Jump to content

Recommended Posts

shocking, indeed - fortunately a few minutes with an open window and they rebound from the experience.

my wife usually gives me a bump to stop it...

 

 

(jack over, back to the thread at hand)

Link to post
Share on other sites

Yeah, you have to torque the inner rear bushings with load on them if I recall.  You have the two large bolts, one each end of the inner control arm, then you have the 4 smaller bolts per side that hold up the arm.  I forget which order you have to install these.  I will probably have to loosen and redo all of these.

 

Captain obvious, I hear what your saying, but the ease at which the removed struts can compress and then slowly or not rise means that there is little to nothing left in the way of gas pressure left.  NO damping to be had in them. I hear what your saying about hard to press down is not an indication of damping, but to me it is an indication of a healthy strut.  The ones I took off are definitely NOT healthy. I equate health to damping more than an arbitrary 'hard to press down'.  I should have been more clear.

Link to post
Share on other sites

Zedyone, I'm not a suspension guy, so my explanations come from the point of view of a non-expert who hasn't known this stuff forever. I apologize in advance if I'm telling you stuff that you already know. That said...

 
Hard to press down is not necessarily an indication of damping. But neither is a slow or non-existent rise after being compressed. So when you say "there is little to nothing left in the way of gas pressure left. NO damping to be had in them", you're mixing somewhat unrelated functions together. The only thing that you can glean from a slow or non-existent rise after compression is that the gas has leaked out. You can't make any claims about the damping functions from that test.
 
The gas pressure inside the shock has nothing (directly) to do with the damping. The only reason the gas is in there at all is to increase the static pressure on the hydraulic fluid which reduces the tendency of the oil to foam as it passes rapidly through the damping valve orifices under strenuous use.
 
It's the oil that provides the damping, not the gas.
 
Under non-strenuous conditions, the shock would work just fine with NO gas pressure in it at all (just like they did in the good old days). In fact, until or unless the oil starts to foam, there will be no difference in damping performance between a brand new gas-charged shock and one that's identical inside, but they forgot to put in the gas.
 
Here's some good info from KYB that talks about the difference between the twin-tube (low pressure) and monotube (high pressure) designs and how the damping is accomplished:
 
 
Don't equate "hard to compress because it's got gas in it" with high damping.
Don't equate "slow or won't rise after being compressed" with low damping.
 
Those tests don't tell you anything about the damping, they just tell you how much gas you have left. Yes, if your shock is supposed to be gas charged and all of the gas has leaked out, it's not healthy like a new one, but assuming it's not worn out inside, it will still damp like a new one until you foam the oil. So, I'm certainly not telling you that you weren't due to change your strut inserts, but your old ones might still provide reasonable damping despite not being gas-charged anymore.
 
Please forgive if you knew this stuff already. I worked on cars for many years and didn't... Here's hoping I wasn't the only one.  :)
Link to post
Share on other sites

As usual your writing and clear choice of words is never insulting or condescending in any way at all. I thank you for the lengthy response and the clarity you provided :)

 

Just a note, decided to get help with the glad nuts on the fronts. I could not move them once I removed the front strut from the car. I had no way of holding them while trying to loosen the nut. I took them to a local shop that has some experience with these cars.  

 

Also ordered a spring compressor and more ATI brake fluid from amazon.  It has been two years since I put that in and it was time.  It had absorbed quite a bit of water in that time.  I may have to go back to using DOT 3 as it is less hydroscopic than DOT 4.

Edited by Zedyone_kenobi
Link to post
Share on other sites

Excellent. One last thing before I bow out and let you get back to the real topic at hand. The KYB guys didn't talk much about the expansion chamber and why it's needed at all. My read on this is twofold:

First, as the hydraulic oil heats up during use, it will expand. And if there isn't some provision for compliance somewhere in the system, the pressure could rise above a level suitable for the shaft seal (or worse).

Second, as the shaft is compressed into the tube, the volume of the shaft itself displaces some oil, and that oil has to have someplace to go. If there wasn't a compressible volume in there somewhere, you could never press the shaft down at all since the internals would be "hydro-locked".

So some answers to questions that you didn't ask, but it puzzled me a little at first when I saw the position of the floating piston change a little as they compressed the monotube. Figured maybe the same thing caught your eye. That changing position is due to the volume of the shock shaft as it enters and leaves the oil chamber.

