2 stroke engines require different standards of lubrication than 4 stroke engines so it is important that you choose the right oil for the right engine. This will ensure that you are protecting the moving parts at all times in both low and high temperature conditions. You can get a good range of both Motul 2 stroke oil and 4 stroke oil from independent parts suppliers and dealers.
- What are mono-grade oils?
Single or mono-grade oils are designed to be used only in a very limited temperature range. These are shown as 5w, 10w or even 50w. The lower number oils are suitable for use in cold weather conditions in which the engine will not be producing higher temperatures. The higher number mono-grade oils are suitable for warmer conditions or when the engine is already warm. The problem with these mono-grade oils is that they can only be used in a very small range of temperatures and this means they are not as practical as other options such as the Motul oil multi-grade range.
- What type of oil is used in the brakes system?
The brakes system requires a very special type of fluid which can stand up to the high temperatures created by braking. You can only use brake fluid in the brake system and these are typically made from Glycol or silicone. Brake fluid is graded in a DOT system and the higher the number the better quality the fluid. DOT 3 fluid is standard for street bikes but if you are using your brakes in a race track situation you may need to upgrade to allow for more extreme braking conditions. You can buy a range of Motul brake fluid products which will suit most modern motorbike braking systems. Glycol Motul brake fluid and other similar products are toxic so you do need to handle them carefully and avoid getting them on paintwork, brightwork, plastics and your skin.
- Can I use castor oil in my engine?
Castor oil was widely used by motorbike racing teams many years ago as it offered very good lubrication properties and performed well under the extreme load and high temperature conditions of the track. However castor oil oxidises quickly and so the engine has to be stripped and cleaned regularly to remove deposits. This is just not practical for the modern bike rider and so it is not a good idea to use castor oil when there are so many cleaner, more efficient synthetic and mineral motorcycle engine oil options on the market. Motul motor oil provides a great range of products suitable for all kinds of motorbikes which will respond to the demands of both street and race track conditions.
- What is the difference between synthetic and mineral oils?
Mineral oils are made from crude oil and are able to withstand high temperatures without oxidising or losing their lubrication properties. Synthetic oils are chemically manufactured and are designed to withstand a very high temperature which makes them ideal for high powered, high performance engines. Synthetic oils do not suffer from oxidation but the higher grades can be a lot more expensive than mineral oils and out of most people's price range.
- What is the most affordable oil that still provides good performance?
You can also get semi-synthetic oils and these are a good compromise between high performance and affordability. Many older models of bikes that have been designed to run on mineral oils will be fine with a semi-synthetic mix but it is always best to check your owner's manual before you add any new oil to your engine. Motul synthetic oil and semi-synthetic oil is widely available and provides a good quality option for modern performance bikes.
- What additives are in Motul lubricants?
There are a wide range of Motul lubricants available for the maintenance and running of motorbikes. These contain different additives which are designed to prolong the life of the lubricant and enhance its properties. For example, detergents are commonly added to Motul engine oil in order to keep the engine cleaner. These detergents hold the by-products in the oil in suspension so that they can be removed from the engine when the oil is changed and help to prevent deposits from building up in the engine. Oxidation and corrosion inhibitors can also be added and these reduce the rate at which mineral oil oxidises and also helps to control corrosion that could be created by acids or water vapour.
- What are gearbox oils?
You use gearbox oils when the gearbox is separate from the engine. This means that when the engine is running the gearbox will not be fed oil from the main oil system so it will need its own oil added. Motul gearbox oil is widely available and this will be listed in a range of SAE grades to measure viscosity and the most common are SAE80 and SAE90. These are slightly different from engine oils but as a general SAE90 Motul gear oil is about the same viscosity as SAE50 engine oil.
- Is Motul Oil good for my bike engine?
Any Motul oil review will tell you how good this superior oil is for your bike engine. Motul oil offers long term protection for your engine with enhanced temperature stability, excellent low-temperature starting and low volatility (oil consumption). Motul oil can offer superior engine performance for off-road, race and street bikes and is an economical and reliable option.
- Can I use car engine oils in my motorbike?
