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Replacing the axle(s) on the MFI trailer for a 2007 SX230

Bruce

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Year
2007
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I thought I had a bad bearing.

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Removed the wheel and hub and was surprised to find good bearings and the spindle wiggling around in the axle.


I found the Carry-On 502T bearing set to be locally available and the right sizes.

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I hired a mobile welder to reweld the spindle.

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The weld lasted about 20 miles.

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So I ordered a replacement axle. After measuring the axle and asking other members for advice I decided upon this 94" axle with loose spring seats to be welded on. 3,500 lb. Straight Axle Tube - 94 Inch Hub Face LM-380-S | 3,500 lb. Straight Axle Tube - 94 Inch Hub Face | Trailer Parts | TrailerPartsUSA.com . Total cost shipped was $294.64. It arrived in three days.

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The spring seats needed to be at 74" centers. I did not find axles available with the correct spacing. This axle was intended for a minimum spring center of 76". Placing the springs at 74" will decrease the carrying capacity below 3,500 but I only need around 2,500.

I put the trailer on blocks across my driveway with all four wheels off of the ground. I sprayed oil on the u-bolts and let it sit for a few days. Fortunately the u-bolt nuts came off with hand tools. I removed the brake lines from the brake calipers and removed the calipers and rotor hubs with the axle. The caliper bolts are easier to remove when the axle is removed and are likely to require an impact. One had to be cut with a grinder. When I removed the side with the broken spindle a week earlier I resorted to a torch to heat those caliper bolts and long extensions to get an impact on at an angle.

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We lined the two axles up and welded the spring seats on. Paint was ground away from the areas to be welded.

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I took the axle home and painted the welded areas. I had planned to use black paint but blue was what I had on hand.

After the paint dried and the sun cooled down I bolted the new axle on. I kept the new spindles wrapped during the earlier stages but had removed the covering at this point. I was disappointed that the spindles had oversprayed black paint from the factory on them. I removed the paint with a one sided razor blade then applied a thin layer of grease to the spindles.

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For now I reinstalled the old rotor hubs, with new bearings and seals, without the calipers. Later I plan to install electric brakes with new hubs, drums and a breakaway controller. I am considering proactively replacing the front axle as well. The tire suffered some damage from the spindle failure so I reassembled with the spare in that position for now. Unfortunately Goodyear Marathon trailer tires are no longer manufactured so I may replace all four, two at minimum.

The new axle has E-Z Lube spindles with grease zerks on the end which are intended to push grease from the back of the hub forward through the bearings. I tried to use those zerks but had difficulty getting grease to feed through them. I removed the grease zerks but will reinstall and try them again next time I am in there. The Trailer Buddy caps that came with the trailer would not fit over the spindles but I had a pair of 1.98" stainless Bearing Buddies that fit fine. Had I had more time and daylight I would have wanted to spend more time getting the E-Z Lube zerks to feed grease. I suspect that they had dried out grease in the path.

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This was not an experience that I wanted to have and I am disappointed that the factory spindle weld failed but the repair was completed in a week and for less than $500. I contacted several trailer shops and all were 3+ weeks out on being able to work on it and all had parts shortages. We hobbled through two days of enjoying the water on two different lakes during the repair process and a third the morning after reassembly.
 
Last edited:

GermanAR230

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Very good write up and imagery Bruce.
I'm also contemplating doing the same thing on my 2007 MFI.
As of right now mine is NOT as severe as yours was but starting with uneven tire wear.
Hub was dirty but fine so I replaced the bearing and turn the tire inside out.
After the season was over the uneven tire wear seem to persist.
I'm sure it will get worse before getting better.

No pictures of the before but for some reason this axel was not equipped with bearing buddy's so installed a set on rear axel.

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Will close the loop once I get mine all sorted out.
 

Ronnie

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Nice job @Bruce especially with all of the current material shortages. I had a spindle/bearings fail on my 2010 mfi trailer a few years ago. Ended up at pacific trailer and left with a new axle, rotors and a $1,200 bill. No boating while it was in the shop so wish my experience was more like yours.
 
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