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Car is 'unalignable'.....

 
Old 12-04-2006, 10:24 PM
  #46  
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Originally Posted by BrendanC
An aligned 928 with new suspension and steering bits drives 1000% different then an unaligned 928 with 50-200k miles bits and pieces.
Agree 100%. I still have some old parts in there, but fresh rack, solid mounts, and a good alignment made my shark feel like a new car. Ball joints and tie rods are all tight, must have been replaced by PO.
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Old 12-04-2006, 10:45 PM
  #47  
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Originally Posted by BrendanC
The racks still move too much under nominal pressures applied for my perception.
Yup. For the shark they made a "floating" rack. Funny when you think about.
The 911,912, 914,930's all had hard mounted racks. As they say "sometimes you can tell if a dime is heads or tails when you run over it".
On the 928,924s,944,951,964,968 and 993 the racks all have vibration mounts between the rack and cross member; whether the design is the 4 point press and swaged vulcanized 928 bushings, or the simple wrap around sleeves or cuffs with the others. I drove a 964 a few weeks ago, comparing it to my (911), besides the more forgiving cushion springs in the rear, the power assist in the 964 as compared to the manual 911 felt strange, responsive but strange.
You could go the route of solid mounts however the vibrations have to be absorbed somewhere other than into the joints, the wheel and your fingers.
So somewhere in the design stages back in the mid to late 70's I guess the powers that be found a reason for "da floating" mount.

Originally Posted by BrendanC
The ends, (as mentioned) when moved out to a high degree (a moderate speed corner, with opposite corrections, say, the bowl at SOW), move back and forth, thereby creating unknowns in the steering geometry. With this movement comes movement of the seals keeping things dry. A stiffer rack will be a longer lasting one it seems.
Hey. Isn't the unexpected the thrill of it all. Heck, lets just drop the tires and run on the rims. Without kidding here I enjoy the feel of the 928 as it is.
As far as movement in the rack shaft between the shaft and the seal, you need a minimum clearance and a particular micro finish (a min and max) on the shaft to insure there is a minimum amount of oil left to provide a lubricant for the lip of the seal otherwise they'll rip or burn.

Originally Posted by BrendanC
The rack on my Honda is Electric, somehow (I signed a contract with my wife to not take it apart), yet it is HUGE in diameter, as are the rack ends. It is bolted more solidly, and seems to be much stiffer by cursory glance then the ZF racks we have controlling a car nearly 1000 pounds heavier.
I agree. Did you ever look at an old Jag rack. Monolithic ! And built just like old BSA motorcycles. A leak under everyone.

Originally Posted by BrendanC
Thsi is OT now, but anything we can do to make these things BETTER then new will help us catch up the 25 years that have passed since they may have been "good" technology.
Ah Yes. New Technology. Lighter materials. Higher tensile strengths. Closer tolerances. Maybe sintered gears. Graphite shafts and cylinders. Heck, never mind the cheap stuff lets make um out of 4340M and we'll shot peen the suckers for life, and annealing after every tool pass. These mothers will put a set of F14 flap boxes to shame. Hey Morty, Fire up the CNC's. Blow out those old "G" codes fellas and the heck with post processors .... we are going direct digital! The polar express is here.
Well maybe. Its all a matter of dollars/units. If you can increase the one of the right the one on the left starts looking better.

Just blowin off the day here Brendan. Now. Where did that Windex bottle go?
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Old 12-04-2006, 10:57 PM
  #48  
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Originally Posted by griffiths

Hey. Isn't the unexpected the thrill of it all. Heck, lets just drop the tires and run on the rims. Without kidding here I enjoy the feel of the 928 as it is.
As far as movement in the rack shaft between the shaft and the seal, you need a minimum clearance and a particular micro finish (a min and max) on the shaft to insure there is a minimum amount of oil left to provide a lubricant for the lip of the seal otherwise they'll rip or burn.
The 928 can use some stiffening and tightening up. Quite a bit. If I wanted a Buick, I would have bought a Toyota Avalon (Some may get that irony). The rubber is getting spongy, and 20 year old rubber doesn't feel right. I have a hard chromer here in San Diego. Last one standing. Should he chrome the whole shaft? How much can be added, or rather, should any be removed before Chroming?

