Link pin assembly trivia

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Frederick Adler
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Link pin assembly trivia

#1 Post by Frederick Adler »

You all have been a huge help given my lack of experience with this car. I own a few different books and most of the time, I can figure it out from one of them. The whole front spindle on both sides have been screwed up so I disassembled and cleaned and from parts found figured out what goes where. I had to find a washer for between the torsion bar lever and the link pin and got it. Now there is a "detail" I need some help with. The "link pins" in front (outward part facing you in the wheel well.) are different. One has a "rectangle" in the middle of the part that shows and the other has a "K" stamped in it. 1. Does it matter which is on top and which is on bottom? 2. Also the end of the link pin towards the back has a flat rectangular you can grab with a wrench (on the link pin). Is that supposed to be up and down orientation or does that matter. It might matter as the grease fitting access to the channel on the link pin. IF this thing was together when I got it, I would have taken notes and drawings but since it was all apart, help is appreciated.

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Greg Bryan
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Re: Link pin assembly trivia

#2 Post by Greg Bryan »

I'm not sure about the detail of the link pins you refer to, but in general, replacement link pins are all identical and any linkpin can be used in any position.
Here's some thoughts on that operation:
New link and king pin kits are available at a very reasonable price and I would recommend replacing the parts and especially the bronze king pin and link pin bushings as they are typically (always) worn. It requires some pressing and fitting the new king pins to the new bushings - usually a machine shop task unless you have a reamer or Sunnen hone at home.
Once all the bushings are back to spec (makes a big difference in the feel of the car while driving) you have to figure out the offset of the two front suspension trailing arms that the front spindle assembly attaches to so that you can arrange the shims compensate for different offsets. This can be done without the special tool, if you're careful, by inserting a new link pin in the trailing arm hole with a 6 inch straight edge against the machined surface of the new link pin. Have someone measure the offset difference between the two arms with feeler gauges or a caliper with a depth gauge feature. Obviously, you have to measure from the trailing arm that sticks out furthest.
Once the offset is determined, look at the chart that comes with the link pin kit - at least the last one I bought had one in it - and arrange the shims accordingly on the link pins, and install them on the spindle assembly. Put the special washer on the end of the link pin and insert the entire assembly onto the trailing arms - carefully align the bump on the special washer with the groove in the trailing arm.
You'll notice that the link pin has a very course and large thread on it - the 10mm pinch bolt goes into the groove and the link pin is turned, using the rectange end you refer to above, until it is snug against the trailing arm - not too tight, it has to pivot freely - orientation of the rectangle once snug is not important, it's the adjustment of the assembled linkpin that will determine the orientation of the adjusted linkpin. Once snug, tighten the pinch bolt; recheck the play after driving the car for a few miles as things can settle in and then every 6000 miles after that.
This operation is described in detail in the repair manual or in the Elfrink book - something you are going to need sooner or later
Good luck!
Greg Bryan

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Frederick Adler
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Re: Link pin assembly trivia

#3 Post by Frederick Adler »

I figured out the special washer fitting into the groove in the trailing arm lever. That was the only way it would keep the grease it, but wondered about what you call the coarse thread. I thought that was just a grease channel for the grease fitting to spread the grease all the way around the link pin. Thanks for the tips. So it is not just 9 shims up and 9 shims down bringing the link pin channel up flush with the head of the link pin. I thought that was it since the rebuild kits give you 36 (9 x 4).

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Greg Bryan
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Re: Link pin assembly trivia

#4 Post by Greg Bryan »

After the offset is measured, you will have to place the shims according to a chart so that the spindle does not bind. Every car has a slightly different offset because of production varients or wear/slight bending from years of use. If it's outside the allowable variance, the trailing arms will have to be cheched for straightness.
There should be 40 total shims with 10 on each link split between the inside and the outside.
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Frederick Adler
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Re: Link pin assembly trivia

#5 Post by Frederick Adler »

Muchas gracias. That makes it completely clear on how to do it. It even clarifies that the special washer with the indent is counted as a shim so the total of 10 is 9 + 1 special. The precision of the car is amazing.