You should use engine oil that has been designed specifically for motorbikes. Motorcycle oil is produced with different additive packages to car oil and these are targeted specifically at motorcycle engine and transmission operation. Car oils are designed for fuel economy and this requires the addition of friction modifiers. Motorcycle design is not so concerned with fuel economy and so these friction modifiers are not included in motorcycle oil. Instead, higher levels of antiwear and high temperature protection additives are required such as phosphorous (ZDDP) to improve engine and transmission performance.
- Should I use synthetic motorbike oil?
Synthetic motorbike oil can be a practical option for your bike. A good quality synthetic oil such as Motul oil will offer enhanced high temperature stability and reduced oil consumption. These oils also contain anti-corrosion additives which are ideal for bikes that sit in the garage for long periods of time in between use. Many Motul oil review sites will tell you where to buy Motul oil and the synthetic options should be available from any good motorcycle parts supplier.
- What motorbike oil should I use for my sports bike?
Sports bikes have high performance multi-cylinder/multi-valve engines and oil is needed to lubricate the engine, transmission and clutch. Because these bikes operate at high speeds and high temperatures you will need a superior engine oil which can perform consistently under these tough conditions. A Motul racing grade product is a top level option for your sports bike and Motul oil review reports rate these products highly. Racing 10W-40 grade oil does not contain any friction modifiers (which could cause clutch slippage) and has a high phosphorous/zinc mix to ensure that the engine is protected under high speed/high temperature conditions. This superior Motul oil also provides enhanced dispersant technology that keeps the engine clean and free from grime to ensure optimum performance.
- Should I be using a different oil for my V-Twin?
You can use a standard motorbike oil on V-Twin models, but it is a good idea to buy a product that is designed specifically for this type of engine design. Air-cooled, large displacement V-Twin bikes can create very high localized oil temperatures at the rear cylinder and a typical design can get very hot due to the unique air flow. This means that if you are sitting in traffic or the weather is particularly warm the engine oil temperature in specific parts of the engine can climb rapidly. This means that a standard motorbike oil can actually start to break down and this can affect engine wear and performance. There are some great V-Twin synthetic 20W-50 motor oils on the market that are designed to withstand temperatures of 150°C and above. This means the oil will last and continue to provide you with optimum performance no matter what localized engine temperatures it is exposed to.
- How often should I change my motorcycle oil?
You need to check your owner's manual to see how often you need to change your engine oil. This will differ depending on what model of bike you own. The average modern street bike will need an oil change around every 8,000 kilometres. This is because engine oil can start to break down over time and will need to be changed to ensure your engine, clutch and transmission is still being properly lubricated. Clean engine oil will increase engine life and improve performance.
- Why do I need to use a high quality engine oil?
A high quality engine oil is designed to provide you with superior performance and will also protect your engine more effectively against general wear and tear. All engine oils break down over time but standard oils can break down much more quickly, particularly when exposed to high temperatures and heavy loads. This means it may not last as long as the recommended oil change in your owner's manual, so you will have to change the oil more often. A high quality motorcycle oil such as Motul will last the full 8,000 kilometres between the average fuel change and you can find out where to buy Motul oil by looking at good motorcycle parts suppliers.
- What do the two numbers mean on motorbike oil products?
Engine oil products are printed with two numbers and are known as multi-grades. These engine oils have been designed to run in engines that have varied operating temperature ranges, so they will have different viscosities depending on the temperature of the engine. For example a 10W-40 oil will behave as a 10 weight when the engine is cold and then as a 40 weight oil when the engine is hot. The lower number indicates the thinner cold operating temperature and the higher number the thicker hot operating temperature.
- In hotter summer temperatures should I be using a higher weight oil?
You can get a number of different multi-grade motorcycle oil products and these are designed to operate in different conditions. If you experience very hot conditions in the summer then you could benefit from using a higher grade oil such as a 15W-40 or a 20W-50. However in most temperatures (up to around 40º ambient) the standard 10W-40 option is perfectly adequate as your engine cooling system will prevent your engine from getting too hot anyway. V-Twin bikes should be using a 20W-50 option all the time because this engine design can cause high localised engine temperatures.
- Can I mix different weight engine oils?
