Spring Shackle Nuts... How tight?

29er

29er

Senior Member
While tidying up the brake backing plates, I noticed the cotter pins were missing from the castle nuts on the spring shackles. "Easily replaced", thought I until I discovered the bolts lacked the holes for those cotter pins. Should I put in the proper bolts? If not, should I simply use split washers? Either way, how tight should the nuts be?

Getting nutty in Oregon,
Mike
 
The way I have done it over the years is to pull the nuts down tight to make sure the shafts of the shackle assembly are pulled all the way into the shackle bushings. Then back the nut off about a half of turn and install cotter pins. definitely install cotter pins so the nut does not vibrate off.

The shackles have to pivot as the car moves up and down and flexes the spring. If you pull them up tight it impedes the pivot action.

Tom Endy
 
I'm with Tom replace or drill the shackles for cotterpins. If not I'd recommend elastic stop nuts as an interim fix since the shackles need to move freely and need to be captivated.

If you have this style of shackle you may want to check to see if you have steel or rubber shackle bushings installed. Had same style of shackles on the rear of my Tudor and found some nasty gummy compressed rubber bushings. Not good for the spring perchs. Tim
 
Ford did supply original replacement shackles that had no cotter pin holes. Drilling the holes will not be easy if they are original they are hardened. Unless your off roading I wouldn't worry about the nut backing off.
 
Many thanks for your responses, guys. There are no holes in the shackle bolts for cotter pins, and the bushings are steel, not rubber. I haven't had any problems but will keep an eye on the shackles and maybe replace them.
 
Since you can't cotter pin the shackles, use two jam nuts as an alternative and lock them against each other.
 
Good solution, KR. Thanks, I hadn't thought of that. RonC's comment that Ford supplied original replacement shackles sans cotter pins is interesting. Wonder what kept the nuts from vibrating off?
 
29er said:
Many thanks for your responses, guys. There are no holes in the shackle bolts for cotter pins, and the bushings are steel, not rubber. I haven't had any problems but will keep an eye on the shackles and maybe replace them.
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The bushings should be steel, not rubber, so yours are right. All of the aftermarket units, and OEM units have the pin holes, check yours carefully, the holes may well be filled with debris if the car has been run without them. Backing the nut off will form the debris into the threads making the hole invisible. Lock washers will interfere with the proper operation. Best to make right if you can. shackles are not expensive, Jammed up, improperly working shackles can damage the spring perch, that is an expensive problem.
 
RonC said:
Ford did supply original replacement shackles that had no cotter pin holes. Drilling the holes will not be easy if they are original they are hardened. Unless your off roading I wouldn't worry about the nut backing off.
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29er said:
Many thanks for your responses, guys. There are no holes in the shackle bolts for cotter pins, and the bushings are steel, not rubber. I haven't had any problems but will keep an eye on the shackles and maybe replace them.
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I us locktite on the shackle nuts and the spring hanger nuts pluss I use the cotter pins. My life is to valuable to take a chance on the suspension coming loose.
 
Should the castle nuts still be snug enough after backing them off and with the cotters installed; i.e., can the nuts be rotated with the cotters installed? The prior owner installed a sway (panhard) bar mounting plate to the passenger side shackle and that plate was loose. It seems enough tension needs to be applied to keep the plate from moving.
 
On my Tudor, I used grade 8 lock washers, and tightened them up to 75 ft pounds.
I have just a stock setup, no issues still tight.
I did not drill and put in new cotter keys... the new U-bolts are too long and have the holes down at the end.
it's a spring to frame connection, it needs to be tight at the fulcrum, the spring leaves do the flexing, not the joint.

Many old U-bolts have the threads worn off and don't hold, I recommend new u-joint bolts no matter how you decide to put the nuts on.

I have been this way for 2 years of hard driving, no issues no looseness.

2nd note:
the key to the spring shackles ( front & back) is that they control the left / right lean of the car, so do a round robin tighten sequence.
 
I apologize, I meant spring hanger castle nut tightening in post 11.. After tightening and then backing off 1/2 turn or so the castles, as mentioned, should they be loose with the cotters installed?
 
