Q: The Best Brake Grease?
A:
A brake caliper has three lubrication points –
1. Sliding Caliper Pin
2. Brake pad
3. Brake Clips
Is there one grease suitable for all three areas? No. Each area has different lubrication needs so three lubricants are needed.
As a brake caliper grips it barely moves – this micro movement makes calipers prone to sticking. ProSlip PIN is a specialist low friction pin lubricant developed to allow caliper micro movement and has a formula recommended by Toyota and Mercedes. It prevents fretting corrosion and maintains these physical characteristics over a temperature range suitable for brake calipers.
ProSlip CLIP is a special lubricant developed to prevent brake pads corroding solid in the clips. Corroded pads make it much harder for the caliper to force the pads onto the disc – energy is wasted overcoming the corrosion meaning there is less force available to slow the vehicle – inefficient brakes
ProSlip PAD is an extreme pressure rated lubricant which reduces metal to metal friction. Brake pads flex under braking and ProSlip PAD allows the metal of the pad and caliper to move against each without noise, vibration and harshness.
Q: Is ProSlip PIN compatible with Rubber?
A: ProSlip PIN is a synthetic base and will not cause the elastomer boot to swell. PAD and CLIP have a mineral base oil and should not be in contact with either the caliper pin boot or the piston dust cover boot.
Q: How often do I grease Caliper Pins?
A: . On most calipers sliding pin is protected from grime by a rubber boot which may not be water tight. Depending on the road conditions water can get behind the rubber boot and onto the caliper pin. This is especially true if you are crossing rivers, driving in snow and jet washing. You may be able to reach the rear caliper pins without taking off the wheel. On most cars with the front wheels on full lock this is also possible. This means re-greasing the pins is a 20 minute job. During winter and exposure to salt roads check your pins regularly as salt will interact with most lubricants including ProSlip PIN.
Q: ProSlip CLIP?
A: Pads are made of base steel and are held by clips made of stainless steel. If the pads are corroded solid in the clips they are harder to push onto the brake disc – braking force is wasted in overcoming the corrosion. If you have to knock the pads out with a hammer then you’ve been driving with inefficient brakes – all the force of the caliper has not been used to slow the vehicle.
Coating the pad ends with ProSlip CLIP prevents corrosion and reduces the friction between pad and clip making it easier for the pad to move in the clip push onto the disc. ProSlip CLIP contains a dry lubricant which makes it extremely resistant to being washed off. Use it to optimise braking efficiency
Q: What is Brake Drag?
A: A caliper must completely release the disc after braking. Force is used in pushing pads against the disc but there is no force pushing the caliper apart. Release of the disc relies on passive movement of the caliper.Brake Drag occurs when the caliper is still gripping the disc slightly. This causes not only increased brake and disc wear but increases fuel consumption and reduces acceleration. If the brakes are binding slightly more revving is needed to get the car moving – higher emissions!
Only a properly lubricated caliper immediately releases the disc after braking. The ProSlip Way is all about lubricating each component to make sure the caliper grips and releases immediately. When this happens there is improved ‘pedal feel’ – the brake pedal needs not only less force to brake but is not as hard under the foot.
Q: Brake Squeal
A: Under braking force brake pads flex and the metal body of the pad moves against the caliper. Without lubrication this would cause noise – ‘squeal’ – harshness and vibration as the metal surfaces grind against each other. Using a dry extreme pressure lubricant like ProSlip PAD controls the sliding of the metal surfaces against each other.
Q: Why do Calipers Stick and Seize
A: There is no visible movement when a caliper squeezes a brake disc. What tends to happen over time is the pads become corroded in the clips, become harder to move which reduces caliper movement even more. Unless a very low friction pin lubricant is used and the pads can slide easily onto the disc the caliper begins to seize up. This happens most often when copper or ‘moly’ grease are used. Both are sold as ‘high temperature’ or anti-seize lubricants but both contain solid particles suspended in a mineral oil grease which dries out causing the caliper to stop moving and seize.
Q: Do I Lube the Piston Seal?
A: . Brake fluid in the caliper is kept from escaping by a silicon rubber seal around the piston. The seal is also responsible for pulling the piston back off the disc after braking. It works like this….as the piston moves forward on braking the seal deforms – this deformation is stored energy..when the brake pedal is released the seal wants to go back to its original form and as it does to pulls the piston with it. Couple of things to note… if there is rust underneath the seal then this will reduce the ability of the piston to pull back of the disc which may then by a cause of binding. A new caliper is needed or a very thourough removal of the rust. If the groove in which the piston sits is deepened however it will reduce the effectiveness of the seal. Lubricate the seal with brake fluid – nothing else.
Q: Synthetic Brake Grease?
A: Many ‘brake greases’ state ‘synthetic’ i.e. man made – in reality most synthetic ‘high temperature’ brake greases are just basic silicone grease. Cheap silicone or glycol greases are man made but not made with brake caliper lubrication in mind, instead they’ve been re-purposed, re-branded if you will as ‘brake grease’. ProSlip PIN on the other hand is a synthetic lubricant developed specifically with sliding caliper pins in mind. The lubrication experts who developed PIN researched how to create a very low friction lubricant with anti-fretting properties.
Q: Is ProSlip PIN OK on any Vehicle
A: Where workshop manuals state silicone grease for sliding caliper pins ProSlip PIN can and should be used instead. Toyota state ‘synthetic glycol with lithium soap ‘ which is the formula for ProSlip PIN.
