E24: Overhauling dust covers / C-V joints on the output shafts
Hey there...
This post describes the replacement of the rubber dust covers and Constant-Velocity joints on the output shafts of an E24 M635CSi as indicated by items 4&5 in the picture below.
Some practical remarks up front:
First of all, this is a fairly simple DIY job. If you're not only going to replace the dust covers but also intend to clean and re-grease the bearings (i.e. the C-V joints) it will be quite time-consuming and messy, but not difficult. Although the repair manual suggests that you'll need a workshop press to push the shaft out of the bearing, this is actually not needed since the splined shaft can be easily removed from the bearing by hand.
Secondly, keep in mind that you need to remove the bearing only on one end of the shaft, then you will be able to replace both rubber bellows.
1) PREPARATION
- Repair kit bellows. The kit comes with the right amount of grease, sealant etc. Or:
- Complete repair kit including C-V joint, bellows and bolts e.g. the VKJA 8810 from SKF.
- Allen key to remove the M10 Fillister-head bolts
- Small screwdriver or large needle to remove protection circlip
- Snap ring pliers to install the new protection circlip
- Rubber gloves, lots of paper towel
2) LIFT CAR
Jack up the rear of the car. Depending on what you're all going to overhaul, you need to find a way to block the wheel from rotating while loosening the Fillister-head bolts. In my case I was overhauling the complete rear axle, including Pitman arm, silent-blocks and brake caliper in case you are wondering about any missing or loosened parts in the pictures. If you're only going to replace the dust cover bellows, in principle you don't even need to remove the wheel, however for manoeuvring convenience this is recommended. You can apply the parking brake to fix the wheel. In my case I removed the brake disk and caliper, and blocked the wheel by inserting a crowbar between the floor and a bolt in the drive flange. How to remove the handbrake line can be read in my other post:
Overhauling brake calipers
3) REMOVE BOLTS
Remove the Fillister-head bolts, 6 on the drive flange and 6 on the final drive. Support the output shaft when moving it away from the flange to prevent it from falling down. I believe the output shaft is symmetric, however you may want to mark which side is connected to the axle flange, and which side to the final drive flange for example with a tie wrap on one side.
Protect the flanges on the final drive and axle against dirt by covering them with a plastic bag and tie wrap.
4) REMOVE SEALING COVERS
The bearing is protected by 2 covers, one on the outside and one on the shaft side. The rubber sleeve is attached to the shaft side cover and does not necessarily need to be detached before removing the cover from the bearing. The covering lids are pressed over the bearing outer shell and can simply be removed by tapping with a screwdriver against the edge.
Remove the smallest of the two metal clamping ties i.e. the one hat fixes the rubber sleeve to the shaft. This allows to slide the sleeve including the sealing lid away from the bearing.
5) REMOVE BEARING
Now it's time to get yer gloves out..... this is going to be messy. Pry off the circlip that prevents the bearing from sliding off the shaft. In my case, the circlip did not have 2 eyes, so the standard snap-ring pliers couldn't be used. Instead a large sturdy needle and some prying did the job.
With the circlip removed, the bearing can easily be pulled off the shaft manually even though the maintenance manual suggests to use a press. I guess this type of bearing -which doesn't rotate but rather allows lateral movement- does not need to be clamped firmly to the shaft
6) REMOVE RUBBER DUST COVERS
Now you may remove the dust covers i.e. rubber bellows from the shaft. As can be seen in the next picture, the bellows that come in a repair kit have already been attached to the sealing lid.
If you will only replace the dust covers, and not clean and re-grease the bearings, you may replace the dust cover from the other end at this stage. In that case you can skip to step 10) of this post. I did a complete overhaul of the shaft and cleaned both bearings so I removed the bearing on the other end as well.
7) CLEAN AND DISASSEMBLE BEARINGS
Put the bearing in a container or bucket with cleaner. I used half a pint of petrol. Clean the grease with a brush. Be careful not to move the inner race too much just yet, the balls will easily slip out and you don't want to damage them.
Once the bearing is completely cleaned, it can be disassembled. Tilt the inner race and remove the balls one by one. Store them in a safe place. In principle the bearing has a 120 degree rotational symmetry, however I marked the individual parts with a tie wrap in order to be able to reassemble the bearing in exactly the same configuration. I did not mark the individual balls since these rotate anyway. The tie wraps may be inserted before removing the last (6th) ball.
Note also that the bearing has a top- and bottom side. Therefore I let the tiewraps all point in the same direction, which in this case is towards the shaft and bellow. The inner race has a collar on that side. The outer race has a groove on the opposite side i.e. the surface that faces the outside.
