Vilhuer

Someone has changed your front end if it doesn't have adjustment. All 928 had it from the factory after '83 MY IIRR. Adjustment doesn't look same as on rear.

Rob Edwards

FWIW, here's my front adjuster ring for comparison. You can see the red ink line I made so I could tell when I completed a revolution. When I got the car you could not see the threads at all, as one of the PO's had lowered the car consideraby. The front is now at 165 or so.

daveo90s4

My past analysis shows for 1988 and 1989
Front springs:
928 343 511 09 (404 brown)
or
928 343 511 12 (504 orange) for M637

Front Shocks
928 343 055 07 boge
or
928 343 055 08 bilstein
or
928 343 055 09 boge for M474 or M637

Rear springs
928 333 531 14 boge
- 301 1 colour band
- 302 2 colour bands
- 303 3 colour bands

Rear shocks
928 333 051 17 boge

1990 and 1991 the same except
Rear shocks
928 333 051 16 boge

1992 same as 1990 and 1991 except
Front springs 928 343 511 12 (504 orange) for M637 and front shocks 928 343 055 08 bilstein not offered.

Notes M474 = "sports shocks"
M637 = "club sport"

jon928se

FWIW

SE - has CS springs had red boges
billies made a huge difference at 100k miles
18" wheels made the ride less harsh and also more positive in terms of direction changes - less sidewall flex and less tyre pressure

90GT no idea on springs but would seem it has S4 springs? has grey non sport boges
comparing with the SE with old shocks it is definitely less stiff - time for some billies and may it gets the SE springs which will then get eibachs or hypercoils.

If doing it yourself I'ld do a shock change first and see what you think then consider changing springs.

If paying to have it done then labour costs soon stack up.

Rob Edwards

Wow, 15 months since I took the above pics, and I'm finally getting around to installing the CS springs. I actually ran into a roadblock compressing the new springs- With the lower spring perch most of the way down, using the typical DIYer threaded rod-type compressors, if I grabbed 4 loops of spring on each side, the spring coils would bottom on the safety pins before I could compress enough to get the nut on the piston rod. Grabbing 5 loops easily gave enough compression but the 24mm bolt head on the compressor would jam against the upper spring perch while trying to loosen. Using the impact wrench was also generating a small pile of metal filings from the threads - in the interest of not becoming a spring compressor Darwin award winner, I gave up and took 'em to Pepe boys to have them assembled. $40.

FAIL.

Bill Ball

Good decision.

I have a Lisle spring compresser that I used airtools on. It has heavy duty rods and the threads handle the abuse.
http://www.amazon.com/Lisle-62300-Ma.../dp/B000COA1F8

Rob Edwards

Bad decision: (address for search engines to find...)

Pep Boys
2946 S BRISTOL ST, COSTA MESA, CA
Tel: 714-549-1533


I should know better. I took the springs and a diagram from the WSM. I left three instructions with them: Orange stripes to the bottom, line up the axis of the bottom mount with the studs on the upper mount, and no air guns.

So what do they do? they put an impact wrench on the brand new lock nut, stripping the threads on the piston rod. So the guy re-threads that one, and assembles it, except the upper mount is rotated 90o from where it should be, and the top washer is upside down. Then he strips the threads on the OTHER shock, then locked up his tools and leaves, 'cause he was done for the night.

Stupid mother****ers. I got my parts and left. Fortunately my 4 year-old was with me, and it's a bit too early to teach him the good swear words.

I hope that a re-threaded piston rpd on a $180, not-available in the US Boge Red will work ok..........

I'll take these to Hergesheimer or Precision on Monday. Stupid me for thinking the mouth breathers at Pep Boys could get this right.

928SS

ouch!!! that sucks! I won't even park my shark at a pep boys... it's just bad karma.

Bill Ball

Oh, I missed that this was PepBoys.

But just for the record....

- Lining up the mounts can be done AFTER the shocks are assembled. They twist rather easily just by using a screwdriver blade in the bottom mount hole for leverage. I install them in the car by the top mount, then work to get the bottom aligned.

- The spring orientation is not important at all. It's a linear rate spring. There is no top or bottom.

- I don't understand how they stripped the shaft threads - the center shaft should spin rather freeley unless you hold it by the notches at the top end. So, driving the top nut on with whatever tool should not overtorque it. I sure hope the rethread holds too!

Rob Edwards

Bill-

You're right on all 3 counts, I didn't think about just mounting the shock in the car and rotating the bottom 'til it fits. And it turns out that they didn't strip the shock threads, they stripped the (incorrect) locknuts that I supplied....


So I may have spoken a little too harshly of Pep Boys the other night, now that I can laugh about their incompetence. Part of this is my fault - I had taken the shock/spring assemblies there with a new pair of locknuts that came in a factory parts bag that was marked N0221411, but had previously been opened and re-closed with a part # sticker. When I looked at what they’d installed, they were the wrong locknut (which had a nylon insert of some sort, I’d never bothered to check them). What had stripped was the locknut threads, not the piston threads. I gave them the wrong locknuts. Don't ask me why the nut stripped and not the shock threads, but I'm not complaining.

