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Weekend project - adjust rear shocks - question

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Old 03-15-2019, 06:06 PM
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1990jim929
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Default Weekend project - adjust rear shocks - question

Hey there 928 world - project for this weekend is to adjust my 1990 - 928's rear shocks. I need another inch in the back +/-

I am not an expert - so need some help from the people that are :-) Thank you in advance.

As seen in the pick - my rears are adjustable (right?) and i need to just turn (to the right) the piece with the tabs cut into it.
I would imagine i need to put the car on jacks - or should it be done w the car on the ground ?
There look to be a lot of threads exposed at the bottom - so i am not sure how much more lift i will get - any comments?
Also - do i need a special tools to do this job ? or just a big pipe wrench ? recommendations ?
PB blaster on here ? I would imagine so.




Old 03-15-2019, 06:23 PM
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Randy V
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If you planned on raising those perches this weekend you should have sprayed them down two weeks ago with Kroil or PB Blaster.

Good luck!
Old 03-15-2019, 06:32 PM
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Speedtoys
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https://docs.google.com/spreadsheets...it?usp=sharing

It is view-only link, go to File, and make your own Copy of it..and have fun, here are the instructions:

Old 03-15-2019, 06:35 PM
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Mark Anderson
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Originally Posted by Speedtoys
https://docs.google.com/spreadsheets...it?usp=sharing

It is view-only link, go to File, and make your own Copy of it..and have fun, here are the instructions:

nicely done Jeff
Old 03-15-2019, 06:57 PM
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jpitman2
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A largish C spanner is the correct tool. IIRC around 70mm opening. Apply some Kroil etc down the inside of the coils, and from below. Take the load off the wheels. You may need an extension on the spanner handle if its the flat steel type - a piece of tubing will also soften the load on your hands.
http://justjap.com/bc-racing-c-spann...-delivery.html
jp 83 EuroS AT 57k
Old 03-15-2019, 07:00 PM
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Wisconsin Joe
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You look to be up a ways already. Are the springs original?
Not sure you are going to get another inch up on that.

I wouldn't use a 'big pipe wrench' on it. You will chew it up pretty well.

There's a specific wrench for the job. Search "hook type spanner wrench" to see what you need.

This came up not too long ago, the thread has a lot of useful info in it, including the spreadsheet posted above:

https://rennlist.com/forums/928-foru...djustment.html
Old 03-15-2019, 07:08 PM
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Speedtoys
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Originally Posted by Wisconsin Joe
You look to be up a ways already. Are the springs original?
Not sure you are going to get another inch up on that.

I wouldn't use a 'big pipe wrench' on it. You will chew it up pretty well.

There's a specific wrench for the job. Search "hook type spanner wrench" to see what you need.

This came up not too long ago, the thread has a lot of useful info in it, including the spreadsheet posted above:

https://rennlist.com/forums/928-foru...djustment.html

Short of removing the collars..if theyre REALLY tight..I mean...tight...

A pipe wrench works dang well.

And a lot less blood and pain from the 'right tool' slipping with all yer arms into it.

At that point, you'll be buying some new ones to be ready next time it all comes apart anyways.
Old 03-15-2019, 08:01 PM
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Geza
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I've used a rubber strap wrench to adjust mine, which were clean and rotated freely.
Old 03-15-2019, 09:01 PM
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Mrmerlin
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Jim in Michigan, those shocks look to be original ,
in reality those shocks should be removed from the car,
all of the parts should be taken apart and properly cleaned/replaced.

At that point I would suggest , you would install new shocks , and new bumpers.
Inspect the dust covers for cracks
Apply fresh grease to the spring perches and threaded collars.

Get an Ohlins collar tool to make the adjustments.

Based on appearances these shocks are ready to be replaced.

You will realize the biggest improvement by installing new shocks.

