Shorten wishbone to get proper caster

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Model T Ford Forum: Forum 2010: Shorten wishbone to get proper caster
Top of pagePrevious messageNext messageBottom of page Link to this message  By Dion Rinaldi on Monday, October 18, 2010 - 04:39 am:

Hello again. It would appear most likely that excessive camber may be my problem with violent shaking as discussed in earlier thread.
My caster was so far out that I dropped the wishbone and made up a ratchet jig to pull axle into proper alignment 1/4" - 5/16".
After doing this the wishbone is too long to re-fit and would need too much bending in my opinion.

I plan to cut, shorten and reweld each arm to get the proper perch bolt fit. Is this a cure that others have used?

Attached are some pics to show how far out the axle alignment was in relation to the perch bolt.
Regards Dion.
Axle alignmentWishbone length


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kerry van Ekeren on Monday, October 18, 2010 - 05:40 am:

Hi Dion, I don't think cutting and welding would be a good idea, maybe pressing a solid steel plug in and tack weld on one side, grind flat and redrilling.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Adrian Whiteman, New Zealand on Monday, October 18, 2010 - 05:51 am:

Dion, glad the hunch about caster was helpful. I can't comment on welding - best leave that to an expert to opine on, but I would hesitate to weld such a key component.
Cheers
Adrian


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dion Rinaldi on Monday, October 18, 2010 - 06:01 am:

The arms of the wishbone appear to be rolled steel tube with a seam full length. The solid ends, front and back are welded onto the tube. Don't see why we can't do the same.

Has anyone done it, it looks to the only solution as bending the wishbone a lot would put a fold/crease in it I would think.

Dion
Australia


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dennis Halpin on Monday, October 18, 2010 - 06:32 am:

HOLD ON A MINUTE. I might be wrong, but positive caster shouldn't cause a wheel shake (going forward). Zero caster or negative caster sure will.
From the looks of those pictures, the axle jig you made has the axle sitting at zero (straight up and down) and bolting the wishbone back on would give you just about the right positive caster.
Don't go changing anything until some of the really smart T guys chime in here.


Top of pagePrevious messageNext messageBottom of page Link to this message  By richard wolf on Monday, October 18, 2010 - 07:23 am:

I wouldn't shorten the wishbone. You need to find what has changed and correct that.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Allan Bennett on Monday, October 18, 2010 - 07:48 am:

Dion,

If you need to cut and shut the wishbone, something is wrong elsewhere.

I cannot tell from your pictures if your spring perches are fitted correctly. The axle has no front or back and can be installed either way around. The caster is set by the spring perches. Correctly installed, the axle will slope back at the top.If not, you need to swap them over.

Removing perches can be a real pain. It may be easier to turn the axle end to end and swap the spindles from one side to the other. Eyeball the perches to make sure the shackle pins are in line. If one goes one way and the next the opposite, you have two perches the same, either both right or both left.

Set the axle with the king pins sloping back at the top. Then fit the spindle with the left hand thread to the right hand end of the axle and the right hand thread goes on the left hand end of the axle. The idea is that the threaded bearing winds out if it comes loose in service, rather than in and causing binding and possible callapse.

When installed in the chassis there is a noticeable slope in the axle towards the rear at the top of the kingpins. If yours does not then you may have a chassis front cross member which has suffered a heavy impact at some time and has been pushed back and/or twisted upwards.

Keep us posted and somebody will be able to help you out.

Allan from down under.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Herb Iffrig on Monday, October 18, 2010 - 08:55 am:

I agree with Richard and Allan, something else is amiss other than the wishbone. How tight is the ball socket on the oilpan?
Does the oilpan look bent? There are jigs around to straighten the pan.

Herb


Top of pagePrevious messageNext messageBottom of page Link to this message  By James C. Eubanks on Monday, October 18, 2010 - 08:57 am:

there is a right and left spring perch, the perches have a flat tab to the outside that should be to the rear


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Tomaso - Milton,WA on Monday, October 18, 2010 - 10:04 am:

It is usually quite apparent if you have positive camber just by looking through the wheel from the side - is there ANY lean of the top of the axle to the rear with the radius rod connected ?


Top of pagePrevious messageNext messageBottom of page Link to this message  By John A Kuehn on Monday, October 18, 2010 - 10:15 am:

The flat tab on the spring perches is the key to which way the front axle is installed just as James said. It is possible to install the axle backwards and that definitely will throw things off. If you look closely at the pic of the axle you can tell that its not pitched toward the back as it should be. If it is backwards to me the easiest thing to do would be to remove it and turn it around. My opinion.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky on Monday, October 18, 2010 - 10:31 am:

Ditto on the spring perches installed on the wrong sides. The spring should be perpendicular to the ground. The axle should have a noticeable tilt back at the TOP when the perches are installed correctly. Think of the "castering" effect as being upside down--The spindle line is behind the lower axle line.


