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Wheel Bearing Replacement on a BMW E30 – Full DIY Guide

BMW Front Wheel Bearing eEuroparts.com

Wheel bearing failure is something that occasionally happens on high mileage cars. The most common symptom you’ll notice is a god awful sound coming from one (if you’re lucky), or both (if you’re not so lucky) wheels. The sound we’re talking about is akin to a really fast money counting machine, and only this one is sucking money in instead counting it out. 

Despite being a somewhat expensive repair, it’s definitely something you can DIY. Our goal today is to show you how using our guinea pig – a beautiful BMW E30 that’s been making crunching noises for a while. Before we get to the guide itself, we’ll talk about diagnosing bearing issues and more.

What Are Wheel Bearings and What Do They Do?

Wheel bearings are what keeps the world moving, quite literally. Every wheeled piece of equipment out there uses them, and once they fail, things tend to grind to a halt. A wheel bearing consists of two metal rings, or races, that have metal balls sandwiched between them. The idea here is to allow the inner and outer ring to spin independently from one another.

The inner portion of the bearing houses the wheel hub while the outer portion is fixed to the suspension. This way, your wheel can actually spin while being controlled by the suspension around it. As you can imagine, worn bearings can be an issue.

Diagnosing Worn Bearings – Identifying the Noise

As we’ve mentioned at the beginning of this guide, one of the easiest ways to know that your bearings are on their way out is the noise. However, identifying the noise can be a tricky task in some cases as it often blends into other noises coming from the front end of your car. With that said, there are a few signature tells that you can use to your advantage.

  • Noise Reacting to Steering Wheel Position – Unless you’re truly unlucky to have both front wheel bearings go bad on you at the same time, the chances are that you’ll only have to deal with just one failing. This is favorable from a diagnostic standpoint because a bad bearing doesn’t do well when loaded. What you can do is get up to around 35 mph and gently turn the vehicle left and right. What you’re looking for is a noise difference when your steering wheel is pointing the car to the left and to the right. This alone can tell you whether your bearings are bad and which side is at fault.
  • Progressively Louder Noise – Very rarely do bearings get shot immediately. More often than not, they fail over time. As a result, you’ll experience a progressively louder noise coming from one or both front ends of your vehicle. We may have been joking about the whole money counter thing, but that’s a pretty close representation of what a failed bearing can sound like. Just imagine a money counter that runs twice as fast and about twice as loud.
  • Steering Bias – One of the non-acoustic methods of diagnosing a bad bearing is to watch for steering bias on a straight patch of road. Get up to speed and let go of the steering wheel. If the car starts moving to left or right, you might have a problem.
  • Uneven Tire Wear – Another non-acoustic way of diagnosing this particular issue is to look at the tires. If you notice that there’s uneven tire wear, especially in patches, that could definitely be one of the symptoms. Keep in mind that uneven tire wear alone can be indicative of various problems, but once it appears in conjuncture with the grinding noise, you’ll know what to blame.

Common Causes for Wheel Bearing Failure

wheel bearing is a fairly simple device. However, all of the important bits are sealed inside as means of protection. Having a bunch of metallic balls grinding against two metallic rings doesn’t really work unless they’re isolated and greased.

The reason why this part fails is almost always the seal. Whether it degrades over time or something else happens that compromises it, a broken seal is the main culprit. Once it goes, water and other debris find their way inside the bearing. Once in there, the grease that lubes everything on the inside gets diluted to a point where it no longer offers any lubrication.

With no lubrication, all of those metal bits that come into contact with each other start to create friction, and ultimately the whole thing fails.

How to Change Wheel Bearings on a BMW E30?

Now that we know how to diagnose the issue, let’s find out how to repair it. We’ll use a BMW E30 for this guide, but the principle is more or less the same on most vehicles. Keep in mind that the tools we list might be different depending on the nut and bolt sizes used by different vehicle manufacturers.

Speaking of tools, here’s what you’ll need for this job:

  • A decent jack to lift the vehicle
  • A jack stand
  • Three jaw puller you can rent from your local auto parts store
  • 17mm socket for wheel lugs
  • 19mm socket for caliper brackets
  • 7mm Allen wrench for calipers
  • 5mm Allen wrench for rotors
  • Flathead screwdriver
  • Hammer or a mallet
  • 36mm thin wall socket (make sure it’s a thin wall kind)
  • A trusty breaker bar

As for the parts, you will need to get the following:

Here’s your starting point:

Step 1 – Lift the Car and Remove the Wheel

  • Park the car on flat ground and make sure it’s secured.
  • Take your 17mm socket and loosen the wheel lugs.
  • Next, take the jacks and get the car off the ground.
  • With the car in the air, place the jack stand under the frame rail. Be careful not to put the stand under the floorboard as that can leave you with a hole in your undercarriage.
  • Optionally, leave the jack under the car as well
  • Take the wheel off and place it under the car as a third failsafe, just in case.

