Spring and U-Bolts Maintenance on BC

cookie

Administrator
Staff member
Something does not look right here. In the first picture, I count five leafs along with a rusty u-bolt and a lot of threads showing. In the other pics, I count six leafs with shiney u-bolts. Hmm.
And Larry, if you are talking about the clamps that are aound one side of the spring pack, I have been told by a local, been in business since springs were invented outfit, that that clamp is basically there to hold the spring pack together for installation. If installed in allignment and u-bolts are properly tightened, the springs should not move. If they have moved out of allignment it is a sign of loose u-bolts. Or they may not have been installed in allignment.
I'm no expert, but that is what I have been told.

Peace
Dave
 

Bobby A

Well-known member
What 5th wheel does Bobby A have?

Tankie, let me jump in hear and answer your question, I have a 2010 3580 Big Horn 1 year old exactly and probably about 2000 miles driving on the coach. Larry was so kind to post the pics for me cause I didn't know how to post them.
 

Bobby A

Well-known member
Something does not look right here. In the first picture, I count five leafs along with a rusty u-bolt and a lot of threads showing. In the other pics, I count six leafs with shiney u-bolts. Hmm.
And Larry, if you are talking about the clamps that are aound one side of the spring pack, I have been told by a local, been in business since springs were invented outfit, that that clamp is basically there to hold the spring pack together for installation. If installed in allignment and u-bolts are properly tightened, the springs should not move. If they have moved out of allignment it is a sign of loose u-bolts. Or they may not have been installed in allignment.
I'm no expert, but that is what I have been told.

Peace
Dave

Hi Dave,
The rusty u-bolt you see( door side rear) is the replacement one that went out on me in October on our way south for the winter, center pin sheared and was replaced also on that same axle spring. We are getting ready for our 1200 mile journey north and I don't wanna have to go through what I did on the way down, I'm still a little gun shy about this axle/u-bolt/spring issue. When you have a bad experiance on the road away from home and in a foreign town you never forget. I just wanted everyone opinion and Larry was so kind to post the pics for me.
Bobby
 

Tankie

Well-known member
Larry,
Very good eye! When I was under there I seen that but didn't think twice about it. I think the safe and smart thing to do is go to spring shop. Thanks Lonnie
 

Bobby A

Well-known member
Something does not look right here. In the first picture, I count five leafs along with a rusty u-bolt and a lot of threads showing. In the other pics, I count six leafs with shiney u-bolts. Hmm.
And Larry, if you are talking about the clamps that are aound one side of the spring pack, I have been told by a local, been in business since springs were invented outfit, that that clamp is basically there to hold the spring pack together for installation. If installed in allignment and u-bolts are properly tightened, the springs should not move. If they have moved out of allignment it is a sign of loose u-bolts. Or they may not have been installed in allignment.
I'm no expert, but that is what I have been told.

Peace
Dave

Dave, good eye !! after you said that about counting 5 or 6 leafs, you got me thinking so I just crawled under there and you are exactly right. On the one that was replaced its missing the smallest spring at the bottom from what I can tell. This work was done at a small Heartland authorize dealership somewhere in Kentucky or Tennessee can't remember which without digging up the paperwork. I don't know what to do at this point ?? I just want peace of mind pulling this beast 1200 miles back to Michigan.
Thanks and good catch !!
 

cookie

Administrator
Staff member
Bobby, you have have been dragging your rig around this far. If it were mine, I would't give a second thought to another 1,200 miles. The spring looks good.
Like you said in an earlier post, the springs seem to be doing their job.

Peace
Dave
 

SouthernNights

Past South Carolina Chapter Leader
Dave, I am not going to dispute what you have been told.

If you ever have built a spring stack, the last thing you do after building the stack, is secure the clamp, so I am not sure how much help they are during assembly.

If you look at the retainers on trailer leafs, they are always on the front of the spring. Sometimes trailer springs have two retainers on a spring stack, fornt and back, but they always have them on the front. The reason for this is to hold the pack together under torsional loading. In other words, when you apply the trailer brakes, the axle wants to stop but trailer wants to keep going. This puts a torsional load on the axle where it connects to the springs (u bolts). If the reatainer was not there, the longest springs just under the main leaf will actually seperate form the main leaf putting more strain on the u bolts and allowing the spring leafs to move more than they do under braking. This can actually lead to wheel hop under severe braking.

If you look under a power unit, most of the time there are retainers in front of and behind the axle. When you accelerate the section of spring behind the axle wants to seperate just like on the trailer. Only this time they are seperating because under acceleration the drive axle wants to go faster than the truck. The retainers help keep the spring pack together once again trying to eleiminate wheel hop.

Aftermarket traction bars ( typically used on higher HP "hot rods")perform somewhat of the same function as the rear retainers are performing. They eliminate wheel hop and axle wrap under severe acceleration.
Of course the front retainers perform the same duty as they do on a trailer. They are there for braking.
 

caissiel

Senior Member
This afternoon I reinstalled the shocks at a 53 Deg angle and while having supper at the table I noticed that the trailer was much more steady. My Wife also noticed the the boucing difference. While I was under I torqued the U-Bolts again to 70 FtLbs.

Does anyone know the proper torquing of the 9/16" U-Bolts, It must be more then the 1/2" U-Bolts. The wheel nuts are 9/16" and I torque them to 140 FtLbs.
 

lwmcguir

Well-known member
120-130 pounds is where we have set them for the past 40 or so years. Here is a link that tends to lean that way. We stop as he suggest when the plate starts deforming no matter what the torque wrench says. Never lost one yet. Center Point Suspension is the best thing anyone can do for the Lippert suspension. Takes the shock off the frame and rides like a dream. We have 8K axles and springs and it rides smoother than our Torsion axle trailers.

http://www.youngspring.com/pages/torque.htm
 

beardedone

Beardedone
120-130 pounds is where we have set them for the past 40 or so years. Here is a link that tends to lean that way. We stop as he suggest when the plate starts deforming no matter what the torque wrench says. Never lost one yet. Center Point Suspension is the best thing anyone can do for the Lippert suspension. Takes the shock off the frame and rides like a dream. We have 8K axles and springs and it rides smoother than our Torsion axle trailers.

http://www.youngspring.com/pages/torque.htm

Can you provide details on your running gear upgrade. I have a mess on my hands (see me post of about 5 minutes ago on "request for bolt pattern information") and need all the info I can get. My questions are what brand of assembly you purchased, did you have to get new wheels, width of springs. I ordered the center point but can't find heavier springs that will fit the center point. Only heavy springs I can get are slipper ones and they won't work. I am in a real pickle right now.
 

jbeletti

Well-known member
Re: Need bolt pattern for wheels

See the attachment. I extracted page 16 from the Lippert Trailer Axle Operation Service Manual that is posted here on the Heartland Owners Manuals site. It has the lug nut torque and sequence for 14", 15" and 16" wheels.
 

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