Understanding the ZF box?

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Jules Dielen
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Re: Understanding the ZF box?

#31 Post by Jules Dielen »

sounds like you had a real expert working on your car Chip, sorry to hear! With that knowledge, I would check every nut and bolt he touched.
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Al Zim
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Re: Understanding the ZF box?

#32 Post by Al Zim »

Mr. Dielen you stated "I would check every nut and bolt he touched" Where would you find the specifications to successfully complete this operation? al zim
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Geoff Fleming
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Re: Understanding the ZF box?

#33 Post by Geoff Fleming »

Ditto to what Jules has said, I'd also recommend examining all the other fasteners. The fact that the adjustment bolt was Lock-Tited is bizarre in itself.

Mr. Zimm,
You do understand that the 356 was a beautifully engineered car, however, it was expected, when the cars were new, for owners to maintain them on a regular basis? The popular Elfrinks manual was designed for the Porsche owner to enable him/her to do some pretty advanced work on their own vehicle, despite the lack of Porsche factory tooling.
Simply because the average owner does not have the professional tooling you own does not mean he or she cannot make adjustments , re-build engines, etc. I have driven to over twenty East Coast Holidays in two 356 coupes, since 1985. I re-built my own engines in each car, never have had any problems and simply followed the advice from the Pellow books and Elfrinks. I did not own any special tools back when I started doing my own work nor was I a 'natural', just an enthusiastic owner.
I also know quite a bit about vehicular accidents, since I worked with a prominent police force doing accident investigations in the N.Y. and N.J. area...aircraft accidents also.
I certainly have no problem with a professional shop wanting to attract customers but I do resent anyone blatantly telling owners they can't do their own work without dire consequences, unless of course, they use your facilities.
My 356s were used as daily drivers, un-garaged, exposed to the elements of the northeast. My experience comes from driving these cars at least three hundred thousand miles, ( probably more), not from guesswork . Have you even driven a 356 more that a few miles in the last decade(s)?
This forum is designed to encourage 356 enthusiasts not to discourage anyone from performing their own work. No matter how the cars are set up, once in regular use ,they will lose that perfect setting, as is true with all mechanical things...what is the owner to do then...other than return to your shop?

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Jules Dielen
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Re: Understanding the ZF box?

#34 Post by Jules Dielen »

Mr Zim,

i have also worked on my and my dad's 356s and 911s for about 25 years, even with non Porsche approved tools. The only 'mishap' i had in all those years was that I once did not tighten 2 lug nuts after a tire change. The rest are 'just nuts and bolts' and with half a brain and a lot of attention many 'operations' can be successfully completed just fine. I would not dare to open an MFI pump or claim i can adjust a CIS sytem, and I would not even think about any type of technical work on a modern car, but a 356 is pretty basic from a mechanical pov.
Jules

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Al Zim
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Re: Understanding the ZF box?

#35 Post by Al Zim »

I think the sills that Zim's possesses are above average and possibly excellent in the maintenance and service of 356's. As you attempt to disassemble a rust frozen king pin or wonder how to get rid of the slop in the spindle where the king pin hole is oversized, or realize the shim stack on your link pins is unusual give us a call. Do you think the plastic bushing that adjusts the end play between the spindle and C carrier would have been a better design if the factory provided better press tooling. How are you gong to check the parts you purchase to see if they are within tolerance. al zim
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Chip Flor
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Re: Understanding the ZF box?

#36 Post by Chip Flor »

SUCCESS!!!!!
Wondering gone!!! Tracks straight...steering wheel centered. Goes into turns with equal precision that I never had before. Brakes stop dead nuts straight ahead. Can't be more happier.

Thanks to all that helped out with this endeavor. I guess the main thing that I got from this is:
1) make sure that you remove your steering box cover and literally show the alignment person the ZF marks on the box that have to be centered to be aligned. Don't ever rely on "experts Porsche mechanic" to know what they are doing.
Again than you to all.
This 356 community is an incredible resource and I am extremely appreciative.
-chip
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Geoff Fleming
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Re: Understanding the ZF box?