Link to post
Share on other sites

I love it when you get everything clean, and you have a couple of hours to get something done and everything goes exactly how you planned it would, due to preparation, skill, organization, and experience.

 

 

 

 

 

 

 

 

 

 

Then you realize in all your awesomeness you built up 4 beautiful struts and left the bump stops off

 

 

GRRRRRRR

Link to post
Share on other sites

I love it when you get everything clean, and you have a couple of hours to get something done and everything goes exactly how you planned it would, due to preparation, skill, organization, and experience.

 

 

 

 

 

 

 

 

 

 

Then you realize in all your awesomeness you built up 4 beautiful struts and left the bump stops off

 

 

GRRRRRRR

I'll do one better, not only did I not install the bump stops, I didn't notice until the struts were installed on the car!  Things flew in the shop that day.

Link to post
Share on other sites

Sorry to hear about the brain fart. I'm just so glad that I'm not the only one that does bonehead stuff like that!

 

I wouldn't worry about it. It's not like you're putting on aftermarket lowering springs or anything... :ph34r:

 

Sorry!

Link to post
Share on other sites

Pretty darn good explanations by Captain Obvious. One additional comment on an "unhealthy strut" is that if the gas has leaked out (determined by "slow or won't rise after being compressed"), it's possible that oil has leaked out as well. When people talk about a shock being "blown" they're usually (whether they realize it or not) referring to that shaft seal you mentioned, Captain, being worn out and allowing gas and/or oil to leak out.  If the damper has lost oil then it is likely to have less damping ability.

 

...My problem now is the car still sags in the rear.  It's better than it was but still noticeable...

 

Matt

Matt, I wanted to chime in on your observation. I think Zedyone mentioned something earlier in the thread about Eibachs potentially messing up the stance of the car. I have Eibachs as well and I also notice a slight rear rake, although only because I'm picky. I would prefer the fender gap to be more uniform but it doesn't bother me too much. If you're noticing a slight sag in the rear it could be the Eibach's fault. It's pretty subtle but it seems to be a problem with the Eibachs. You can even see it in Diseazd's pics of his orange car. If your car is much worse than that though, there's probably something else going on.

 

The problem with any modern shock upgrade is that the gas charge (which the original shocks did not have) actually adds spring rate and subsequently adds ride height. Keeping stock springs and adding a new shock will raise the car somewhat (I can't quantify exactly how much). Obviously we have to buy modern dampers, so if we don't want the car higher than stock, our only off-the-shelf choice is one of the available lowering spring options. I struggled with this when I was redoing my suspension because I didn't want the car higher, but I didn't want it excessively low either, or to create a harsh ride. Ultimately I also went with Tokico shocks and Eibach springs, just like you and Zedyone. I haven't put many miles on since but so far I'm pretty happy with the set-up.

 

PS - Zedyone, do you have a build/update thread for your roadster?

Edited by bacarl
Link to post
Share on other sites

I have been taking pictures here and there of the roadster as I complete a project, but I have not posted them here on the Z forum. Always seemed like the wrong place for it.  I usually post on www.311s.org  but have not in a while. I have just been enjoying the drive since I finished the exhaust redo, carb redo, and interior redo.  Car is just a beautiful thing to putt around in.  Oh and it is fairly quick! :)

Link to post
Share on other sites

front two are fixed, and I took the opportunity to grease everything that has moving parts.  I also put a dab of grease on the bump stop. 

 

Next up the rears!  Should have the struts back on the car today. Then I have to wrestle with the new stainless brake lines.  But will need to go by a 11mm brake line wrench.  I just refuse to round off those damn things.

Link to post
Share on other sites

All the struts are now together and the bolts finger tight. I have to get the rear inner Bushings on the A arm retightened. I put new ones on there 5 years ago, but I may as well replace them again since I am here.

 

Just need to look up all the torques for all the fasteners.

Link to post
Share on other sites

Don't forget to do the tightening of the bushing nuts with the car on the ground. You might even consider loosening the other bushing locations as well and resetting them to a new "normalized" position. I'm thinking that your new springs and strut inserts might establish a different neutral stance than your old parts and it would be good to re-normalize everything. 

 

Loosen everything up both front and rear, jounce around a couple times, (have someone sit in the driver's seat if you're that concerned) and tighten them up again?

 

Wait a minute... You're running stock style rubber bushings, not poly, right?

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

By using this site, you agree to our Privacy Policy and Guidelines. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.