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  This post is about repacking wheel bearings using my VK Commodore as the guinea pig however the same principles apply to any hub and axle set-up, be it a caravan, trailer, boat trailer, if it has tapered roller bearings in the hubs please read on and I hope you find it useful.

 The first item on our list is to remove the brake caliper and bracket and secure it to prevent stress on the rubber brake hose. Generally speaking there will be two bolts securing the caliper bracket to the strut or stub axle assembly. Tie wire is useful for securing the caliper however you don’t want it falling on you while working so be sure it’s well tied up.                                

 The next step is to remove the grease cap in the centre of the hub. Multi grip pliers work best for this, however if you have a stuborn one careful prying off with a screwdriver may be needed. Once the grease cap is removed we have a split pin and nut and washer arrangement in front of the outer bearing. Side cutting pliers are best for removing split pins, just don’t squeeze too hard or you may cut the split pin in two! Once the split pin is removed we can unscrew the hub nut and remove it and it’s washer.

 The outer bearing may fall out at this stage - if it doesn’t come out by itself it will once we start removing the disc/hub. Being careful not to let the hub drop onto the stub axle and possibly mark the axle and destroy the rear seal, remove the disc/hub. It may take a few wriggles before it comes loose. Once you have the disc removed it is time to clean all the old grease from the stub axle and inspect the area where the seal runs. If there is a noticeable groove some fine grade wet and dry sandpaper should take care of this.

 Now take your disc/hub over to your bench or kitchen table (if you want to get shot!) and place a block of wood under one side of the disc. Using a suitable punch and hammer drive the inner bearing out from the hub. Go gently and evenly around the bearing and with any luck the seal will come out with minimal damage, however I would advise you to replace the hub seal seeing as though you have come this far and they are not expensive. Now is the time to get a bit dirty (no, don’t go and hassle your wife! Not that kind of dirty!), we need to get all the old grease out from inside the hub and the only way to do this is to wipe it all out with your fingers. Make sure you have plenty of rags to clean up with. The cleaner the better so it will probably take a few goes to get it all out.

 If you are replacing your wheel bearings I would suggest removing the bearing cone at this stage. Using a punch with good square edges and the hammer drive the cone out of the hub. The outer one will come out from the front and inner from the rear. You may need to feel around a little until you find a lip of the cone to sit your punch on. When you are installing the new cones make sure that they are knocked all the way home - you will hear and feel the difference once they are seated correctly. Once again a punch with good square edges is important when fitting new bearing cones.

 If you are re-using your bearings it is time to give everything a thorough clean. This includes the grease cap, both bearings, the nut and washer and if you aren’t replacing the split pin give it a wash as well. I use petrol for this as it evaporates quickly so is unlikely to contaminate the new grease that you put in, however it is definately not the safest thing to use and is terrible for your skin. Any cleaning solution or degreaser will do the job, just make sure it is all gone before applying the new grease. Once everything is clean lay it all out on a clean rag and now we can start the real dirty part

 Unless you have a bearing packer like the one pictured this next bit is not real fun. Have plenty of rags ready for cleaning your hands. The idea is to place a reasonable amount of grease into the palm of one hand, grip the bearing as shown in the other hand and ‘rake’ the bearing through the grease with a bit of downward pressure to drive the grease in and around the rollers, not pretty but effective! Keep doing this in the one spot until you see grease coming out from the top of the rollers. If there is old grease coming out as well that is OK just keep going until you have clean grease coming to the top and wipe away any old stuff. Once you have one area done move around to the next bit and so on. If you have grease showing out the top all around the bearing then that one is done.

 Continue on to the next one and once both are done grab some more grease in your finger tips and deposit a reasonable amount inside the hub itself. This can help to waterproof the bearings to a certain extent. Now it’s time to sit the inner bearing into the hub and refit the hub seal. Gentle, even hits with a small hammer is all that is needed to fit the seal. The hub seal on my Commodore that we used for the pictures actually loacates on the stub axle and is a loose fit into the hub but I don’t know of too many vehicles that are the same.

 It’s time now to go back over to the vehicle with your hub/disc and the cleaned washer, nut, split pin and grease cap. If you notice that the middle of the grease cap is dented in (usually caused by people with big hammers refitting the cap!), now would be a good time to do a bit of panel beating and knock the dent out from the inside. They can be noisy when rubbing on the stub axle or split pin and it shortens their lifespan.

 Once again be careful not to mark the stub axle or damage the hub seal, carefully push the hub into position. Grab your already greased outer bearing and fit it in place. Without letting go of the hub slide the washer into place ( it may have a locating tag with corresponding cut out on the stub axle) and grab your hub nut and screw it up hand tight. The correct adjustment for wheel bearings is just tight enough not to allow play in the wheel. My method is while turning the hub tighten the nut with mult-grips until you feel slight resistance and you’ll be pretty close. A better way of doing it is to fit the wheel to the hub ( depends on what type of wheel you are running of course ) and if you can still get to the adjusting nut loosen it off and grab the wheel top and bottom and if you can feel movement in the wheel they are too loose. You want to adjust it until that movement has been eliminated but no tighter. I know this method is not very ‘technical’ but believe me it works!

 The next thing to do once you have the adjustment right is to fit the split pin and the grease cap. I allways put some grease inside the cap and on the surface where it contacts the hub, to try and lessen the damaging effect of water penetration - especially important on boat trailers. Gentle hits on the outside of the grease cap is all that is needed to push it home. Refit the brake caliper making sure the brake pads are fitted correctly and the mounting bolts are nice and tight and your ready for the next side!