So I made a quick run to see Greg Brown today over lunch hour. He disassembled the one shock/spring assembly that the Pep Boys dude assembled. They had indeed installed the top washer upside down, and the spring perch was perpendicular to how I instructed. As Greg removed the upper half of the upper shock mount, we found that Pep Boyee had not installed the other big washer that goes INSIDE the upper mount (convex side up, FWIW). So P.B. made three errors despite a printed workshop manual image and instructions from me.
All is well now, I just need a few hours to get them back in the car. Lesson learned! And a big thanks to GB for helping me get these together without an appointment.

jon928se

Cor Blimey Guvnor. And to think that the post before yours I was contemplating a similar project and I am half way through it now.

I too have given up on spring compressors of the DIY type for exactly the same reasons. Bolt head on compressor snagging on spring perch or threaded rod snagging on spring - now I use a shop press with a spacer that allows me to press the spring and get at the top mount. Much quicker and safer - just boring pumping the press down 139 strokes from fully up to fully down.

Commiserations on the Pep boys experience. I guess it happens. I have been fortunate with the local alignment shop that their alignment guy's eyes light up when I take a 928 in - something different for a change and quite happy to learn from the 2nd hand rennlist wisdom.

Bill Ball

Hi Jon:

I'd sure like to see a picture of this spacer and setup on your press. What prevents the compressed spring from taking a trip out the side of the press? The Lisle strut compressor, as simple as it is, has held up perfectly under a bunch of shock changes, but if I could use my press safely to do this, I'd like to learn about that. Thanks.

UKKid35

It may be easy on a CA car, but it is near impossible on a UK car (the query was about a London based car), unless it has never been out in the wet, and definitely never seen any road salt.

I fitted new adjuster rings/sleves before I switched to Bilstiens, these froze within a few months.


Like the original poster I would like to firm up the ride slightly. I am running on the original S4 springs. I'm still not entirely sure what the best option is, as i want to preserve the ride height and don't want to compromise ride comfort.

jon928se

Hi Bill a couple of photos below. Couldn't take one of them in action without removing a shock/spring form a 928 so apologies for the pic of an old rear shock, and old rear spring with a lower front spring perch on the top to simulate. (Don't have any spare top of spring perches and mounts)

The Tube is 75mm OD (3") ,3.6mm wall thickness and 125mm (5") long. The length of the tube is a function of the stroke of the shop press (139mm or about 5 5/8" in my case) and the spacing of the holes in the uprights of the press to move the lower platen up or down. This required some careful thought and comparison of the free and compressed lengths (ie off the car but still completely assembled ) of the springs.

The hole in the side of the "Tube" is approx 1 1/2" square and was sized and spaced to allow the insertion of both an 8? mm spanner for the top of the shock rod and a straight ratchet spanner 19mm ring spanner for the nut on the shock. In reality you can loosen the nut far enough so it will be finger tight once the spring is compressed before the assy is put in the press but this can be difficult to judge on dissasembly.



Once installed in the press I use a pair of angles on the lower platen, bolted together finger tight around the shock body to ensure they don't spread, to support the lower adjuster ring. The large diameter of the Compressor tube (chosen specifically because it just fits between the three top mounting bolts of the shock/spring assembly) resting against the bearer beam of the press serves well enough to prevent the compressor "Tube" and shock/spring assy "buckling".



Compared to using screw type spring compressors this method is very quick and I am happy is very safe. The limiting factor on how quick it is, is dependant upon how fast you can pump the shop press jack with a finger in the handle hole! - Its about 80 pumps for the full 139mm stroke.

For anyone contemplating building a similar "Compressor Tube" The OD can't be bigger than 75mm (3"). A wall thickness of 3mm(1/8") will be more than adequate. The length as stated above is dependant upon the stroke of your shop press. You must must use a bottom support that cannot spread -ie it is bolted together or it is one piece. And finally I would not use this method on a shop press where the jack is inverted. As you can just about see in the photo my shop press uses a simple 20T jack orientated the same way up as you would use it under a car. - ie the fat part sits on the cross beam and the piston goes up as you pump it, forcing the cross beam down. If your shop press uses an inverted jack (fat part stays still and the piston goes down when you pump it) then the "Compressor Tube" will not work safely.

928SS

news flash - one thing you GOTTA do is corner balance after messing w/the springs. just did mine yesterday at doc browns and its a whole nuther car. I can't believe how smoothly it handles rough patches, control is effortless, amazingly consistant from rt to left and unbelievably sure footed at any speed. (um, theoretically of course, as we never speed on public roads)

it wasn't really off a lot to begin with, only about -39 on the cross wt, and only about 120 lbs on the LRrear corner, a few on the LFrnt.

now it's at -6 on the cross wt and within 1.5 - 6 lbs everywhere else w/a 200lb driver and 1/2 tank of go juice.

only regret is that wish I'd done it 4 yrs ago when I updated my suspension. was really missing out.

interestingly, even w/all my wt reducing efforts, it's still a "petite" 3550 lbs.

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