!! IMPORTANT NOTE !!
The C-V joint that comes in repair kit VKJA-8810 from SKF, has some differences compared to the original BMW joint. If you happen to replace your C-V joint, carefully read through my other post:
Replacing C-V joint
8) OVERHAUL OUTPUT SHAFT
Clean the output shaft. Remove any rust and loose paint with a steel brush.
Paint the center part with Hammerite or other protecting paint e.g. POR-15.
9) REASSEMBLE AND GREASE BEARINGS
The bearing can be reassembled in the reverse order of disassembly. First insert the inner race into the ring.
Then insert the ring+inner race into the outer race.
NOTE:
The groove on the outer race and the collar on the inner race shall be on opposite sides of the bearing!! Picture below shows the relative position of each element.
Finally put the balls back, one by one, by tilting the inner race. Note that you may already apply some grease to the ball passages before putting the balls back. Finally the reassembled bearing should look something like this:
You'll need the repair kit, a snap ring pliers, the shaft and the C-V joint.
The repair kit comes with 120 mils of grease, the exact amount for one bearing. Apply the grease, starting with the side that will be facing the shaft i.e. the side where the inner race has the collar.
10) REPLACE DUST COVERS
If you removed only the bearing from one end of the shaft in step 6), now is the time to slide both replacement dust covers back on. First the one for the bearing that is still attached to the shaft. Don't forget to slide the small clamping ring over the end of the dust cover. Proceed with the dust cover plus clamping ring belonging to the bearing that was removed.
If you removed both bearings in step 6) you can just slide on one dust cover with its clamping ring. Put some grease into the inside of the bellow as well. Keep the splined end of the shaft clean!!
11) ATTACH BEARING TO SHAFT
Slide the bearing over the splined shaft, the collar on the inner race facing down. Install the new circlip with snap ring pliers.
Note:
If you install the bearing upside down, it will not completely slide over the shaft, and you will not be able to install the circlip. The teeth on the inner race at the collar side do not run all the way to the edge.
Apply some more grease to the topside of the bearing. Make sure that the surface is kept clean. Finally apply sealant to the sides of the bearing, and press the covering lids over it. You may use a small hammer to firmly press the lids on.
Job done! Time for tea.
12) RE_INSTALL OUTPUT SHAFTS
This post describes the replacement of the rubber dust covers and Constant-Velocity joints on the output shafts of an E24 M635CSi as indicated by items 4&5 in the picture below.
First of all, this is a fairly simple DIY job. If you're not only going to replace the dust covers but also intend to clean and re-grease the bearings (i.e. the C-V joints) it will be quite time-consuming and messy, but not difficult. Although the repair manual suggests that you'll need a workshop press to push the shaft out of the bearing, this is actually not needed since the splined shaft can be easily removed from the bearing by hand.
Secondly, keep in mind that you need to remove the bearing only on one end of the shaft, then you will be able to replace both rubber bellows.
1) PREPARATION
- Repair kit bellows. The kit comes with the right amount of grease, sealant etc. Or:
- Complete repair kit including C-V joint, bellows and bolts e.g. the VKJA 8810 from SKF.
- Allen key to remove the M10 Fillister-head bolts
- Small screwdriver or large needle to remove protection circlip
- Snap ring pliers to install the new protection circlip
- Rubber gloves, lots of paper towel
2) LIFT CAR
Jack up the rear of the car. Depending on what you're all going to overhaul, you need to find a way to block the wheel from rotating while loosening the Fillister-head bolts. In my case I was overhauling the complete rear axle, including Pitman arm, silent-blocks and brake caliper in case you are wondering about any missing or loosened parts in the pictures. If you're only going to replace the dust cover bellows, in principle you don't even need to remove the wheel, however for manoeuvring convenience this is recommended. You can apply the parking brake to fix the wheel. In my case I removed the brake disk and caliper, and blocked the wheel by inserting a crowbar between the floor and a bolt in the drive flange. How to remove the handbrake line can be read in my other post:
Overhauling brake calipers
3) REMOVE BOLTS
Remove the Fillister-head bolts, 6 on the drive flange and 6 on the final drive. Support the output shaft when moving it away from the flange to prevent it from falling down. I believe the output shaft is symmetric, however you may want to mark which side is connected to the axle flange, and which side to the final drive flange for example with a tie wrap on one side.
Protect the flanges on the final drive and axle against dirt by covering them with a plastic bag and tie wrap.
