Check your pin box & jack mounting bolts

[CoChris]

Doing some "spring clean up and checks" and had two rude surprises on our 2018 Solitude;

- I was checking the jack mounting bolt torques. According to LCI, for 1/2-20 grade 8 bolts (which our Solitude uses) the torque should be around 85 #-ft. Each of my 6 hydraulic jacks has 6 mounting bolts. On each jack, at least one bolt was <20#-ft and most were around 60~65#-ft. On the left front landing gear (which is at ~3 deg angle and take a huge side load raising and lowering) three bolts were <45 #-ft, 1 was <20#-ft and two were just finger tight. All are now properly torqued and I will be checking them regularly until I am satisfied they are not loosening. A big "shame on me" for not ever checking these.

Per LCI, for a National Coarse 1/2-13 bolt the torques should be 75#-ft. I had to EMail them to get the specs as I found at least 4 different values in LCI publications.

- The second one I actually found shortly after getting the trailer last year. Check the pin box to frame mounting bolts. On our 310GK there are five 5/8-11 grade 5 bolts on each side. I notice a lot of cracked and flaking/missing paint around the bolt heads (indicating movement). That got my attention. Spec torque (per LCI) is 160 #-ft. I put a torque wrench on the head and held the nut with a socket on an extension (poor form I know). Half (5 of 10) of them were <45#-ft. Three were about 110 #-ft and two were good to 160 #-ft. Considering the importance and loads on this mounting ... lets just say it Really got my attention. I torqued all ten bolts to 160 #-ft. Spot check a few times during the year. Now, with about 5,000 miles and a year later, no further sign of movement. Two bolts had lossened to ~110 #-ft the rest were 155~160 #-ft. Again, I will be checking them regularly!

Hope this helps someone avoid a problem

Chris

PS Yes, my trailer was actually built on Friday

[CWSWine]

On aircraft, we use slippage mark paint to make the nuts to the surface and to the threads so you can visually check for slippage. What works well is some fingernail polish with the small brush to apply.

[CoChris]

On aircraft, we use slippage mark paint to make the nuts to the surface and to the threads so you can visually check for slippage. What works well is some fingernail polish with the small brush to apply.

Yup, bolts are now marked with Dykem Torque Seal. A hold over from my racing days . I did consider safety wire, but want to get the trailer on the road this year

Chris

[powerscol]

The other bolts to check are the spring pack U bolts. Many of us have found them way not even close to how tight they should be. There is a thread on the issue. While under there make sure the wet shackle bolts are actually greased.

[CoChris]

The other bolts to check are the spring pack U bolts. Many of us have found them way not even close to how tight they should be. There is a thread on the issue. While under there make sure the wet shackle bolts are actually greased.

Good point/reminder. I had checked mine earlier (last year) and they were about 1/2 the spec torque (70~80 #-ft). Found one U-bolt was stripped. Contacted Grand Design customer service. They blew me off (disassemble, take pictures, submit and we will review and maybe we will send a replacement part. Probably take a couple of weeks). I called Dexter and they happily sent me two U-bolts w/nuts.

I replaced the stock shakes and bronze bushing with the MorRyde heavy duty shackles. OEM bolts and shackles were OK. All had bronze bushings. Bushing wear was minimal after ~6,000 miles. A couple of the bronze bushing had been poorly installed (cracked and distorted - one had a good size piece missing). All of the spring eyes were poorly formed.

Chris

[moenoodle]

WOW, after reading your post, I went to check our 310GK pin box and hydraulic leveling rams. We have owned our 310 since Sept 2018 and have towed it about 1000 miles since then. Now it was towed from Indiana to Texas and back to Oklahoma before we purchased it but I would like to think these items were checked before we purchased the unit. I am thinking now that maybe they were not and these checks should be added to all PDI lists!!

Our pin box bolts were anywhere from 120ft lbs to 160ft lbs, only one or two were completely tight. Almost all of the bolts on the leveling jacks were loose, maybe one or two bolts per jack were completely tight. I did not find any of the bolts were loose enough I could move them with my fingers but some were very very loose.

I torqued the pin box bolts to 160ft lbs and the leveling jacks to 85ft lbs. Next I will be checking the u-bolts on the axles and springs.

Thank you so much for your post, it probably saved me a lot of grief!!