You can add different weight motorcycle oil to your engine without affecting performance. If your engine was half full of 10W-40 and you wanted to top up with 15W-40 this should be fine an d you would end up with a multi-grade of around 12.50W-40. However it is recommended that you avoid mixing synthetic and mineral engine oils if possible. This will not harm the engine but it could reduce the performance of the oils.
- Oil Level
Quick steps to check your oil level!
Checking your motorcycle's oil level is a simple but essential operation once every 1,000 kilometers.
To make a precise check of this level, prop your motorcycle on its center stand. If it only has a side stand, make sure you set your motorcycle perfectly upright a few seconds just before reading the dipstick.
Most OEMs recommend running the engine two to three minutes so that the oil spreads throughout the internal lubrication circuit. After that, stop the engine, wait for a minute and read the level either using the dipstick or by looking through the little window on the sump. In the first case, unscrew the dipstick, wipe it, reinsert it without screwing, and then take a precise reading.
The correct level is located between the 'max' and 'min' marks, and must not be higher or lower. Too low a level of oil could cause serious engine damage because of oil starvation, whereas too high a level causes excessive pressure hence damaging the lubrication circuit.
If the level is too low, add just the right complement, taking care not to add too much oil. Proceed in stages and always wait for a few seconds for the oil to descend into the engine sump.
To avoid introducing foreign bodies into the sump, especially little stones, work in a clean manner by cleaning around the dipstick or cap before unscrewing them. Do not rely only on the oil display to make this check!
Motul lubricants are precisely formulated to take into account the exacting specifications and requirements from bike manufacturers. They are therefore advanced products which perfectly meet the technical constraints of bike engines. An engine oil is a complex mixture of base oils and chemical additives selected for their qualities and represent the optimum balance between performances, protection and longevity.
Adding an additive to the oil would impart the overall balance of the lubricant and therefore endanger the longevity of the engine. On the other hand, regular and careful maintenance will promote its longevity.
Last but not least, motorcycle engine oil typically lubricates the gearbox and clutch as well as the engine. Therefore, motorcycle lubricants are very complex in nature. The Motul range of motorcycle lubricants perfectly meets these constraints, without the need for other type of additives.
In 2-stroke engines, oil is directly injected into the engine and is therefore entirely consumed. The word sump is no longer used but reservoir, which must be filled regularly. A red display lighting up indicates a low reservoir level. If it begins to flicker, fill up the reservoir as soon as possible with a specific Motul lubricant for 2-stroke engines.
- Fork Oil
The right suspension!
The fork has the tricky job of providing suspension for the front axle, thereby determining the comfort and quality of road behavior and riding feelings.
Whether upside-down or not, the fork remains above all a hydraulic system. Each fork arm encloses a precise quantity of oil, which is forced, under compression, to follow a precise, calibrated circuit, thereby providing suspension for the front axle. If the fork has adjustments, these directly influence the size of the oil passages so as to modify the characteristics of the suspension and rebound, for instance. Some motorcycles have an oleopneumatic fork, which additionally requires a certain air pressure to operate correctly. When adjusting this pressure, take care to use a special pump. Never use a tyre inflator, which would be too powerful.
The most important element in a fork is of course the oil, which determines the motorcycle's road behavior. As this oil is subject to high pressures and heating, it should periodically be replaced with a perfectly adapted quality lubricant. Replacing fork oil is no easy operation. It requires a large number of tools, especially to raise the motorcycle, and good knowledge of mechanics. Play safe and entrust this operation to a specialist.
On the other hand, you can choose the viscosity which best suits your motorcycle and your riding style. A fork that's a bit soft or too hard can thus be corrected only by changing the viscosity of the oil. Motul offers on the market 8 different fork oils so you can find the optimum lubricant to suit your riding style. Fork oil is to be replaced every 10,000 to 15 000 kilometres.
Please contact your local Motul technical hotline for advices on which fork oil to use.
- Chain Lubrication
A motorcycle chain requires careful lubrication and adjustment every 1,000 km. Two simple, but essential operations.