Top of pagePrevious messageNext messageBottom of page Link to this message  By CharlieB-Toms River N.J. on Monday, October 18, 2010 - 11:31 am:

ALOT of good information here. All of it in regards to what has changed/bent or whatever in the wishbone system.I haven't noticed if you said you bought the car this way or if it started suddenly.From the pictures (and paint) I assume the parts have been on the car a while. If you bought it this way you have some checking/measuring to do to see what parts may be wrong. If it started suddenly something is bent or twisted.Check carefully before $pending.


Top of pagePrevious messageNext messageBottom of page Link to this message  By tyrone thomas on Monday, October 18, 2010 - 01:17 pm:

well yea. He is pulling the bottom of his boards to the rear of the car which uprights the spindles.


Top of pagePrevious messageNext messageBottom of page Link to this message  By George...Cherry Hill, NJ on Monday, October 18, 2010 - 01:41 pm:

I hate to chime in as an also ran, but to me there is almost no natural way to get THAT amount of mis-alignment!

Go back to basics, you've started in the right direction...assure the spring is set right and sqaure to level into the cross frame and both the spring and the cross frame is not bent or twisted, do the plumb-bob check for proper tilt with the wishbone out, assure your perches are right.

That proven, then something really isn't right and it is outside of the area you are concentrating on! Time to check is the wishbone stock, has the wishbone keeper been modified or rebrazed as I can't imagine an engine going in and sitting forward that much-create too many other issues elsewhere, or did they just wad in the back side of the ball keeper for other reasons that were not understood?

At some level, I could possibly question the spring arch of a replacement spring and geometry, but even that I don't think can give you that much off as you'd probably visually see it before you needed to measure it!

Last, and I may be wrong on this and offer it for thought...but if the perches are indeed backwards...I think you may be seeing twice the actual built up error in your picture? Someone feel free to comment on that assumption.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Randy Driscoll on Monday, October 18, 2010 - 03:02 pm:

Reversed perches would result in a 5 1/2 degree negative caster, whereas this case is 5 1/2+ degrees positive.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Monday, October 18, 2010 - 03:06 pm:

I agree with most of what has been said. Positive caster is needed and it looks as if you need to tip the axle back almost enough to fit the wishbone. Too much caster does NOT cause shimmy or darting. I had one with too much caster, it steered okay up to about 20mph and above that could hardly be steered at all. It only wanted to go solidly straight ahead. It was a lowered speedster and needed the wishbone bent to compensate for the drop.
I have found many model Ts have a bit of an issue with getting the wishbone to set nicely between the axle and the pan. The amount yours is off is so common as to be considered normal. (Yes, if everything is undamaged perfect original, it should all line up and drop into place.) They always seem to be just fine once they are forced together as long as all the geometry is good.
I would ask, also, what is the history on this problem? Has it been like this? Or has something changed? I know you have checked and replaced all the usual stuff. Look closely for any signs of old damage to the frame and pan as well as the front axle pieces. Check the tie rod closely for signs of developing a crack. I had one break a few years ago. I was lucky. I was making a minor adjustment to the toe-in in my driveway the day before going on a 200 mile endurance run.
At this point, I would suggest changing the the spindles, both of them. Camber can also cause steering problems. Random chance occasionally puts a pair together that are not compatible. I have known of several cars that had troublesome steering that was finally fixed only by replacing the spindles. They are still easy to get, and not difficult to change. Careful measuring has shown they vary a few degrees on the camber. And make sure they are on the correct sides.
Truly, this is one of those trying troubles that drive you batty. But, chin up. You can get through it as many have, and go on to enjoy that T for many many years and miles.
Drive carefully, W2


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dion Rinaldi on Monday, October 18, 2010 - 04:07 pm:

Thank you all for the assistance. The perches are definately the right way around. The pics are not the greatest but while the axle is held with the strap (both sides) the caster is correct at 5/16" tilt to the rear measured with a set square off the concrete even though the pic makes it look upright.
The vehicle was almost complete when got from a deceased estate but not mobile for quite a long time. There is no avenue to seek any history about it. The only odd thing at the front is that it has a six leaf front spring but since I got this I have seen another with a six leaf as well. Spring is located correctly and is perpendicular to chassis.
I am back at it again today so will keep looking for answers but the drop saw is very tempting. (so are the matches!)
Cheers all.
Dion
Australia.
T ford


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Monday, October 18, 2010 - 04:29 pm:

Do not cut the wishbone. If you want more positive caster, the bottom of the axle would be front of the top of the axle. I think from the appearance in the pictures, it is correct. The axle needs to be tilted so the spring purchase can be inserted and the nut tightened. Your shake is caused by something else. Perhaps the wishbone ball is loose, or some other part is lose. It could also be caused by crooked wheels or tires out of balance.