Brian

[boyscout]

Doing some "spring clean up and checks" and had two rude surprises on our 2018 Solitude;

- jack mounting bolt torques.

- pin box to frame mounting bolts.

Thanks Chris.

I've looked often at the sticker on our pin-box which proudly boasts that its bolts were "torqued in the star pattern" and wondered why someone didn't write on it what the torque should be! Thanks for providing that information along with your warning.

Do you know what should be the torque on the wheel nuts of the 310GK?

After half a year of travel and your warning note I expect that the torque wrench I bought with best intentions two years ago will get its first use soon.

[moenoodle]

[QUOTE=boyscout;235255]Thanks Chris.



Do you know what should be the torque on the wheel nuts of the 310GK?

That information is in the GD Owners manual, there is a chart depending on the wheel size and lug size in the manual. Our Rig has 16" tires so I torqued our wheel lugs to 130ft lbs. I only found 1 or two that were loose, most of them were at the correct torque.

Brian

[CoChris]

Thanks Chris.

I've looked often at the sticker on our pin-box which proudly boasts that its bolts were "torqued in the star pattern" and wondered why someone didn't write on it what the torque should be! Thanks for providing that information along with your warning.

Do you know what should be the torque on the wheel nuts of the 310GK?

After half a year of travel and your warning note I expect that the torque wrench I bought with best intentions two years ago will get its first use soon.

The torque value was written on our sticker, but faded very quickly. I think it was 120 #-ft

From the Dexter manual the wheels should be torqued in multiple steps. For our Solitude with 1/2-20 wheel lugs I use 110 #-ft for my final torque. Spec are 20~25 1st step, 50~60 2nd step and 100~120 #-ft for final step. I believe Lionshead said max 120#-ft on their wheels, but I cannot find that document right now. The full the specs from Dexter are;



Chris

[TucsonJim]

I spent 30 years manufacturing missiles for the U.S. Navy. In most missile applications, torque is critical. The vibration during transportation, launch and flight is very severe. In order to verify proper torque values are being applied, we'd re-inspect missiles frequently for analysis. Here are some things we learned.

1 - Torque wrench calibration. A frequent cause of torque issues was a wrench that was out of calibration. All torque wrenches were recalibrated every year. On average, about 10% of the wrenches were not within the 5% allowable tolerance. If the torque was more than 25% out of tolerance, then the missiles that were assembled with that particular wrench were subject to recall. This was a rare occurrence, but it did happen a few times during my career. If you have any doubt about the calibration of your torque wrench, I'd suggest you get it calibrated or replace it. And remember that the wrenches we used were some of the best money could buy. They were not your normal Harbor Freight variety.

2 - Fastener Relaxing. When you torque a fastener, it will relax over time. The bolt, threads and thread interfaces all will deform and stretch. Every quarter, we'd select a missile for complete tear down and analysis. Part of that analysis was to measure torque on all fasteners. Acceptable torque values were 80% of the original torque. For example, if a fastener was originally torqued to 100 Ft/Lb, it was acceptable to measure over 80 Ft/Lb upon re-check. This was because of relaxation of the fastener and it's interfaces. So the lesson learned is that if you check a fastner at a specific torque value and find it turns, it was probably torqued to the correct setting, but the fastener has stretched during usage.

3 - Dual Locking. All missiles require every fastener to have a dual locking feature. Torque is one of the locking features. The other locking feature could be a lock washer, torque wire, thread locker, crush nuts, etc. If you don't have dual locking, you need to be very diligent about checking the torque on those fasteners. A good example of this are wheel lug nuts. Every time they are removed and reinstalled, the torque needs to be checked frequently as outlined in your manuals.

4 - Thread Locking Compounds. If you use thread locking compounds, Do Not check the torque on that fastener at a later date. You run the risk of cracking the thread locking compound and losing the secondary locking feature.

5 - Crush Nuts. I'm not sure about Dexter suspensions, but Lippert suspension components such as shackle bolts are mated with crush nuts. These nuts are purposely deformed in order to provide the secondary locking feature. They are a one-time use fastener only. If you remove the nut, it must be replaced with a new one or you must apply thread locking compound. When I see a suspension bolt that has fallen out, I assume it is because the crush nut was removed and reapplied without any thread locker. And it may not have been the owner that did so. Unless properly trained, many dealer techs don't know that these are a one-time use fastener.

Jim