Does the spool valve main shaft need to be surfaced?

Does the seal go lip out or in? As in down or up?

Do the 91+ racks actually have different seals then what is Supplied by Corteco/Fruedenburg NOK for all earlier racks?

Are there rebuilt pieces available for the later steering pumps?

They come apart - I know that. The early pumps were rebuildable, with pieces readily available. The WSMs even had the procedure. Not so with the later pumps.
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Old 12-05-2006, 12:23 AM
  #49  
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Originally Posted by BrendanC
How do I lessen the spring tension in the spool valve to lighten up the steering?


Long Answer
Well lets see what they tried to do before 91 or so.
I guess between 78 and pre 85 they had a steering system designed with a rack and a pump that had a threshold cut out of 75 bars.
The rack went through 3 design changes then. The first changed the path for air displacement between the boots or bellows from the exterior via the black plastic tube to the interior, through a partially hollow shaft (you need the “displacement” we’ll call it, for the term of the moment, or was it Luftversetzung Weg? or else the boot will pop off the rack end). That cut the weight down of the rack assembly a pound or two. Planned for? Who knows.

Then they lengthened the rack shaft a few cm’s. Why? I don’t know. Maybe someone said something about “stay away from the tie rods Henrich, if Otto finds out your goose is cooked”, or maybe the parent company's sister company was on one of those 3 month Euro vacations. Anyway the rack shaft got longer. A few internal parts changed, such as from a bronze bushing/back-up washer to a (cough) plastic bushing. A steel back up washer (cough) became plastic. Somebody said the cost for the cushiony steering stops were overinflated and someones’s cousin had a screw machine shop that was slow, so they changed the steering stops to a one piece aluminum donut with a liquorice flavored o-ring inside. Otherwise the rack remained the same in terms of fit, form and function. Then around 1985 or so Klaus said “Hey Hans!. Dis fella called ya and he vandid you to make his steeering ezer”. So Hans thought about the torque bar, connected inside the input shaft/pinion’s spline, connected to the spool valve, connected to the pinion gear and Hans said “Ey, vata aya Nutz!. Just tell the fella to Pump Ur Up. Idz da same ding. Or geta bigga veel”. Now Klaus was a smart guy when it came to people skills.
And he knew if he if told this fella to simply pump up the pump pressure or to find a bigger steerng wheel the guy would either laugh at him or throw sausage at his car. So Klaus simply said "Sorry sir. That is not the way this car was designed to perform".

Well sometime around 1985 Fredrick, one of the second cousins who ran the rack plant, anyway Fred was making all the power steering pumps, and he was making a ton of money because he was using the same casting tools for this pump that he used for the bimmer pumps and he had charged both customers for the same set of tools (some business people are smart). So one day these fat cats are strollin through his plant getting the nickel tour (do they have nickels in Europe?) and they see whats going on. They took poor Fred outside, handcuffed him to an old VW and made him were a sign that said "I'm not a VW I'm a Porsche". I'm getting carried away here aren't I. Bottom line they decided to make a design "improvement" (cutting down on raw materials and the weight, I think it was the weight that was the selling point) and they basically took the same internal parts in form and function and dropped them into a different housing. By the way the bimmer company and the P company both ate the tooling.... again.

Then around 1991 or so someone found this poor old fella sitting on the front steps of the P facilities corporate office, well no, actually he was leaning against the building trying to hold it up. When they approached him he whispered somethng that sounded like "E. Z. Steering". So they carefully pried him off the stainless steel column, amazing how the skins sticks to metal when it gets cold outside, and huddled him into the Vorsitzender's Office (thats the guy who watches chairs) and sat him down. The Chairman asked who this old ratty looking fella was and they said "Why Sir. This is Mr. E. Z. Steering".

So things kinda grind to a halt here,,,, and that is exactly what they did.
They ground down the diameter of the torque bar to make things more flexible.
No. Maybe I'm wrong. They enlarge the diameter the torque bar to make things more stiffer. Anyway they did that. And its suppose to work.