The front axle should be tilted forward at the bottom (positive castor), the bottom of the wheels in at the bottom (camber), and the front of the wheels closer together than the back (toe in) Any other combination will make the car unstable, either shaking or worse yet, it will violently pull to one side or the other, tearing the steering wheel out of your hands.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Billy Rose Garland Texas on Monday, October 18, 2010 - 05:51 pm:

It looks to me that the rig in the photo is pulling the axle to the rear causing it to lean forward. ??????


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dennis Halpin on Monday, October 18, 2010 - 05:54 pm:

OK, I could be way out in left field here, but since there is no "history" on this speedster I have to wonder.
This is a right hand drive "Aussie" Speedster. Is there a possibility that the steering/axle is comprised of left hand drive and right hand drive parts and could that make a difference?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dion Rinaldi on Monday, October 18, 2010 - 06:11 pm:

The wishbone ball is very round and does not appear to worn unless worn evenly all over.
There is a small amount of looseness in the ball cap but no matter how I pull or push the wishbone it does not go rearward far enough to allow fitting to perch studs when wheels have proper positive caster. Movement is much less than 1/16".
While I will fit a new ball cap while I am at it I still need to find and fix the problem.

By chance would someone know the exact ball diameter perhaps of the new replacement type ones. If need be I can replace that as well while I am at.

Thanks again all
Dion
Australia


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dion Rinaldi on Monday, October 18, 2010 - 06:15 pm:

In the Mac's Catalogue - page 9 there is an accessory style radius rod ball cap #T2737. - how and where does this fit?
Dion


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dennis Halpin on Monday, October 18, 2010 - 06:19 pm:

One more thing. In that top picture of the spring perch, spring and axle. It sure looks to me like the spring perch is directing the spring toward the back of the axle? It might be an optical illusion but shouldn't that be the opposite way?
I think if it was mine, I'd disconnect the axle from the spring perches and steering and just turn it around and re connect the perches and see if that axle all of a sudden lines up with the wishbone, if for no other reason than to eliminate something from the trouble shooting.
What if the guy who use to have this thing used a left hand drive axle and converted it to right hand drive by installing it the opposite way and swapping only the spindles?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dion Rinaldi on Monday, October 18, 2010 - 06:33 pm:

Dennis - Thanks for that but with RHD-LHD as far as I can see the only component that is different is the steering column bottom mount. Fitted tightly against generator on RHD. The drag link would be reversed with the adjuster on the passenger side and all other steering parts would be the same as far as I can tell.

Several people have said the axle can be fitted either way (with the stubs reversed) so the perch hole must be orientated the same either way. I don't mind trying it though.

Regards Dion.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Kelsey on Monday, October 18, 2010 - 06:53 pm:

Dion:

I skimmed through the messages so I might be duplicating what others have said, but I ran into an immense shimmy with my car when it went over 30 mph. I checked the camber, caster and even thought that my axle was bent. The wheels ran true, the steering was tight and still it darted all over the road. Even as you described, the ball was round and didn't look all that worn; however, that was the problem. Upon the advice of a friend, I took a quarter, set it upon a open socket of the same size, took a hammer and punch and made it fit the shape of the ball. Stuck both back into the pan and the shimmy went away. I just recently purchased the T2737; however, I think the quarter worked just as well. That's my two bits.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Sims Reed City MI. on Monday, October 18, 2010 - 07:00 pm:

Dion, forget most of what you have told on this thread. Even I am confused with all the things you have been told .Reattach your wishbone and then with your square again check that the top of your spindle is tipped to the rear of the car. If the top of the spindle is less than one inch to the rear and both sides are the same, you can believe that the caster is not your problem. I have 4 different T's with caster measuring anywhere from 1/2 to over 3/4 inch caster with absolutly no problems.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Lindsay Martin on Monday, October 18, 2010 - 11:06 pm:

Does it have the correct length drag link?


