Upper Rear Shock Mounts - Broke 'em both

[socalsnake]

This adds to my fear of going with rear coilovers. That mount looked we to me before, now I'm really suspicious...

+1

Now I've got rethink the Ridetech and KW V3 CO's.

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[Anthony@HTM]

+1

Now I've got rethink the Ridetech and KW V3 CO's.

KWs mount just like OEM and use bump stops...

 

[socalsnake]

KWs mount just like OEM and use bump stops...

I thought that the KW V3 was a true rear coilover and the KW V1 where like the OEM rear set-up.

 

[Anthony@HTM]

I thought that the KW V3 was a true rear coilover and the KW V1 where like the OEM rear set-up.

Nope

Only difference is v3 is rebound and compression adjustable. Whereas V1 is not.

 

[socalsnake]

Nope

Only difference is v3 is rebound and compression adjustable. Whereas V1 is not.

Thanks for the clarification. Good to know!

Tirerack's picture is misleading even though they do say its an approximation of the product...

http://www.tirerack.com/suspension/...toYear=2015&autoModClar=GT+w/+Performance+Pkg

Will definately reach out to you when I'm ready to order either the V1 or V3. I'm assuming you can match or beat the Tirerack price on both of them?

I'm running the KW HAS system on my M4 and the ride is superb. I'm far from a track junkie so the progressive springs on the V1 and helper springs (I'm assuming) on the V3 don't bother me at all.

 

[Anthony@HTM]

Thanks for the clarification. Good to know!

Tirerack's picture is misleading even though they do say its an approximation of the product...

http://www.tirerack.com/suspension/...toYear=2015&autoModClar=GT+w/+Performance+Pkg

Will definately reach out to you when I'm ready to order either the V1 or V3. I'm assuming you can match or beat the Tirerack price on both of them?

I'm running the KW HAS system on my M4 and the ride is superb. I'm far from a track junkie so the progressive springs on the V1 and helper springs (I'm assuming) on the V3 don't bother me at all.

Yeah those are not the correct picture. I can beat their price no problem.

They are a nice coil over.

I'm personally waiting for their Clubsport models.

 

[BackinBlackS550]

Here's a couple pictures. I don't have the replacement part but it appears that the thin center section on top of the mount blew out. The rubber bushing/isolator that you see on the shock rod normally sits in the center of the mount. Both sides look exactly the same (i.e. failed the same way).

No other apparent damage to the suspension components.

 

[BackinBlackS550]

Here's a couple pictures. I don't have the replacement part but it appears that the thin center section on top of the mount blew out. The rubber bushing/isolator that you see on the shock rod normally sits in the center of the mount. Both sides look exactly the same (i.e. failed the same way).

No other apparent damage to the suspension components.

 

[Schu]

Not a break I was expecting to see... now that I have seen those pictures and the build quality, I want beefed up aftermarket mounts ASAP.

It does seem as though a washer would have spread out the forces slightly.

Is it just me, but aren't those mounts installed upside down on the strut?

 

[BackinBlackS550]

The mounts were installed correctly.

I'm no engineer, but at this point it seems like a combination of the stiffer valving on the Viking shocks and the probably less than optimally engineered top of the mount are what contributed to the failure. I really don't think the shock could have bottomed out all the way to hit the mount (it's a lot of travel). I'm hoping to hear from people who have good opinions/solutions so we can avoid this in the future.

 

[DickR]

What size are the shaft threads and nut OD on the shock rod with the Viking's?

The oem shaft thread is 10 mm and the collar which bears on the mount is 17 mm OD.

The Koni's I'm using have 10 mm threads and the nut which bears on the mount is 17 mm OD.

Regarding the failure we had a similar experience with a Bilstein on a camper van. The van used the old style washers with bushings. The shocks came with 2 thickness of washer but NO instructions regarding which to put on the shock side of the mount. The installer we used installed the thinner washer towards the shock on one side of the van. The shaft punched through after a few thousand miles. Probably due to a freeway bump.

The "thin" washer which failed wasn't very "thin".

Agreed by the way that the mount is correct. It won't assemble to the car properly if upside down (speaking from experience :-) )

 

[DickR]

Regarding travel and bump stop use. Even though Viking says they aren't needed you might check with Steeda (the spring mfgr?) to see what they recommend. It is possible that they have designed the springs to be used in combination with either their bumps stops or the oem Ford bump stops.

 

[BackinBlackS550]

What size are the shaft threads and nut OD on the shock rod with the Viking's?

The oem shaft thread is 10 mm and the collar which bears on the mount is 17 mm OD.

The Koni's I'm using have 10 mm threads and the nut which bears on the mount is 17 mm OD.

Regarding the failure we had a similar experience with a Bilstein on a camper van. The van used the old style washers with bushings. The shocks came with 2 thickness of washer but NO instructions regarding which to put on the shock side of the mount. The installer we used installed the thinner washer towards the shock on one side of the van. The shaft punched through after a few thousand miles. Probably due to a freeway bump.

The "thin" washer which failed wasn't very "thin".

Agreed by the way that the mount is correct. It won't assemble to the car properly if upside down (speaking from experience :-) )

The Vikings look like 10mm on the threaded part and 19mm at the collar where it bears on the bottom of the mount.

 

[DickR]

Looking at the Vorshlag picture and at my car the nut/collar on the shaft does not bear on the casting (aluminum?). It actually bears on the black steel collar with the hex in the middle. I don't know what originally secured the hex collar and rubber bushing into the mount. "Something" was strong enough to normally prevent vertical movement of the hex collar and to break portions of the "rolled look" portion of the casting. Originally there is a black disk that "looks and feels" like plastic but that is missing. I cannot tell whether the hex collar was originally bonded to the rubber bushing or even a press fit.

Reverse engineering is a challenge when you 1) don't have enough information and 2) aren't a mechanical engineer. :-) All that I can say is that it appears to have functioned as a mechanical fuse i.e. like a shear pin.

 

[BackinBlackS550]

Looking at the Vorshlag picture and at my car the nut/collar on the shaft does not bear on the casting (aluminum?). It actually bears on the black steel collar with the hex in the middle. I don't know what originally secured the hex collar and rubber bushing into the mount. "Something" was strong enough to normally prevent vertical movement of the hex collar and to break portions of the "rolled look" portion of the casting. Originally there is a black disk that "looks and feels" like plastic but that is missing. I cannot tell whether the hex collar was originally bonded to the rubber bushing or even a press fit.

Reverse engineering is a challenge when you 1) don't have enough information and 2) aren't a mechanical engineer. :-) All that I can say is that it appears to have functioned as a mechanical fuse i.e. like a shear pin.

The rubber isolator that sits in the mount has a hard (i think metal) insert in it that the black steel collar with the hex contacts. That insert also contacts the top part of the mount that broke. So as far as I can tell, the only thing all of the force of the shock absorption hits is the piece at the top of the mount (that broke).

I can see someone coming up with an aftermarket mount that would help tremendously. I'll try to make a few calls next week and see if anyone has ideas. The other notable data point is there are supposedly 120 of the mounts being manufactured by the OE supplier and due to hit the distribution centers on July 16, and I'm told all of them are spoken for.

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