Wet bolt install

[TSQ]

Was under the trailer the other week giving everything a spring check and decided to overhaul the suspension prior to our long trip this summer.

Ordered up a Dexter K71-358-00 HD Suspension Kit which includes wet bolts, shackle links, and bronze spring bushings. This should fit most single axle trailers with 1-3/4" wide double eye springs (9/16 diameter bolts).

Fairly straightforward intall, as long as you have the tools and don't mind crawling around under your trailer. The included instruction cover it pretty well but I figured I'd do a little write up as well.

In part #2 I am also going to modify my rear hangers since they are the open type. Alternatively I could have bought a set of Dexter 030-020-00 rear hangers, but I think it'll be easier to just weld a bit of pipe inside my existing ones.

Tools I used:
- Jack
- Jack stand
- Grease
- Hammer/mallet
- Punch (not really required)
- Box wrenches (11/16 & 13/16)
- Torque wrench (good for 50 ft.lbs, w/ 11/16 socket)

1) Jack up the trailer and support the trailer frame with a jack stand.
2) Remove the wheel.
3) Take the weight off the spring using the jack under the axle.
4) Remove the three bolts - the are likely knurled under the cap so you may have to hammer them out.
5) Lower the jack/axle so you have room to work on the spring bushings

(note the old plastic bushing - I left my upper shackle link bolts in for now because I'm going to modify the hanger)
6) Slide one of the new bronze bushings over one of bolts your removed - if there is a knurled portion that the new bushing catches on file/grind it off first. Insert the end of the bolt into one of the old bushings.

7) Grease it all up

8) Hammer the new bushing in, which will push the old one out - make sure it goes in straight. If the old one won't come out cut it lengthwise from the inside using a hacksaw blade first.

(note the worn hole on the shackle link)
9) Install the new wet bolts and shackle links (except if, like me, you are going to modify the rear hangers) - you may need to hammer the knurled part of the wet bolt into the front bracket using a nut or socket or similar on the head of the bolt (to protect the grease zerk). I ended up tightening the nut a turn, giving it a few whacks, tightening a turn, etc until it was fully seated. Note that the instructions say to have the grease hole in the bolt at the side, not the top or bottom.
10) Torque them to 50 ft.lbs.

(I did install my front wet bolts)
11) Pump some grease into the wet bolts until it comes out the ends.

Don't forget to torque your wheel nuts when you put them back on.

I'll try and get around to modifying the rear hangers this week and post part #2.

 

[theseus]

Looks good! I think you'll enjoy the better suspension. My first camper had shot suspension and I re-did the entire axle and suspension. It sure rode better after.

 

[TSQ]

Had some time today so I got around to part #2

My rear hangers were the open type, without the steel bushing that some have.

This was causing the bolts to wear excessively where they rubbed on the hangers as the load was concentrated in a small area. Plus the wet bolts were useless in these hangers.

As the hangers themselves were not overly worn I decided to weld a section of steel pipe inside each hanger instead of replacing them. Schedule 160 3/4" steel pipe has an ID of 0.614" (a 9/16 bolt is 0.563) so it fits well - it also has a nearly 1/4" wall thickness so you don't have to worry about deforming it while welding. I needed two 1-1/4" pieces to fit inside my rear hangers.

I used one of the old bolts to hold it in place while I made a few welds - both sides front and back. I didn't try and weld it up completely, just enough to hold it in place.

A quick clean up with a chipping hammer and wire brush, and them some rattle-can black. I stuck a bolt through the hole to keep paint from going in while I sprayed it. If you paint it while it is still warm from welding the paint dries very quickly.

After the paint dried I installed the new shackle links and greased everything up.

I was surprised how much wear was on the old hardware - I think the trailer only has about 5000km (3000mi) on it.

A lot of the holes were elongated, and a lot of the bolts were worn where they were contacting the shackle links and hangers.

 

[cozwurth]

Something else to add to your suspension re-work would be to re-pack your leaf springs. When I rebuilt the suspension on my '68 Rancho I reworked the leaf spring packs as well. When the springs do their thing they will slide against each other. Mine were very rusty, so they didn't do much sliding. I took each leaf pack apart, wire brushed them clean and ground a small bevel on the ends of the leaves that rode against another leaf. I could see some slight wear where the rough-cut ends had been sliding on the leaf above. I painted each leaf individually, and then used a light coat of grease on the contact surfaces before reassembling. That made a WORLD of difference in the ride.

 

[Anthony Hitchings]

re: hanger and link wear - yup - and its a lazy design, which is why I replaced all my hardware including a new hanger for the links- a hanger that takes a replaceable bushing

 

[Coreym95]

re: hanger and link wear - yup - and its a lazy design, which is why I replaced all my hardware including a new hanger for the links- a hanger that takes a replaceable bushing

I feel like this is more than lazy. It's almost guaranteed that a trailer is going to have this problem at some point in its life. I just ordered the heavy duty shackle kit. Fingers crossed my hanger holes aren't all oblong.

 

[Anthony Hitchings]

Yup - I also used teh H.D. shacklles. My installer seemed a bit surprised at them being so stout.

And now that I think about it - the elongated holes in the hanger shackles and hangers themselves reflect simple underdesign - never sized correctly for the true dynamic loads and the actual contact areas.