A chain is correctly adjusted when its sag, i.e. its vertical mobility, is comprised between 15 and 25 mm (neither too slack nor too tight) in the most central position between the gearbox output pinion and the rear wheel sprocket. Make this check with a rag and on the lower chain run (the upper chain run is generally protected). Also check wheel alignment: the index marks on both sides of the swing arm must be at the same level. If you can push the chain up more than 25 mm, it is too slack and must be tightened. To adjust its tension, you need a minimum amount of tools, usually to be found in the OEM's motorcycle tool case. To carry out this operation, which is always messy, choose a flat surface and prop the motorcycle on its centre stand, if it has one.
1 - Loosen the rear axle (without removing the nut) and the tighteners to be able to move the wheel.
2 - Adjust the tighteners, by 8ths or 16ths of a turn simultaneously on both sides (you screw clockwise to tighten the chain in most cases). When the ideal adjustment is found, check the alignment once more.
3 - Tighten the locknuts, tighten again the rear wheel axle and check once again the alignment of the wheel as it may shift during these two operations.
4 - After this adjustment, lubricate the chain with Chain Lube, and spray the inside of the chain, in other words the lower run and the little plates on each side. Check that all the length has been well treated and that no projections have reached the brake or the tyre tread.
Why a specific lubricant?
A chain lubricant is a product which must meet severe mechanical constraints. It must be fluid enough to get between the chain rollers and plates. It must also be thick enough and adhesive enough to withstand high rotations. On top of that it has a water-repellent role. Last, chain lubricants come in ideal aerosol packaging with a precision sprayer minimising overspray. Motul offers on the market 3 different chain lubricants as well as 1 chain paste. To clean the chain, do not use too aggressive a product like petrol, which could well attack the small rubber O-rings between the rollers. Motul Chain Clean product was especially formulated to perform this operation
Off-road motorcycles: a case apart
Off-road motorcycles with their suspensions with a lot of slack require less tension. A certain amount of chain slack is even a good thing. Allow 30 to 40 mm on a trail motorcycle, even when used on roads. Last, riding in a dusty or sandy environment in no way exempts you from lubricating, but requires a specific product for off-road motorcycle chains such as Motul Chain Lube Off Road.
- MOTUL MC Care Line
24 products to show you care about your bike!
Motul offers on the market 24 products designed to maintain the longevity of your bike. Segmented in 5 sections, Motul MC Care line will ensure your bike performs and looks the way it should.
Section P: Mechanical Parts Maintenance
Section C: Chain Maintenance
Section A: Air Filter Maintenance
Section E: External Care
Section M: Motorcyclist and Equipment Care
Please refer to our Products section for a detailed description of each segment of Motul MC Care line.
- What are Motul maintenance products?
Motul is a specialist supplier of high quality lubricants for engine parts. The company began over 150 years ago in New York under the name Swan & Finch and later moved to France and became Motul. This company produces a range of high performance maintenance products such as multi-grade oil and chain lube which will keep your engine running at maximum levels. In fact, Motul was the first company to produce multi-grade oil (1953) and 100% synthetic oil with Ester (1971).
- How often do I need to carry out maintenance on my bike chain?
Motorbike chains have improved so much over the last decade that it can be easy to forget about them when you carry out routine maintenance. However chains do need to be lubricated properly otherwise they will dry out and get rusty. This can lead to breakages and if the chain goes when you are riding your bike not only could it cause a nasty accident but it could also lead to a lot of expensive damage for your suspension and engine. You will need to lube your chain at least every 800 kilometres of road riding. It may also need a good clean every 5,000 kilometres or so with some proper chain cleaner. If you are a keen off-road rider you may have to do this more often as exposure to the more extreme conditions of muddy, dusty or sandy environments can be more demanding on the chain.
- Why do I need to lube my motorbike chain?
The chain is exposed to a lot of friction as it turns, particularly at high speeds or while carrying heavy loads, and this can cause a lot of heat to build up. Chain lube protects the metal of the chain from this intense heat and will prevent it from stretching excessively whilst in use. This will help to ensure your chain lasts as long as possible and is providing you with optimum performance. If you have an O-Ring chain then lube will help to protect your O-Rings from corrosive elements such as road salt, sand, ozone and UV light.
- How do you lube O-ring chains?
