GL10 shock replacement problems

[Larry K]

I have an 1987 GL10 wagon, front wheel drive (not 4WD) and am replacing rear shocks.  Locating the correct shocks was a a long process thru local dealer and NAPA.  Now I’m trying locate a small “bumper” that fits over the shock.  The attached photo shows it located on shock.  It’s some kind of composite material that’s crumbled apart with age.  2nd pic shows it located on shaft and along side is the only bumper and cover that dealer could find.  I've tried fitting this one without success as it seems to be too small to fit on shaft and over the retainer ring area of shaft.  Has anybody come across this before?  Thanks

[DaveT]

After i wrote this i noticed rear....  but probably similar sutuation.  All of my front ones have crumbled. 

Got new ones for the front from Jeggs.

Haven't gotten to install yet.

 

[GeneralDisorder]

They aren't needed. Especially on a 2wd. Just throw them away. The original struts on some cars have these dust covers and piston wipers - my Trans Am had them originally. The KYB AGX's didn't have this provision. No issues. We routinely delete them if in that condition and have not had any complaints from doing so. Aftermarket struts often do not have these or they cannot be fitted. They are dust covers and wipers to protect the seal on the piston. I doubt they would be significantly useful on a 2WD. 

GD

[el_freddo]

They’re also used as a dampener if the strut comes close to full compression. Good if you’ve got a loaded vehicle on rough tracks, and has been great on my lifted L series that doesn’t have extended swing arm bump stops...

I doubt you’ll need them on your 2wd. 

Cheers 

Bennie

[carfreak85]

That's not a wiper, the foam spring is a bump stop that keeps your suspension from bottoming out during a large compression.  If you drive like a grandma, you'll never know its missing.  If you rally around, drive off-road (unlikely, since your car is 2WD) or live on an awful road, you may notice they're missing if not replaced.

These are tuned specifically for your car, but you can always use universal bump stops, most auto parts stores should have at least one style to choose from.  If they are too long, you can trim one of the segments off, but this will raise the spring rate of the bump stop. 

[GeneralDisorder]

Yeah but that foam isn't worth much as a bump stop..... you'll hit spring coil bind before you bottom out the strut cartridge anyway I suspect. At any rate I have never seen ANY adverse effect (noise or otherwise) from eliminating them. Heck half the cars we look at they are disintegrated so there's virtually nothing there already. 

GD

Edited November 20, 2018 by GeneralDisorder

[carfreak85]

1 hour ago, GeneralDisorder said:

...You'll hit spring coil bind before you bottom out the strut cartridge anyway I suspect...

That would depend on the design of the aftermarket strut, Subaru put it there to keep the OE strut from bottoming out.  If coil bind happened before that, there would be no need for the "added cost" of the bump stop.

 

I'm not saying they're necessary, by any means, but if you do the types of things that Subarus are good at, the bump stops should be installed to prevent damage to the struts and to smooth out the transition to instantaneous understeer that occurs when front struts bottom out as the spring rate then goes to infinity.

[idosubaru]

1 hour ago, GeneralDisorder said:

Yeah but that foam isn't worth much as a bump stop..... you'll hit spring coil bind before you bottom out the strut cartridge anyway I suspect. At any rate I have never seen ANY adverse effect (noise or otherwise) from eliminating them. Heck half the cars we look at they are disintegrated so there's virtually nothing there already. 

GD

same here - they're so commonly missing or broken/dry rotted trash i assumed they weren't necessary.  other than a time or two i've never worried about not installing them. 

i'm not hard core but i've never noticed a difference on our unmaintained gravel mountain roads where i blow a tire or two a year just daily driving. 

[GeneralDisorder]

1 hour ago, carfreak85 said:

That would depend on the design of the aftermarket strut, Subaru put it there to keep the OE strut from bottoming out.  If coil bind happened before that, there would be no need for the "added cost" of the bump stop.

 

I'm not saying they're necessary, by any means, but if you do the types of things that Subarus are good at, the bump stops should be installed to prevent damage to the struts and to smooth out the transition to instantaneous understeer that occurs when front struts bottom out as the spring rate then goes to infinity.

Not necessarily - the coil bind will probably occur before the strut bottoms out (it should - from an engineering perspective - just like a valve spring), but not actually before the bump stop cushion hits - I suspect it's there to dampen the coil bind - which would be  metal-on-metal and probably somewhat harsh. Either way I've never been able to bottom out a strut like that unless the strut is totally blown and has no dampening.... which I'm positive would destroy that little foam bugger anyway. I mean - look at the foam piece - you really think that little bit of foam has a chance against 3000lb of automobile bouncing on it? I call BS - that's a quarter-a$$ed attempt on engineering's part. That's not going to do $hit in the real world.