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Re: Link pin assembly trivia

#6 Post by Dick Weiss »

When rebuilding the front spindle assembly, you'll need a sufficient press to R & R the king pin(s)
and after replacing the bushings and reaming them to size and alignment, you'll need to fit the thrust shim(s) between the stub axle and 'C' link to get the minimun clearance near zero.
Remember to add the special O-ring seals to the special washers to the link pins.
Finally, if the 'C' links have some wear in the linkpin faces, you should shim the setup to get the nominal 7mm offset to the trailing arm 'eye faces' or compenstate their offset differences.

Dick

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Eric Thomas
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Re: Link pin assembly trivia

#7 Post by Eric Thomas »

Install per manual or per feel?

I removed everything & cleaned, measured twice, top arm was in/offset 7.5 mm from bottom so put 5 shims all-around per the chart, but the lower seal is not all the way set - I verified each inner washer bump was in the arm cut-away, and I don't think the arms are bent, there's no evidence of any damage... Top looks good.` Before cinching up the bolts there was very little play, perhaps 1mm wiggle, once I cinch up both bolts everything feels pretty good, but still have that gap on the lower seal
So what would be better - install shims per chart, or move a few around so it "feels" better?

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Re: Link pin assembly trivia

#8 Post by Dick Weiss »

Hopefully you 'cammed' the linkpin in the right direction, but the seal looks narrower than the other seal(?)
Also, make sure all the shim diameters (under the head) are inside the co-bore.

Dick

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Larry Coreth
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Re: Link pin assembly trivia

#9 Post by Larry Coreth »

New seals will often "roll under" like that. Use a small flat bladed screw driver or very small spatula to pry up the rolled under side, use grease or oil on the screw driver to ease the prying action. Then tighten the link pins by turning clockwise (looking from the end with the 2 wrenching flats) until each is snug. Then tighten the securing pinch bolts. Assuming you measured the trailing arm off set correctly and distributed the shims per the manual’s chart properly, all should snug up squarely. If not, re-measure and redistribute the shims to suit. If none of this allows the C link to line up squarely with the trailing arms , then it is time to check for damaged parts.
Larry Coreth
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Al Zim
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Re: Link pin assembly trivia

#10 Post by Al Zim »

The reason you have two different link pins is that the car was crashed and the put a new spindle on the car probably the one that has the square end. It would probably be best to remove the trailing arms and have them check for straightness. These cannot be repaired.
When using a press to take the spindle apart, you can easily destroy the "C" carrier where the link pin bushings are installed. If the link pin hole is oval you can purchase a new (or used) carrier or you can have a machine shop make an over sized bushing.
If you lubricate you king pins when you use the factory oil change interval of 1500 miles you will never have front end problems. You can also use the Iron bushings successfully with proper service. The cost difference will allow you to purchase an excellent grease gun and a lifetime supply of grease.
If you are mixing and matching from spindle to C carrier you may need a different metal shim that goes on the top of the spindle. We exchange them for $20.00 each and your old shim.
We have the facilities to check the trailing arms, Pittman location, and "C" carrier offset and straightness. We can take apart badly rusted king pins without damaging any components. Zim's also repairs worn king pin holes in the spindle. al zim
Last edited by Al Zim on Fri Mar 02, 2012 12:41 pm, edited 1 time in total.
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Trond Vidar
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Re: Link pin assembly trivia

#11 Post by Trond Vidar »

I noticed some aftermarket bushings are slightly longer than the hole in the carrier, not much but close to 1 shim size.

