Advice to other new owners looking at "HD Upper Spring Seats" Topic is solved

[mrbrian200]

The product description on those HD spring seats don't mention that they are not compatible with your OE equipped upper strut mount/bearing. HD spring seats and HD upper strut mount must be purchased together/and replaced as a complete assembly.

Upgrade chassis parts for any other make I've ever worked on tend to specify whether or not they are compatible with other OE parts in the chain. These don't.

HD upper mounts use a thicker bearing (presumably, I don't have one in front of me to verify). The matching spring seats account for this. Strut extension rate is controlled (if your struts are working properly). Matching a HD seat +OE mount + Sachs OE struts leaves approximately 3/4" gap between the top washer and bearing, which under certain circumstances (sharp bumps at highway speed, potholes) the spring seat can drop down out of the bearing resulting in momentary caster/camber play + thumps/clunks, wild handling characteristics until the strut (remind: controlled extension rate) allows the spring to expand back out and reseat back together. FYI.

For the time being I'm going to cut/fit rubber spacers from an inner tube to hold the spring seats up where they belong while I decide whether to spend more $ on the matching upper mounts or just revert back to the OE spring seats.

[mrbrian200]

I zipped an email to CS at the webstore where I got the spring seats (and new struts). They seem confident this large clearance between the top washer/mount bearing is the way it is supposed to be. I respectfully disagree. This is not the OE design (read bottom para).

See pic, bottom. Used rubber from sidewall off an old tire (quality rubber, nylon reinforced, should last). Installed between mount bearing and top nut (cross shaped one), hence the hole in the middle. Clunky-Thumpy over bumps/RR tracks/potholes GONE. Handling/tracking over said obstacles DRAMATICALLY IMPROVED.

I got an alignment while I was in Chicago last week. It tracked excellent on smooth road (before and after the alignment). However the instability and noise over bumps/holes remained. Went over it again with a comb. Couldn't find anything wrong then I remembered not being terribly confident about the top end when I put it back together a week or so back. Was thinking at the time "it doesn't seem right to have loose play up there, maybe on the car spring tension will keep it tight". Well, yes (if you're sitting still)...but no.

If your struts are "shot" or not to OE spec (lacking control of, or, very fast extension rate valving) spring tension would more likely hold this seated and it wouldn't present a problem. With new/OE spec struts you've got a problem if you see a noticeable gap there.

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Not OE design:
In November when I was car shopping, all of the S60s I looked at, including this one, still had the factory installed struts. None of them had this sort of clearance: The top washer rested on the mount bearing or if there was clearance it was due to obvious wear of the rubber on the top washer. The one exception (with this 1/2" or so clearance) was a 2004, which interestingly, had records showing the struts were replaced.

[vtl]

All Volvo OE parts except strut mount from Lemforder, which is OEM. No signs of rubbing wear on upper edge of mount, i.e. mount cap and mount do not meet. Are you using old sagged springs, which can't do their job anymore?

Also how this tiny gap can worsen handling of the car? Toe angles already jump back and forth like crazy when suspension works to the full depth. Camber change on rebound is unmeasurable.

[mrbrian200]

Springs are fine. They hold a 3500lb car off the ground at the proper ride height they certainly have enough tension to do their job in this respect. However, worn/saggy springs, even if that were the case, wouldn't make a difference/not the underlying issue. See para 3.

I'm thinking dimensional specs changed on the struts, seats, or bearings which has been applied to older chassis numbers and nobody's caught it. I'm serious here. There aren't many low mileage P2s with the factory suspension intact, but those are the cars I was hunting (in Chicago: city dwellers who rarely drive long distance/use public transit and/or fly everywhere). Vertical travel of the spring seat within the bearing is supposed to be limited to the "squish" of the rubber on the top washer (1/16" or so). On the OE setup, measurable clearance between the top washer and mount bearing indicates a bad spring seat (allowing the strut rod to extend) or a worn top washer. I wish now I had taken pictures of the factory set on my car before I took it apart.

I'm not sure you're understanding what I mean by controlled extension rate of the strut and what is going on. Scenerio: put the car on jack stands, then support a wheel with a block just short of lifting the car off the stand. Now kick the block out with a sledge. The wheel does not snap/extend freely under spring tension. The strut slows this "return" in a controlled manner. Under certain driving conditions this can allow the spring seat to drop out of the strut bearing. For ride quality Volvo designed their system to allow a small amount of travel (1/16" or so as allowed by rubber on the top washer that is designed to rest on the strut bearing under light pressure). Somewhere along the line replacement parts have been incorrectly sized/matched allowing 1/2-3/4" of travel before the top washer contacts the strut bearing. This is too much/incorrect and results in unpredictable/unstable handling over "road hazards".