And of course a competitor in on the seal end of things, who wanted the seal busines for years, showed up the next day. The other fella, what's his initials....CfW? Heck, we'll just call him Charlie F W. So Charlie made his seals using black stuff and these new guys, let me think KOCA or COkA or is it KACO, anyway they were really sharp. They presented a set of seals that were not black but green/blue, no maybe closer to a Bermuda green. Lovely things. And they added a few extra ridges on the contact lip, kinda a mix between a design patent and a utility patent, and called the stuff it was made out of something like SoyGum. Anyhoot, these new seals were presented because they had special properties, such as high heat resitance and wear resistance. The size is the same but they are special stuff. And someone else came along, maybe related, ya never know, and they said "Hey, ya know that problem you got with rings grooves forming in those castings that pinion valve thing goes into. We'll mine are Bermuda green too! Well the OEM vehicle guys new a good opportunity when they saw it so it was time for a SUPERSESSION ! That's right! Change the bill of materials. Time for drawing revisions !

As you recall Fred was handcuffed to a 914, or was it a VW. Anyway Fred's wife finds him out there one day, sooner or later I don't know, and she takes out an old hack saw blade, I think it was P tool P1427, and she cuts of the cuffs and drags Fred home. She says to Fred "Tsk Tsk. Uze supose da me my huzband. Wer da heck have you bin?. I'll tell ya wear ya bin, you hav bin hanging around doze lousy VW's too long! In the mean time ur couzin haz bin changin al kindza things. Itz tyme you made sumthin of ur zelf". And she throws poor Fred back onto the street and tells him never to come back until he's done something useful.

So Fred is walking down the street and he runs into poor Charlie F. The guy who made really good seals for along time but he lost the account with P or was it the Z guys. Charlie tells him that his competitor came in one day and sold P on a snow job about seals they needed which withstand higher pressures and so forth. Fred thinks about this and suddenly a light buld goes off and he runs back to his shop and proceeds to build the HP Super Pumper! A few weeks down the road Fred sold the new design to P, kicken up the pressure from 75 bar to 100+. Plus he go he got a bonus for.... that's right,
another SUPERCESSION! End of story.

Short Answer:
You don’t. You either increase the pressure or increase the diameter of the steering wheel. Again a matter of dollars divided by units. And as a side note the Boxster/996 may have gone the same route, with respect to the "stiffness" of the torque bar.
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Old 12-05-2006, 12:45 AM
  #50  
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[I]I have a hard chromer here in San Diego. Last one standing. Should he chrome the whole shaft? How much can be added, or rather, should any be removed before Chroming?
Count his blessings that he is still "standing". You would only hard chrome if the shaft diameter was not within tolerance or became so after removal of imperfections. You would not know if it was or not (out of spec) unless you mic'd it. You would also have to determine how much the shaft is out round. Then resurface the shaft, or if severe grind back, hard chrome, bake out for hydrogen embrittlement, grind to spec. You would "mask" the gear side, the inner threads for the tie rod ends, and the piston's snap ring grooves.
How much hard chrome... .well how much do you need to "finish it up"?

Does the spool valve main shaft need to be surfaced?
The spool valve is an assembly with the pinion gear and input shaft. There is a low pressure seal on the top and one of the bottom. There are four high pressure sealing rings, "skeeved" (****) as they say along with back up orings.

Does the seal go lip out or in? As in down or up?
Geez! some guys just want egg in their beer! The lip contacts the shaft.
Which side (cup) faces the what is determined by examing the function.

Do the 91+ racks actually have different seals then what is Supplied by Corteco/Fruedenburg NOK for all earlier racks?
That is a difficult question to answer because, isn't Corteco a div of /Fred; providing distribution and NOK a mfg?

Are there rebuilt pieces available for the later steering pumps?
What kinda of rebuilt pcs?

They come apart - I know that. The early pumps were rebuildable, with pieces readily available. The WSMs even had the procedure. Not so with the later pumps. OK ?
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Old 12-05-2006, 02:18 AM
  #51  
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What is the minimum diameter of the shafts on early (really early) and 85+ racks?