From what I have read it is most important that the inner flange is aligned, any comments on this? If there is .5 mm sticking out on the inner flange it will affect the camber so that make sense.
posi_linkp.jpg
'56A coupe & '63B coupe

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Larry Coreth
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Re: Link pin assembly trivia

#12 Post by Larry Coreth »

Yes, the bushing needs to be pressed in such that it is flush with the C-link mating surface as shown in your drawing. The extra length goes to the outside where it has no effect on the trailing arm off set shim adjustment. The only effect will be to position the link pin and unused shims outward by 0.5mm which is inconsequential.
BTW if you press the bushing in from the outside of the C-link against a flat surface the desired flush result will be easily achieved.
Larry Coreth
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Albert Tiedemann
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Re: Link pin assembly trivia

#13 Post by Albert Tiedemann »

Al Zim wrote: When using a press to take the spindle apart, you can easily destroy the "C" carrier where the link pin bushings are installed. If the link pin hole is oval you can purchase a new (or used) carrier or you can have a machine shop make an over sized bushing.
If you lubricate you king pins when you use the factory oil change interval of 1500 miles you will never have front end problems. You can also use the Iron bushings successfully with proper service. If you are mixing and matching from spindle to C carrier you may need a different metal shim that goes on the top of the spindle. We exchange them for $20.00 each and your old shim.
We have the facilities to check the trailing arms, Pittman location, and "C" carrier offset and straightness. We can take apart badly rusted king pins without damaging any components. Zim's also repairs worn king pin holes in the spindle. al zim

Yes, the link can be easily made unserviceable when removing the king pin, but either the existing link bores or a used link [if you can get them]bores could be oval after sucessful removal. These should be honed round again and oversized bushings installed. The nominal size is 28 mm. Oversize bushings are not available from the usual suppliers so a custom manufactured one as Al suggested is a requisite. I do not know the material used in the original bronze colored bushings, but whatever material used, they should be a light press fit in the reconditioned bores. I do not think new links are available but I have in work a fixture for holding a new VW link for machining the flange off to accept the sealed shim pack that interfaces with the suspension arm eyes.

..."Never say never"--from a picture I recall seeing a long time ago.

If the shim is thicker than 4.5 mm [likely if the old fiber washer is used{ more on this in another post} ] does Zims supply a new shim?


I understand the need for a check on suspension arm deformation, but pittman [arm}location? This should just be a visual since the arm is matched marked to the shaft.


It would be instructive to know how you repair worn king pin holes as this is a considerablely long press fit and is likely damaged only by tearing away material from the bore on king pin removal. Since the stub axle is a heat treated part, the procedure used is even more intriging.

...."C" carrier offset and straightness" and correction implied by Dick Weiss in a previous post as well. Correction could amount to one shim or more in the "shim pack" table.
Albert Tiedemann, C356C
"The Hermit"

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Al Zim
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Re: Link pin assembly trivia

#14 Post by Al Zim »

Without the proper checking device it is impossible to know if the Pittman arm on the spindle is in its proper location. Once the Pittman arm has been moved the tires are no longer able to achieve the Ackerman (sp) effect so turning corners does not happen like the factory designed the car to work.
In the shop manual if the "C" carrier is a small bit offset that correction can be made by adding or subtracting a shim from the offset of the trailing arms. Enough variance in the offset using the factory measuring tools is possible without serious and careful consideration when using the tool.
Honing the link pin bushing hole is not a good idea. Every bit of metal that is removed makes the link pin bushing fit looser in the "C" carrier. Fortunately the design of the system is such that the Link Pin will hold the suspension together if the bushing is loose.
Finally, the king pin bores do wear out especially if the front end never receives grease. While there are still 356A and B spindles available the 356C (disc brake) parts are in short supply.
We have learned a lot about repairing front end parts over the years and offer a repair service that is as good as you can get. It ain't cheap but it should last a lifetime with a little grease. al zim
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Trond Vidar
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Re: Link pin assembly trivia

#15 Post by Trond Vidar »

A little off the thread but anyone know if the pittman arm is the same for type 1 beetle and the pre 58 356?

http://www.356registry.org/tech/vwtoporsche.html


My '56 steering box may be too tight setup or just worn and I am looking at one of the new TRW boxes, cheap = yes, good = ... ?

http://www2.cip1.com/ProductDetails.asp ... D415%2D061
'56A coupe & '63B coupe

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