GD

Edited November 20, 2018 by GeneralDisorder

[Larry K]

Holy smokes, I'm overwhelmed by all the responses!  All good thoughts.  As I'm a believer in originality and agree that manufacturers don't include something if it isn't beneficial.  I'll figure a way to get them mounted but good to know I have the "oh the hell with them" option this weekend!  Promised my wife she could have her side of the garage back by Thanksgiving lol.  First time I've participated in a forum, great resource.  Thanks all!

[carfreak85]

1 hour ago, GeneralDisorder said:

Not necessarily - the coil bind will probably occur before the strut bottoms out (it should - from an engineering perspective - just like a valve spring), but not actually before the bump stop cushion hits - I suspect it's there to dampen the coil bind - which would be  metal-on-metal and probably somewhat harsh. Either way I've never been able to bottom out a strut like that unless the strut is totally blown and has no dampening.... which I'm positive would destroy that little foam bugger anyway. I mean - look at the foam piece - you really think that little bit of foam has a chance against 3000lb of automobile bouncing on it? I call BS - that's a quarter-a$$ed attempt on engineering's part. That's not going to do $hit in the real world.

GD

That's fine, not all of us can be right ALL of the time GD .  The fact of the matter is this:  If your suspension coil binds before the body/chassis hits the ground, you'll be in for a WILD ride.  The bump stops are there (on damn near every style of "modern" suspension) specifically because a harsh bottoming or binding event can instantly upset a vehicle's chassis.  Also, these little foam guys CAN and DO take all sorts of compression, that's why they get so beat up (hint, it's not due to UV degradation...)  None of them take 3,000 lbs. because your car would have to pancake flat for that to happen (and the body should touch down first anyway).  They act like bumpers at a bowling ally, they don't control suspension movement, they gradually absorb compression and prevent bottoming out.  It's not a half-assed attempt on some engineer's part, this has been an accepted solution for suspension tuning for decades.

Imagine you dive into a corner hard and are near the limit of adhesion.  You hit a BIG bump.  Without a bump stop (or with insufficient suspension travel in compression) either the strut will bottom out or the spring coils will bind.  When this happens you no longer have a bouncy, absorbent suspension; you now have a solid rod connecting the wheel to your chassis.  This is essentially an infinite spring rate.  In our imaginary scenario, you will instantly lose traction, understeering right off the road or into a guard rail.

Now, lets assume there is a bump stop.  Same scenario.  Hit the BIG bump, but instead of an instant, infinite spring rate, we have a gentle ramping up of the spring rate, then that absorbed energy helps to push the strut back, away from the bottom of its travel.  Instead of completely losing traction in a split second, you have a gradual loss of traction that is smaller, and controllable.

I'll say it again though:  You do not NEED bump stops to drive down the road.  But they are so damn cheap and serve such an important enough purpose, why not just replace them?

[ferp420]

I think your only gona get coil bind with the fwd struts ive never noticed it with 4wd struts or the nissan 300zx struts i did blow the purch off of the fwd ones the only way that happens is if the coils bind

[GeneralDisorder]

I actually have hit stuff that hard, and it bends the strut housings to a banana shape and the front wheels camber in.... the foam wouldn't stop that kind of force. 

GD

[carfreak85]

1 minute ago, GeneralDisorder said:

I actually have hit stuff that hard, and it bends the strut housings to a banana shape and the front wheels camber in.... the foam wouldn't stop that kind of force. 

GD

Bump stops can't account for a lack of mechanical empathy, GD...

[GeneralDisorder]

Well when I go off road I don't consider I'm doing it right if I don't break stuff. EA suspension doesn't have enough damping on its own. 

GD

 

[el_freddo]

14 hours ago, GeneralDisorder said:

Well when I go off road I don't consider I'm doing it right if I don't break stuff. EA suspension doesn't have enough damping on its own. 

GD

 

I’m guessing that you only go wheeling as day trips, close to town, in a group that makes recovery/fix easy?

I’ve never bent a front or a rear strut and have been pretty loaded up. I can’t afford to break stuff out bush, especially if help is more than a day or two’s walk. That = very expensive just to get back into town let-a-lone all the way back home if parts aren’t easily accessible. 

Cheers 

Bennie