I am a bit confused, but it is probably self imposed. I want to be sure that the conversation has not drifted off...Are you referring to the Castle Nuts in the Red Circles or in the Yellow circle in this image. If you are still referring to the nuts/cotter keys in the Yellow circle then they should be tightened up until the pin can be inserted. Depending on your nuts and the shaft thread, you might be able to turn the nut a little against the cotter key from castile to castile on the nut after the cotter key has been inserted. It is imperative that the shackle pins float and are not overly tightened. Personally I grease, assemble, tighten them up by hand, then give them a tweak with a wrench (maybe an 1/8 turn at most) just to be sure every thing is in place, then back them off a turn and tighten them finger tight to the spot where the cotter key will insert and the shoulder of the castle nut is as close to the shackle as it can be..
 

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My experience was I had to really crank down hard, very hard to make the nut go far enough down the shackle bolt to expose the cotter pin hole enough to insert the cotter pin. This was a constant force, I did not tighten and then turn back any.

In my case, I want to restore my 31 model A to as closely as possible to the original. I want it to be judge worthy, but I am not going to judging. I want a safe touring vehicle.

That being said. I would either install shackles with the cotter pins, or I would use double lock nuts. In this instance, I would not use lock washers or lock nuts. There is a lot of stress in this area. This is the only area the has the body connecting to the chassis. (Front also).

That is my two cents worth.
 
PHP:
I suspected that the conversation had migrated a bit, the original post was regarding the Shackles (Yellow Circles) Photo shows the Shackle.

This may be more information that you want, but....

The rear spring assembly includes the assembled spring pack with the square head center bolt installed, the square sides of bolt should be lined up parallel to the springs, place the spring pack into position below the cross member, lay a piece of Body Welt (I used a hard rubber gasket material) with a hole cut in it for the square head on top of the top leaf. so it will end up between the top most Spring and the rear cross member, insert the spring pack into the cross member with the square head sticking up through square hole in the frame, this is important because it keeps the spring centered.

The U-Bolt "kit" is two u-bolts, two u-bolt brackets (also called "clip bars"), and 4 castle nuts (size=7/8 wrench)/cotter pins.

Assemble each U-bolt assembly with the clip bar on the bottom, and the u-bolt coming down from the top over the crossmember. The Castle nuts go on last and pinch the clip bar against the bottom most spring. There are no lock washers.

Tighten the castle nuts, they will need to be surprisingly tight to get access to the cotter pin hole and insert the pin.

One word of advice though, tighten each side systematically with the same number of turns going back and forth from U-bolt to U-bolt. Example, x number of turns front right nut, then same number of turns left front, then rear right, rear left, etc until you pull it up tight.

Lastly you you bolt the spring eyes to the shackles, put on your wheels and set it on the ground bounce it a couple of times and measure the frame to the floor. I was not able to find any information on this in the Service Bulletins or Les's book, but it took me three tries to install the springs and have the frame set level. The first two times I tried it, the frame listed to one side or another.

Could have been my general lack of experience, but it took me 3 tries non the less.
 

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I just installed new Ubolts and castles from one of the vendors to hold the front spring to the frame cross member. The old ones were too long, and the holes for the cotters were too far down from the nuts. The new castle nuts were installed but required a 1/16" th. flat washer to allow the nuts to align with the cotter holes .After tightening in an alternating fashion, I checked the nuts with a torque wrench which seemed very snug at 35'#. Should the torque value be more or just good and tight?
 
They should be tighter than 35ft-lbs, I would guess at least 60 if not 70 or more. You need them TIGHT, don't forget, the front end is held to the frame by them 4 nuts.
 
katy said:
They should be tighter than 35ft-lbs, I would guess at least 60 if not 70 or more. You need them TIGHT, don't forget, the front end is held to the frame by them 4 nuts.
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The nuts hold absolutely no load other than keeping the through-bolts or yoke in position. It is the shear strength of those bolts or yoke itself that takes the load of the spring and vehicle weight. Adding tensile load (stretch) to them actually reduces their shear strength. 35 ft-lbs is plenty, much more than needed.
 
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