The factory setup on my '06 wasn't like this (81k miles, all original suspension as purchased). Nor were any of the handful of other low mileage P2/S60s I looked at. I replaced the control arms right away (to correct a hard right pull) but drove it about a week with the original struts/mounts while I waited for a better spring compressor to arrive. It drove beautiful during that week. The original struts weren't actually "bad", nor were the upper spring seats, but I decided with the mileage just to go ahead and change them. After the change handling over bumps/potholes etc was whacked, along with clunks/thumps that was not happening with the original setup. This was the cause. I fixed it yesterday by filling this gap.

Also, those "HD front end links" need the bottom bolt at the sway bar resized. It needs to fit snug through the hole with a smooth shank in the sway bar. That bolt/hex key size is too small to get enough torque on the bolt to keep it fixed under compression force alone (another potential noise issue sooner or later). I'm souring on "upgrade" parts from this vendor. Either they don't have a *qualified* engineer designing this stuff or they're asleep at the wheel.

[vtl]

Somewhere along the line replacement parts have been incorrectly sized/matched allowing 1/2-3/4" of travel before the top washer contacts the strut bearing. This is too much/incorrect and results in unpredictable/unstable handling over "road hazards".

Can you describe how this results in unpredictable/unstable handling?

[xHeart]

IMG_20160209_094929883.jpg

All Volvo OE parts except strut mount from Lemforder, which is OEM. No signs of rubbing wear on upper edge of mount, i.e. mount cap and mount do not meet. Are you using old sagged springs, which can't do their job anymore?

Also how this tiny gap can worsen handling of the car? Toe angles already jump back and forth like crazy when suspension works to the full depth. Camber change on rebound is unmeasurable.

Mine looks same as yours, vtl. The ride on my 850 is far better than V70XC. Handling over uneven road, manhole, and bumps V70XC does wobbles way to much than our 850.

I feel OP is insightful here. I will explore more this too. The gap is star nut.

[vtl]

Mine looks same as yours, vtl. The ride on my 850 is far better than V70XC. Handling over uneven road, manhole, and bumps V70XC does wobbles way to much than our 850.

I feel OP is insightful here. I will explore more this too.

I have P2 V70 with new suspension and exactly same gap. It handles way better than XC70. Reason? It's obvious: lower ground clearance.

Both cars don't have any noise in suspension and handles great over road imperfections. I take XC70 to a slight offroad for my mountain bike exercises, it handles predictably.

[JRL]

They ALL have the gap, this is normal

[vtl]

Also some mechanical theory. Strut does not go down out of mount on rebound: compressed spring discharges way more energy than gravity can supply to a wheel in air + moving suspension parts to drop them down. Spring always pushes seat against mount. If it's not able to do so, suspension is broken and car is dangerous to drive.

Bad handling of XC70 over obstacles comes from capacity of it's suspension: when strut compresses (and it compresses a lot on a high ground clearance car) it changes toe angle drastically, because movement of control arm and tie rod in a horizontal projection is not equal. Did you notice that sports car have very limited vertical movement allowed in suspension?

When you replace 10 years old sagged suspension on XC70 and set camber bolts into same position, toe goes from 0.1 to like 0.5..0.7. And that's just a mere inch of height increase or so.

[mrbrian200]

Finally got around to putting OE upper spring seats back on the car.
On smooth highway/good roads no noticable difference. However, on bumpy/poorly maintained county roads the difference is night and day.

Looking at the two and how it fits together what I notice: The aftermarket seats have a tapered/conical shape where they go through the mount/bearing (the OE seats are straight/cylindrical). Also on the aftermarket: top caps sit higher after installed/wheels on the ground. With the assembly off the car or wheels off the ground the OE seats' rubber flexes and the top cap rests on the top of the bearing. On the aftermarket ones the cap is positioned higher and the rubber does not appear to flex.

Clearly Volvo designed the seat to drop down through the bearing under certain driving conditions, with movement limited by the top cap. The aftermarket ones both allow more movement than originally designed, and the tapered/conical shape introduces caster/camber play during these conditions.

So I stand by my original assessment: don't use those aftermarket seats. The OE ones may not last as long but it's not really that difficult to change them (I did both sides in just over 2 hours). Stick with the Volvo OE spring seats.