Originally Posted by griffiths
[I]I have a hard chromer here in San Diego. Last one standing. Should he chrome the whole shaft? How much can be added, or rather, should any be removed before Chroming?
Count his blessings that he is still "standing". You would only hard chrome if the shaft diameter was not within tolerance or became so after removal of imperfections. You would not know if it was or not (out of spec) unless you mic'd it. You would also have to determine how much the shaft is out round. Then resurface the shaft, or if severe grind back, hard chrome, bake out for hydrogen embrittlement, grind to spec. You would "mask" the gear side, the inner threads for the tie rod ends, and the piston's snap ring grooves.
How much hard chrome... .well how much do you need to "finish it up"?

Does the spool valve main shaft need to be surfaced?
The spool valve is an assembly with the pinion gear and input shaft. There is a low pressure seal on the top and one of the bottom. There are four high pressure sealing rings, "skeeved" (****) as they say along with back up orings.

Does the seal go lip out or in? As in down or up?
Geez! some guys just want egg in their beer! The lip contacts the shaft.
Which side (cup) faces the what is determined by examing the function.

Do the 91+ racks actually have different seals then what is Supplied by Corteco/Fruedenburg NOK for all earlier racks?
That is a difficult question to answer because, isn't Corteco a div of /Fred; providing distribution and NOK a mfg?

Are there rebuilt pieces available for the later steering pumps?
What kinda of rebuilt pcs?

They come apart - I know that. The early pumps were rebuildable, with pieces readily available. The WSMs even had the procedure. Not so with the later pumps. OK ?
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Old 12-05-2006, 08:23 AM
  #52  
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Originally Posted by BrendanC
What is the minimum diameter of the shafts on early (really early) and 85+ racks?
Which side of the shaft?
The early is the same as the late.
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Old 12-05-2006, 11:50 AM
  #53  
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Originally Posted by BrendanC
Charles: How do I lessen the spring tension in the spool valve to lighten up the steering?
FYI: assume one rack had a torsion bar (what opens the spool valve) that had a range of 0 to 9.6 N-m (newton meters or 85 lbf.in), vs. a rack that had 0-17 N-m; 1/2 relatively. When would the "lighter" effort come in handy?
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Old 12-05-2006, 01:44 PM
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Originally Posted by griffiths
Which side of the shaft?
The early is the same as the late.

The "Smooth Side" as you have described.
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Old 12-05-2006, 01:56 PM
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Originally Posted by BrendanC
The "Smooth Side" as you have described.
Well the smooth side or RH on US starts off at 1.023" nominal from the factory, however that is not the low limit.
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Old 12-05-2006, 02:33 PM
  #56  
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So Brendan, I think we have strayed enough from 959's original topic, alignment, we gone past the suspension issues and now we are down to subcomponents.
Before we go, tell me, when are you going to the put the Avatar back in the beast it came from?
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Old 12-06-2006, 05:48 PM
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Originally Posted by griffiths

Are there rebuilt pieces available for the later steering pumps?
What kinda of rebuilt pcs?

They come apart - I know that. The early pumps were rebuildable, with pieces readily available. The WSMs even had the procedure. Not so with the later pumps. OK ?
later pump kit from rennbay:

http://cgi.ebay.com/ebaymotors/Porsc...60558980QQrdZ1
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Old 12-06-2006, 05:56 PM
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[QUOTE=BrendanC]later pump kit from rennbay:



And I thought I was looking at the makings of a high spun ice cream maker.
.... ah darn.
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Old 12-06-2006, 06:12 PM
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[QUOTE=griffiths]
Originally Posted by BrendanC
later pump kit from rennbay:



And I thought I was looking at the makings of a high spun ice cream maker.
.... ah darn.

Did you watch the video? Where would I increase the pressure from the pump? On that valve on the side?
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Old 12-07-2006, 10:57 AM
  #60  
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[QUOTE=BrendanC]
Originally Posted by griffiths


Did you watch the video? Where would I increase the pressure from the pump? On that valve on the side?
Watched Video: Yes
Critique: well lets see if we can set a better example this time, lot's of tomatoes still on the screen :
Positive suggestions :
A) It would be easier if you use a 13 mm wrench
B) You NEVER hammer seals, you press them:
C) If the pump has internal leakage or noise because the vane guides
are shot, or the cam is shot, new seals won't help you

Why don't you buy a remanufactured pump or a "new" pump already with a higher pressure? You could call Jeannie or David at 928 Spec.
http://www.928gt.com/
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