Some bikes will have O-ring chains and you should lube these straight after a ride when the chain is still warm. This will allow the lube to be drawn up into the chain and will ensure that the whole chain and all the O-Rings are properly lubricated. You should spray a good covering of Motul chain lube on the inside of the chain to help drive the oil into the chain when you are riding and also spray some lube directly onto the O-Rings. You can do this easily by putting the bike into neutral and spinning the wheel manually whilst you are spraying. Never attempt to lube the chain whilst the motor is running. There are many horror stories of even experience mechanics losing some fingers this way as they can get caught in the moving parts.
- What types of chain lube are there?
There are several different types of chain lube on the market including basic wax, conventional lube and foaming wax/lube. These all provide different levels of protection or ‘fling’ for your chain. The less fling the more frequently you will have to lube your chain. The Motul chain lube range provides some high quality products for lubricating your chain.
- How do I clean my bike chain?
Over time dirt and grime will become embedded in your chain and so it is important to give it a good clean every 5,000 kilometres or so. You can buy special chain cleaner which will allow you to clean the chain quickly and easily. Avoid using hard solvents on your chain as these can damage the O-Rings and make it more difficult to lube the chain afterwards. Don’t use a hard scrubbing brush on your chain as this can scratch the surface. If the chain is very dirty leave the chain cleaner on to soak for a few minutes and then wipe it clean with a soft rag. You should also clean around the front sprocket as well as lube can build up here and attract dirt and grime.
- How often should I adjust my chain?
You need to lube your chain every 800 kilometres and this is a good time to check and see if it needs adjustment. If you are an everyday rider this will mean you will need to check your chain at least twice a month. You should check your owner’s manual for the correct chain adjustment on your bike but generally you will need between 1 and 1.5 inches of slack. The slack allows your chain to adjust to the different heights in suspension as you go over bumps on the road surface. If the chain is too tight it can cause a number of problems including damage to your countershaft. If it is too loose it will affect the bikes performance and could even fly off the sprockets as you are riding along causing an accident. Check the chain slack and then use a good lube such as Motul chain lube as part of your regular bike maintenance routine.
- Do I need to lube the sprockets as well as the chain?
Sprockets do not need to be treated with lube separately as the chain will automatically lube the sprocket in the right places as it passes over the teeth. You do need to check the sprocket when you apply your chain lube to make sure the teeth are still meshing well. If there are any signs of wear or damage then your chain may need adjusting and the sprocket may need replacing. Grime and lube can also build up on the front sprocket so give it a quick wipe over with a good chain cleaner now and again.
- Can I use WD40 to lube my chain?
Although WD40 is a versatile lubricant it cannot be used on motorcycle chains. This is because the formula of WD40 contains ingredients that can displace grease in the O and X-rings. This means your chain will not be fully protected against high running temperatures and will be subject to increased wear and shortened chain life.
- What is the difference between wet and dry lube?
Both wet and dry lubes are designed to protect the chain from high temperatures and corrosive elements to ensure it provides optimum performance and lasts as long as possible. The fundamental difference is that wet lube contains oil and dry lube contains wax. It has been shown that wet oil lube can attract and hold grit which can cause wear on the chain surface. Dry chain lube is thought to provide a more effective barrier against corrosive elements such as road salt but the deposit of lube on the chain can get rubbed away more easily.
- What is brake fluid used for?
Brake fluid is used in hydraulic brake systems and transmits pressure from the braking lever (or pedal in a car) to the master cylinder and on to the calliper and brake pads. This is a carefully balanced process and you need the correct brake fluid for your brake system. Always check your owner’s manual before you buy any brake fluids.
- What types of brake fluid are there for motorcycles?
There are two basic types of types of brake fluid available for motorbikes, Glycol and silicone. Glycol is the most common fluid used in the automotive industry and is graded in a DOT system, the higher the number the better quality the brake fluid. Glycol brake fluid is actually very toxic so needs to be treated very carefully. When you are working with Glycol you need to make sure you do not spill it on paintwork or your skin. Silicone brake fluids are not toxic and this is why they are so popular with classic motorcycle enthusiasts as they can be used safely without risk to the paintwork, brightwork or plastics.