4) REMOVE SEALING COVERS
The bearing is protected by 2 covers, one on the outside and one on the shaft side. The rubber sleeve is attached to the shaft side cover and does not necessarily need to be detached before removing the cover from the bearing. The covering lids are pressed over the bearing outer shell and can simply be removed by tapping with a screwdriver against the edge.
Remove the smallest of the two metal clamping ties i.e. the one hat fixes the rubber sleeve to the shaft. This allows to slide the sleeve including the sealing lid away from the bearing.
5) REMOVE BEARING
Now it's time to get yer gloves out..... this is going to be messy. Pry off the circlip that prevents the bearing from sliding off the shaft. In my case, the circlip did not have 2 eyes, so the standard snap-ring pliers couldn't be used. Instead a large sturdy needle and some prying did the job.
With the circlip removed, the bearing can easily be pulled off the shaft manually even though the maintenance manual suggests to use a press. I guess this type of bearing -which doesn't rotate but rather allows lateral movement- does not need to be clamped firmly to the shaft
6) REMOVE RUBBER DUST COVERS
Now you may remove the dust covers i.e. rubber bellows from the shaft. As can be seen in the next picture, the bellows that come in a repair kit have already been attached to the sealing lid.
If you will only replace the dust covers, and not clean and re-grease the bearings, you may replace the dust cover from the other end at this stage. In that case you can skip to step 10) of this post. I did a complete overhaul of the shaft and cleaned both bearings so I removed the bearing on the other end as well.
Put the bearing in a container or bucket with cleaner. I used half a pint of petrol. Clean the grease with a brush. Be careful not to move the inner race too much just yet, the balls will easily slip out and you don't want to damage them.
Once the bearing is completely cleaned, it can be disassembled. Tilt the inner race and remove the balls one by one. Store them in a safe place. In principle the bearing has a 120 degree rotational symmetry, however I marked the individual parts with a tie wrap in order to be able to reassemble the bearing in exactly the same configuration. I did not mark the individual balls since these rotate anyway. The tie wraps may be inserted before removing the last (6th) ball.
Note also that the bearing has a top- and bottom side. Therefore I let the tiewraps all point in the same direction, which in this case is towards the shaft and bellow. The inner race has a collar on that side. The outer race has a groove on the opposite side i.e. the surface that faces the outside.
!! IMPORTANT NOTE !!
The C-V joint that comes in repair kit VKJA-8810 from SKF, has some differences compared to the original BMW joint. If you happen to replace your C-V joint, carefully read through my other post:
Replacing C-V joint
Clean the output shaft. Remove any rust and loose paint with a steel brush.
9) REASSEMBLE AND GREASE BEARINGS
The bearing can be reassembled in the reverse order of disassembly. First insert the inner race into the ring.
Then insert the ring+inner race into the outer race.
NOTE:
The groove on the outer race and the collar on the inner race shall be on opposite sides of the bearing!! Picture below shows the relative position of each element.
Finally put the balls back, one by one, by tilting the inner race. Note that you may already apply some grease to the ball passages before putting the balls back. Finally the reassembled bearing should look something like this:
You'll need the repair kit, a snap ring pliers, the shaft and the C-V joint.
The repair kit comes with 120 mils of grease, the exact amount for one bearing. Apply the grease, starting with the side that will be facing the shaft i.e. the side where the inner race has the collar.
10) REPLACE DUST COVERS
If you removed only the bearing from one end of the shaft in step 6), now is the time to slide both replacement dust covers back on. First the one for the bearing that is still attached to the shaft. Don't forget to slide the small clamping ring over the end of the dust cover. Proceed with the dust cover plus clamping ring belonging to the bearing that was removed.
If you removed both bearings in step 6) you can just slide on one dust cover with its clamping ring. Put some grease into the inside of the bellow as well. Keep the splined end of the shaft clean!!
11) ATTACH BEARING TO SHAFT
Slide the bearing over the splined shaft, the collar on the inner race facing down. Install the new circlip with snap ring pliers.
Note:
If you install the bearing upside down, it will not completely slide over the shaft, and you will not be able to install the circlip. The teeth on the inner race at the collar side do not run all the way to the edge.
Apply some more grease to the topside of the bearing. Make sure that the surface is kept clean. Finally apply sealant to the sides of the bearing, and press the covering lids over it. You may use a small hammer to firmly press the lids on.
Job done! Time for tea.
12) RE_INSTALL OUTPUT SHAFTS
BeantwoordenVerwijderenMany Autos repair and replace ABS sensor, ABS pump,ABS ring for all makes and models in Reading, United Kingdom. We also provide free collection and Delivery service from your home or place of work.