| autoluke | -- 09-15-2019 @ 5:38 AM |
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Thought that I would tackle alignment of the front end on my '41 convertible, but have hit a brick wall trying to orchestrate the relationship between the pitman link and toe in adjustments. The box and column are new from Lares, so that the steering wheel is centered when the pitman arm is vertical, but can't find the sweet spot when adjusting the pitman link...controls basically the position of the right wheel , but throws the toe on adjustment out of spec, Ideas ?
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| 40cpe | -- 09-15-2019 @ 6:45 AM |
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The tie rod sets the toe-in. Then get the steering box on the center of its travel and adjust/attach the drag link.
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| therunwaybehind | -- 09-16-2019 @ 8:15 AM |
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Now this is why I joined the club. In the book, 1941-48 Ford Book by the Early Ford V-8 Club on page 4-5 it clearly shows a cross over link to the right side from the steering gear box and two mounting locations the passenger knuckle for that link and the end of the tie rod on that side coming over from the opposite (driver's side) steering knuckle. This is how my 1948 was rigged and I have been shown it was like that since 1937???!!! Pitman arm? vertical? That is for the earlier cars. You did write '41 convertible. Call me a virtual virtuoso with no current hardware but I don't buy this post. OK I looked for the less slang term and found 11A-3590C arm, steering gear LHD draglink and straight end to go with the 3306 drag link on page 4-5. By vertical did you mean most forward and vertical in the car or straight down (perpendicular to the steering mast) with the steering gear out and lying flat on a bench. In the car,the arm swings left and right in a plane that is inclined to the earth and perpendicular to the mainshaft up to the steering wheel. http://www.vanpeltsales.com/FH_web/flathead_steerngear_adjstmt1937-48.htm "Pitman" arm is something that comes from lumbering and the way the saw was used by two men vertically one above and one in the pit just like "flathead" is a term for the guys who made the actual cutoff of the stump to fell the tree. Back me off 4 notches on this one. This message was edited by therunwaybehind on 9-16-19 @ 11:52 AM
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| autoluke | -- 09-17-2019 @ 5:37 AM |
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The pitman arm is in a true 90 degree position plane when the steering wheel is in the center of travel. Not sure about your question.
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| therunwaybehind | -- 09-17-2019 @ 11:33 AM |
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I understand the special position of the 1941 steering arm in the parts world, the note in what I referenced in the Green book that says straight end , refers to the later cars having a bent end to the crossover drag link. This I would guess is because the 1941 frame is slightly higher in the car than the later frames. Page 4-5 says "An important feature of the 1942 Ford was the lowering of the body relative to the frame-which gave the 1942 Ford a 1" lower center of gravity. Hmm? I searched out a post of someone who installed a 1937-39 steering box and shaft in a 1935-36 Ford. There he points out the same crossover draglink design but gives some differences in how the steering box is installed. My previous experience with a Pitman arm was with a 1934 Ford where it is indeed vertical and outboard of the frame to connect with the left or driver's side wheel. https://www.hotrod.com/articles/1107sr-f1-steering-boxes-for-pre-35-fords/ and the pickup in 1948 had gone back to that earlier style. This is where my question about "vertical" came from.