Step 2 – Caliper Disassembly and Rotor Removal

  • Take the 7mm Allen wrench and remove caliper slide bolts.
  • With the caliper off the brake rotor, use a zip tie or a piece of wire to hang it on the springs. The point is not to let it hang on the brake line as that’s an excellent way to ruing it.
  • Now that the caliper is secured take the 19mm socket and remove the caliper bracket.
  • Use the 5mm Allen wrench and remove the bolt that keeps the brake rotor in place.

Step 3 – Remove the Axle Nut

  • With the brake rotor out of the way, get yourself a screwdriver and hammer off the notch in the wheel nut. Don’t use an impact gun for this step as doing so can easily damage the nut. Since you’ll be reusing it, it’s a good idea to be gentle.
  • Next up, take the 36mm thin wall socket (it has to be a thin wall, or it won’t work) and remove the axle nut. You might have to use the breaker bar, so keep that close by just in case!

Step 4 – The Jaws 

  • Here’s where the only specialized tool needed for this job comes into place. Take the three-jaw puller and an appropriately sized socket and use them to pull the assembly off the spindle. Truth be told, you could technically do this without the three-jaw puller, but that method involves a lot of savagery that can do more harm than good. Renting one of these bad boys is always the better option.

 

Step 5 – Remove the Inner Race

  • With the assembly off, it’s time to remove the bad bearing. Depending on how bad yours got, you might have a struggle on your hands. Disintegrated races that are rusted in place can be a pain to remove. Be ready for that.
  • Now that you have the old bearing off the spindle take the new one and press it in.
  • To do this, you’ll need a socket that is of similar size as the new part that you can use to hammer the new part into the spindle.
  • Once it’s on far enough to expose a good portion of threads on the stub axle, you can use the nut to tighten it on the rest of the way.
  • In our case, we’ll be tightening the nut to 210 ft/lbs of torque. Consult your car’s service manual to see what the right torque values are. One the nut is torqued down, put a new notch in it.
  • Install the dust cap by tapping around the perimeter with a hammer. Give one spot a few good whacks, so it stays on tight.

 

Step 6 – Reinstall the calipers and Mount the Wheel

From this point on, just do everything in reverse.

  • Install the caliper bolts to 81 ft/lbs of torque
  • Reinstall the brake rotor and set screws
  • Reinstall the caliper with brake pads and torque the guide bolts to 24 ft/lbs
  • Mount the wheel and tighten the lugs as tight as possible
  • Lower the car and torque the lugs to 81 ft/lbs
The old bearing

 

Shiney.

 

Summary

At this point, you’ve completed the replacement of a wheel bearing and got rid of the irritating noise for good. Not only that, but you’ve saved a decent chunk of money with this DIY project. Depending on the state of your bearings, you may or may not have had an easy time doing this repair. Either way, you’ve fixed the issue, and your car is once again good to go!

 

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3 thoughts on “Wheel Bearing Replacement on a BMW E30 – Full DIY Guide

  1. Nice write up!! Why remove the brake caliper in 2 stages? Just spread the pads slightly and remove the brake caliper with the bracket/carrier, saves a step 🙂

    1. Very true! I typically like to clean and re-grease the slide pins so this is a good opportunity to do so.

  2. So, I guess the other drivers on the track with you are okay with you riding on an untorqued wheel bearing nut? Nuts torqued as high as a wheel bearing are designed to slightly deform under the torque load. Because of this, the assumption that just turning the nut to the same place it was before removal is completely flawed. I guarantee that nut is not under enough torque.

    Also, declaring that a jack stand is “not required” is an extraordinarily irresponsible thing for a DIY writeup to suggest. Jack stands are ALWAYS required when you lift a vehicle up to work on it. If you don’t want to use one, that’s fine, but don’t even suggest that it is acceptable.

    If you want to race your car you need to invest in the necessary equipment to do the work. Go buy a proper torque wrench and stop endangering everyone else on the track with you.

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