Bobber Rear Axle Problem

[FarmerRob]

Ok, I don't know if my truck is different than everybody else's or I'm just being an idiot but I have a problem with my rear axle location and nothing I've searched for shows me that anybody else has had this issue.

I used front deuce springs to bob my truck and used the center axle for the conversion. I installed the axle onto the pins that were the same distance apart as the spring packs... and my axle is offset to the left by about three inches.

What am I missing???

 

[militarytrucks.com]

Bring it to me, and I will fix it for you

The factory axle locator pins will not work to center your axle. You must weld spring perches to the axle.

 

[FarmerRob]

Huh. Really?? Why does nobody (including XM381.com) mention this??

 

[militarytrucks.com]

Because they do not have as much experience building bobbed deuce trucks as I do.

I am not trying to brag. Experience does count for a lot when building a custom truck. Having built over 20 bobbed deuce trucks, and many other custom trucks during my career, there are some things that I have learned.
#1 There is no manual for custom work.
#2 There is no substitute for experience.
#3 If there is no manual, then wright one, but only share it for a fee.

 

[FarmerRob]

Because they do not have as much experience building bobbed deuce trucks as I do.

I am not trying to brag. Experience does count for a lot when building a custom truck. Having built over 20 bobbed deuce trucks, and many other custom trucks during my career, there are some things that I have learned.
#1 There is no manual for custom work.
#2 There is no substitute for experience.
#3 If there is no manual, then wright one, but only share it for a fee.

No argument with any of that but I've read dozens of threads about bobbing and nobody else has mentioned the axle pins not being centered. Made me wonder if people were just bolting the springs on the flat part of the axle and hoping for the best.

 

[Floridianson]

Why would you need to weld the Deuce perches. When the locator pin is used on a non bobbed truck the pin just sets the rears in the correct spot no guess work no measure when replacing a rear. The perches have tabs that cup the axle both top and bottom and prevent it from going anywhere if you use the perches from the Deuce front axle. Yes you will have to measure side to side and front to back to keep the axle in line and centered but that is not a big problem.

I believe using new and correct U bolts.

 

[FarmerRob]

Why would you need to weld the Deuce perches. When the locator pin is used on a non bobbed truck the pin just sets the rears in the correct spot no guess work no measure when replacing a rear. The perches have tabs that cup the axle both top and bottom and prevent it from going anywhere if you use the perches from the Deuce front axle. Yes you will have to measure side to side and front to back to keep the axle in line and centered but that is not a big problem.

Because the front springs (and the front axle pins) are centered under the frame, while the rear suspension and rear axle pins are mounted outboard of the frame, with a third pin for the torque rod. When using front springs on a rear axle, the pins don't line up right. For this reason, I have just decided that it's better to use the M105 suspension, since the springs are outboard of the frame and should line up with the pins.

 

[dilligaf13]

Pictures??? I never had to cut anything off or weld anything onto any of my bobbers axles.

 

[FarmerRob]

Pictures???

I'll get some tonight. After a phone conversation with militarytrucks.com, I guess it's a common problem but nobody has ever talked about it. Really makes me wonder how many bobbers are out there without having hard stops on the axle and are just trusting the u-bolts to keep everything from sliding sideways.

 

[Robc]

When I did mine (using front springs) I measured about 38 times maybe more and tighten ubolts down. I then cut pieces of 1/4 in square stock and welded to the axles snug against the springs. Be running for almost 3 years and no movement.

 

[Floridianson]

Really makes me wonder how many bobbers are out there without having hard stops on the axle and are just trusting the u-bolts to keep everything from sliding sideways.

I worry more about an axle sliding on the springs than I ever would going side to side. That is why I use the correct perches and new correct bent U bolts. Do what ever make you feel right.

 

[FarmerRob]

I worry more about an axle sliding on the springs than I ever would going side to side. That is why I use the correct perches and new correct bent U bolts. Do what ever make you feel right.

Both need to be accounted for, fore-aft movement and side-to-side movement, just like the original suspension.

 

[Floridianson]

Over thinking it maybe. If the u bolts were loose enough to go side to side then as soon as you hit the brakes the axle would walk all the way back to the spring hanger. Do what you feel is right.

 

[FarmerRob]

It's not so much about the u-bolts being loose but the setup being able to handle the lateral stress that it was originally designed for. Friction and clamping force aren't really sufficient to keep the axle perfectly located under all conditions. That's why all solid axle setups have some way of keeping everything exactly where it's supposed to be, whether it's locating pins, welds or whatever. I'm not saying that it's going to slide across the axle tube and bang into the center section but it could walk itself back and forth as little as 1/8" and cause problems.

But like you said... do what you feel is right. Personally, I feel that everything should be held in place with hard stops and the u-bolts should only be providing clamping force.

 

[Floridianson]

Well if we don't blow smoke and we have done a lot of trucks then we would know where to relocate the pin. So we remove the axles drill another hole, thread it and screw in another stud. That way when we go to place the axle on the bob there is no measuring and we do nothing but tighten up the U bolts. Also if any axle damage is incurred we just unbolt the U bolts and slide in the new rear. No cutting off old perches or buying new ones.
That's what I would do if you wanted me to if I built a bobber for you.

 

[Floridianson]

Both need to be accounted for, fore-aft movement and side-to-side movement, just like the original suspension.

If you look at a front end there is no locator pin on the axle just the rears and just the clamping force of the U bolt. I would worry more about someone cutting the 105 frame and welding it to the Deuce frame just so they can run 53's. I would worry more about home built perches or lifting blocks that have been out there. I like to use Deuce perches and you don't have to make the top wedge to the correct angle to tip the axle down to get a good drive line angle. Also as said I only like using new u bolts and I retighten them after maybe 100 miles. I also use a $700.00 mag drill and annular bits to cut the new holes for the hangers.
Yes they are some good builders and welders and they can build anything and there are cheap and poor builders out there too.

 

[FarmerRob]

Thanks for your input. I've never taken apart the front suspension on a deuce but I just googled images of 2½ ton Rockwell axles and every one of them has locating pins for the springs.
And nobody has suggested not using the deuce perches. Militarytrucks is just talking about welding a bead on the axle to hold them in place.

 

[Floridianson]

Yep look at a front axle no pin in the axle itself only the rears. The only bolt that would come into play is the one that holds the front spring pack together. So I guess the top perch could be locked into the spring pack but nothing to hold the bottom or top perch to the front axle. New bolts to right torque and re torque twice and I believe they should stay put if using Deuce perches.
Do believe there would be a lot of extra force when there are the tandems back there and when in a turn the rear rear is force to follow the front tandem but one would think in a bobbed this would be lower amount of force.

 

[dilligaf13]

Plus all the movement of the tandems "walking" back and forth that isn't present on a bobber.

 

[FarmerRob]

Yep look at a front axle no pin in the axle itself only the rears. The only bolt that would come into play is the one that holds the front spring pack together. So I guess the top perch could be locked into the spring pack but nothing to hold the bottom or top perch to the front axle. New bolts to right torque and re torque twice and I believe they should stay put if using Deuce perches.

I don't know what axles you've been working on but I'm going to have to disagree. Front axles do have locator pins. Valence has even broken one of his off while trying to change his caster. Here's pics: http://www.steelsoldiers.com/showth...-G-177-tires&p=1762653&viewfull=1#post1762653

Plus all the movement of the tandems "walking" back and forth that isn't present on a bobber.

Very true, but every axle has side load. Tandem axles just increase it exponentially.