Strut Mount Question

[ianc]

This pic of the strut stack from the E90 Bentley makes it clearer. If the rubber section of the guide support (in red) gets mashed down over time, it will bring the upper spring plate closer to the strut tower mounting studs, thus decreasing ride height. Not expensive to replace those buggers parts-wise, but a big headache...

An interesting experiment would be to measure the distance from the strut tower down to the bottom. Any takers? OP, yours is new, would make a good baseline...

ianc

[ianc]

This is the dimension I'm talking about:

[Tommm]

Thats what prompted my ??. The whole assembly is taller. From the top spring plate doen they are the same. All the height difference is in the mount. I will do the second strut this sunday. I will take a picture of the two assemblies. It will be like the one i posted from the spring up. The two areas highlighted in your pic are compressed

[Tommm]

Big headache is an understatement. If the bearings are good why?

[ianc]

Big headache is an understatement. If the bearings are good why?

To prop up the ride height. I'm at 24" from the ground to the front fender lip now. Getting rubbing over bumps, etc. Tried to get it aligned last weekend and they couldn't do it because their sensor clipped to the tire rather than the rim and they couldn't rotate it properly: no clearance.

Not to mention it just looks wacky that low...

ianc

[Tommm]

Originally Posted by ianc

To prop up the ride height. I'm at 24" from the ground to the front fender lip now. Getting rubbing over bumps, etc. Tried to get it aligned last weekend and they couldn't do it because their sensor clipped to the tire rather than the rim and they couldn't rotate it properly: no clearance.

Not to mention it just looks wacky that low...

ianc

are you on coil overs? I didn't go that route because I didn't want to corner balance the car so I put 135 springs on the Koni Sports I bought.

If it is running low, too low, then yes, the bearing/top hat will give you additional height.

I have the $50 harbor freight spring compressor, and rented a set of suicide compressors to do my job. I used the harbor freight to compress the spring and then get the spring plate on with the nut. then compress the spring some more, take off the nut and put the bearing and nut on.

[ianc]

Nope, Eibachs and Koni Sports. I have some crappy Craftsman spring compressors which work but aren't well suited to our cars.

I may think about doing this over the xmas break, but would like to know how bad it really is first.

Can you try to take that measurement I show above at some point and let me know what it is? If I compare it to mine, that will give me an idea of how much ride height I'll gain by going through the whole painful business...

Thanks,

ianc

[gjm120]

Just a suggestion - take and compare measurements from center of the wheel hub to fender lip to take tire pressure out of the equation.

[Tommm]

I will turn the strut upside down on the garage floor and measure fom the upoer spring plate, part 8 down to the floor on both the old and new. Everything below that plate is the same, and will be the same until weighted and compressed by the car. The part below the plate is the strut at full extension, and the stiffest, softest, longest, shortest soring will give the same measurement. The only variable is the height of the bearing/giude support, part 1.

[ianc]

I took that measurement on my own car last nite and got ~35 mm. If you subtract the 5 mm thickness of the Dinan camber plates, that means the bottom of the rubber portion is only 30 mm. from the lip at top. The second and third shots are of the ride height as it is now, and immediately following the spring\strut install in 2010:

[Tommm]

Driver's side has the 135 springs, Koni sports, and all new hardware.
Center of roundel to lip of wheel well 14 1/8"

Passenger side had stock 128 springs, stock suspension 52k miles

Same, maybe 1/16 difference.

[ianc]

I'm at 12 7/16". Were you able to take the measurement I show above to the lip of the strut tower? I measured my wife's e90 and came up with ~30 mm also, but her car has ~130K mi on it...

Was this distance approximately the same on the two mounts in the first pic in this thread, or was there a significant diff?

Thanks for any info...

ianc

[Tommm]

The difference was exactly the difference in the first pic. The two struts when fully extended were identical. at the top of the strut, where the threads end, the piston's diameter is larger. Look at your diagram. the spring plate fits over that area. So everything from the spring plate down is the same.

I just measured both sides, old and new. trying to be as vertical as possible I got 30 on each side.

[ianc]

I just measured both sides, old and new. trying to be as vertical as possible I got 30 on each side.

So I'm taking from this that the dimension X we measured is unaffected by the wear shown in your first pic?

That is, the bottom of the strut mount can be all pounded down like that on the left in the first pic, but the top of the mount is unaffected?

Basically, I'm trying to find a way to determine whether my problem is sagging springs or worn out mounts. Maybe I need to pull a wheel again and try to measure the mount to spring cup gap...

ianc

[Tommm]

My old strut is on a shelf in back of two sets of stacked track tires, and the new one is on the floor of the car. I plan on installing the other front Wednesday before thanksgiving when my mother in law is in town.

I will measure the concave part of the two, and you can see the convex part in the picture I took. That should get you a good idea if you can wait. We have to go east this weekend otherwise I would take care of it for you sooner.

[ianc]

No big rush: the added 5 mm height of the camber plates along with an extra degree or so of camber have stopped the worst of the rubbing I was getting with 225's up front.

I'm thinking xmas holidays to look into\resolve things.

Thanks again for the help. Never would have suspected the mounts of getting mashed that much...

ianc

[Tommm]

Got the other/passenger side installed this morning. Hang the strut with a few threads, turn the wheel inboard, insert the strut, push and pull and it should pop in. I used a jack on the knuckle on the drivers side. Didn't need it today.

I took pictures that I will upload tonight. the difference in height is all in the bearing cap.

[ianc]

Thanks, will be interested to see...

ianc

[Tommm]

I cant resize the pictures. PM me your email and I will send the three I took today to you.