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| therunwaybehind | -- 09-17-2019 @ 1:10 PM |
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We come to very old and simple measuring instruments when speaking or writing about "vertical." The plumb bob is an old way of determining if something is vertical. The king pins can be compared to a plumb bob and used to examine inclination. How you would use a plumb bob to find your steering arm is vertical I don't know. For the steering wheel with two spokes you could lay a level across the spokes to see when the wheel is truly centered once the issue of turns lock to lock is cleared. Now then we come to the steering arm. We would like to show that it's bore for the tapered rod end is the same distance from the frame at a point an equal distance from the front on both sides of the frame. Of course it is closer by a lot to the driver's side but we can allow for that. How high or low it is effects the slant length of the measurements and I would ask if you are familiar with Pythagoras formulas for right triangles to make useful the various ups and outs to get a hypotenuse. Now back to a more direct way that depends on what you have just written that the plane that includes the steering arm and the steering mast up to the steering mast is vertical when the middle is achieved so place a long bolt through the bore of the steering arm and then attach a plumb bob (string or wire and weight) to the end furthest from the steering arm and as you turn the wheel ever so slightly note how the string either lays or does not lay against the lower part of the bolt. Hmmm! It hangs beyond the tip of the arm so you must also attach, perhaps with clamp, another rod to the top of the steering arm laid along it to touch the hanging plum bob. Now probably it is on one side or the other of the string. You could back it off and make it pointed until it just touches the string at a point. Next you want to set the wheels so that they both point not only parallel to each other but also parallel to the frame. This where king pin inclination becomes important. Yes, it should be fixed on a beam axle as on a Ford and would require bending if it wasn't but also we come to issues with trail of the axle position behind the tire contact point which makes the dynamics of the alignment stable as we run down the road. (This is something motorcycle and bicycle folks like to fuss with.) Next is something called Ackermann which is how much the inside wheel leads the outside in angle in a turn and was once seen as important to low tire scrub but has vanished as an issue in modern race car design. So we have the king pins inclined slightly back and somehow figured out the exact value in a similar way comparing to other plumb bobs laid along them. Camber is out next thought. We should find the king pins inclined so the tops of the tires are slightly further out than the bottoms. This is also important for stability of direction on a road. (It isn't really to drive on crowned roads.) As I remember Ford toe-in it is best at zero which is how the wheels are angled to the axle centerline side to side in a horizontal plane. Typically what one would see is strap iron rods run forward and aft from the wheel spindles perhaps attached to the spindles beyond the castellated nuts hidden by the caps over the bearings. and with a simple joint out front and back so one could adjust two more straps laid on top of the fore and aft ones one forward and one back so these run from side to side or right to left. Now once we know that the two measurements of the rods one front and one back are identical we are ready to use our plum bob again. Make a straight line that will be under the car from back to beyond the front where a plumb bob exactly hanging from the mid point of the front side to side rod is located touches the mid-point line of the car. Yes you may need a tape measure beyond the plumb bobs to measure the rods in the wheel frame. Vertical has taken you a long ways.
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| therunwaybehind | -- 09-17-2019 @ 1:33 PM |
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Once the bores of the respective future positions of the rod ends are fixed in space is hoped that the tie rod end tapered pins and the cross link ends will simply drop in! Now wouldn't that be wonderful. The next steps are to use the clamps and sleeves on the loosen the threaded parts so the length of the active parts of the car can allow this drop in. This may involve some angular movements of the ball and slot until there is no push or pull to throw off the semirigid frame we have built to hold the steering knuckles and the steering arm and the steering wheel. Force free is the goal. It is my belief that all the tapered pins go down through their mating bores. Whether they are truly "vertical" is something you will experience. If not there is friction but these are not places to lubricate. Because they are tapered bores they will vary a bit in draw down as the nuts on them are tightened. The rigged fixture described in my earlier post is the way to maintain management of the overall alignment.
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| autoluke | -- 09-22-2019 @ 8:22 AM |
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Thank you for the lesson in angular physics, but my problem seems to be otherwise. In order to be sure that my steering system was within all tolerances I replaced king pins and bushings, the entire steering box and worm shaft, pitman arm, and the two adjustable links. With the steering wheel centered, and the pitman in true vertical, the front wheels turn well in one direction, but in a substantially smaller arc in the other. ( toe in has been set to spec. ). Has been driving me up a wall, so that any ideas would be much appreciated.
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| 37RAGTOPMAN | -- 09-22-2019 @ 10:44 AM |
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HI autoluke its seems to me the splines on the pit man arm shaft , and the pit man arm are off, there should have been factory alignment marks, when assembling, grooves in the splines should match up with grooves in arm pull the pitman arm back off, there should be marks where it lines up., I guess you did not mark anything before removing the parts, you can center the wheels, pull the pitman shaft off, center your steering wheel go from one side to the other, try finding the center, now attach both parts only snug up,[for time being } make SURE Tight after everything is ok, now try turning the wheels and back and forth from one side to the other, when the wheels straight ahead you steering wheel should be center, you can tweak it by adjusting the drag link, if it is off a little, to make sure the steering wheel is dead center, It is important because if everything is center, this is were the least amount of play is, soon and it come off center, you get a little more play, make sure there is no binding between the sector shaft and worm, let us know how you make out, are you using a shop manual ? hope this helps, 37Ragtopman
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| therunwaybehind | -- 09-22-2019 @ 11:23 AM |
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Are you complaining about Ackermann? That the wheels do not track exactly parallel and even in reverse seem almost to cause upset? Let me look up that term as it has gone out of style in design circles. https://en.wikipedia.org/wiki/Ackermann_steering_geometry ????