Q: Copper Grease on Brakes?
Brake Calipers – Treat them to the Best -They’re Worth It!
Hit the brake pedal and some 4000lbs per square inch of pressure are applied to the brake disc – enough to crush bone. It takes that much as the small four discs have to slow the momentum of over a tonne of vehicle as it hurtles forward. So much heat results that the gas layer between the brake pad and the disc can become ‘super heated’ and resists braking force. This is causes brake fade and is the reason discs are drilled grooved and brake pads have a slot down the middle – to allow the gas to escape. Brake pads flex significantly when braking pressure which reduces the pad-disc contact area. Twin calipers aim to reduce the amount of flexing by spreading the braking force over a wider surface area of the pad
Brake pads are in permanent contact with the disc so are made of low friction material. Low friction but not zero friction. If you’ve ever had to push your vehicle you know that the hardest part is that initial push to get it moving. This is because the resting resistance at the pad-brake is a lot more than zero. If you were to take out your brake pads, it would make it a lot easier to get the vehicle rolling. Once moving the friction at the brake-pad becomes negligible compared to the comparatively huge forward momentum of the vehicle which is why you’re able to tell the kind passer-by ‘thanks I’ll take it from here!’
Anything which increases the pad-disc friction will make it harder for a vehicle to move off from stationary and when driving you have to rev to overcoming that ‘rolling resistance’. The revving engines of vehicles moving off – at traffic lights, roundabouts, over speed bumps – makes a massive contribution to air pollution. Pad-disc friction affects acceleration from standstill.
It stands to reason that anything you can do to reduce rolling resistance will improve fuel economy, acceleration and emissions. Your choice of brake caliper grease and how you apply it affects rolling resistance of your vehicle – here’s why.
Lots of heat is generated when braking.- see https://www.youtube.com/watch?v=-1N5nBDLQMg. This heat will eventually cause petroleum based grease to dry out. Not necessarily a problem if the brake grease has a ‘dry lubricant’ – it still operates as a lubricant.
Copper grease became the choice for lubricating calipers and this still persists to-day, unfortunately. Copper particles do not slide easily over each other and so copper grease cannot act as a dry lubricant. It is a better anti-seize compound, the idea being that copper resists corrosion, which must be the reasoning behind why it is mistakenly used on the brake pin – not so much lubricating as stopping them seizing.
Heat reaching the caliper pin means any suitable caliper pin grease must be ‘high temperature’ and this inevitably means a synthetic grease. Silicone grease resists high temperatures, is compatible with rubber and is cheap. It is very poor metal to metal lubricant however which is why it is not used in CV joints or bearings. Most ‘high temperature’ brake greases are usually simply cheap silicone.
If your caliper pin grease does not contain an ingredient to protect the metal surfaces of the pin and the pin seat then fretting corrosion can occur which shows as pitting on the surface of the caliper pin. Fretting corrosion is a severe wear pattern which occurs when two heavily loaded metal surfaces undergo repeated micro movements – exactly what happens when you hit the brake pedal.
Your caliper pin grease needs to be not only ‘high temperature’ and hence synthetic but also have an additive package which protects the metal. These requirements already rule out 99% of brake greases on the market. Even adding dry lubricants to silicone such as PTFE will not prevent fretting corrosion.
It is unclear what the ingredients of those greases with ‘Ceramic’ in the title contain. Many state they are ‘metal free’ but the significance of this is unclear. They are cheap however which suggests they have not been specifically engineered for brake caliper pins at least – that takes an investment in time and money usually reflected in the retail price. The science of lubrication is a huge topic and specialist lubricants can be very expensive.
While there is 4000lbs of force pushing the pads against the disc there is no force pushing them off. The only force which allows the pads to sit back off the disc after braking is the weight of the pads and the caliper. However for this to happen relies on two things. Firstly the caliper pin grease must allow this recoil of the pad – if it has dried out then it will resist this passive movement. Secondly if the ends of the pads are corroded into the clips then the pads will move forward to grip the disc under the large braking force but not allow the pad to readily sit back off the disc – caliper relaxation we call it.
It goes without saying if the pads are corroded into the clips so you have to knock them out with a hammer then more force is need to actually push them onto the disc in the first place. Not good, you don’t want to be jumping on the brake pedal. At rest the caliper should be adding zero extra friction to that of the pads resting on the disc. For this two occur the pads must be able to move in the clips and the caliper pin must be able to allow the pads to passively sit back.
This provides a clue as to a key physical characteristic of your ideal caliper pin grease – it must facilitate the micro movements of the caliper in both directions, one under force the other passive. As we’ve implied many greases will allow the caliper to grip, but very few will aid the ‘relaxation’ of the caliper. ProSlip PIN was developed precisely with this in mind and was synthesised to have a very high lubricity – be extremely slippy. This is noticed at the pedal in improved ‘pedal feel’ – the pedal feels less hard. This is because with the caliper properly greased the ‘recoil’ of the caliper relaxing is communicated by the brake fluid to the pedal.Other branded brake greases are not engineered with such low friction, to make a grease with this particular characteristic isn’t easy. With ProSlip you’ve found the answer to your search. One last thing – a dry piston seal offers very significant resistance to the piston moving . Watch ‘The ProSlip Way’ video here to see our method for lubricating that seal. Hope we’ve answered some of your questions here![/vc_column_text]