Four Year Suspension Upgrade

[Crespro]

Four Year Upgrade of Suspension, Batteries and Water Pump

In order to reduce risk of a failure, it seems good to replace the tires and the suspension at the four year mark. I had a friend who had a $2,200 trailer blowout, but the cost is less a factor than sitting by the edge of a busy freeway with that problem. In my view, we should reduce risk by this suspension upgrade. I think Jim is right the suspension should be rebuilt periodically. I also upgraded the batteries to lithium, the converter and the water pump. Finally, the truck has four new Michelin radials.

I want to thank Rob, Jim and Howard for good posts on these topics. I will share my experience with this project. The parts and tools are available on Amazon. There are good YouTube videos on both suspension and bearing replacements.

In my view, the fifth wheel suspension is under engineered. It was probably initially set up for a 7K TT and is too small for a 15K or 20K fifth wheel. For a 15K or 20K fifth wheel, the manufacturer should use 11/16” wet bolts (not the 9/16” wet bolts), double the thickness of the hanger plates and the bushings and increase the spring eyelet size. That is not likely to happen, so the solution is either IS or X Factor braces. I decided to install three X Factor braces. This provides better stability and better strength for the wet bolts. If you install X Factor braces, you need to be careful backing in to tight RV spaces because some of the stress will be transferred to your rear tires. The recorded hanger and bushing failures seem to be the rear hangers, so the evidence suggests that is the prime location for stress.

I decided to retain the axles, hubs, brakes and X Factor braces. The remaining parts and tires were all replaced.

Parts: Lug Nuts(32), Timkin for 7K Dexter Axle, OB 14125A(4), OBR 14276(4), IB 25580(4), IBR 25520(4), Seal 412920(4), Red & Tacky Grease tub and grease cartridge, 3,500# leaf springs(4), 9/16 inch U Bolt Axle Sets(4), CRE 3000(2), MorRyde bushing/shackle set, long wet bolts for X Factors(6), Hankook Vantra TH31 Tires(4), Litime BCI Group 24 Lithium LiFePO4 Batteries (2), RecPro RV Converter, RV Water Pump Shurflo 4008-101-A65, Michelin Defender Tires (4).

Tools: Six jack stands, air impact wrench, breaker bar, torque wrench, seal puller, race punch, lever punch, bottle jacks with axle saddles(2), bearing packer, flat crowbar (to lift tires for reinstalling), 1½ inch socket, ball joint press, hammer, socket wrench set, grease gun with 90 degree fitting, rubber gloves(50).

[Crespro]

Demo of Suspension

1. Use Manual operation on front and rear jacks to raise RV.
2. Install six 6K jack stands with rubber saddles next to each RV jack.
3. Install two 6K bottle jacks with metal saddles under each axle.
4. Raise each wheel 1/2 inch off surface. Use impact wrench to remove lug nuts.
5. Remove both wheels with tires.
6. Use impact wrench and deep hex sided socket to remove wet bolt nuts (7).
7. The two top bolts on each X-Factor brace will hold the brace in place without the wet bolt.
8. Place wet bolt nut on loosely and hammer to knock each wet bolt out beyond splines and remove wet bolts on end of springs. Option: use ball joint press to remove wet bolts.
9. Remove with hammer the shackles and wet bolts.
10. Remove the center wet bolt with hammer and remove CRE 3000.
11. Use breaker bar to loosen nuts on ½ inch OEM u-bolts. Remove nuts, plates and u-bolts.
12. Lift off each 3,500# spring. Inspect bronze bushings. Rear bushing will be shot, but others may be fine.
13. Discard all old bushings, springs, wet bolts, nuts, plates and u-bolts.

Replacement of Suspension

1. Use ½ inch by four inch bolt and washer to tap in eight bronze bushings in new springs.
2. Use your grease gun to check all wet bolts for passage of grease through the hole.
3. Mark the grease hole position on each wet bolt with a small score with a hacksaw.
4. Install CRE 3000 wet bolt with ball joint press with grease hole at three or nine o’clock.
5. Place two 3,500# springs on axle holders with metal wrap on forward side.
6. Install new 9/16 inch u-bolts and plates with nuts on front and rear spring. Do not tighten.
7. Use ball joint press to install rear and front long wet bolts with grease holes at three or nine o’clock. Use a small socket with ball joint press to protect zerks.
8. If you plan to use a 90 degree grease fitting, install zerks on exterior for easy access. (As a seasoned person, I want to avoid crawling underneath, so exterior access to zerks with the 90 degree grease fitting is better).
9. Do not fully tighten wet bolt nuts until all are installed.
10. After three long wet bolts installed, install shackles with bolts. You may need to adjust axle height with bottle jacks to position shackle bolts.
11. Torque all wet bolts to 40 ft/lbs.
12. Recheck hanger bolts on X Factor braces.
13. Install with electrical tape for stability the 90 degree fitting on the grease gun.
14. Grease all wet bolts.
15. Tighten 9/16 inch u-bolts. Suggest 90 ft-lbs. After first 50 miles, you will lose about 10 ft-lbs when u bolts are fully seated, but the ½ inch OEM bolts have about 70 ft-lbs after 50 miles and seem to work fine. The center spring bolt fits in the fitting on top of the axle. The 9/16 U bolts should have sufficient torque after seating.

