Rear Spherical Bearings Conversion on Stock Arms

I'm wondering if the snapped bolts may be due to the bolts working loose? I'm gonna loctite them.

Good reminder to check the bolts. I have my wheels off to do some other work so a good time to check these.

spikenipple wrote

Hi folks,

I've produced a batch of tapered spacers today as the user ericliew on m3cutters, amongst a few others, mentioned the failures due to using the McGill spacers.
Not to mention due to this guide (and it's cutters counterpart) I needed a set myself as I'm converting to spherical bearings on my own car!

I have 12 sets ready to go out.
Made from 304 stainless on my CNC lathe.

I'm asking £20 delivered in the UK, and £24 delivered worldwide. (Per set of 4)

Best wishes to you all!
Mike

Has anyone ordered these and confirmed the fitment is perfect?

Only two sets have been sent stateside, the rest sold in the UK and Europe. I've made up another batch though so get in touch if you're interested.
I'll take some photos tomorrow showing the angle on an OEM bush and the angle on my spacers (on a Mitutoyo profile projector).
Bore size is 12.20-12.30mm
I've also reduced the 14mm face/taper intersection diameter closer to the bore size to increase the contact area.

Apologies for not coming back sooner, I've had a mad week at work!

Photos in the imgur album here:
https://imgur.com/a/DvDFLb2

Parts are labelled 'OEM' and 'Washer'

You can see the OE bush is 120deg inclusive, and mine is also 120deg inclusive - both overall measurements within 15 minutes or so. (0.25 degrees)
The OE tapered face was a little corroded/worn so line of best fit was used to take the measurements.

Cheers

Doing some wrenching on my car and wanted to double check all of the bolts for my own setup and I found that all 4 were most definitely no longer tightened as much as they should be. Two of them definitely looser than others. I have some of the original batch of washers.

I'll definitely plan to keep an eye on this. One of my big issues and it could be the same for others....I don't see how anyone can properly torque these down with the subframe in the car. It seems as though you really need everything out of the car to have proper access.

//steve\\ wrote

Doing some wrenching on my car and wanted to double check all of the bolts for my own setup and I found that all 4 were most definitely no longer tightened as much as they should be. Two of them definitely looser than others. I have some of the original batch of washers.

I'll definitely plan to keep an eye on this. One of my big issues and it could be the same for others....I don't see how anyone can properly torque these down with the subframe in the car. It seems as though you really need everything out of the car to have proper access.

Loose on the subframe side, hub side, or both?

houtan wrote

Loose on the subframe side, hub side, or both?

Subframe side is fine and the torque spec on those isn't as high (possibly because it's a nut and bolt vs just bolts on the hub side. I'm talking hub side. Good catch!

//steve\\ wrote

Doing some wrenching on my car and wanted to double check all of the bolts for my own setup and I found that all 4 were most definitely no longer tightened as much as they should be. Two of them definitely looser than others. I have some of the original batch of washers.

I'll definitely plan to keep an eye on this. One of my big issues and it could be the same for others....I don't see how anyone can properly torque these down with the subframe in the car. It seems as though you really need everything out of the car to have proper access.

I just replaced all 4 bolts in the hub-side as preventive. The old ones didn't loosen at all, phew. Tightened the new ones to 100Nm + a dab of Loctite for safety.

I did this change as well. Actually, I believe one can tighten them properly with the subframe in the car. What I did was actually remove the parking brake, and then remove the dustshield. It won't come off because the hub is in the way. But now, you can rotate it so the 'opening' is up where the bolts are. You now have plenty of room to wrench them. I did the factory spec of 100Nm + 90 degree. Hopefully that's good.

I will add I did find a good way to get all the bolts torqued down and none of them were quite to spec. For the more forward arm that has the bolt lower I found by disconnecting the endlinks I could move the swap enough to get an extension through from the rear.

I will still likely buy all new bolts and retorque again in the near future with some blue loctite.

Just to be sure, 4 of these are needed for both of the trailing arms correct?

https://www.fcpeuro.com/products/bmw-suspension-control-arm-bushing-3147100005#fitment

Dean__Sanchez wrote

Just to be sure, 4 of these are needed for both of the trailing arms correct?

https://www.fcpeuro.com/products/bmw-suspension-control-arm-bushing-3147100005#fitment

Yes that is correct. 4 pieces of Meyle 3147100005 if you're only doing the rear trailing arm bushes.

How often would I have to replace the bushings for the rear trailing arms (item B). I got the Meyle ones since that was all I could find.
Also, is there any other recommendations for the Rear Lower Control arm? I know turner, IRP, Milway, and fall line make full Solid/Spherical ones.
But Powerflex makes one too. Does anyone know how that would compare to one of the ones mentioned above? Less direct but would last longer?
Or should I just go with BW since it’s the best of both since it’s sealed and still a spherical one?