  I think that covers all you need to know on this subject, I feel like I’ve been typing for hours so hopefully it has! Remember if you strike trouble or have any other questions I can be contacted at http://www.autofix.com.au/. All the best.

Take care and be safe on the roads.

Craig

  Easy to do, extremely important to get right! But don’t let that phase you, replacing disc brake pads is and easy job and as long as you are careful all will be good. The vehicle we are doing the brake job on is a 1985 VK Commodore. These brakes are typical of many makes and models over several years and the principles remain the same to all vehicles. Although the mounting bolts or piston layout may be different this guide will be useful for all vehicles. If you are noticing a vibration in the steering wheel or brake pedal when applying the brakes, particuarly at speeds around 80km/hr then the front discs will need machining. Refer to the brake machining post for info.

Parts/Tools required.

1. Replacement brake pads.
2. Spanners/Sockets for removing caliper bolts.
3. Tool for pushing piston back. A pry bar or large screwdriver or large multi-grips can be used however there is a specific tool available at auto shops for doing this.
4. Grease or anti-sieze compound to lubricate the caliper slides.

Doing the job.

1. Raise the vehicle and remove the wheel. Support the vehicle with chassis stands or at the very least position the wheel under the car.
2. Remove the bottom caliper retaining bolt. It may be necessary on some vehicles to remove both top and bottom bolts. In this case we have a 15mm bolt and a 17mm head on the caliper slide so two spanners have to be used.
3. Lift the caliper up and slide it across to release it from it’s bracket. If you had to remove both bolts you may have to pull the caliper towards you to remove it.
4. Remove the brake pads taking note of the position of any spring clips or anit-rattle clips.
5. Squarely push the piston back into the caliper. If you are using a pry bar or large multi-grips be sure to push evenly on both sides of the piston.
6. Fit the new brake pads ensuring that any spring clips or rattle clips are position correctly.
7. Lubricate the caliper slides with grease or anti-sieze compound. Slides that are stuck are a major cause of uneven brake pad wear.
8. Refit the caliper and once you are sure that everything is fitted correctly, refit the retaining bolt and tighten.
9. Repeat on the other side.
10. Check the brake fluid level and then pump the brake pedal several times to push the piston out to contact the brake pads. If you find that the pedal is soft or spongy a bleed of the brake system will be needed.
11. Re-check the fluid level.
12. Refit the wheels and lower the car. Re-check wheel nuts once the car is on the ground.
13. Most brake pad manufacturers will have a list of instructions on how to bed the new brake pads in. Generally this is a series of stops from around 60km/hr to heat the pads, but be careful not to overheat and then ‘glaze’ the pads.

All done! Next week we will take a look at replacing rear disc brake pads. Because the handbrake is usually incorprated in the rear brakes things can get a little tricky. I will try to get as many pictures as I can to illustrate the differences between a few makes and models.

Until then take care and be safe on the roads.

Craig

  There are a few schools of thought on the best way of bleeding brakes, however I will go through a procedure that I have used for ten years without any dramas. You can even buy a vacuum operated brake bleeder to connect to a air compressor making it a one man (or woman!) job. We’ll stick to the basics here so that anyone with basic hand tools can do it.

  Always start with the brake caliper furtherest away from the master cylinder. So in normal cars (right hand drive!) this would be the left rear and in all others the right hand rear. Even when you are only doing the front brakes start with the one furtherest away. Make sure that the spanner that you are using is a nice snug fit on the brake bleeder because once they are rounded off they are very difficult to remove.

  Have an assistant sit in the car and when you are in position have them pump the pedal three times and hold their foot down on the pedal. We don’t want the brake pedal to go through the firewall when you release the bleed valve, in fact we don’t want the piston in the master cylinder to go anywhere near it’s full length of travel so warn them that the pressure on the pedal will drop and tell them not to take the pedal past halfway of it’s travel or not past half way to the floor. When the piston is taken past it’s usual length of travel it has the potential to get stuck down there especially if the fluid has not been flushed for a while and build-up prevents it from coming back.

  Once the assistant has pumped the pedal three times (up and down three times) release the bleed valve. I use a small length of hose that fits over the bleeder and a small coke bottle with a hole drilled in the lid and the hose pushed through to catch the fluid on it’s way out (very high-tech us Australians!). A large flat container placed under the car will do same job however you will need to hose down any remaining brake fluid with water to remove it.

  Now before your assistant lifts their foot at all close the bleed valve. This prevents air entering the system when the pedal is released. You will know when to close the bleed valve as the fluid pressure is released the fluid will initially come spurting out and then slow right down to a trickle - close the valve when it’s at a trickle. Repeat this step three times on each brake and if the pedal is still not right or you haven’t seen or heard air being expelled, then go around and repeat each step again.

  Have your assistant keep a close eye on the fluid level in the master cylinder. Keep it above half way at all times. Even if your assistant has to get out of the vehicle and check it while your moving to the next wheel. If it’s not kept topped up air could enter the system at the master cylinder and that would be defeating the purpose!

  So that’s the most simple yet affective way of bleeding your brakes. Just remember to keep the master cylinder topped up and it may take more than one ’round’ to get all the air out of the system. Good luck!

Take care and be safe on the roads.

Craig