 

[Coreym95]

Yup - I also used teh H.D. shacklles. My installer seemed a bit surprised at them being so stout.

And now that I think about it - the elongated holes in the hanger shackles and hangers themselves reflect simple underdesign - never sized correctly for the true dynamic loads and the actual contact areas.

Yeah, it would be so easy to use hangers that had a bushing. Those things go for like $10 each, so I'm assuming they can be manufactured for pennies more than what they are currently using. I'm surprised nobody has sued them for damages or injury due to an axle dropping while traveling from a sheared bolt. Seems grossly negligent.

It's a safety issue. Not like it's something relatively benign like leaky plumbing or a poorly caulked roof.

 

[TSQ]

Assuming:
- 9/16" bolts
- 1.75" wide springs
- 1800 axle load (900 lbs per side)

9/16" bolt has a circumference of 1.75". Say 20% of the circumference is making contact/wearing, so 0.35".

Prior to modification my open hangers were made out of 3/16" steel, so both sides added up to a thickness of 0.375".
0.35" x 0.375" = 0.13125 in².
900 lbs / 0.13125 in² = 6,860 psi.

A closed/bushed hanger has a thickness of 1.75"
0.35" x 1.75" = 0.6125 in²
900 lbs / 0.6125 in² = 1,470 psi.

Plus the closed/bushed hangers can be lubricated, while the open one can not.

Another issue with my original shackle links was that even through all the bolts were knurled, a lot of them were still loose in the shackle link / hanger holes. This meant that some of the bolts that went through the original plastic spring bushings would wear on the shackle links / hangers instead of the the plastic bushings .

Truly a race to the bottom in terms of quality.

The bolts is the new kit have much better knurling that grips the shackle links / hangers much better so this is unlikely to be an issue in the future.

I have pulled the trailer a few times since installing the new kit and modifying the hangers - it is way better. No clunks, no squeaks, no rattles. The suspension now feels (and sounds) like a single integrated system instead of a bunch of parts loosely bolted together.

 

[Coreym95]

So I just received the Dexter heavy duty suspension kit. I was messing with the parts, dry fitting them together, etc and noticed the bolts in the shackle link assemblies are about 1/16" off. These are the ones that come attached to the shackles. They seem to be just a bit off. They are about 1/16" closer together at the ends then they are at the base. So I can't slide the other shackle onto the bolts. Is this by design? They are both pretty much exactly the same so it seems like it was done on purpose.

 

[Anthony Hitchings]

my Dexter HD shackle kit bolts did not line up either. My mechanic would have forced something to fix that situation.

 

[Coreym95]

my Dexter HD shackle kit bolts did not line up either. My mechanic would have forced something to fix that situation.

Do you know what they did? I'm sure I could figure out a way to get them lined up (ie. a spreader clamp) but I don't want to compromise the integrity of the bolt either.

 

[Anthony Hitchings]

BTW, IF you tried to do a Cad dwg looking along your leaf spring, you would tend to put all the shackle and spring and clamp elements in a common vertical plane, and you SOA (if u have SOA) spring perch top surface is at right angles to the vertical plane. BUT your cambered axle has a simple kink in the middle which creates a center-to-outboard cross slope that does not mate up with the spring perch nor with the spring clamp plate. So something is either forced to fit or built out of position. I dread to think how my mechanic assembled my suspension, but it did survive around 8k-9k miles.

 

[TSQ]

Do you know what they did? I'm sure I could figure out a way to get them lined up (ie. a spreader clamp) but I don't want to compromise the integrity of the bolt either.

As Anthony mentioned the suspension will not be completely lined up anyways so I wouldn't worry about it.

Mine lined up fairly well out of the box, enough that they would go together.

But once through the bushings they no longer lined up so I raised/lowered the jack under my axle until I could get the other shackle link on.

Bascially:
1) get everything greased up
2) raise/lower the axle to get the bolts started through the hanger and the leaf spring bushing
3) push/press/hammer the bolts through
4) raise/lower the axle until the free shackle link fits on (lower the jack and the weight of the axle will spread the bolts, raise the jack and it will push them closer together)
5) you might need to twist the leaf spring with an adjustable wrench a little as well - this is easiest done with two people (one to twist and one to fit the shackle link), or a pipe wrench but watch the teeth on the springs

Maybe you'll be lucky and they won't line up out of the box but they will once they are on the trailer.

 

[Coreym95]

As Anthony mentioned the suspension will not be completely lined up anyways so I wouldn't worry about it.

Mine lined up fairly well out of the box, enough that they would go together.

But once through the bushings they no longer lined up so I raised/lowered the jack under my axle until I could get the other shackle link on.

Bascially:
1) get everything greased up
2) raise/lower the axle to get the bolts started through the hanger and the leaf spring bushing
3) push/press/hammer the bolts through
4) raise/lower the axle until the free shackle link fits on (lower the jack and the weight of the axle will spread the bolts, raise the jack and it will push them closer together)
5) you might need to twist the leaf spring with an adjustable wrench a little as well - this is easiest done with two people (one to twist and one to fit the shackle link), or a pipe wrench but watch the teeth on the springs

Maybe you'll be lucky and they won't line up out of the box but they will once they are on the trailer.

Thanks for the tips. I kind of thought they would line up once in and some weight was put on them, but I just didn't want to start the job before getting some confirmation.