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Stroud on Monday, October 18, 2010 - 11:47 pm:

Dion, this won't help solve your problem, but it may help you maintain control while road testing your car. If it starts to shimmy, let loose of the steering wheel, don't let go, just loosen your grip enough to allow the wheel to slip in your hands. This takes out the "resonance" or "springiness" in the steering shaft and will let it stop shaking, at least it does on my Coupe, but it doesn't have nearly as bad of a problem as yours. I had a small shimmy and installed an Apco ball end stabilizer and pretty well took care of it. Might give it shot if you have troble on your next shakedown run. I learned this little trick about the steering wheel right here on this forum. Just keep at it, something will show up without having to make any drastic changes. Good luck. Dave


Top of pagePrevious messageNext messageBottom of page Link to this message  By jack daron-Indy. on Monday, October 18, 2010 - 11:52 pm:

I'm tempted to tell you to loosen the front spring mount,then assemble wishbone to axle. when it is all lined up,retighten front spring mount bolts. Your front cross member may be bent backwards a bit.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Schedler, Sacramento on Tuesday, October 19, 2010 - 01:26 am:

Here's how Milt Webb and I have our Ts rigged. We took a ball cap (Langs part 2728) and installed it above the ball, and another below the ball, dropping the wish bone about an inch (or so), giving us more forward caster. It improves the steering when going forward but probably makes it worse in reverse. I'm not sure about wobble. We installed about 5 lock washers on each stud below the cap, instead of the springs, and tightened the nuts quite tight before safety wiring the two studs together. M2CW


Top of pagePrevious messageNext messageBottom of page Link to this message  By peter kable Kiama Australia on Tuesday, October 19, 2010 - 01:52 am:

Dion,

LHD and right hand drive only have some components the same. the axle is the same so are the perch bolts the stub axles are the same but the connecting rod is different and so is the drag link and then there are 4 drag links.

So do a quick check and see if when the wheels are facing straight forward the the pitman arm is pointing directly down or not.

If its not then you have the wrong drag link, If the pitman arm is sloping to one side you may have little forward direct control over the steering and it may want to swerve.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dion Rinaldi on Tuesday, October 19, 2010 - 04:50 am:

Thank you so much everyone. I am a bit overwhelmed at the moment by the volume of information provided and need some time to digest it all.

My problem is basically that with the correct caster set, no damage or bends to chassis, springs, perches or any other steering component, the wishbone is not ever going to fit.
When it was fitted the axle is pushed way too far forward, and as the spring mounting is a fixed point above at the chassis, all the axle can do is tilt way backwards at the top giving about 1" of positive caster.

I will work it out, whether I need to cut the wishbone, move the motor or redesign my own wishbone set up.

Even when this is sorted, I am still not sure if the driving/steering problem would be cured. As mentioned it is by no means a wobble or shimmy, this is a very violent shaking that moved the front of car incredibly from side to side, in my opinion it could easily result in leaving the road or even flipping the car.

I need some time to think on everyone's suggestions.

I would still like to know the correct diameter of the wishbone ball if anyone has a new one to measure.

Kind regards
Thank you again.
Dion
Australia


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dennis Halpin on Tuesday, October 19, 2010 - 07:38 am:

There are some really sharp Model T guys "down under" Peter Cable for instance. But it's a really big country (like up here).
Why don't you post your location here or on your profile and see if there is one of them reasonably close to you that can take a look at it?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Seth Harbuck - Shreveport, LA on Tuesday, October 19, 2010 - 07:41 am:

His location is on his profile.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dennis Halpin on Tuesday, October 19, 2010 - 07:52 am:

I mentioned it here because mostly, it would take another Aussie would know where he is?


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Stroud on Tuesday, October 19, 2010 - 11:36 am:

Dion, have you compared your wishbone to another one? Maybe someone lengthened your wishbone in the past. Just a thought. Dave


Top of pagePrevious messageNext messageBottom of page Link to this message  By Larry Smith on Tuesday, October 19, 2010 - 11:45 am:

If you have a 4 dip pan, the ball socket could be out of alignment. A good many of them are.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem on Tuesday, October 19, 2010 - 03:57 pm:

Its' probably been stated several times above already but, here goes. You do not have to do anything to your wishbone. Too much caster will only make the car steering harder, nothing more. If anything, it will serve to eliminate or reduce your "violent shaking". The violent shaking is called shimmy. It's due to excessive wear in some, many or all of your steering, linkages, joints and bushings. Address those issues first and I think your violent shaking will end.