NOTE do not jack up the car until you have taken ride height measurements.
This advice will save a lot of time once the car has been lifted
Old 03-15-2019, 09:17 PM
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chart928s4
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I have used two of those C spanner tools and they both were terrible. Next time: Big pipe wrench per Jeff's advice.

On the plus side, replacing the shocks is not a huge job and in some ways easier than adjusting the nut in situ.
Old 03-15-2019, 10:13 PM
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dr bob
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The hard steel jaws of a pipe wrench will chew up the adjusting collar in a very short time. The actual contact area of the adjusting ring is small, the access with a pipe wrench is virtually none with wheels on and the anti-roll bar links in place. Use The Right Tool, so when it slips off the collar it doesn't rip up the threads on the sleeve.

A casual look and measurement on my similar car shows that the bottom of the adjusting collar is sitting almost exactly two inches above the bottom of the threaded sleeve at spec ride height. There's at least another half-inch of room to go up, probably an inch or more just sticking a finger down through the spring to the lower perch. I put new springs and Boge dampers in about ten years ago now.

Spend some time with some cleaner to get as much of that crud off and out of the threads as you can. The lower spring perch is a crud funnel that directs dirt and water and corrosive everything right down through the threads. Not Good. You can dump stuff down there like Kroil or ATF/acetone blend, and it will soften what's in there some. It will also wash any crud down into the threads. Kroil and a few other things will help with corrosion bonds, but I think you'll be a lot happier in the long run by following Stan's (Mrmerlin) advice and at least take the thing apart before cleaning and any adjustment. Of course at that point you will be considering new dampers while you have it apart, maybe new springs if you are concerned about maintaining ride height, and.... It's a slippery slope.

Good used adjusters and sleeves are usually available from 928 International, as are good replacement springs, along with the dampers. Those original dampers are due for replacement.
Old 03-15-2019, 10:37 PM
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Originally Posted by dr bob
Use The Right Tool, so when it slips off the collar it doesn't rip up the threads on the sleeve.

Dont get me wrong.

I agree.

But when youre not in the shape to tear it apart, and youre going to install new when you get the chance, AND theyre just short of totally frozen.

Sometimes you gotta throw some cast physics at it.

Yes, it chews up the collar. Yes it COULD bite the threads...but since the critical issue may be ground clearance and you cant hurt those threads..you gotta do what you gotta do to solve the today problem while planning for tomorrows larger picture refresh of the HW.

Im not pro "hurt things"

Old 03-15-2019, 11:36 PM
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1990jim929
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wow - that is fast.

Thanks for the comments and advice - this place really rocks.

Wish you were all closer... would be St Pat's day beer on me.

Jim
Old 03-15-2019, 11:43 PM
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1990jim929
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Originally Posted by Speedtoys
https://docs.google.com/spreadsheets...it?usp=sharing

It is view-only link, go to File, and make your own Copy of it..and have fun, here are the instructions:

Speedtoys - that file is awesome. Thanks
Old 03-16-2019, 02:32 AM
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dr bob
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Jeff,

Like you, most of my shared advicee comes from tough first- or second party experience. It's from a mistake I made or a mistake I had to clean up, often both. I can safely say that there's no part or project on a 928 that uses a pipe wrench on a part I plan on using again. Ditto a smoke wrench or anything bigger than a 12oz tapping mallet. Yes those tools exist in my collection, but anytime I find myself looking twice at them I force myself to step back and rethink the project and options. I' also a confessed tool-a-holic, and have no trouble hunting down the correct $100 tool to solve a $10 problem correctly.

How many in the group have stared at some pipe wrench scars on the end of a crankxhaft snout where a ham-fisted repair artist needed to turn the crank by hand. How about pipe wrench scars on a rear axle nut because that same artist didn't have a socket to fit? Using a pipe wrench on a height adjuster might be "ok" if the boogered part is going to be replaced immediately with new. Our cars can easily become colkections of casual shortcuts and band-aids if we don't pay full attention.

[/rant mode]


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