Replacement of Seals, Bearings and Races

1. Use hammer and screwdriver to gently remove cap on axle.
2. Remove clip (or cotter pin if used) so 1½ inch axle nut is exposed.
3. Remove 1½ inch nut and washer next to outer bearing (OB).
4. I used an old shelf on the corner of a utility trailer to make a temporary work bench. I placed a cardboard box on the work bench, a box with 50 nitrile gloves, the new races, seals and bearings, the red and tacky grease, the bearing packer, the race punch, a hammer, race and seal driver and trash bags in the trailer bed.
5. Remove OB and carefully remove the hub with seal, races and bearings.
6. Place the hub on the cardboard, remove the seal with the seal puller, the IB and the OB. Discard the old bearings and seal.
7. Clean the old grease off the axle hub with many paper towels.
8. Use the hammer and race punch to remove the inner and outer races.
9. Use the hammer and race and seal driver to seat inner and outer races. Make certain both are fully seated.
10. Use the bearing packer or pack the IB and OB by hand. I decided I could do a better job by hand and rotated the bearing with the new grease before installing.
11. Lubricate the hub races with Red and Tacky grease.
12. Insert the IB and use a short 2x4 to install the grease seal flush with the hub.
13. Flip over the hub and install the OB.
14. Place old cardboard under the axle and use brake cleaner fluid to clean brakes. The old cardboard will catch the runoff.
15. Clean the old grease off the axle with several paper towels. Use red and tacky grease to lubricate the axle.
16. Carefully install the hub back on the axle. Clean the washer, lubricate with grease and place next to the OB.
17. Install the 1 ½ inch nut and torque to 50 ft-lbs. Back off 1/6th of a turn and check to see the hub moves but does not have excessive play.
18. Install the hub nut clip and the cap.
19. Repeat process for second hub on that side.

Replacement of Tires

1. Use air impact wrench to remove lug nuts. Discard old lug nuts.
2. Remove tire and wheel from lug bolts.
3. I changed two wheels at a time because I have two 6K bottle jacks. I used a six foot 2x12 to roll each wheel up to my pickup bed.
4. My tire dealer uses Tire Rack and they carry the Hankook TH31 G-rated tires, so I ordered four of those. I changed two at a time.
5. The tire mechanic unloaded tires and wheels from my pickup bed, changed to the new tires and loaded them back up. At the RV, I unloaded each tire and wheel.
6. I once watched a mechanic change 22.5 inch bus tires without lifting the tire, so used the same method. (Seasoned folks do not lift wheels and tires). Use the bottle jack to set the top wheel lug at the height of the top on the wheel. Use a flat crowbar under the tire to gently tilt the wheel and engage the top lug. Loosely place a new lug nut on that lug bolt, jack up the wheel one inch and all lugs will line up.
7. Install the new eight lug nuts in an X pattern. Use air impact wrench to tighten. Use torque wrench at 100 ft-lbs for final tightening.

After one RV side is done, repeat all steps for the other side.

[Jlawles2]

Great write up.

For those without a bearing / seal driver, I found that keeping one of the old races from the inner and out work well as a driver spacer. Be sure to put the thick end of the old one used as a drive against the thin edge of the new one. This gives you a surface to drive the old race out after you seat the new one. I also used a heavy punch laid across the old race and drive against that rotating between strikes that so the new one drives squarely until it was most of the way in then went to driving straight against the old race.

I also use a drop of drywall for catching oil and other contaminants when doing oil changes or other fluid heavy work that could stain the concrete. It also provides a little of cushion when you drop things by accident. I think my current section of drywall is 10 years old and probably would be considered an environmental hazard.

[TucsonJim]

Awesome job Crespro! Nailed it.

Jim

[Scott'n'Wendy]

In your first post, second picture. Is that a bolt with a crack in the hex head?

[Jlawles2]

Scott'n'Wendy I noticed the line in the head aligns with the hole. almost looks like it was marked some way.

[Country Campers]

I am guessing the line aligns the grease hole.

Brian

[Crespro]

I am guessing the line aligns the grease hole.

Brian

Yes, I used a hacksaw to mark the bolt head so I could be certain to install with the grease hole at the 9 o'clock position.

I actually think all wet bolts should be marked by the manufacturer. It would make installation easy if they were marked.

Charles

[Jlawles2]

I think Keith (Yoda) used a punch on the head to indicate the grease hole position. Either way, marking from MFG should be mandatory, but even then proper installation is more critical than marking the bolt and I would not be surprised if we find that markings are all over the place.

[Scott'n'Wendy]

I would not be surprised if we find that markings are all over the place.

You think the RV industry has QA/QC issues?.....lol