Just read a bit more. Look like a might go with the Rouge engineering one. Price is good and it seems to be built to last a long time. Has anyone tried it yet?

Don't know if the RE rear subframe bushing is sealed or not, can't see from their pics. But in their description they do recommend you spray it with WD40, so probably not sealed. Personally I'd still go with a sealed bearing for longevity, especially if you live in wet/winter climates.

I write down my experiences in case it helps a bit.

My M is a track only car and has been doing very, very much track driving.

In my case, the left upper bolt snapped twice.
One was the bolt when the vehicle was produced, and the other was the new genuine bolt.
New bolt was installed according to the specified torque value and installation method.

Except for the solid bushing on the subframe, all arm bushings of mine were in stock condition.
Unlike the subframe side, there is only one side where the bushing is fixed to the knuckle, so the stress on the bolt seems to be considerable.

Because of my experience, I think the monoball bushing, which has no elasticity at all, can put more stress on the bolt, so I have maintained stock buhings until now.

However, since I always wanted to mount a monoball bushing for more accurate and consistent vehicle movement, I installed monoball bushing with a reinforced bolt ( ARP bolt ).

And, in order to further reduce the play between the washer and the bolt, the washer was newly manufactured with a smaller value than the I.D. 12.2mm.

IMO, the reason is that the smaller the play between bolt and washer, the more effectively the force transmitted to the bolt can transmit to the knuckle like the stock bushing.

Whether my idea will work or not will only be known after a lot of track driving. I will notify you if there is a problem.

% Differential bolts have also been snapped once. So, I plan to install reinforced bolts.

maicol76 wrote

I write down my experiences in case it helps a bit.

My M is a track only car and has been doing very, very much track driving.

In my case, the left upper bolt snapped twice.
One was the bolt when the vehicle was produced, and the other was the new genuine bolt.
New bolt was installed according to the specified torque value and installation method.

Except for the solid bushing on the subframe, all arm bushings of mine were in stock condition.
Unlike the subframe side, there is only one side where the bushing is fixed to the knuckle, so the stress on the bolt seems to be considerable.

Because of my experience, I think the monoball bushing, which has no elasticity at all, can put more stress on the bolt, so I have maintained stock buhings until now.

However, since I always wanted to mount a monoball bushing for more accurate and consistent vehicle movement, I installed monoball bushing with a reinforced bolt ( ARP bolt ).

And, in order to further reduce the play between the washer and the bolt, the washer was newly manufactured with a smaller value than the I.D. 12.2mm.

IMO, the reason is that the smaller the play between bolt and washer, the more effectively the force transmitted to the bolt can transmit to the knuckle like the stock bushing.

Whether my idea will work or not will only be known after a lot of track driving. I will notify you if there is a problem.

% Differential bolts have also been snapped once. So, I plan to install reinforced bolts.

Curious, was the washer you used to get the correct conical shape at the knuckle one of the originals that were produced from this thread or one of the off the shelf, looks just right options, that someone posted later?

For me personally, after some miles I had to retorque the bolts. All 4 were loose to varying amounts. I've driven a lot more miles since then and last time I had wheels off I checked them again and none were loose.

maicol76 wrote

However, since I always wanted to mount a monoball bushing for more accurate and consistent vehicle movement, I installed monoball bushing with a reinforced bolt ( ARP bolt ).

Can you share the part number of the ARP bolts you used for the rear upper arms please?

//steve\\ wrote

Curious, was the washer you used to get the correct conical shape at the knuckle one of the originals that were produced from this thread or one of the off the shelf, looks just right options, that someone posted later?

For me personally, after some miles I had to retorque the bolts. All 4 were loose to varying amounts. I've driven a lot more miles since then and last time I had wheels off I checked them again and none were loose.

I always mark all bolted joints to make sure they don't come loose. Both of the two broken bolts used with the stock bushings have never come loose.

As I mentioned, because I had a bad experience, I'm rather strict and careful about parts related to suspension joints, including making washers.
It was produced by a precision manufacturer using the drawings posted on this forum. After fabrication of the washer, the figures were confirmed to exactly match the drawings.

But, there is some play between the threaded part of the M12 bolt and the washer's inner diameter of 12.2 mm, so I ordered new washers with a smaller inner diameter.
I haven't installed it yet, I'm busy these days. I'm gonna install it soon.

Redd wrote

Can you share the part number of the ARP bolts you used for the rear upper arms please?

I bought these

inside : arp M12 x 70mm
outside : arp M12 x 80mm

I installed it with big flat washers like stock bolts.

IMO, preventive maintenance and using reinforced parts are the best I can do for the track car. So, I already changed almost all stock bolts related to rear arms to ARP's.

Broken bolt in the track....This is a disaster.

Thanks. These ARP bolts may be a worthwhile upgrade for track cars.