#37 Post by Geoff Fleming »

Good news, Chip! I learned not to trust self proclaimed 'experts' many years ago, after receiving my car back and finding it had steering with 1 lock to the left and two to the right. I later realized this shop had removed my steering box, ( without my authorization, since the car was only there for some bodywork and paint!), and sold it to another customer. They then installed a second rate box in my coupe and never bothered to remotely center it. This shop has since folded...and not a minute too soon.

Jim Hohensee
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Re: Understanding the ZF box?

#38 Post by Jim Hohensee »

Just to add a couple of important points to the excellent advice already given. In order to get a parallel string line you have to allow for the difference between front and rear track width. Front- 1306 mm Rear - 1272 mm. According to the factory work shop manual "a certain amount of play in the steering when the vehicle is stationary and the front wheels are turned from the straight ahead position is quite normal. When the vehicle is on the road and rounding a curve, this play is compensated for by caster action of the front wheels, acting thru the tie roads and the drop arm, which forces the steering peg against the steering worm. The book also recommends 4 to 6 inch pounds of drag in the straight ahead position and never too tight.
Hope this helps,
Jim

Geoff Fleming
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Re: Understanding the ZF box?

#39 Post by Geoff Fleming »

Jim,
Exactly. Good advice about never cinching up the adjustment to the point where it is binding anywhere throughout the range.

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Jim Clement
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Re: Understanding the ZF box?

#40 Post by Jim Clement »

chip, a basic question back to the begining..
did you have a ZF box or a VW box.. the VW box has two studs, the ZF box has 4 ??
 

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Chip Flor
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Re: Understanding the ZF box?

#41 Post by Chip Flor »

My car came with a VW box. It came also with a solid none adjustable (drivers side) tie rod link.
I purchased a ZF box (with both adjustable right and left links and tie rods) from Jim Breazeale (EASY) a decade or so ago.
As it turns out the ZF was/is a nightmare to fit. On my '56 T-1 the lower cover is welded in as per the factory.
Later cars had the front cover removable.
There is a pin on the torsion tube which locates both boxes into the correct position.
Like Vic said earlier you can not center the ZF box with the solid non adjustable link.
You need both adjustable links for this reason.
This is critical to this particular swap.
 

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Randy Mittelstet
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Re: Understanding the ZF box?

#42 Post by Randy Mittelstet »

Chip, I've never taken the top off the zf box, only the filler plug.
Please describe the peg that you mentioned should be centered if properly aligned. I have located the center mark on my steering shaft but have never found the centerline on the ZF box.... so maybe I can use your method. Maybe someone has a photo of this view into the box.
Thank you.
Randy Mittelstet
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Geoff Fleming
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Re: Understanding the ZF box?

#43 Post by Geoff Fleming »

Randy'
If you remove the filler plug you can watch the mechanism below as the steering wheel is turned. When the top of the circular peg is directly centered below the plug, the box is at the center point. The more common method is to locate the score mark on the box itself; however, since you can't find it, you can measure the width of the box where the steering shaft enters and then divide by two and this will give you the center. Do this a few times in order to correctly determine the true center. Now you can scribe a new line for future reference.

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Randy Mittelstet
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Re: Understanding the ZF box?

#44 Post by Randy Mittelstet »

Thank you Geoff...... that is a great description of how to solve my issue. This forum always comes through when help is needed because fellow owners are willing to take the time to read the forum and give input when they can.
Randy Mittelstet
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Steve Douglas
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Re: Understanding the ZF box?

#45 Post by Steve Douglas »

Hi Chip, good to hear you got your coupe back and running. This week i decided it was time to swap ZF boxes, 305,000 miles for one that had less than 40,000 when the car was totaled. I bought the used box from a wrecking yard for $25 many years ago. Took it apart cleaned it and put it away. A few differences, the one from the wreck doesn't have a locating pin or a hole, so drilled a hole matching the location the pin in the original box, threaded a screw into the hole and cut the head off. Also subtile differences in pitman arm, as well as the different part numbers. The wreck was a 60 or 61, and mine is a late 59. The box is back in, tie rods were just painted and will go back in tomorrow. Surprisingly the damper still works smoothly and with even resistance after 60 years. But will be doing a new damper, new tie rod ends, and steering shaft coupling. Guess this should be a regular 300,000 mile / 60 year maintenance item. Once this all dialed in hopefully the car will be a bit more steady in cross winds and grooved pavement.

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