- What grade brake fluid should I use?
Most brake systems will run on DOT 3 standard brake fluid which is widely available and affordable. However if you are running a high performance sports bike you may need to consider using one of the better quality brake fluids. DOT 4 will provide a slightly firmer, more responsive feel to the brakes which is useful when you are pushing your bike hard. You can buy a great range of Motul brake fluid products which are ideal for most types of motorbike braking systems.
- How should I store brake fluid?
Brake fluid such as DOT 3 is hygroscopic which means it will absorb water from the atmosphere and degrade over time. This will significantly impact the brake fluid’s boiling point and its overall effectiveness and if you use brake fluid with a high water content it can cause corrosion inside the brake system. You should avoid buying more brake fluid than you need as you cannot store it and you should only ever top up your brake system using fluid from a sealed container. Motul brake fluid products and those of other leading manufacturers are deliberately sold in small containers to prevent storage issues.
- How often should I replace my brake fluid?
Brake fluid will absorb water through the tiny porous holes in the brake system cables and degrade over time. This can cause a number of problems such as brake fade so you will need to replace the brake fluid in your motorbike brake system now and again to ensure you are getting the best performance. The average street rider should change brake fluid once every 5 or so years, however if you take part in race conditions this may need to be carried out more often to ensure optimum brake performance. Motul brake fluid products are affordable, of a high quality and make a great choice for a replacement fluid.
- What brake fluid should I use for competitive racing?
If you ride in competitive events then you will need to upgrade from standard brake fluid as this will not have a high enough boiling point for top performance engines. You can get some highly refined glycol brake fluids for track use that have boiling points over 300 degrees C, but if you only ride the occasional track day then a DOT 4 brake fluid will be a more affordable and practical choice.
- Can you mix Glycol and Silicone brake fluid?
Glycol and silicone brake fluids have very different formulas and cannot be put into the same brake system. They do not mix and will globulate which prevents the essential power transfer process occurring from the brake lever to the master cylinder. This basically means your brakes will not work properly. Also the calliper and cylinder seals in braking systems are typically designed for one type of brake fluid, so if you pour the wrong one into your system it will destroy the seals creating a very expensive repair bill.
- Why are there two types of DOT 5 brake fluid on the market?
This is a bit confusing but basically for a long time silicone brake fluid was marketed as DOT 5. However then some manufacturers started producing a more refined Glycol brake fluid, which they also called DOT 5 or DOT 5.1. So you have two very different types of brake fluids going by the same name. You do need to be very careful when using DOT 5 that you have selected the right one for your brake system.
- Is silicone brake fluid better than Glycol?
Silicone brake fluids are not toxic like Glycol and so can be used more safely in the workshop. Also silicone is not hygroscopic which means it will not degrade over time by absorbing water from the air. Silicone has been shown to perform well under extreme conditions (such as high temperatures and heavy loads) and this is why some of the big V-twin custom motorcycles on the market use this type of brake fluid system. However silicone can be very expensive and this is why very few standard factory motorbikes are designed with brake systems that use this type of brake fluid. You can only use the fluid your bike has been designed for otherwise you will damage the cylinder and calliper seals so you do need to refer to the owner’s manual before you replace brake fluid.
- How do I replace my brake fluid?
You can bleed your brakes to remove the old brake fluid yourself but this can be a tricky job and needs to be performed correctly to ensure the brakes work properly afterwards. If you have never done this before it is a good idea to get some help the first time from someone with plenty of experience. You need to make sure your tools and the area around your bike are clean before you start so that you do not accidentally contaminate the brakes with dirt. You will need an unopened, fresh container of the right brake fluid for your system. You can bleed the old fluid through the brake nipples on the brake callipers/wheel cylinder and start with the one furthest away from the master cylinder first. Place a clear plastic hose over the nipple and drain the fluid into a glass jar. This will help to prevent any of the toxic fluid getting on your paint work or hands. Top up the brake fluid level with the new brake fluid until you start to see it coming through the bled nipple. Gently hold the brake lever down when you close off the nipple to help prevent any air from working back into the system. You can use a good Motul brake fluid or any other top brand to replace the old fluid.