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| autoluke | -- 09-27-2019 @ 8:46 AM |
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Carefully examined all the components, AND measured the turning radius on both wheels.. Pitman marks align with shaft Pitman and drag link aligned per specifications. As mentioned earlier.. new king pins, bushings and connecting links. Steering wheel turn-to-turn identical in both directions. THE PROBLEM Readings from the bearing mounted table under each wheel... RIGHT TURN Right wheel : 30degrees/ Left Wheel 35 degrees LEFT TURN Right Wheel 20 degrees/ Left wheel 30 degrees Peerhaps a bent axle ??????
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| therunwaybehind | -- 09-27-2019 @ 4:15 PM |
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So now we are to the right hand steering arm having two tapered bores and the left one has only one. Is it possible to switch the positions of the cross over link end with the tie rod end on the right hand side? Before doing any changes you could measure the distance from the actual tie rod end on each end to the king pin axis. If it's the same as you have assembled everything after taking everything apart, --- I refer to right as the passenger side as if in the driver's seat and left as the driver's side. Apparantly, some suppliers view the car from the front,---but any way--the early Ford book as two drawings that show the tie rod as above the radius rod and there is test to note this confusion. With the suppliers it is the part numbers for the tie rod ends where the green book shows 21A and 8C prefixes of 3290 and 3289 and replaced by 3271 and 3270 where the lower numbered part is unique and there are two of the higher numbers and no number at all for the end that is with the pitman arm as the draglink includes it as 3306. I think that 3289 assy is the tie rod end that goes in the front hole of the passenger side steering arm and spindle. in that arm the 3290 goes in the rear hole and becomes part of the drag link that crosses over from the steering box and joins with 3306 near that location. Another 3290 goes at the other (driver's side) end of the tie rod. Checking for a bent radius rod 3405 might also be appropriate. Folks want to write mostly about bump steer now . Does one of the two in a pair of 3290/3289 have a left hand thread for the tie rod? An indexing cut for the tapered pin? This message was edited by therunwaybehind on 9-28-19 @ 5:01 PM
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| autoluke | -- 09-29-2019 @ 4:36 AM |
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Switching the positions by reversing the attachments would not work. The drag link which has been installed is the correct one.
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| therunwaybehind | -- 09-29-2019 @ 8:23 AM |
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We are back at your first post where attaching the drag link threw things off. That leads me to think you have the length of the tie rod wrong and that caused you to over adjust the drag link to compensate for what happened when you moved the wheels later. So I would offer the measurement of where the center of the tie rod is when both wheels are pointing most forward. You could set the toe in to zero at this point to simplify. Use the plumb bob at the center of the car method to find where the center of the tie rod should be. Then measured to each steering arm on each spindle. Is it the same? Next I would lift the car by the axle so the wheels could be turned by hand with the drag link unattached. I would now go through turning them equally left and then right and see if the angular measurements agree with the results with the drag link attached as you have reported. Hmmm-- The setup is rigid between the axle and king pins and the tie rod and it's ends. You can measure diagonals on it if you suspect any sides of this rectangle is bent. The rubber in the system is in one of the spring shackle ends on each end of the spring, the one in the spring. Then the other rubber is in the ball at the transmission end of the radius rod wishbone. The axle could be skewed by wear in these rubbers. This would not matter until you hooked up the drag link to a point rigidly attached to the frame. I now have the book Ford v-8 Service Bulletins 1938-40 which I purchased used from Amazon. I see that all depends on a KRW-525 wheel aligner and KRW 526 correction tools. The procedures described include any bent or distorted parts. This message was edited by therunwaybehind on 10-6-19 @ 10:08 AM
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| autoluke | -- 10-20-2019 @ 5:39 AM |
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The calendar is full, so have decided to place the Ford in winter storage. I'll attack the problem again in April, and want to thank everyone for their comments.
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