Think about it, how does a wishbone suddenly become too long? (Hmmm, wish my bone..... oops, sorry)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Randy Driscoll on Tuesday, October 19, 2010 - 04:02 pm:

The wishbone ball when new measured 1 1/4". 1/16" play is too much unless the rest of the chassis is perfect.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Randy Driscoll on Tuesday, October 19, 2010 - 04:38 pm:

I am fighting the "darting" problem on an '11 touring right now. I have the front end apart now and believe I have identified the worst of the problem. The guy I got it from (I don't know how he dared drive it faster than 2 mph) built up the worn holes in the perches (high wishbone) and then reamed, drilled or machined the holes to the wrong angle. Instead of 5 1/2 degrees positive castor It wound up about 1 degree positive. I made pins to fit the four holes in the bare axle. It and the other 9 or 10 axles I checked were all bent to some degree.
If the frame is spread the front crossmember is buckled and can result in having the bottom of the spring kick out.
In my situation it appears my wishbone is too short! I compared 6 or 7 early wishbones and they all varied in length. I also compared 7 or 8 sets of perches, from NOS to slightly worn and found them to vary about 1 1/2 degrees. The ends on early wishbones are not always inline either, causing a change in castor. So, with my axle alignment pins and a bevel protractor I will find the right combination of parts to give me the 5 1/2 degrees and see how it fits the car.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John A Kuehn on Tuesday, October 19, 2010 - 07:02 pm:

Dion, is the engine still in the frame in its stock position? Maybe things were altered years ago and the earlier driver had the same problem you are. Just a thought.


Top of pagePrevious messageNext messageBottom of page Link to this message  By CharlieB-Toms River N.J. on Tuesday, October 19, 2010 - 10:53 pm:

Bottom line. He's got something bent/twisted or replaced with the wrong part and he hasn't found it yet.


Top of pagePrevious messageNext messageBottom of page Link to this message  By CharlieB-Toms River N.J. on Tuesday, October 19, 2010 - 10:58 pm:

I'll guess that wishbone ball was replaced years ago and it's too long. Especially if nothing else appears altered. Think about it. It's the simplest answer for incorrect caster.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Billy Rose Garland Texas on Wednesday, October 20, 2010 - 05:06 pm:

Perches could be reversed, axel reversed, spindles on wromg side, drag link/tierods missadjusted, bad fit on all ball joints, bent frame/crossmember, spring locked (needs some slickum), you name it. Fom the pictures it looks like it could use some lube all the way around. ??????????? Looks like it is a one piece at a time T and the previous owner doesn't have that problem any more.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bill Dodd in Adelaida Calif on Wednesday, October 20, 2010 - 10:08 pm:

Early wishbone on a late car or visa-versa?

Bill


Top of pagePrevious messageNext messageBottom of page Link to this message  By Chris Barker, Somerset, England on Friday, October 22, 2010 - 09:34 am:

I'll try to make my observations short and clear:

1. Late Model Ts were lowered by flattening the front spring. If the wishbone wasn't shortened at the same time, the late cars must have more caster (rear tilt of the axle). I'm FAIRLY sure i have read that later wishbones were shorter, but I can't find the reference.

2. I have had shimmy on my '26 Coupe. It has a lot of caster. After replacing ALL the bushes, balls etc with any wear, I still had shimmy at about 12mph. The ONLY sure cure I have found is to 'nip' the spindle bolts just a little to add friction. ADjust it with both wheels off the ground and check the steering wheel effort as you go.
I guess one of the modern dampers which acts on the track rod should do the same.

3. Shimmy is an instability like a motorcycle 'tank slapper' or a clarinet reed. It is function of stiffness, friction, wheel gyroscopic effects and steering geometry. Reducing castor may improve matters - but I have the same difficulty as Dion with wishbone length. It's evident from Fahnstock that shimmy was a problem in the 1920s, with no proven cure.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Verne Shirk on Friday, October 22, 2010 - 10:40 am:

I've tried to read all of the posts and hope I haven't missed anything. I'm kinda wondering if the wishbones changed in length over the years. Did the wishbone length change from 3 to 4 dip pan? There was at least one different style of the later below-the-axle wishbone. It used flat bottom nuts instead of beveled ones. I always thought these were the earliest below-the-axle style. If you could find some other wishbones, try measuring the length to see if there is a difference.

Here's another thought. Did you oil up the front end parts? Parts in particular would be the spindles and tie rod ends. That will cause shimmy on a worn out front end assembly. I found that out the hard way. The quick correction for that is to wipe off all the oil and put it back together. Long term fix is to rebuild it.
Verne


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